Constant volume combustor

A pressure wave apparatus utilizing the principles of pulsed detonation and wave rotor technologies. The apparatus includes inlet and outlet ports that interface with a plurality of fluid flow passageways on a rotor. A buffer gas is routed through some of the inlet and outlet ports and into and out of the plurality of fluid flow passageways. One of the inlet ports is a buffer gas inlet port that when placed in registry with a fluid flow passageway allows the flow of buffer gas into the respective passageway. Fuel is delivered into the buffer gas proximate the buffer gas inlet port so that only a portion of the buffer gas inlet port receives any fuel.

BACKGROUND OF THE INVENTION

The present invention relates generally to a constant volume combustion device including detonative combustion. More specifically, one form of the present invention is a combustion unit having a high pressure rise, a near time-steady inflow and outflow, while being self cooled. The constant volume combustor has properties of pulse detonation and wave rotor technologies. Although the present invention was developed for use as a combustor within a gas turbine engine, certain applications may be outside of this field.

One of the next big challenges in the area of commercial and military flight is the improvement in fuel economy as flight speeds increase well into the supersonic range. In order to address fuel consumption goals there will be continued engineering advancements in compressor and turbine aerodynamics, higher temperature materials, improved cooling schemes, and the utilization of lightweight materials. It is recognized that the engineering and scientific community should continue to develop greater efficiency for engine components, however more revolutionary change may be required to meet the anticipated future demands for gas turbine engines.

The present application is directed to more revolutionary change through a combustion apparatus utilizing pulsed detonation and wave rotor technologies. Since the 1940's wave rotors have been studied by engineers and scientists and thought of as particularly suitable for a propulsion system. A wave rotor is generally thought of as a generic term and describes a class of machines utilizing transient internal fluid flow to efficiently accomplish a desired flow process. Wave rotors depend on wave phenomena as the basis of their operation, and these wave phenomena have the potential to be exploited in novel propulsion systems, which include benefits such as higher specific power and lower specific fuel consumption. Pulse detonation engines have been researched as a replacement for rockets and as an alternative propulsion system in gas turbine engines. However, a significant drawback with pulse detonation has been the unsteady flow produced due to the sequencing of detonations to produce thrust or combustion. This unsteady flow is envisioned to result in a multiplicity of mechanical and aerodynamic based challenges.

There are a variety of wave rotor devices that have been conceived of over the years. However, until the present invention the potential for wave rotor and pule detonation technologies has not been realized. The present invention harnesses the potential of wave rotor and pulse detonation technology in a novel and unobvious way.

SUMMARY OF THE INVENTION

One form of the present invention contemplates a pressure wave apparatus, comprising: a rotatable rotor having a plurality of passageways therethrough, the rotor having a direction of rotation; a pair of exit ports disposed in fluid communication with the rotor and adapted to receive fluid exiting from the plurality of passageways, one of the pair of exit ports is a combusted gas exit port for passing a substantially combusted gas from the plurality of passageways and the other of the pair of exit ports is a buffer gas exit port for passing a buffer gas from the plurality of passageways; a pair of inlet ports disposed in fluid communication with the rotor and adapted to introduce fluid to the plurality of passageways, one of the pair of inlet ports is a working fluid inlet port for passing a working fluid into the plurality of passageways and the other of the pair of inlet ports is a buffer gas inlet port for receiving the buffer gas from the buffer gas exit port and passing the buffer gas into the plurality of passageways, the buffer gas exit port is adjacent to and sequentially prior to the buffer gas inlet port; and, a fuel deliverer adapted to deliver a fuel within the buffer gas exit port adjacent the rotatable rotor, wherein the fuel deliverer delivers fuel into a first portion of the buffer gas exit port and not into a second portion of the buffer gas exit port.

Another form of the present invention contemplates a method, comprising: rotating a wave rotor having a passageway with a first end and a second end; introducing a quantity of working fluid into the passageway through the first end of the passageway; delivering a quantity of fuel into the passageway through the first end of the passageway; burning the fuel within the passageway and creating a combusted gas; compressing a portion of the working fluid within the passageway to define a buffer gas; discharging a first portion of the buffer gas from the passageway through the first end of the passageway; discharging a portion of the combusted gas from the passageway through the second end of the passageway; parking a second portion of the buffer gas within the passageway proximate the first end; and, routing the first portion of the buffer gas from the discharging back into the passageway through the first end of the passageway.

Yet another form of the present invention contemplates a method for starting a gas turbine engine. The method, comprising: providing an engine including a compressor, a combustor including a wave rotor having a plurality of passageways and a turbine; rotating the wave rotor within the combustor; fueling at least a portion of the plurality of passageways; combusting the fuel within the plurality of passageways to form a flow of exhaust gas; discharging at least a portion of the exhaust gas from the wave rotor and delivering to a bladed rotor within the turbine; rotating the bladed rotor within the turbine with the exhaust gas from the discharging; and, the above acts to bring the compressor and turbine up to an operating condition.

Yet another form of the present invention contemplates an apparatus, comprising: a compressor for increasing the pressure of a working fluid passing therethrough, the compressor having a compressor discharge; a constant volume combustor in fluid communication with the compressor discharge, the constant volume combustor including a rotatable wave rotor and a fuel deliverer, the wave rotor including a plurality of cells for receiving at least a portion of the working fluid from the compressor discharge and a fuel from the fuel deliverer that undergoes combustion within the cells to produce an exhaust gas flow; a turbine in fluid communication with the exhaust flow from the constant volume combustor; and an active electromagnetic bearing operable to support the wave rotor.

One object of the present invention is to provide a unique constant volume combustor.

Related objects and advantages of the present invention will be apparent from the following description.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference toFIG. 1, there is illustrated a schematic representation of a propulsion system20which includes a compressor21, a pulsed combustion wave rotor22, a turbine23, a nozzle32, and an output power shaft26. The compressor21delivers a precompressed working fluid to the pulsed combustion wave rotor device22. Wave rotor device22has occurring within its passageways the combustion of a fuel and air mixture, and thereafter the combusted gases are delivered to the turbine23. The working fluid that is precompressed by the compressor21and delivered to the wave rotor device22is selected from a group including oxygen, nitrogen, carbon dioxide, helium or a mixture thereof, and more preferably is air. In one embodiment the pulsed combustion wave rotor device22replaces the compressor diffuser and combustor of a conventional gas turbine engine. The present invention contemplates both a pulsed detonation combustion process and a pulsed deflagration combustion process. While the present invention will generally be described in terms of a pulsed detonation combustion process, it also contemplates a pulsed deflagration combustion process.

In one embodiment the components of the propulsion system20have been integrated together to produce an aircraft flight propulsion engine capable of producing either shaft power or direct thrust or both. The term aircraft is generic and includes helicopters, airplanes, missiles, unmanned space devices and other substantially similar devices. It is important to realize that there are multitudes of ways in which the propulsion engine components can be linked together. Additional compressors and turbines could be added with inter-coolers connected between the compressors and reheat combustion chambers could be added between the turbines. The propulsion system of the present invention is suited to be used for industrial applications, such as but not limited to pumping sets for gas or oil transmission lines, electricity generation and naval propulsion. Further, the propulsion system of the present invention is also suitable to be used for ground vehicular propulsion requiring the use of shaft power such as automobiles and trucks.

With reference toFIGS. 1–3, further aspects of the propulsion system20will be described. Compressor21is operable to increase the pressure of the working fluid between the compressor inlet24and the compressor outlet25. The increase in working fluid pressure is represented by a pressure ratio (pressure at outlet/pressure at inlet) and the working fluid is delivered to a first wave rotor inlet port42. The first wave rotor inlet port42generally defines a working fluid inlet port and is not intended to be limited to an inlet port that is coupled to the outlet of a conventional turbomachinery component. A second wave rotor inlet port43is referred to as a buffer gas inlet port, and is located adjacent to and sequentially prior to the first wave rotor inlet port42. Wave rotor inlet ports42and43form an inlet port sequence, and multiple inlet port sequences can be integrated into a waver rotor device. In one preferred embodiment there are two inlet port sequences disposed along the circumference of the wave rotor device.

