Rotor assembly with cooling channels separated by ribs for a rotary engine

A rotor housing for an aircraft rotary engine includes a side housing body and a rail. The side housing body extends along an axis between and to an inner side and an outer side. The side housing body forms a fluid cooling passage and a plurality of ribs. The fluid cooling passage extends about the axis at the inner side. The plurality of ribs are coincident with and extend into the fluid cooling passage. The plurality of ribs are distributed about the fluid cooling passage as an array of ribs. The rail is disposed at the plurality of ribs. The rail extends about the fluid cooling passage. The side housing body and the rail form a plurality of fluid cooling channels connected in fluid communication with the fluid cooling passage.

TECHNICAL FIELD

This disclosure relates generally to rotary engines for aircraft and, more particularly, to a rotor housing for a rotary engine.

BACKGROUND OF THE ART

A rotary engine for an aircraft may be configured, for example, as a Wankel engine. The rotary engine includes one or more rotors configured to eccentrically rotate within a rotor housing. Various rotor housing configurations are known for rotary engines. While these known rotor housings have various advantages, there is still room in the art for improvement.

SUMMARY

It should be understood that any or all of the features or embodiments described herein can be used or combined in any combination with each and every other feature or embodiment described herein unless expressly noted otherwise.

According to an aspect of the present disclosure, a rotor housing for an aircraft rotary engine includes a side housing body and a rail. The side housing body extends along an axis between and to an inner side and an outer side. The side housing body forms a fluid cooling passage and a plurality of ribs. The fluid cooling passage extends about the axis at the inner side. The plurality of ribs are coincident with and extend into the fluid cooling passage. The plurality of ribs are distributed about the fluid cooling passage as an array of ribs. The rail is disposed at the plurality of ribs. The rail extends about the fluid cooling passage. The side housing body and the rail form a plurality of fluid cooling channels connected in fluid communication with the fluid cooling passage.

In any of the aspects or embodiments described above and herein, each fluid cooling channel of the plurality of fluid cooling channels may include a channel inlet and the channel inlet may be disposed at the fluid cooling passage.

In any of the aspects or embodiments described above and herein, each fluid cooling channel of the plurality of fluid cooling channels may include a channel outlet and the channel outlet may be disposed at the inner side.

In any of the aspects or embodiments described above and herein, each fluid cooling channel of the plurality of fluid cooling channels may be formed by adjacent ribs of the plurality of ribs.

In any of the aspects or embodiments described above and herein, the side housing body may form an outer radial side, an inner radial side, and an outer axial side of the fluid cooling passage. The outer radial side and the inner radial side may extend between and to the inner side and the outer axial side.

In any of the aspects or embodiments described above and herein, each rib of the plurality of ribs may extend from the outer radial side into the fluid cooling passage.

In any of the aspects or embodiments described above and herein, the rail may include an axially-extending portion and a radially-extending portion. The axially-extending portion may extend from the radially-extending portion to the inner side.

In any of the aspects or embodiments described above and herein, the radially-extending portion may extend from the axially-extending portion to a distal end of each rib of the plurality of ribs.

According to another aspect of the present disclosure, a rotary engine assembly for an aircraft includes a rotatable engine shaft extending along a rotational axis, a rotor coupled to an eccentric portion of the rotatable engine shaft, and a rotor housing. The rotor housing surrounds and forms a rotor cavity for the rotor. The rotor housing includes a side housing body, a rail, and a side plate. The side housing body forms a fluid cooling passage and a plurality of ribs. The fluid cooling passage extending about the rotational axis. The plurality of ribs are coincident with and extend into the fluid cooling passage The rail is disposed at the plurality of ribs. The rail extends about the fluid cooling passage. The side plate includes an inner side, an outer side, and a perimeter edge. The perimeter edge is disposed at the rail. The inner side forms a portion of the rotor cavity.

In any of the aspects or embodiments described above and herein, the rotatable engine shaft may extend through the side housing body and the side plate along the rotational axis.

In any of the aspects or embodiments described above and herein, the rotor housing may further include a seal disposed between the rail and the side plate.

