Patent Abstract:
A pulsed detonation engine wave rotor apparatus and method of using a pressure wave to compress a buffer gas disposed within the engine flow passages. The high pressure buffer gas is routed out of the wave rotor and subsequently reintroduced to the wave rotor to discharge and scavenge the latter stages of the combustion gas remaining under the engine flow passages.

Full Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a non-steady flow device utilizing pulse combustion to produce thrust. More particularly, in one embodiment of the present invention a wave rotor utilizing pulse detonation compresses an energy transfer gas disposed within the wave rotor flow passages. The compressed energy transfer gas is routed out of a first port of the wave rotor and reintroduced through a second port into the wave rotor to forcefully discharge and scavenge the latter stages of combustion gases within the wave rotor flow passages. Although the present invention was developed for use with wave rotor based pulsed detonation engines, certain applications may be outside of this field. 
     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. Since the 1940&#39;s wave rotors have been studied by engineers and scientists and thought of as particularly suitable for a propulsion system. 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. 
     There are a variety of wave rotor devices that have been conceived of over the years. While these prior wave rotors and methods of using transient gas flows are steps in the right direction the need for additional improvement still remains. The present invention satisfies this need in a novel and unobvious way. 
     SUMMARY OF THE INVENTION 
     One form of the present invention contemplates a pulsed combustion wave rotor engine utilizing a flow of buffer gas to scavenge the latter stages of the expansion and enhance the discharge of combusted gas from the rotor. The present invention contemplates a device having rotatable passageways or rotatable endplates with ports therein. 
     Another form of the present invention contemplates a method, comprising: introducing a quantity of working fluid into a passageway of a wave rotor; placing a fuel within one end of the passageway; combusting the fuel within the passageway and creating a quantity of combusted gas adjacent the one end of the passageway and compressing a portion of the working fluid within the passageway to define a high pressure buffer gas adjacent the combusted gas within the passageway; discharging the high pressure buffer gas out of the passageway; discharging a first portion of the combusted gas out of the passageway; and routing the high pressure buffer gas from the discharging back into the passageway to purge a second portion of the combusted gas out of the passageway. 
     In another form of the present invention there is contemplated a method, comprising: providing a wave rotor device including a rotatable rotor with a plurality cells adapted for the passage of fluid therethrough, the rotor having a direction of rotation; rotating the rotor to pass the plurality of cells by a plurality of inlet ports and a plurality of outlet ports; flowing a working fluid through one of the plurality of inlet ports and into at least one of the cells; introducing a fuel into the at least one of the cells at the inlet end portion; detonating the fuel and a first portion of the working fluid within the at least one of the cells, the detonating forming combusted gas and compressing a second portion of the working fluid to define a high pressure buffer gas; discharging the high pressure buffer gas through one of the plurality of outlet ports; discharging a first portion of the combusted gas through another of the plurality of outlet ports; and routing in the direction of rotation of the rotor the high pressure buffer gas from the one of the plurality of outlet ports and reintroducing through another of the plurality of inlet ports into the at least one of the cells to discharge a second portion of the combusted gas from the cell. 
     In a further form of the present invention there is contemplated a method, comprising: providing a wave rotor device including a plurality of stationary passageways adapted for the passage of fluid therethrough; rotating a plurality of inlet ports and a plurality of outlet ports by the plurality of stationary passageways to control the passage of fluid into and out of the stationary passageways, the plurality of ports having a direction of rotation; flowing a working fluid through one of the plurality of inlet ports and into at least one of the stationary passageways; introducing a fuel into the at least one of the stationary passageways; detonating the fuel and a first portion of the working fluid within the at least one of the stationary passageways, said detonating forming combusted gas and compressing a second portion of the working fluid to define a high pressure buffer gas; discharging the high pressure buffer gas through one of the plurality of outlet ports; discharging a first portion of the combusted gas through another of the plurality of outlet ports; and routing in the direction of rotation of the ports the high pressure buffer gas from the one of the plurality of outlet ports and reintroducing through another of the plurality of inlet ports into the at least one of the stationary passageways to discharge a second portion of the combusted gas from the passageway. 