Wave rotor device22has an outlet port sequence that includes an outlet port45and a buffer gas outlet port44. The outlet port45generally defines a combusted gas outlet port and is not intended to be limited to an outlet port that is coupled to a turbine. In the preferred embodiment of propulsion system20the outlet port45is defined as to-turbine outlet port45. The to-turbine outlet port45in propulsion system20allows the combusted gases to exit the wave rotor device22and pass to the turbine23. Compressed buffer gas exits the buffer gas outlet port44and is reintroduced into the rotor passageways41through the second wave rotor inlet port43. In one embodiment the buffer gas outlet port44and the second wave rotor inlet port43are connected in fluid communication by a duct. In one form the duct between the outlet port44and outlet port43is integral with the wave rotor device22and passes through the interior of rotor40. In another form the duct passes through the center of shaft48. In another form of the present invention the duct is physically external to the wave rotor device22.

The reintroduced compressed buffer gas does work on the remaining combusted gases within the rotor passageways41and causes the pressure in region70to remain at an elevated level. The relatively high energy flow of combusted gases from the to-turbine port45is maintained in region74by the reintroduction of the high pressure buffer gas entering through the second wave rotor inlet port43. The flow of the high pressure buffer gas from buffer gas outlet port44to the second wave rotor inlet port43is illustrated schematically by arrow B inFIG.3. In one form of the present invention a portion of the high pressure buffer gas exiting through outlet port44can be used as a source of turbine cooling fluid. More specifically, in certain forms of a propulsion system of the present invention the pressure of the gas stream going to the turbine23through exit port45is higher than the pressure of the working fluid at the compressor discharge25. Therefore, the requirement for higher pressure cooling fluid can be met by taking a portion of the high pressure buffer gas exiting port44and delivering to the appropriate location(s) within the turbine.

Wave rotor outlet ports44and45form the outlet port sequence, and multiple outlet port sequences can be integrated into a waver rotor device. In one preferred embodiment there are two outlet port sequences disposed along the circumference of the wave rotor device. The inlet port sequence and the outlet port sequence are combined with the rotatable rotor to form a pulsed combustion wave rotor engine. Routing of the compressed buffer gas from the buffer gas outlet port44into the wave rotor passageways41via port43provides for: high pressure flow issuing generally uniformly from the to-turbine outlet port45; and/or, a cooling effect delivered rapidly and in a prolonged fashion to the rotor walls defining the rotor passageways41following the combustion process; and/or, a reduction and smoothing of pressure in the inlet port42thereby aiding in the rapid and substantially uniform drawing in of working fluid from the compressor21.

Combusted gasses exiting through the to-turbine outlet port45pass to the turbine23where shaft power is produced to power the compressor21. Additional power may be produced to be used in the form of output shaft power. Further, combusted gas leaves the turbine23and enters the nozzle32where thrust is produced. The construction and details related to the utilization of a nozzle to produce thrust will not be described herein as it is believed known to one of ordinary skill in the art of engine design.

Referring toFIG. 2, there is illustrated a partially exploded view of one embodiment of the wave rotor device22. Wave rotor device22comprises a rotor40that is rotatable about a centerline X and passes a plurality of fluid passageways41by a plurality of inlet ports42,43and outlet ports44,45that are formed in end plates46and47. Preferably, the rotor is cylindrical, however other geometric shapes are contemplated herein. In one embodiment the end plates46and47are coupled to stationary ducted passages between the compressor21and the turbine23. The pluralities of fluid passageways41are positioned about the circumference of the wave rotor device22.

In one form the rotation of the rotor40is accomplished through a conventional rotational device. In another form the gas turbine23can be used as the means to cause rotation of the wave rotor40. In another embodiment the wave rotor is a self-turning, freewheeling design; wherein freewheeling indicates no independent drive means are required. In one form the freewheeling design is contemplated with angling and/or curving of the rotor passageways. In another form the freewheeling design is contemplated to be driven by the angling of the inlet duct42aso as to allow the incoming fluid flow to impart angular momentum to the rotor40. In yet another form the freewheeling design is contemplated to be driven by angling of the inlet duct43aso as to allow the incoming fluid flow to impart angular momentum to the rotor. Further, it is contemplated that the inlet ducts42aand43acan both be angled, one of the inlet ducts is angled or neither is angled. The use of curved or angled rotor passageways within the rotor and/or by imparting momentum to the rotor through one of the inlet flow streams, the wave rotor may produce useful shaft power. This work can be used for purposes such as but not limited to, driving an upstream compressor, powering engine accessories (fuel pump, electrical power generator, engine hydraulics) and/or to provide engine output shaft power. The types of rotational devices and methods for causing rotation of the rotor40is not intended to be limited herein and include other methods and devices for causing rotation of the rotor40as occur to one of ordinary skill in the art. One form of the present invention contemplates rotational speeds of the rotor within a range of about 1,000 to about 100,000 revolutions per minute, and more preferably about 10,000 revolutions per minute. However, the present invention is not intended to be limited to these rotational speeds unless specifically stated herein.

The wave rotor/cell rotor40is fixedly coupled to a shaft48that is rotatable on a pair of bearings (not illustrated). In one form of the present invention the wave rotor/cell rotor rotates about the centerline X in the direction of arrow Z. While the present invention has been described based upon rotation in the direction of arrow Z, a system having the appropriate modifications to rotate in the opposite direction is contemplated herein. The direction Z may be concurrent with or counter to the rotational direction of the gas turbine engine rotors. In one embodiment the plurality of circumferentially spaced passageways41extend along the length of the wave rotor device22parallel to the centerline X and are formed between an outer wall member49and an inner wall member50. The plurality of passageways41define a peripheral annulus51wherein adjacent passageways share a common wall member52that connects between the outer wall member49and the inner wall member50so as to separate the fluid flow within each of the passageways. In an alternate embodiment each of the plurality of circumferentially spaced passageways are non-parallel to the centerline, but are placed on a cone having differing radii at the opposite ends of the rotor. In another embodiment, each of the plurality of circumferentially spaced passageways are placed on a surface of smoothly varying radial placement first toward lower radius and then toward larger radius over their axial extent. In yet another embodiment, a dividing wall member divides each of the plurality of circumferentially spaced passageways, and in one form is located at a substantially mid-radial position of the passageway. In yet another embodiment, each of the plurality of circumferentially spaced passages form a helical rather than straight axial passageway.

The pair of wave rotor end plates46and47are fixedly positioned very closely adjacent the rotor40so as to control the passage of working fluid into and out of the plurality of passageways41as the rotor40rotates. End plates46and47are designed to be disposed in a sealing arrangement with the rotor40in order to minimize the leakage of fluid between the plurality of passageways41and the end plates. In an alternate embodiment auxiliary seals are included between the end plates and the rotor to enhance sealing efficiency. Seal types, such as but not limited to, labrynth, gland or sliding seals are contemplated herein, however the application of seals to a wave rotor is believed known to one of skill in the art.

With reference toFIG. 3, there is illustrated a space-time (wave) diagram for a pulsed detonation wave rotor engine. A pulsed detonation combustion process is a substantially constant volume combustion process. The pulsed detonation engine wave rotor described with the assistance ofFIG. 3has: the high pressure energy transfer gas outlet port44and the to-turbine outlet port45located on the same end of the device; and the high pressure energy transfer gas inlet port43and the from-compressor inlet port42on the same end of the device. In one form of the present invention there is defined a two port wave rotor cycle including one fluid flow inlet port and one fluid flow outlet port and having a high pressure buffer gas transfer recirculation loop that may be considered internal to the wave rotor device. The high pressure energy transfer inlet port43is prior to and adjacent the from-compressor inlet port42. Arrow Q indicates the direction of rotation of the rotor40. It can be observed that upon the rotation of rotor40, each of the plurality of passageways41are sequentially brought into registration with the inlet ports42,43and the outlet ports44,45and the path of a typical charge of fluid is along the respective passageway41. The wave diagram for the purpose of description may be started at any point, however for convenience the description is started at60wherein the low-pressure working fluid is admitted from the compressor. The concept of low pressure should not be understood in an absolute manner, it is only low in comparison with the rest of the pressure levels of gas within the pulsed detonation engine wave rotor.