In any of the aspects or embodiments described above and herein, the outer side may further form the fluid cooling passage.

In any of the aspects or embodiments described above and herein, the side housing body and the rail may form a plurality of fluid cooling channels connected in fluid communication with the fluid cooling passage.

In any of the aspects or embodiments described above and herein, the side housing body and the rail may form a channel inlet and a channel outlet for each fluid cooling channel of the plurality of fluid cooling channels.

In any of the aspects or embodiments described above and herein, the rail may include an axially-extending portion and a radially-extending portion. The perimeter edge may be disposed at the axially-extending portion and the outer side may be disposed at the radially-extending portion.

According to another aspect of the present disclosure a rotor housing for an aircraft rotary engine includes a rotor housing body, a side housing body, a rail, and a side plate. The rotor housing body is disposed about an axis. The rotor housing body extends between and to a first axial end and a second axial end. The side housing body is disposed at the first axial end. The side housing body forms a first fluid cooling passage and a plurality of ribs. The first fluid cooling passage extends about the axis. The plurality of ribs are coincident with and extend into the first fluid cooling passage. The plurality of ribs are distributed about the fluid cooling passage as an array of ribs. The rail is disposed at the plurality of ribs. The rail extends about the fluid cooling passage. The side plate is positioned between and contacting the rail and the rotor housing body.

In any of the aspects or embodiments described above and herein, the rotor housing body may form a second fluid cooling passage connected in fluid communication with the first fluid cooling passage.

In any of the aspects or embodiments described above and herein, the side housing body and the rail may form a plurality of fluid cooling channels connected in fluid communication with the first fluid cooling passage.

In any of the aspects or embodiments described above and herein, the plurality of fluid cooling channels may connect the second fluid cooling passage in fluid communication with the first fluid cooling passage.

In any of the aspects or embodiments described above and herein, each fluid cooling channel of the plurality of fluid cooling channels may be formed by adjacent ribs of the plurality of ribs.

DETAILED DESCRIPTION

FIG.1illustrates an engine assembly10. The engine assembly10may form a portion of a propulsion system for an aircraft. Briefly, the aircraft may be a fixed-wing aircraft (e.g., an airplane), a rotary-wing aircraft (e.g., a helicopter), a tilt-rotor aircraft, a tilt-wing aircraft, or another aerial vehicle. Moreover, the aircraft may be a manned aerial vehicle or an unmanned aerial vehicle (UAV, e.g., a drone). The engine assembly10may also form a portion of an auxiliary power unit (APU) or onboard generator for an aircraft. However, the present disclosure is not limited to any particular application of the engine assembly10. The engine assembly10ofFIG.1includes an engine12, a rotational load14, a compressor section16, a turbine section18, a rotational assembly20, and an engine control system22.

The engine12ofFIG.1is configured as a rotary intermittent internal combustion engine, which intermittent internal combustion engine includes a rotor assembly24and an engine shaft26. As will be described in further detail, the rotor assembly24may be configured, for example, as a Wankel engine in which an eccentric rotor configuration is used to convert fluid pressure into rotational motion.

The rotor assembly24is coupled to the engine shaft26and configured to drive the engine shaft26for rotation about a rotational axis28. The engine shaft26is coupled to the rotational load14such that rotation of the engine shaft26by the rotor assembly24drives rotation of the rotational load14. The engine shaft26may be coupled to the rotational load14by a speed-reducing gear assembly30of the engine12. The speed-reducing gear assembly30may be configured to effect rotation of the rotational load14at a reduced rotational speed relative to the engine shaft26. The rotational load14ofFIG.1is configured as a propeller. Rotation of the propeller by the engine12may generate thrust for an aircraft which includes the engine assembly10. The engine assembly10of the present disclosure may additionally or alternatively be configured to drive other rotational loads, such as, but not limited to, an electrical generator(s), a rotational accessory load, a rotor mast, a compressor, or any other suitable rotational load configuration.