     One object of the present invention is to provide a unique pulsed combustion engine wave rotor. 
     Related objects and advantages of the present invention will be apparent from the following description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation of a propulsion system comprising a compressor, a pulsed combustion engine wave rotor, a turbine, a nozzle and an output power shaft. 
     FIG. 1 a  is a schematic representation of an alternate embodiment of a propulsion system comprising a compressor, a pulsed combustion engine wave rotor, a turbine, a nozzle and an output power shaft. 
     FIG. 2 is a partially exploded view of one embodiment of a pulsed combustion engine wave rotor comprising a portion of FIG.  1 . 
     FIG. 3 is a space-time (wave) diagram for one embodiment of a pulsed detonation engine wave rotor of the present invention wherein the high-pressure energy transfer gas outlet port and the exhaust gas to-turbine port are on the same end of the device. 
     FIG. 4 is a schematic representation of a pulsed combustion engine wave rotor intended to be used as a direct thrust-producing propulsion system without conventional turbomachinery components. 
     FIG. 5 is a schematic representation of another embodiment of a pulsed combustion engine wave rotor intended to be used as a direct thrust-producing propulsion system without conventional turbomachinery components. 
     FIG. 6 is a schematic representation of an alternate embodiment of a propulsion system comprising a compressor, a pulsed combustion engine wave rotor, a turbine, a nozzle and an output power shaft. 
     FIG. 6 a  is a schematic representation of another embodiment of a propulsion system comprising a compressor, a pulsed combustion engine wave rotor, a turbine, a nozzle and an output power shaft. 
     FIG. 7 is a partially exploded view of one embodiment of a pulsed combustion engine wave rotor comprising a portion of FIG.  6 . 
     FIG. 8 is a space-time (wave) diagram for an alternate embodiment of a pulsed detonation engine wave rotor wherein the high-pressure energy transfer gas outlet port and the combustion gas exit port are on opposite ends of the device. 
     FIG. 9 is a schematic representation of a pulsed combustion engine wave rotor intended to be used as a direct thrust-producing propulsion system without conventional turbomachinery components. 
     FIG. 10 is a schematic representation of another embodiment of a pulsed combustion engine wave rotor intended to be used as a direct thrust-producing propulsion system without conventional turbomachinery components. 
     FIG. 11 is a partially exploded view of another embodiment of a pulsed combustion engine wave rotor comprising stationary fluid flow passageways between rotatable endplates having inlet and outlet ports. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. 
     With reference to FIG. 1, there is illustrated a schematic representation of a propulsion system  20  which includes a compressor  21 , a pulsed combustion wave rotor  22 , a turbine  23 , a nozzle  32 , and an output power shaft  26 . The compressor  21  delivers a precompressed working fluid to the pulsed combustion wave rotor device  22 . Wave rotor device  22  has occurring within its passageways the combustion of a fuel and air mixture, and thereafter the combusted gases are delivered to the turbine  23 . The working fluid that is precompressed by the compressor  21  and delivered to the wave rotor device  22  is 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 device  22  replaces 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 system  20  have 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 to FIGS. 1-3, further aspects of the propulsion system  20  will be described. Compressor  21  is operable to increase the pressure of the working fluid between the compressor inlet  24  and the compressor outlet  25 . 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 port  42 . The first wave rotor inlet port  42  generally 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 port  43  is referred to as a buffer gas inlet port, and is located adjacent to and sequentially prior to the first wave rotor inlet port  42 . Wave rotor inlet ports  42  and  43  form 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 device  22  has an outlet port sequence that includes an outlet port  45  and a buffer gas outlet port  44 . The outlet port  45  generally 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 system  20  the outlet port  45  is defined as to-turbine outlet port  45 . The to-turbine outlet port  45  in propulsion system  20  allows the combusted gases to exit the wave rotor device  22  and pass to the turbine  23 . Compressed buffer gas exits the buffer gas outlet port  44  and is reintroduced into the rotor passageways  41  through the second wave rotor inlet port  43 . In one embodiment the buffer gas outlet port  44  and the second wave rotor inlet port  43  are connected in fluid communication by a duct. In one form the duct between the outlet port  44  and outlet port  43  is integral with the wave rotor device  22  and passes through the interior of rotor  40 . In another form the duct passes through the center of shaft  48 . In another form of the present invention the duct is physically external to the wave rotor device  22 . 