The low-pressure portion60of the wave rotor engine receives a supply of low-pressure working fluid from compressor21. The working fluid enters passageways41upon the from-compressor inlet port42being aligned with the respective passageways41. In one embodiment fuel is introduced into the low-pressure portion60by: stationary continuously operated spray nozzles (liquid)61or supply tubes (gas)61located within the inlet duct42aleading to the from-compressor inlet port42; or, into region62by intermittently actuated spray nozzles (liquid)61′ or supply tubes (gas)61′ located within the rotor; or, into region62by spray nozzles (liquid)61″ or supply tubes (gas)61″ located within the rotor endplate46. Separating region60and62is a pressure wave73originating from the closure of the to-turbine outlet port45. In this way, a region62exists at one end of the rotor and the region has a fuel content such that the mixture of fuel and working fluid is combustable. The fuel air mixture in one end of the rotor, regions60and62, is thus separated from hot residual combustion gas within regions68and69by the buffer gas entering the rotor through port43and traveling through regions70,71,72and64. In this way undesirable pre-ignition of the fuel air mixture of regions60and62is inhibited.

A detonation is initiated from an end portion of the rotor40adjacent the region62and a detonation wave63travels through the fuel air mixture within the region62toward the opposite end of the rotor containing a working-fluid-without-fuel region64. In one form of the present invention the detonation is initiated by a detonation initiator80such as but not limited to a high energy spark discharge device. However, in an alternate form of the present invention the detonation is initiated as an auto-detonation process and does not include a detonation initiator. The detonation wave63travels along the length of the passageway and ceases with the absence of fuel at the gas interface65. Thereafter, a pressure wave66travels into the working-fluid-without-fuel region64of the passageway and compresses this working fluid to define a high-pressure buffer/energy transfer gas within region67. The concept of high pressure should not be understood in an absolute manner, it is only high in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

In one embodiment the high pressure buffer/energy transfer gas is a non-vitiated working fluid. In another embodiment the high pressure buffer/energy transfer gas is comprised of working fluid having experienced the combustion of fuel (vitiated) regardless of what other compression or expansion process have taken place after the combustion. Working fluid of this type would generally be characterized as having a portion of the oxygen depleted, the products of combustion present and the associated entropy increase remaining relative to the non-combusted working fluid starting from the same initial state and undergoing the same post combustion processes. An incomplete mixing can take place between the vitiated and non-vitiated gas portions adjoining each other in the passageway and thus realize a mixture of the two which thus comprises the high pressure buffer/energy transfer gas.

The high pressure buffer/energy transfer gas within region67exits the wave rotor device22through the buffer gas outlet port44. The combustion gases within the region68exit the wave rotor through the to-turbine outlet port45. Expansion of the combusted gas prior to entering the turbine results in a lower turbine inlet temperature without reducing the effective peak cycle temperature. As the combusted gas exits the outlet port45, the expansion process continues within the passageway41of the rotor and travels toward the opposite end of the passageway. As the expansion arrives at the end of the passage, the pressure of the gas within the region69at the end of the rotor opposite the to-turbine outlet port45declines. The wave rotor inlet port43opens and allows the flow of the high pressure buffer/energy transfer working fluid into the rotor at region70and causes the recompression of a portion of the combustion gases within the rotor. In one embodiment, the admission of gas via port43can be accomplished by a shock wave. However, in another embodiment the admission is accomplished without a shock wave. The flow of the high pressure buffer gas adds energy to the exhaust process of the combustion gas and allows the expansion of the combusted gas to be accomplished in a controlled uniform energy process in one form of the invention. Thus, in one form the introduction of the high pressure buffer/energy transfer gas is adapted to maintain the high velocity flow of combusted gases exiting the wave rotor until substantially all of the combusted gas within the rotor is exhausted.

In one embodiment, the wave rotor inlet port43, which allows the introduction of the high-pressure buffer/energy transfer gas, closes before the to-turbine outlet port45is closed. The closing of the wave rotor inlet port43causes an expansion process to occur within the high pressure buffer/energy transfer air within region71and lowers the pressure of the gas and creates a region72. Following the creation of this lowered pressure gas region72, a passageway41is in registration with port42and gas flowing within port42enters the passageway41creating region60. The strong and compact nature of the expansion process in region71causes a beneficially large pressure difference between the pressure in port45and the pressure in port42. In one embodiment the pressure of the gas delivered to the turbine23is higher than the pressure delivered from the compressor21and hence the power output of the engine enhanced and/or the quantity of fuel required to generate power in the turbine is reduced. The term enhanced and reduced are in reference to an engine utilizing a combustion device of common practice, having constant or lowering pressure, located between the compressor and turbine in the place of the present invention. The expansion process71occurs within the buffer/energy transfer gas and allows substantially all of the combustion gases of region68to exit the rotor leaving the lowest pressure region of the rotor consisting essentially of expanded buffer/energy transfer gas. The to-turbine outlet port45is closed as the expansion in region71reaches the exit end of the passageway. In one form of the present invention as illustrated in region75a portion of the high-pressure buffer/energy transfer gas exits through the outlet port45. This gas acts to insulate the duct walls45afrom the hot combusted gas within region74of the duct45b. In an alternate embodiment the high pressure buffer/energy transfer gas is not directed to insulate and cool the duct walls45a.The pressure in region72has been lowered, and the from-compressor inlet port42allows pre-compressed low-pressure air to enter the rotor passageway in the region60having the lowered pressure. The entering motion of the precompressed low-pressure air through port42is stopped by the arrival of a pressure wave73originating from the exit end of the rotor and traveling toward the inlet end. The pressure wave73originated from the closure of the to-turbine outlet port45. The design and construction of the wave rotor is such that the arrival of pressure wave73corresponds with the closing of the from-compressor inlet port42.

With reference toFIG. 4, there is illustrated schematically an alternate embodiment of a propulsion system30. In one embodiment the propulsion system30includes a fluid inlet31, a pulsed combustion detonation engine wave rotor22and nozzle32. The wave rotor device22is identical to the wave rotor described in propulsion system20and like feature number will be utilized to describe like features. In one form propulsion system30is adapted to produce thrust without incorporation of conventional turbomachinery components. In one embodiment the combustion gases exiting the wave rotor are directed through the nozzle32to produce motive power. The working fluid passing through inlet31is conveyed through the first wave rotor inlet port42and into the wave rotor device22. High pressure buffer gas is discharged through wave rotor outlet port44and passes back into the wave rotor device through wave rotor inlet port43. The relatively high energy flow of combusted gases flows out of outlet port45and exits nozzle32.

With reference toFIG. 5, there is illustrated schematically an alternate embodiment of a rocket type propulsion system100. In one embodiment, the propulsion system100includes an oxidizer and working gas storage tank101, a pulsed combustion detonation engine wave rotor22and nozzle32. The wave rotor device22is identical to the wave rotor device discussed previously for propulsion system20and like feature numbers will be utilized to describe like features. In one form propulsion system100is adapted to produce thrust without incorporation of conventional turbomachinery components. The first wave rotor inlet port42is in fluid communication with the oxidizer and working gas storage tank100and receives a quantity of working fluid therefrom. High pressure buffer gas is discharged through the wave rotor outlet port44and passes back into the wave rotor device through wave rotor inlet port43. The relatively high energy flow of combusted gases pass out of the outlet port45and exits nozzle32to produce motive power.

A few additional alternate embodiments (not illustrated) contemplated herein will be described in comparison to the embodiment ofFIG. 4. The use of like feature numbers is intended to represent like features. One of the alternate embodiments is a propulsion system including a turbomachine type compressor placed immediately ahead of the wave rotor22and adapted to supply a compressed fluid to inlet42. The turbomachine type compressor is driven by shaft power derived from the wave rotor22. Another of the alternate embodiments includes a conventional turbine placed downstream of the wave rotor22and adapted to be supplied with the gas exiting port45. The second type of alternate embodiment does not include a nozzle and delivers only engine output shaft power. A third embodiment contemplated herein is similar to the embodiment ofFIG. 1, but the nozzle32has been removed and is utilized for delivering output shaft power. The prior list of alternate embodiments is not intended to be limiting to the types of alternate embodiments contemplated herein.

With reference toFIG. 6, there is illustrated a schematic representation of an alternate embodiment of propulsion system200which includes compressor21, a pulsed combustion wave rotor220, a turbine23, a nozzle32and an output power shaft26. The propulsion system200is substantially similar to the propulsion system20and like features numbers will be utilized to describe like elements. More specifically, the propulsion system200is substantially similar to the propulsion system20and the details relating to system200will focus on the alternative pulsed detonation engine wave rotor220.