     The reintroduced compressed buffer gas does work on the remaining combusted gases within the rotor passageways  41  and causes the pressure in region  70  to remain at an elevated level. The relatively high energy flow of combusted gases from the to-turbine port  45  is maintained in region  74  by the reintroduction of the high pressure buffer gas entering through the second wave rotor inlet port  43 . The flow of the high pressure buffer gas from buffer gas outlet port  44  to the second wave rotor inlet port  43  is illustrated schematically by arrow B in FIG.  3 . In one form of the present invention a portion of the high pressure buffer gas exiting through outlet port  44  can 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 turbine  23  through exit port  45  is higher than the pressure of the working fluid at the compressor discharge  25 . Therefore, the requirement for higher pressure cooling fluid can be met by taking a portion of the high pressure buffer gas exiting port  44  and delivering to the appropriate location(s) within the turbine. With reference to FIG. 1 a , there is illustrated the delivery of the high pressure buffer gas exiting through outlet port  44  and being delivered through passageway 510 to the turbine. 
     Wave rotor outlet ports  44  and  45  form 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 port  44  into the wave rotor passageways  41  via port  43  provides for: high pressure flow issuing generally uniformly from the to-turbine outlet port  45 ; and/or, a cooling effect delivered rapidly and in a prolonged fashion to the rotor walls defining the rotor passageways  41  following the combustion process; and/or, a reduction and smoothing of pressure in the inlet port  42  thereby aiding in the rapid and substantially uniform drawing in of working fluid from the compressor  21 . 
     Combusted gasses exiting through the to-turbine outlet port  45  pass to the turbine  23  where shaft power is produced to power the compressor  21 . Additional power may be produced to be used in the form of output shaft power. Further, combusted gas leaves the turbine  23  and enters the nozzle  32  where 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 to FIG. 2, there is illustrated a partially exploded view of one embodiment of the wave rotor device  22 . Wave rotor device  22  comprises a rotor  40  that is rotatable about a centerline X and passes a plurality of fluid passageways  41  by a plurality of inlet ports  42 ,  43  and outlet ports  44 ,  45  that are formed in end plates  46  and  47 . Preferably, the rotor is cylindrical, however other geometric shapes are contemplated herein. In one embodiment the end plates  46  and  47  are coupled to stationary ducted passages between the compressor  21  and the turbine  23 . The pluralities of fluid passageways  41  are positioned about the circumference of the wave rotor device  22 . 
     In one form the rotation of the rotor  40  is accomplished through a conventional rotational device. In another form the gas turbine  23  can be used as the means to cause rotation of the wave rotor  40 . 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 duct  42   a  so as to allow the incoming fluid flow to impart angular momentum to the rotor  40 . In yet another form the freewheeling design is contemplated to be driven by angling of the inlet duct  43   a  so as to allow the incoming fluid flow to impart angular momentum to the rotor. Further, it is contemplated that the inlet ducts  42   a  and  43   a  can 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 rotor  40  is not intended to be limited herein and include other methods and devices for causing rotation of the rotor  40  as 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 rotor  40  is fixedly coupled to a shaft  48  that 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 passageways  41  extend along the length of the wave rotor device  22  parallel to the centerline X and are formed between an outer wall member  49  and an inner wall member  50 . The plurality of passageways  41  define a peripheral annulus  51  wherein adjacent passageways share a common wall member  52  that connects between the outer wall member  49  and the inner wall member  50  so 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 plates  46  and  47  are fixedly positioned very closely adjacent the rotor  40  so as to control the passage of working fluid into and out of the plurality of passageways  41  as the rotor  40  rotates. End plates  46  and  47  are designed to be disposed in a sealing arrangement with the rotor  40  in order to minimize the leakage of fluid between the plurality of passageways  41  and 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 to FIG. 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 of FIG. 3 has: the high pressure energy transfer gas outlet port  44  and the to-turbine outlet port  45  located on the same end of the device; and the high pressure energy transfer gas inlet port  43  and the from-compressor inlet port  42  on 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 port  43  is prior to and adjacent the from-compressor inlet port  42 . Arrow Q indicates the direction of rotation of the rotor  40 . It can be observed that upon the rotation of rotor  40 , each of the plurality of passageways  41  are sequentially brought into registration with the inlet ports  42 ,  43  and the outlet ports  44 ,  45  and the path of a typical charge of fluid is along the respective passageway  41 . The wave diagram for the purpose of description may be started at any point, however for convenience the description is started at  60  wherein 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 portion  60  of the wave rotor engine receives a supply of low-pressure working fluid from compressor  21 . The working fluid enters passageways  41  upon the from-compressor inlet port  42  being aligned with the respective passageways  41 . In one embodiment fuel is introduced into the low-pressure portion  60  by: stationary continuously operated spray nozzles (liquid)  61  or supply tubes (gas)  61  located within the inlet duct  42   a  leading to the from-compressor inlet port  42 ; or, into region  62  by intermittently actuated spray nozzles (liquid)  61 ″ or supply tubes (gas)  61 ′ located within the rotor; or, into region  62  by spray nozzles (liquid)  61 ″ or supply tubes (gas)  61 ″ located within the rotor endplate  46 . Separating region  60  and  62  is a pressure wave  73  originating from the closure of the to-turbine outlet port  45 . In this way, a region  62  exists 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, regions  60  and  62 , is thus separated from hot residual combustion gas within regions  68  and  69  by the buffer gas entering the rotor through port  43  and traveling through regions  70 ,  71 ,  72  and  64 . In this way undesirable pre-ignition of the fuel air mixture of regions  60  and  62  is inhibited. 
     A detonation is initiated from an end portion of the rotor  40  adjacent the region  62  and a detonation wave  63  travels through the fuel air mixture within the region  62  toward the opposite end of the rotor containing a working-fluid-without-fuel region  64 . In one form of the present invention the detonation is initiated by a detonation initiator  80  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 as an auto-detonation process and does not include a detonation initiator. The detonation wave  63  travels along the length of the passageway and ceases with the absence of fuel at the gas interface  65 . Thereafter, a pressure wave  66  travels into the working-fluid-without-fuel region  64  of the passageway and compresses this working fluid to define a high-pressure buffer/energy transfer gas within region  67 . 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 region  67  exits the wave rotor device  22  through the buffer gas outlet port  44 . The combustion gases within the region  68  exit the wave rotor through the to-turbine outlet port  45 . 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 port  45 , the expansion process continues within the passageway  41  of 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 region  69  at the end of the rotor opposite the to-turbine outlet port  45  declines. The wave rotor inlet port  43  opens and allows the flow of the high pressure buffer/energy transfer working fluid into the rotor at region  70  and causes the recompression of a portion of the combustion gases within the rotor. In one embodiment, the admission of gas via port  43  can 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 port  43 , which allows the introduction of the high-pressure buffer/energy transfer gas, closes before the to-turbine outlet port  45  is closed. The closing of the wave rotor inlet port  43  causes an expansion process to occur within the high pressure buffer/energy transfer air within region  71  and lowers the pressure of the gas and creates a region  72 . Following the creation of this lowered pressure gas region  72 , a passageway  41  is in registration with port  42  and gas flowing within port  42  enters the passageway  41  creating region  60 . The strong and compact nature of the expansion process in region  71  causes a beneficially large pressure difference between the pressure in port  45  and the pressure in port  42 . In one embodiment the pressure of the gas delivered to the turbine  23  is higher than the pressure delivered from the compressor  21  and 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 process  71  occurs within the buffer/energy transfer gas and allows substantially all of the combustion gases of region  68  to exit the rotor leaving the lowest pressure region of the rotor consisting essentially of expanded buffer/energy transfer gas. The to-turbine outlet port  45  is closed as the expansion in region  71  reaches the exit end of the passageway. In one form of the present invention as illustrated in region  75  a portion of the high-pressure buffer/energy transfer gas exits through the outlet port  45 . This gas acts to insulate the duct walls  45   a  from the hot combusted gas within region  74  of the duct  45   b.  In an alternate embodiment the high pressure buffer/energy transfer gas is not directed to insulate and cool the duct walls  45   a . The pressure in region  72  has been lowered, and the from-compressor inlet port  42  allows pre-compressed low-pressure air to enter the rotor passageway in the region  60  having the lowered pressure. The entering motion of the precompressed low-pressure air through port  42  is stopped by the arrival of a pressure wave  73  originating from the exit end of the rotor and traveling toward the inlet end. The pressure wave  73  originated from the closure of the to-turbine outlet port  45 . The design and construction of the wave rotor is such that the arrival of pressure wave  73  corresponds with the closing of the from-compressor inlet port  42 . 