With reference toFIGS. 6–8, further aspects of the propulsion system200will be described. As discussed previously, a substantial portion of the propulsion system200is identical to the propulsion system20and this information will not be repeated as it has been set forth previously. A pressurized working fluid passes through the compressor outlet25and is delivered to a first wave rotor inlet port221. A second wave rotor inlet port222is referred to as a buffer gas inlet port, and is located adjacent to and sequentially prior to the first wave rotor inlet port221. Wave rotor inlet ports221and222form an inlet port sequence, and multiple inlet port sequences can be integrated into a wave rotor device. In one preferred embodiment there are two inlet port sequences disposed along the circumference of the wave rotor device220.

Wave rotor device220has an outlet port sequence that includes an outlet port223and a buffer gas outlet port224. In one embodiment of propulsion system200the outlet port223is defined as a to-turbine outlet port223. The to-turbine outlet port223of propulsion system200allows the combusted gases to exit the wave rotor device220and pass to the turbine223. Compressed buffer gas exits the buffer gas outlet port224and is reintroduced into the rotor passageways41through the second wave rotor inlet port222. In one embodiment, the buffer gas outlet port224and the second wave rotor inlet port222are connected in fluid communication by a duct. In a further alternate embodiment, the duct functions as a high pressure buffer gas reservoir and/or is connected to an auxiliary reservoir which is designed and constructed to hold a quantity of high pressure buffer gas. This reintroduced buffer gas does work on the remaining combusted gases within the rotor passageways41and causes the pressure in region225to remain at an elevated level. The relatively high energy flow of combusted gases from the to-turbine port223is maintained in region226by the reintroduction of the high pressure buffer gas entering through the second wave rotor inlet port222. The flow of the high pressure buffer gas from buffer gas outlet port224to the second wave rotor inlet port222is illustrated schematically by arrows C inFIG. 8.

Wave rotor outlet ports223and224form the outlet port sequence, and multiple outlet port sequences can be integrated into a wave rotor device. In one preferred embodiment, there are two outlet port sequences disposed along the circumference of the wave rotor device. The inlet port sequence and the outlet port sequence are combined with the rotatable rotor to form a pulsed combustion wave rotor engine. Routing of the compressed buffer gas from the buffer gas outlet port224into the wave rotor passageways41provides for: high pressure flow issuing generally uniformly from the to-turbine outlet port223; and/or a cooling effect delivered rapidly and in a prolonged fashion to the rotor walls defining the rotor passageways41following the combustion process; and/or a reduction and smoothing of pressure in the inlet port221thereby aiding in the rapid and uniform admission of working fluid from compressor21.

Referring toFIG. 7, there is illustrated a partially exploded view of one embodiment of the wave rotor device220. Wave rotor220comprises a cylindrical rotor40that is rotatable about a centerline X and passes a plurality of fluid passageways41by a plurality of ports221,222and224formed in end plate225and outlet ports223formed in end plate226. In one embodiment, the end plates225and226are coupled to stationery ducted passages between the compressor21and the turbine23. The plurality of fluid passageways41is positioned about the circumference of the wave rotor device220.

In one form a conventional rotational device accomplishes the rotation of rotor40. In another form the gas turbine23can be used as the means to cause rotation of the wave rotor40. In another embodiment the wave rotor is a self-turning, freewheeling design; wherein freewheeling indicates no independent drive means are required. In one form, the freewheeling design is contemplated with angling and/or curving of the rotor passageways. In another form, the freewheeling design is contemplated to be driven by the angling of the inlet duct221aso as to allow the incoming fluid flow to impart angular momentum to the rotor40. In yet another form, the free-wheeling design is contemplated to be driven by angling of the inlet duct222aso as to allow the incoming fluid flow to impart angular momentum to the rotor. Further, it is contemplated that the inlet ducts222aand221acan both be angled, one of the inlet ducts is angled or neither is angled. The use of curved or angled rotor passageways within the rotor and/or by imparting of momentum to the rotor through one of the inlet flow streams, the wave rotor may produce useful shaft power.

The wave rotor/cell rotor40is fixedly coupled to a shaft48that is rotatable on a pair of bearings (not illustrated). In one form of the present invention, the wave rotor/cell rotor rotates about the center line X in the direction of arrows Z. While the present invention has been described based upon rotation in the direction of arrow Z, a system having the appropriate modifications to rotate in the opposite direction is contemplated herein. The direction Z may be concurrent with or counter to the rotational direction of the gas turbine engine rotors. In one embodiment the plurality of circumferentially spaced passageways41extend along the length of the wave rotor device220parallel to the center line X and are formed between the outer wall member49and an inner wall member50. The plurality of passageways41define a peripheral annulus51wherein adjacent passageways share a common wall member52that connects between the outer wall member49and the inner wall50so as to separate the fluid flow within each of the passageways. In an alternate embodiment each of the plurality of circumferentially spaced passageways are non-parallel to the center line, but are placed on a cone having different radii at the opposite ends of the rotor. In another embodiment, a dividing wall member divides each of the plurality of circumferentially spaced passageways, and in one form is located at a substantially mid-radial position. In yet another embodiment, each of the plurality of circumferentially spaced passageways form a helical rather than straight passageway. Further, in another embodiment, each of the plurality of circumferentially spaced passageways are placed on a surface of smoothly varying radial placement first toward lower radius and then toward larger radius over their axial extent.

The pair of wave rotor end plates225and226are fixedly positioned very closely adjacent to rotor40so as to control the passage of working fluid into and out of the plurality of passageways41as the rotor40rotates. End plates225and226are designed to be disposed in a sealing arrangement with the rotor40in order to minimize the leakage of fluid between the plurality of passageways41and the end plates. In an alternate embodiment, auxiliary seals are included between the end plates and the rotor to enhance sealing efficiency. Seal types, such as but not limited to, labrynth, gland or sliding seals are contemplated herein, however, the application of seals to a wave rotor is believed known to one of skill in the art.

With reference toFIG. 8, there is illustrated a space-time (wave) diagram for a pulsed detonation wave rotor engine. The pulsed detonation engine wave rotor described with the assistance ofFIG. 8has: the high pressure energy transfer gas outlet port224, the high pressure energy transfer gas inlet port222and the from-compressor inlet port221on the same end of the device; and the to-turbine outlet port223located on the opposite end of the device. In one form of the present invention there is defined a two port wave rotor cycle including one fluid flow inlet port and one fluid flow outlet port and having a high pressure buffer gas recirculation loop that may be considered internal to the wave rotor device. The high pressure energy transfer inlet port222is prior to and adjacent the from-compressor inlet port221. It can be observed that upon the rotation of rotor40each of the plurality of passageways41are sequentially brought in registration with the inlet ports221and222and the outlet ports223and224, and the path of a typical charge of fluid is along the respective passageways41. The wave diagram for the purpose of description may be started at any point, however, for convenience, the description is started at227wherein the low-pressure working fluid is admitted from the compressor. The concept of low pressure should not be understood in absolute manner, it is only low in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

The low pressure portion227of the wave rotor engine receives a supply of low-pressure working fluid from compressor21. The working fluid enters passageways41upon the from-compressor inlet port221being aligned with the respective passageways41. In one embodiment fuel is introduced into the region225by: stationery continuously operated spray nozzles (liquid)227or supply tubes (gas)227located within the duct222aleading to the high pressure energy transfer gas inlet port222; or, into region228by intermittently actuated spray nozzles (liquid)227′ or supply tubes (gas)227′ located within the rotor; or, into region228by spray nozzles (liquid)227″ or supply tubes (gas)227″ located within the rotor end plate226. Region228exists at the end of the rotor and the region has a fuel content such that the mixture of fuel and working fluid is combustable.

A detonation is initiated from an end portion of the wave rotor40adjacent the region228and a detonation wave232travels through the fuel-working-fluid air mixture within the region228toward the opposite end of the rotor containing a working-fluid-without-fuel region230. In one form of the present invention, the detonation is initiated by a detonation initiator233, such as but not limited to a high energy spark discharge device. However, in an alternate form of the present invention the detonation is initiated by an auto-detonation process and does not include a detonation initiator. The detonation wave232travels along the length of the passageway and ceases with the absence of fuel at the gas interface234. Thereafter, a pressure wave235travels into the working-fluid-without-fuel region230of the passageway and compresses this working fluid to define a high-pressure buffer/energy transfer gas within region236. The concept of high pressure should not be understood in an absolute manner, it is only high in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

The high pressure buffer/energy transfer gas within region236exits the wave rotor device220through the buffer gas outlet port224. The combusted gases within the region237exits the wave rotor through the to-turbine outlet port223. Expansion of the combusted gas prior to entering the turbine results in a lower turbine inlet temperature without reducing the effective peak cycle temperature. As the combusted gas exits the outlet port223, the expansion process continues within the passageways41of the rotor and travels toward the opposite end of the passageway. As the expansion arrives at the end of the passage, the pressure of the gas within the region238at the end of the rotor opposite the to-turbine outlet port223declines. The wave rotor inlet port222opens and allows the flow of the high pressure buffer/energy transfer working fluid into the rotor at region225and causes the recompression of a portion of the combusted gases within the rotor. The admission of gas via port222can be accomplished by a shock wave. The flow of the high pressure buffer gas adds energy to the exhaust process of the combustion gas and allows the expansion of the combusted gas to be accomplished in a controlled, uniform energy process in one form of the invention. Thus, in one form the introduction of the high pressure buffer/energy transfer gas is adapted to maintain the high velocity flow of combusted gases exiting the wave rotor until substantially all of the combusted gas within the rotor is exhausted.

In one embodiment, the wave rotor inlet port222, which allows the introduction of the high pressure buffer/energy transfer gas, closes before the to-turbine outlet port223is closed. The closing of the wave rotor inlet port222causes an expansion process to occur within the high pressure buffer/energy transfer air within region240and lowers the pressure of the gas and creates a region241. This expansion process occurs within the buffer/energy transfer gas and allows this gas to preferentially remain within the rotor at the lowest pressure region of the rotor. The to-turbine outlet port223is closed as the expansion in region240reaches the exit end of the passageway. In one form of the present invention as illustrated in region242, a portion of the high pressure buffer/energy transfer gas exits through the outlet port223. This exiting buffer/energy transfer gas functions to insulate the duct wall223afrom the hot combusted gas within region226of the duct223b. The pressure in region241has been lowered and the from-compressor inlet port221allows pre-compressed low pressure working fluid to enter the rotor passageways in the region227having the lowered pressure. The entering motion of the pre-compressed low-pressure working fluid through port221is stopped by the arrival of pressure wave231originating from the exit end of the rotor and traveling toward the inlet end. The pressure wave231originated from the closure of the to-turbine outlet port223. The design and construction of the wave rotor is such that the arrival of the pressure wave231corresponds with the closing of the from-compressor inlet port221.

With reference toFIG. 9, there is illustrated schematically an alternate embodiment of a propulsion system300. In one embodiment the propulsion system300includes a fluid inlet31, a pulsed combustion detonation engine wave rotor220and a nozzle32. The wave rotor device220is identical to the wave rotor described in propulsion system200and like feature numbers will be utilized to indicate like features. In one form propulsion system30is adapted to produce thrust without incorporation of conventional turbomachinery components. The working fluid passing through the inlet31is conveyed through the first wave rotor inlet port221and into the wave rotor220. High pressure buffer gas is discharged through wave rotor outlet port224and passes back into the wave rotor device through wave rotor inlet port222. The relatively high energy flow of combusted gases flows out of the outlet port223and exits through nozzle32to produce motive power.

With reference toFIG. 10, there is illustrated schematically an alternate embodiment of a rocket type propulsion system400. In one embodiment, the propulsion system400includes an oxidizer and working gas storage tank101, a pulsed combustion detonation engine wave rotor220and a nozzle32. The wave rotor device220is identical to the wave rotor described in propulsion system200and like feature numbers will be utilized to indicate like features. In one form propulsion system400is adapted to produce thrust without incorporation of conventional turbomachinery components. The first wave rotor inlet port221is in fluid communication with the oxidizer and working gas storage tank101and receives a quantity of working fluid therefrom. High pressure buffer gas is discharged through the wave rotor outlet port224and passes back into the wave rotor device through wave rotor inlet port222. The relatively high energy flow of combusted gases pass out of the outlet port223and exits nozzle32to produce motive power.

A few of the additional alternate embodiments (not illustrated) contemplated herein will be described in comparison to the embodiment ofFIG. 9. The utilization of like feature numbers is intended to represent like features. One of the alternate embodiments includes a turbomachine type compressor placed immediately ahead of the wave rotor220and adapted to supply a compressed fluid to inlet221. The turbomachine type compressor is driven by shaft power derived from the wave rotor220. A second alternate embodiment includes a conventional turbine placed downstream of the wave rotor220and adapted to be supplied with the gas exiting port223. The second type of alternate embodiment does not include a nozzle and delivers only engine output shaft power.

The present invention is also applicable to a mechanical device wherein the plurality of fluid flow passageways are stationery, the inlet and outlet ports are rotatable, and the gas flows and processes occurring within the fluid flow passageways are substantially similar to those described previously in this document. Referring toFIG. 11, there is illustrated a partially exploded view of one embodiment of the wave rotor device320. The description of a wave rotor device having rotatable inlet and outlet ports is not limited to the embodiment of device320, and is applicable to other wave rotors including but not limited to the embodiments associated withFIGS. 1–5and9–10. The utilization of like feature numbers will be utilized to describe like features. In one form wave rotor device320comprises a stationary portion340centered about a centerline X and having a plurality of fluid passageways41positioned between two rotatable endplates325and326. The endplates325and326are rotated to pass by the fluid passageways a plurality of inlet ports221and222and outlet ports224and223. Endplates325and326are connected to shaft348and form a rotatable endplate assembly. In one embodiment a member349mechanically fixes the endplates325and326to the shaft348. Further, the endplate assembly is rotatably supported by bearings, which are not illustrated. In one embodiment the endplates325and326are fitted adjacent to stationary ducted passages between the compressor21and turbine23. Sealing between the stationary ducts and the rotating endplates is accomplished by methods and devices believed known of those skilled in the art. In a preferred form the stationary portion340defines a ring and the plurality of fluid passageways41are positioned about the circumference of the ring.

In one form a conventional rotational device is utilized to accomplish the rotation of the endplate assembly including endplates325and326. In another form the gas turbine23can be used as the means to cause rotation of the endplates325and326. In another embodiment the endplate assembly is a self-turning, freewheeling design; wherein freewheeling indicates no independent drive means are required. In one form the freewheeling design is contemplated with the use of an endplate designed so as to capture a portion of the momentum energy of the fluid exit stream of port224and hence provide motive force for rotation of the endplate. In another form the freewheeling design is contemplated to be driven by a portion of the momentum energy of the exit stream of port223. In another form the freewheeling design is contemplated to be driven by a portion of the momentum energy of the inlet stream of port222. In yet another form the freewheeling design is contemplated to be driven by a portion of the momentum energy of the inlet stream of port221. In all cases a portion of the endplate port flowpath may contain features turning the fluid stream within one or two exit endplate port flowpaths and one or two inlet endplate port flowpaths in the tangential direction hence converting fluid momentum energy to power to rotate the endplate. The use of curved or angled passageways within the stationary portion340may aid in this process by imparting tangential momentum to the exit flow streams which may be captured within the endplate through turning of the fluid stream back to the axial direction. In each of these ways the rotating endplate assembly may also provide useful shaft power beyond that required to turn the endplate assembly. This work can be used for purposes such as but not limited to, driving an upstream compressor, powering engine accessories (fuel pump, electrical power generator, engine hydraulics) and/or to provide engine output shaft power. The types of rotational devices and methods for causing rotation of the endplate assembly is not intended to be limited herein and include other methods and devices for causing rotation of the endplate assembly as occur to one of ordinary skill in the art. One form of the present invention contemplates rotational speeds of the endplate assembly within a range of about 1,000 to about 100,000 revolutions per minute, and more preferably about 10,000 revolutions per minute. However, the present invention is not intended to be limited to these rotational speeds unless specifically stated herein.

The endplates325and326are fixedly coupled to the shaft348that is rotatable on a pair of bearings (not illustrated). In one form of the present invention the endplates rotate about the centerline X in the direction of arrow C. While the present invention has been described based upon rotation in the direction of arrow C, a system having the appropriate modifications to rotate in the opposite direction is contemplated herein. The direction C may be concurrent with or counter to the rotational direction of the gas turbine engine rotors.