     With reference to FIG. 4, there is illustrated schematically an alternate embodiment of a propulsion system  30 . In one embodiment the propulsion system  30  includes a fluid inlet  31 , a pulsed combustion detonation engine wave rotor  22  and nozzle  32 . The wave rotor device  22  is identical to the wave rotor described in propulsion system  20  and like feature number will be utilized to describe like features. In one form propulsion system  30  is adapted to produce thrust without incorporation of conventional turbomachinery components. In one embodiment the combustion gases exiting the wave rotor are directed through the nozzle  32  to produce motive power. The working fluid passing through inlet  31  is conveyed through the first wave rotor inlet port  42  and into the wave rotor device  22 . High pressure buffer gas is discharged through wave rotor outlet port  44  and passes back into the wave rotor device through wave rotor inlet port  43 . The relatively high energy flow of combusted gases flows out of outlet port  45  and exits nozzle  32 . 
     With reference to FIG. 5, there is illustrated schematically an alternate embodiment of a rocket type propulsion system  100 . In one embodiment, the propulsion system  100  includes an oxidizer and working gas storage tank  101 , a pulsed combustion detonation engine wave rotor  22  and nozzle  32 . The wave rotor device  22  is identical to the wave rotor device discussed previously for propulsion system  20  and like feature numbers will be utilized to describe like features. In one form propulsion system  100  is adapted to produce thrust without incorporation of conventional turbomachinery components. The first wave rotor inlet port  42  is in fluid communication with the oxidizer and working gas storage tank  100  and receives a quantity of working fluid therefrom. High pressure buffer gas is discharged through the wave rotor outlet port  44  and passes back into the wave rotor device through wave rotor inlet port  43 . The relatively high energy flow of combusted gases pass out of the outlet port  45  and exits nozzle  32  to produce motive power. 
     A few additional alternate embodiments (not illustrated) contemplated herein will be described in comparison to the embodiment of FIG.  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 rotor  22  and adapted to supply a compressed fluid to inlet  42 . The turbomachine type compressor is driven by shaft power derived from the wave rotor  22 . Another of the alternate embodiments includes a conventional turbine placed downstream of the wave rotor  22  and adapted to be supplied with the gas exiting port  45 . 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 of FIG. 1, but the nozzle  32  has 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 to FIG. 6, there is illustrated a schematic representation of an alternate embodiment of propulsion system  200  which includes compressor  21 , a pulsed combustion wave rotor  220 , a turbine  23 , a nozzle  32  and an output power shaft  26 . The propulsion system  200  is substantially similar to the propulsion system  20  and like features numbers will be utilized to describe like elements. More specifically, the propulsion system  200  is substantially similar to the propulsion system  20  and the details relating to system  200  will focus on the alternative pulsed detonation engine wave rotor  220 . 
     With reference to FIGS. 6-8, further aspects of the propulsion system  200  will be described. As discussed previously, a substantial portion of the propulsion system  200  is identical to the propulsion system  20  and this information will not be repeated as it has been set forth previously. A pressurized working fluid passes through the compressor outlet  25  and is delivered to a first wave rotor inlet port  221 . A second wave rotor inlet port  222  is referred to as a buffer gas inlet port, and is located adjacent to and sequentially prior to the first wave rotor inlet port  221 . Wave rotor inlet ports  221  and  222  form 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 device  220 . 