The pair of rotating endplates325and326are fixedly positioned very closely adjacent the stationary portion340so as to control the passage of working fluid into and out of the plurality of passageways41as the endplates rotate. Endplates325and326are designed to be disposed in a sealing arrangement with the stationary portion340in order to minimize the leakage of fluid between the plurality of passageways41and the endplates. In an alternate embodiment auxiliary seals are included between the end plates and the rotor to enhance sealing efficiency. Seal types, such as but not limited to, labrynth, gland or sliding seals are contemplated herein, however the application of seals to a wave rotor is believed known to one of skill in the art.

With reference toFIG. 12, there is illustrated a space-time (wave) diagram for an alternate embodiment of a pulsed detonation engine wave rotor. The pulsed detonation engine wave rotor is similar to the pulsed detonation engine wave rotor described with the assistance ofFIG. 8. However, the pulsed detonation engine wave rotor described with the assistance ofFIG. 12has the fuel distribution changed within the region prior to high pressure energy transfer gas inlet port222. The changing of the fueling at the region just prior to the high pressure energy transfer gas inlet port222is utilized to adjust the exit temperature of the fluid from the pulsed detonation engine wave rotor. The fuel adjustment can be used to tailor the fluid exit temperature to materials utilized in the turbine downstream from the outlet and/or to alter the quantity of power output delivered by operation of the device by altering the exit temperature. A plurality of fuel delivery devices400is located across the duct222aprior to the high pressure energy transfer gas inlet port222. In one form the fuel delivery devices400are active elements that can be controlled to selectively delivery fuel into the duct222a.In the embodiment illustrated inFIG. 12, the fuel delivery devices400a,400band400care delivering fuel and the remaining fuel delivery devices are not activated to deliver fuel. The quantity and location of the fuel delivery devices inFIG. 12is not intended to be limiting and other quantities and locations are contemplated herein. The fuel may be delivered in a liquid or gaseous form.

In one form of the present invention, a leading first unfueled portion401of the high pressure energy transfer gas inlet port222is left unfueled. The leading first unfueled portion401is within a range of about two to about seventy-five percent of the inlet port222, and in a preferred form is about15percent of the inlet port222and the rest of the port is fueled. In another form of the present invention, a second last unfueled portion402of the high pressure energy transfer gas inlet port222is left unfueled and the rest of the port222is fueled. The second unfueled portion is within a range of about two to about fifty percent and the rest of the port is fueled, and in a preferred from the second unfueled portion is about 10percent and the rest of the port is unfueled. A preferred form of the present application includes a first unfueled portion401and a second unfueled portion402, and preferably the first unfueled portion is about 15 percent and the second unfueled portion is about 10 percent. However, other percentages for the unfueled portions are contemplated herein.

The pulsed detonation engine wave rotor described with the assistance ofFIG. 12has the high pressure energy transfer gas outlet port224, the high pressure energy transfer gas inlet port222and the from-compressor inlet port221on the same end of the device; and the to-turbine outlet port223located on the opposite end of the device. In one form of the present invention there is defined a two port wave rotor cycle including one fluid flow inlet port and one fluid flow outlet port and having a high pressure buffer gas recirculation loop that may be considered internal to the wave rotor device. The high pressure energy transfer inlet port222is prior to and adjacent the from-compressor inlet port221. It can be observed that upon the rotation of rotor40each of the plurality of passageways41are sequentially brought in registration with the inlet ports221and222and the outlet ports223and224, and the path of a typical charge of fluid is along the respective passageways41. The wave diagram for the purpose of description may be started at any point, however, for convenience, the description is started at227wherein the low-pressure working fluid is admitted from the compressor. The concept of low pressure should not be understood in absolute manner, it is only low in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

The low pressure portion227of the wave rotor engine receives a supply of low-pressure working fluid from compressor21. The working fluid enters passageways41upon the from-compressor inlet port221being aligned with the respective passageways41. Fuel is introduced into the region403by the fuel delivery devices400a,400band400c. The region403is a fueled region and the regions404and405are non-fueled regions with a non-vitiated working fluid. A portion of the region403exists at the end of the rotor and this region has a fuel content such that the mixture of fuel and working fluid is combustible.

A detonation is initiated from an end portion of the wave rotor40adjacent the region228and a detonation wave232travels through the fuel-working-fluid air mixture within the region403toward the opposite end of the rotor containing a working-fluid-without-fuel region230. In one form of the present invention, a detonation initiator233initiates the detonation; such as but not limited to a high energy spark discharge device. However, in an alternate form of the present invention the detonation is initiated by an auto-detonation process and does not include a detonation initiator. The detonation wave232travels along the length of the passageway and ceases with the absence of fuel at the gas interface234. Thereafter, a pressure wave235travels into the working-fluid-without-fuel region230of the passageway and compresses this working fluid to define a high-pressure buffer/energy transfer gas within region236. The concept of high pressure should not be understood in an absolute manner, it is only high in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

The high pressure buffer/energy transfer gas within region236exits the wave rotor device220through the buffer gas outlet port224. The combusted gases within the region237exits the wave rotor through the to-turbine outlet port223. Expansion of the combusted gas prior to entering the turbine results in a lower turbine inlet temperature without reducing the effective peak cycle temperature. As the combusted gas exits the outlet port223, the expansion process continues within the passageways41of the rotor and travels toward the opposite end of the passageway. As the expansion arrives at the end of the passage, the pressure of the gas within the region238at the end of the rotor opposite the to-turbine outlet port223declines. The wave rotor inlet port222opens and allows the flow of the high pressure buffer/energy transfer working fluid into the rotor at region225and causes the recompression of a portion of the combusted gases within the rotor. The admission of gas via port222can be accomplished by a shock wave. The flow of the high pressure buffer gas adds energy to the exhaust process of the combustion gas and allows the expansion of the combusted gas to be accomplished in a controlled, uniform energy process in one form of the invention. Thus, in one form the introduction of the high pressure buffer/energy transfer gas is adapted to maintain the high velocity flow of combusted gases exiting the wave rotor until substantially all of the combusted gas within the rotor is exhausted.

In one embodiment, the wave rotor inlet port222, which allows the introduction of the high pressure buffer/energy transfer gas, closes before the to-turbine outlet port223is closed. The closing of the wave rotor inlet port222causes an expansion process to occur within the high pressure buffer/energy transfer air within region240and lowers the pressure of the gas and creates a region404. This expansion process occurs within the buffer/energy transfer gas and allows this gas to preferentially remain within the rotor at the lowest pressure region of the rotor. The to-turbine outlet port223is closed as the expansion in region240reaches the exit end of the passageway. As illustrated in region242, the portion of the high pressure buffer/energy transfer gas in region405exits through the outlet port223. This exiting buffer/energy transfer gas functions to insulate the duct wall223afrom the hot combusted gas within region226of the duct223b. The pressure in region404has been lowered and the from-compressor inlet port221allows pre-compressed low pressure working fluid to enter the rotor passageways in the region227having the lowered pressure. The entering motion of the pre-compressed low-pressure working fluid through port221is stopped by the arrival of pressure wave231originating from the exit end of the rotor and traveling toward the inlet end. The pressure wave231originated from the closure of the to-turbine outlet port223. The design and construction of the wave rotor is such that the arrival of the pressure wave231corresponds with the closing of the from-compressor inlet port221.

With reference toFIG. 13, there is illustrated a space-time (wave) diagram for a pulsed detonation engine wave rotor that utilizes a cycle that is substantially similar to the cycle set forth inFIG. 8. However, the pulsed detonation engine wave rotor described with the assistance ofFIG. 13has the location of the gas interface600in a different location to facilitate mass flow balancing within the system. The mass flow balancing is accommodated by parking a quantity of the high-pressure buffer/energy transfer gas from region236in region601. The energy of compression imparted previously to the gas of region601by compression wave235is released to the flow of gas moving to exhaust port226by the arrival of expansion wave238and acts to expel it to the exhaust port in an energetic manner. The parked gas in region601, being non-vitiated and does not gain fuel. This gas601thus separates the vitiated combustion gas of elevated temperature from the stationary end wall401hence avoiding heating of wall401. Similarly, the gas of region601separates the vitiated combustion gas of region237and the gas with fuel added entering from port222. Gas in region601moves to pass into region242and thereby insulates surface223afrom the combustion gas of region226. The pulsed detonation engine wave rotor described with the assistance ofFIG. 13has the high pressure energy transfer gas outlet port224, the high pressure energy transfer gas inlet port222and the from-compressor inlet port221on the same end of the device; and the to-turbine outlet port223located on the opposite end of the device. In one form of the present invention there is defined a two port wave rotor cycle including one fluid flow inlet port and one fluid flow outlet port and having a high pressure buffer gas recirculation loop that may be considered internal to the wave rotor device. The high pressure energy transfer inlet port222is prior to and adjacent the from-compressor inlet port221. It can be observed that upon the rotation of rotor40each of the plurality of passageways41are sequentially brought in registration with the inlet ports221and222and the outlet ports223and224, and the path of a typical charge of fluid is along the respective passageways41. The wave diagram for the purpose of description may be started at any point, however, for convenience, the description is started at227wherein the low-pressure working fluid is admitted from the compressor. The concept of low pressure should not be understood in absolute manner, it is only low in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

The low pressure portion227of the wave rotor engine receives a supply of low-pressure working fluid from compressor21. The working fluid enters passageways41upon the from-compressor inlet port221being aligned with the respective passageways41. In one embodiment fuel is introduced into the region225by: stationery continuously operated spray nozzles (liquid)227or supply tubes (gas)227located within the duct222aleading to the high pressure energy transfer gas inlet port222; or, into region228by intermittently actuated spray nozzles (liquid)227′ or supply tubes (gas)227′ located within the rotor; or, into region228by spray nozzles (liquid)227″ or supply tubes (gas)227″ located within the rotor end plate226. Region228exists at the end of the rotor and the region has a fuel content such that the mixture of fuel and working fluid is combustible.

A detonation is initiated from an end portion of the wave rotor40adjacent the region228and a detonation wave232travels through the fuel-working-fluid air mixture within the region228toward the opposite end of the rotor containing a working-fluid-without-fuel region230. In one form of the present invention, a detonation initiator233initiates the detonation; such as but not limited to a high energy spark discharge device. However, in an alternate form of the present invention the detonation is initiated by an auto-detonation process and does not include a detonation initiator. The detonation wave232travels along the length of the passageway and ceases with the absence of fuel at the gas interface234. Thereafter, a pressure wave235travels into the working-fluid-without-fuel region230of the passageway and compresses this working fluid to define a high-pressure buffer/energy transfer gas within region236. The concept of high pressure should not be understood in an absolute manner, it is only high in comparison with the rest of the pressure level of gas within the pulsed detonation engine wave rotor.

A portion of the high pressure buffer/energy transfer gas within region236exits the wave rotor device220through the buffer gas outlet port224and a portion is maintained within the wave rotor device220in region601. As discussed previously, the energy of the compression imparted previously to the gas of region601by compression wave235is released to the flow of gas moving to exhaust port236by the arrival of expansion wave238and acts to expel it to the exhaust port. This parked gas within the region601separates the vitiated combusted gas of elevated temperatures from the end wall401. Similarly, the gas within region601separates the vitiated combustion gas of region237and the gas with fuel added entering from port222. The gas within region601passes into region245and insulates surface233afrom the combustor gas within region226

The combusted gases within the region237exits the wave rotor through the to-turbine outlet port223. Expansion of the combusted gas prior to entering the turbine results in a lower turbine inlet temperature without reducing the effective peak cycle temperature. As the combusted gas exits the outlet port223, the expansion process continues within the passageways41of the rotor and travels toward the opposite end of the passageway. As the expansion arrives at the end of the passage, the pressure of the gas within the region238at the end of the rotor opposite the to-turbine outlet port223declines. The wave rotor inlet port222opens and allows the flow of the high pressure buffer/energy transfer working fluid into the rotor at region225and causes the recompression of a portion of the combusted gases and the gas from region601within the rotor. The admission of gas via port222can be accomplished by a shock wave. The flow of the high pressure buffer gas adds energy to the exhaust process of the combustion gas and allows the expansion of the combusted gas to be accomplished in a controlled, uniform energy process in one form of the invention. Thus, in one form the introduction of the high pressure buffer/energy transfer gas is adapted to maintain the high velocity flow of combusted gases exiting the wave rotor until substantially all of the combusted gas within the rotor is exhausted.

In one embodiment, the wave rotor inlet port222, which allows the introduction of the high pressure buffer/energy transfer gas, closes before the to-turbine outlet port223is closed. The closing of the wave rotor inlet port222causes an expansion process to occur within the high pressure buffer/energy transfer air within region240and lowers the pressure of the gas and creates a region240. This expansion process occurs within the buffer/energy transfer gas and allows this gas to preferentially remain within the rotor at the lowest pressure region of the rotor. The to-turbine outlet port223is closed as the expansion in region240reaches the exit end of the passageway. In one form of the present invention as illustrated in region242, a portion of the high pressure buffer/energy transfer gas exits through the outlet port223. This exiting buffer/energy transfer gas functions to insulate the duct wall223afrom the hot combusted gas within region226of the duct223b.The pressure in region241has been lowered and the from-compressor inlet port221allows pre-compressed low pressure working fluid to enter the rotor passageways in the region227having the lowered pressure. The entering motion of the pre-compressed low-pressure working fluid through port221is stopped by the arrival of pressure wave231originating from the exit end of the rotor and traveling toward the inlet end. The pressure wave231originated from the closure of the to-turbine outlet port223. The design and construction of the wave rotor is such that the arrival of the pressure wave231corresponds with the closing of the from-compressor inlet port221.

With reference toFIG. 14, there is illustrated a space-time (wave) diagram for an alternate embodiment of a pulsed detonation engine wave rotor. The pulsed detonation engine wave rotor cycle includes the fuel distribution system ofFIG. 12and the mass flow balancing ofFIG. 13that is accommodated by parking a quantity of the high-pressure buffer/energy transfer gas from region236in region601. The combination of the two embodiments results in the embodiment ofFIG. 15operating within a select range of exhaust port223gas temperatures generally higher or lower than that of the other embodiments depending on fuel heat capacity and limits on fuel to air combustability ratios. The fueled portion of the gas in region403is made to arrive at the exit end of a passage at the end of port223an hence bring fueled gas into region228.

With reference toFIGS. 15 and 16there are illustrated space-time (wave) diagrams for alternative embodiments of pulsed detonation engine wave rotors. Each of the respective systems includes a high pressure energy transfer gas inlet port222and a high pressure energy transfer gas outlet port224that are not separated by a mechanical divider. It should be understood herein that the embodiments are applicable broadly to the systems and aspects disclosed within this application. The high pressure inflow and outflow occurring adjacent one another in two ports that are not separated by a mechanical divider. Referring toFIG. 15, there is illustrated the compressed gas of region236flowing into port224. As any passageway of the rotor40proceeds due to rotation in direction Q, the arrival of expansion waves238slows the gas entry into port224. There exists at some point D, a condition at which the gas entry into port224ceases due to an equilibrium of pressures in region236and port224. At point D, port224is essentially closed due to gas action rather than the presence of a physical wall401as in the embodiment ofFIG. 14. As rotation of rotor40continues and arrival of expansion wave238continues to reduce the pressure, region225is reached where gas issues from port222a.Fuel is admitted utilizing the identical method of227as described embodiment with reference toFIG. 8.

Referring toFIG. 16, there is illustrated an embodiment of the present invention in which, for reasons of gas mass balance, the combustion gas of region237reach or very nearly reach point D as described with the assistance of the embodiment ofFIG. 15. The relative positioning of the interface between regions236and237and the interface between regions225and237in the embodiments ofFIGS. 15 and 16respectively is in the existence of a parked gas region601inFIG. 15. This unfueled portion of gas results in the layer of relatively cool gas of region405which proceeds to exit port223. This gas within region405functions in the same manner described in the embodiment ofFIG. 14.

With reference toFIG. 17, there is illustrated an exploded view of one embodiment of the constant volume combustor200. Constant volume combustor200includes a transition duct201for providing fluid communication pathway with the compressor and/or other inlet of the engine. The constant volume combustor200further includes an endplate202with a plurality of ports220, and an endplate203with a plurality of exit ports221and detonation initiation devices204. Fluid passes through the plurality of exit ports221into a transition duct206including fluid flow passageways passages207. Further, the constant volume combustor200includes a plurality of buffer ducts208that deliver the buffer air to different locations within the rotor205. The reader should appreciate that the delivery of air through the buffer ducts208is in the direction of rotation. Each of the buffer ducts208may includes a fuel delivery mechanism. The constant volume combustor has been described with the aid ofFIG. 17, however the present application contemplates other constant volume combustors capable of utilizing the cycles described previously in this application. In a preferred form, the constant volume combustor200has detonative combustion occurring therein.