     Wave rotor device  220  has an outlet port sequence that includes an outlet port  223  and a buffer gas outlet port  224 . In one embodiment of propulsion system  200  the outlet port  223  is defined as a to-turbine outlet port  223 . The to-turbine outlet port  223  of propulsion system  200  allows the combusted gases to exit the wave rotor device  220  and pass to the turbine  223 . Compressed buffer gas exits the buffer gas outlet port  224  and is reintroduced into the rotor passageways  41  through the second wave rotor inlet port  222 . In one embodiment, the buffer gas outlet port  224  and the second wave rotor inlet port  222  are 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 passageways  41  and causes the pressure in region  225  to remain at an elevated level. The relatively high energy flow of combusted gases from the to-turbine port  223  is maintained in region  226  by the reintroduction of the high pressure buffer gas entering through the second wave rotor inlet port  222 . The flow of the high pressure buffer gas from buffer gas outlet port  224  to the second wave rotor inlet port  222  is illustrated schematically by arrows C in FIG.  8 . 
     Wave rotor device  220  has an outlet port sequence that includes an outlet port  223  and a buffer gas outlet port  224 . In one embodiment of propulsion system  200  the outlet port  223  is defined as a to-turbine outlet port  223 . The to-turbine outlet port  223  of propulsion system  200  allows the combusted gases to exit the wave rotor device  220  and pass to the turbine  223 . Compressed buffer gas exits the buffer gas outlet port  224  and is reintroduced into the rotor passageways  41  through the second wave rotor inlet port  222 . In one embodiment, the buffer gas outlet port  224  and the second wave rotor inlet port  222  are 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. With reference to FIG. 6 a , there is illustrated an auxiliary reservoir  500  for receiving a quantity of the high pressure buffer gas. This reintroduced buffer gas does work on the remaining combusted gases within the rotor passageways  41  and causes the pressure in region  225  to remain at an elevated level. The relatively high energy flow of combusted gases from the to-turbine port  223  is maintained in region  226  by the reintroduction of the high pressure buffer gas entering through the second wave rotor inlet port  222 . The flow of the high pressure buffer gas from buffer gas outlet port  224  to the second wave rotor inlet port  222  is illustrated schematically by arrows C in FIG.  8 . 
     Referring to FIG. 7, there is illustrated a partially exploded view of one embodiment of the wave rotor device  220 . Wave rotor  220  comprises a cylindrical rotor  40  that is rotatable about a centerline X and passes a plurality of fluid passageways  41  by a plurality of ports  221 ,  222  and  224  formed in end plate  225  and outlet ports  223  formed in end plate  226 . In one embodiment, the end plates  225  and  226  are coupled to stationery ducted passages between the compressor  21  and the turbine  23 . The plurality of fluid passageways  41  is positioned about the circumference of the wave rotor device  220 . 
     In one form a conventional rotational device accomplishes the rotation of rotor  40 . In another form the gas turbine  23  can be used as the means to cause rotation of the wave rotor  40 . 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 duct  221   a  so as to allow the incoming fluid flow to impart angular momentum to the rotor  40 . In yet another form, the free-wheeling design is contemplated to be driven by angling of the inlet duct  222   a  so as to allow the incoming fluid flow to impart angular momentum to the rotor. Further, it is contemplated that the inlet ducts  222   a  and  221   a  can 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 rotor  40  is fixedly coupled to a shaft  48  that 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 passageways  41  extend along the length of the wave rotor device  220  parallel to the center line X and are formed between the outer wall member  49  and an inner wall member  50 . The plurality of passageways  41  define a peripheral annulus  51  wherein adjacent passageways share a common wall member  52  that connects between the outer wall member  49  and the inner wall  50  so 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 plates  225  and  226  are fixedly positioned very closely adjacent to rotor  40  so as to control the passage of working fluid into and out of the plurality of passageways  41  as the rotor  40  rotates. End plates  225  and  226  are designed to be disposed in a sealing arrangement with the rotor  40  in order to minimize the leakage of fluid between the plurality of passageways  41  and 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 to FIG. 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 of FIG. 8 has: the high pressure energy transfer gas outlet port  224 , the high pressure energy transfer gas inlet port  222  and the from-compressor inlet port  221  on the same end of the device; and the to-turbine outlet port  223  located 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 port  222  is prior to and adjacent the from-compressor inlet port  221 . It can be observed that upon the rotation of rotor  40  each of the plurality of passageways  41  are sequentially brought in registration with the inlet ports  221  and  222  and the outlet ports  223  and  224 , and the path of a typical charge of fluid is along the respective passageways  41 . The wave diagram for the purpose of description may be started at any point, however, for convenience, the description is started at  227  wherein 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 portion  227  of the wave rotor engine receives a supply of low-pressure working fluid from compressor  21 . The working fluid enters passageways  41  upon the from-compressor inlet port  221  being aligned with the respective passageways  41 . In one embodiment fuel is introduced into the region  225  by: stationery continuously operated spray nozzles (liquid)  227  or supply tubes (gas)  227  located within the duct  222   a  leading to the high pressure energy transfer gas inlet port  222 ; or, into region  228  by intermittently actuated spray nozzles (liquid)  227 ′ or supply tubes (gas)  227 ′ located within the rotor; or, into region  228  by spray nozzles (liquid)  227 ″ or supply tubes (gas)  227 ″ located within the rotor end plate  226 . Region  228  exists 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 rotor  40  adjacent the region  228  and a detonation wave  232  travels through the fuel-working-fluid air mixture within the region  228  toward the opposite end of the rotor containing a working-fluid-without-fuel region  230 . In one form of the present invention, the detonation is initiated by a detonation initiator  233 , 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 wave  232  travels along the length of the passageway and ceases with the absence of fuel at the gas interface  234 . Thereafter, a pressure wave  235  travels into the working-fluid-without-fuel region  230  of the passageway and compresses this working fluid to define a high-pressure buffer/energy transfer gas within region  236 . 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 region  236  exits the wave rotor device  220  through the buffer gas outlet port  224 . The combusted gases within the region  237  exits the wave rotor through the to-turbine outlet port  223 . 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 port  223 , the expansion process continues within the passageways  41  of 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 region  238  at the end of the rotor opposite the to-turbine outlet port  223  declines. The wave rotor inlet port  222  opens and allows the flow of the high pressure buffer/energy transfer working fluid into the rotor at region  225  and causes the recompression of a portion of the combusted gases within the rotor. The admission of gas via port  222  can 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 port  222 , which allows the introduction of the high pressure buffer/energy transfer gas, closes before the to-turbine outlet port  223  is closed. The closing of the wave rotor inlet port  222  causes an expansion process to occur within the high pressure buffer/energy transfer air within region  240  and lowers the pressure of the gas and creates a region  241 . 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 port  223  is closed as the expansion in region  240  reaches the exit end of the passageway. In one form of the present invention as illustrated in region  242 , a portion of the high pressure buffer/energy transfer gas exits through the outlet port  223 . This exiting buffer/energy transfer gas functions to insulate the duct wall  223   a  from the hot combusted gas within region  226  of the duct  223   b . The pressure in region  241  has been lowered and the from-compressor inlet port  221  allows pre-compressed low pressure working fluid to enter the rotor passageways in the region  227  having the lowered pressure. The entering motion of the pre-compressed low-pressure working fluid through port  221  is stopped by the arrival of pressure wave  231  originating from the exit end of the rotor and traveling toward the inlet end. The pressure wave  231  originated from the closure of the to-turbine outlet port  223 . The design and construction of the wave rotor is such that the arrival of the pressure wave  231  corresponds with the closing of the from-compressor inlet port  221 . 