With reference toFIG. 18, there is illustrated a cross-sectional view of a gas turbine engine with the constant volume combustor200integrated therein. The term gas turbine engine is intended to be interpreted broadly and the present inventions are contemplated for utilization with virtually all typical forms of gas turbine engines unless specifically provided to the contrary. The constant volume combustor200receives a working fluid from the primary flowpath of the compressor section210through transition duct201. In one form of the present invention the working fluid discharged from the compressor has a temperature of about 1212° F., however other working fluid temperatures are contemplated herein. The working fluid is delivered to the constant volume combustor200and a first portion of the working fluid is utilized in the ensuing combustion within the wave rotor passages225. A second portion of the working fluid is extracted through port212and is utilized as cooling fluid for the low pressure turbine airfoils and to provide secondary cooling airflow to the low pressure turbine seals.

The constant volume combustor200raises the pressure of working fluid from the primary flowpath211above the pressure from the compressor discharge and therefore the compressor discharge working fluid is too low in pressure to be utilized for high pressure turbine cooling. In one form of the present invention, the constant volume combustor200raises the pressure of the working fluid from the primary flowpath211about 20%. The present invention contemplates pressure rises within the range of about 10% to about 50%; however, other pressure rises are contemplated herein. The turbine section215includes a first stage nozzle216ahaving a plurality of nozzle guide vanes216. In one form of the present invention the nozzle guide vanes216are transpiration cooled, therefore the cooling media delivered to the respective nozzle guide vanes216must be at a pressure higher than the working fluid flow exiting the constant volume combustor200. In one form of the present invention in order to provide cooling media to the plurality of guide vanes216, some of the working fluid from the constant volume combustor return ducts208is bled off, and ducted around the constant volume combustor to the nozzle guide vane216. In one form the working fluid flows through a passageway defined between the constant volume combustor rotor205and the outer combustor case235. The working fluid follows the flowpath as indicated by arrows A to cool the guide vanes216. The working fluid bled from the constant volume combustor return duct is relatively high in pressure and above the pressure of the discharged working fluid from the constant volume combustor discharge; making it an excellent source for cooling fluid. A portion of the working fluid from the constant volume combustor return duct passes directly through the first stage nozzle216aand is used to cool blades220of the high pressure turbine. However, the present application is applicable to propulsion systems having nozzle guide vanes that are not actively cooled.

In one form of the present invention the constant volume combustor200is located within the combustor case235and has an inner vent cavity226and an outer vent cavity227adjacent thereto. These cavities form a relatively lower pressure sink to enable one form of the constant volume combustor endplates202and203to function. In one embodiment of the present invention, each of the endplates202and203float hydrostatically on a cushion of working fluid and are located a small distance from the rotating face of the rotor205. In one form of the present invention the small distance is within a range of about 0.0005 inches to about 0.0015 inches. With reference toFIGS. 18a–b, there is schematically illustrated the operation of the sealing plates202and203.FIG. 18arepresents a circumferential view at the ports220.FIG. 18brepresents a circumferential view between the ports220. The sealing plate illustrated is the forward sealing plate and has a face700that sees the pressure from the constant volume combustor rotor passage200and the vent cavity226. A quantity of the high pressure working fluid208abled from the constant volume combustor return duct208is supplied into the sealing plate and is discharged through a plurality of ports701into the gap adjacent the rotating rotor end. The discharged working fluid from the plurality of ports701allows the seal plate to float hydrostatically on a thin film of working fluid and remain a finite small gap from the end of the rotating rotor. The aft seal plate is free to move axially in a stationary structure in order to seek it own location. At the other end of the rotor there is located a substantially similar seal plate that functions in substantially the same fashion as the aft sealing plate. However, in a preferred form of the present application, this seal plate is fixed to the outer combustor case.

With reference toFIG. 18c,there is schematically illustrated various features of the sealing plate202and by extension the plate203. The sealing plate illustrated is the forward sealing plate in very close proximity to the rotor205. A quantity of the high pressure working fluid208abled from the constant volume combustor return duct208is supplied into the sealing plate and is discharged through the aforementioned ports701not shown here, into the very small spacing between the seal plate202and the adjacent rotating rotor end. The discharged working fluid208afrom duct208allows the seal plate to float hydrostatically on a thin film of working fluid and remain at high pressure in the finite small space. In this embodiment, confinement of this high pressure gas is enhanced by the presence of labyrinth knife seal of design knowledgeable by one schooled in this art placed at the inner and outer diameter of the rotor. Also in this embodiment, the seal plate is confined in its axial movement relative to the stationary structure201by “C” seal and spring500in order to balance the forces on the seal plate202and prevent bleed air208afrom duct208from entering unrestrained into port220. An anti-rotation pin505is fixed to201and mated to a slot in plate202to avoid rotation of plate202. Similarly in this embodiment at the other end of the rotor there is located a substantially similar seal plate that functions in substantially the same fashion as the forward sealing plate.

A fan duct705has a quantity of fan duct working fluid flowing therethrough. A portion of the fan duct flow is bled off and used to cool selected components within the engine. In one form the fan duct flow is utilized to cool magnetic bearings located within the engine. Feature numbers710,711,712and713sets forth examples of the magnetic bearings. In one embodiment of the present invention the constant volume combustor rotor205is supported by and rotates on radial magnetic bearings710and711. With reference toFIG. 19, the radial magnetic bearings710and711each have a stator portion720coupled to a member721that is connected to the mechanical housing725and a rotor portion731that is coupled with an attachment structure742of the constant volume combustor rotor205. In a preferred form the magnetic bearings710and711are active electromagnetic bearings that are controlled by a controller. In one form of the present invention there is a significant thermal gradient between the constant volume combustor rotor205and the magnetic bearings720. Presently, magnetic bearings are generally limited to applications having environmental temperatures of up to about 800° F. In one form, the present invention substantially isolates in a thermal sense the magnetic bearing from the rotor205. More specifically, a thermal conduction limiting structure is utilized to couple the constant volume combustor rotor205with the magnetic bearings.

With reference toFIG. 20, there is illustrated one form of the thermal conduction limiting structure including a pin joint730of the plurality of pin joints coupling the rotor205with the supporting structure731. The pin joint730includes a radial pin732mechanically connecting the structure760of the rotor205with the supporting structure742and the pin joint limiting the conductive heat transfer path between the wave rotor205and the supporting structure731. The limited conductive heat transfer path associated with the radial pin732is due to the reduced flowpath for energy by conduction and is one means to thermally isolate the rotor205from the radial magnetic bearings. The present application further contemplates a system utilizing other forms of bearings and other coupling structures for the bearings, whether the bearings are magnetic bearings or some other type of bearing also needing thermal isolation as known to one of skill in the art.

The constant volume combustor rotor205could be designed as a free wheeling structure or one that is driven during at least portions of its operating cycle. One embodiment of the present invention contemplates the utilization of the radial magnetic bearings and a conventional electrically driven starter motor located with the magnetic bearings720supporting the rotor, said motor functioning to cause rotation of the rotor. Further, the present invention contemplates conventional means to drive the rotor205during start up or at other engine operating conditio ns. One system contemplates a conventional starter operatively coupled to the rotor205to provide the initial rotation necessary to start the constant volume combustor.

The present application contemplates that, in the starting of the engine including the constant volume combustor, the constant volume combustor would be started before the rest of the machine and hence act to start the rest of the machine. The rotor205of the constant volume combustor would be brought up to a predetermined speed and fuel added and upon ignition the constant volume combustor would discharge working fluid that impinges on the high pressure turbine which starts the high pressure turbine rotor, the output of which then starts the low pressure rotor spinning. The spinning high pressure and low pressure turbines would continue as the rest of the machine is started. Further, in another embodiment the constant volume combustor includes a starter and a generator. The starter and generator are controllable to provide the ability to modify the rotational speed of the constant volume combustor rotor. The starter could be engaged to increase the speed and add energy during desired operating parameters, while the generator could be engaged to decrease the speed and extract energy during desired operating parameters.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. It should be understood that while the use of the word preferable, preferably or preferred in the description above indicates that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, that scope being defined only by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one,” “at least a portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.