     With reference to FIG. 9, there is illustrated schematically an alternate embodiment of a propulsion system  300 . In one embodiment the propulsion system  300  includes a fluid inlet  31 , a pulsed combustion detonation engine wave rotor  220  and a nozzle  32 . The wave rotor device  220  is identical to the wave rotor described in propulsion system  200  and like feature numbers will be utilized to indicate like features. In one form propulsion system  30  is adapted to produce thrust without incorporation of conventional turbomachinery components. The working fluid passing through the inlet  31  is conveyed through the first wave rotor inlet port  221  and into the wave rotor  220 . High pressure buffer gas is discharged through wave rotor outlet port  224  and passes back into the wave rotor device through wave rotor inlet port  222 . The relatively high energy flow of combusted gases flows out of the outlet port  223  and exits through nozzle  32  to produce motive power. 
     With reference to FIG. 10, there is illustrated schematically an alternate embodiment of a rocket type propulsion system  400 . In one embodiment, the propulsion system  400  includes an oxidizer and working gas storage tank  101 , a pulsed combustion detonation engine wave rotor  220  and a nozzle  32 . The wave rotor device  220  is identical to the wave rotor described in propulsion system  200  and like feature numbers will be utilized to indicate like features. In one form propulsion system  400  is adapted to produce thrust without incorporation of conventional turbomachinery components. The first wave rotor inlet port  221  is in fluid communication with the oxidizer and working gas storage tank  101  and receives a quantity of working fluid therefrom. High pressure buffer gas is discharged through the wave rotor outlet port  224  and passes back into the wave rotor device through wave rotor inlet port  222 . The relatively high energy flow of combusted gases pass out of the outlet port  223  and exits nozzle  32  to produce motive power. 
     A few of the additional alternate embodiments (not illustrated) contemplated herein will be described in comparison to the embodiment of FIG.  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 rotor  220  and adapted to supply a compressed fluid to inlet  221 . The turbomachine type compressor is driven by shaft power derived from the wave rotor  220 . A second alternate embodiment includes a conventional turbine placed downstream of the wave rotor  220  and adapted to be supplied with the gas exiting port  223 . 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 to FIG. 11, there is illustrated a partially exploded view of one embodiment of the wave rotor device  320 . The description of a wave rotor device having rotatable inlet and outlet ports is not limited to the embodiment of device  320 , and is applicable to other wave rotors including but not limited to the embodiments associated with FIGS. 1-5 and  9 - 10 . The utilization of like feature numbers will be utilized to describe like features. In one form wave rotor device  320  comprises a stationary portion  340  centered about a centerline X and having a plurality of fluid passageways  41  positioned between two rotatable endplates  325  and  326 . The endplates  325  and  326  are rotated to pass by the fluid passageways a plurality of inlet ports  221  and  222  and outlet ports  224  and  223 . Endplates  325  and  326  are connected to shaft  348  and form a rotatable endplate assembly. In one embodiment a member  349  mechanically fixes the endplates  325  and  326  to the shaft  348 . Further, the endplate assembly is rotatably supported by bearings, which are not illustrated. In one embodiment the endplates  325  and  326  are fitted adjacent to stationary ducted passages between the compressor  21  and turbine  23 . 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 portion  340  defines a ring and the plurality of fluid passageways  41  are 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 endplates  325  and  326 . In another form the gas turbine  23  can be used as the means to cause rotation of the endplates  325  and  326 . 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 port  224  and 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 port  223 . In another form the freewheeling design is contemplated to be driven by a portion of the momentum energy of the inlet stream of port  222 . In yet another form the freewheeling design is contemplated to be driven by a portion of the momentum energy of the inlet stream of port  221 . 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 portion  340  may 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 endplates  325  and  326  are fixedly coupled to the shaft  348  that 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 endplates  325  and  326  are fixedly positioned very closely adjacent the stationary portion  340  so as to control the passage of working fluid into and out of the plurality of passageways  41  as the endplates rotate. Endplates  325  and  326  are designed to be disposed in a sealing arrangement with the stationary portion  340  in order to minimize the leakage of fluid between the plurality of passageways  41  and 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. 
     All publications, patents, and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference and set forth in its entirety herein. 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, equivalents, and modifications that come within the spirit of the invention are desired to be protected.

Technology Classification (CPC): 5