The rotational assembly20ofFIG.1includes a shaft32, a bladed compressor rotor34of the compressor section16, and a bladed turbine rotor36of the turbine section18. The shaft32interconnects the bladed compressor rotor34and the bladed turbine rotor36. The shaft32, the bladed compressor rotor34, and the bladed turbine rotor36are mounted to rotation about a rotational axis38. Ambient air is received by the compressor section16. The air is compressed by rotation of the bladed compressor rotor34and directed to an air intake of the engine12. Combustion exhaust gases from the engine12are directed to the turbine section18causing the bladed turbine rotor36to rotate and rotationally drive the rotational assembly20. The engine shaft26and the rotational assembly20may be rotatably coupled by a gearbox40of the engine assembly10, thereby allowing the engine12and/or the bladed turbine rotor36to rotationally drive the bladed compressor rotor34. The present disclosure, however, is not limited to the particular engine12and rotational assembly20configuration ofFIG.1.

Referring toFIGS.2and3, the rotor assembly24includes a rotor housing46, one or more rotors48, and a fuel system50.FIG.2illustrates a side, cutaway view of the rotor assembly24.FIG.3illustrates a cutaway view of the rotor assembly24at an axial position relative to the rotational axis28. The rotor assembly24ofFIG.2includes a single rotor48, however, the present disclosure is not limited to any particular number of rotors48for the rotor assembly24. For example, the rotor assembly24may alternatively include a plurality of rotors48.

The rotor housing46ofFIGS.2and3includes a rotor housing body52and opposing side housing assemblies54. The rotor housing body52may extend (e.g., axially extend) between and to a first end56of the rotor housing body52and a second end58of the rotor housing body52. The rotor housing body52may extend about (e.g., completely around) the rotational axis28. The side housing assemblies54may be mounted to or otherwise disposed at (e.g., on, adjacent, or proximate) the first end56and the second end58. For example, the side housing assemblies54may include a first side housing assembly54A disposed at the first end56and a second side housing assembly54B disposed at the second end58. Each of the first side housing assembly54A and the second side housing assembly54B may include a respective shaft aperture (not shown) through which the engine shaft26may extend along the rotational axis28. The rotor housing body52and the side housing assemblies54form a rotor cavity60of the rotor assembly24.

FIG.3illustrates the rotor housing body52surrounding and forming the rotor cavity60. The rotor cavity60ofFIG.3is formed with two lobes, which two lobes may collectively be configured with an epitrochoid shape. The rotor housing body52further forms an intake port62, an exhaust port64, and one or more fuel system passages66. The intake port62is in fluid communication with the rotor cavity60. The intake port62is configured to direct compressed air to the rotor cavity60, for example, from the compressor section16(seeFIG.1). The exhaust port64is in fluid communication with the rotor cavity60. The exhaust port64is configured to direct combustion exhaust gas out of the rotor cavity60. For example, the exhaust port64may be configured to direct the combustion exhaust gas from the rotor cavity60to the turbine section18(seeFIG.1). The fuel system passages66provide access to the rotor cavity60for a spark plug or other ignition device and/or for one or more fuel injectors of a fuel system50.

The rotor48ofFIGS.2and3is coupled to an eccentric portion68of the engine shaft26. The rotor48is disposed within the rotor cavity60. The rotor48is configured to rotate (e.g., in rotation direction R) with the eccentric portion68about a rotational axis70of the rotor48to perform orbital revolutions within the rotor cavity60. The rotational axis70may be offset from and parallel to the rotational axis28.

Briefly, the rotor48ofFIG.3includes three sides72and three apex seals74. The sides72of the rotor48form a generally triangular cross-sectional shape of the rotor48(e.g., along a plane extending perpendicular to the rotational axis70). The sides72may be configured with a convex curvature, which convex curvature faces away from the rotational axis70. Each side72intersects each other side72at an apex portion76of the rotor48. Each apex seal74is disposed at a respective one of the apex portions76. Each apex portion76may include a slot, channel, or other attachment configuration for retaining a respective apex seal74. Each apex seal74extends outward (e.g., radially outward) from each respective apex portion76toward the rotor housing body52. The apex seals74may be configured as spring-loaded seals, which spring-loaded seals may be biased toward an outer radial position. Each apex seal74is configured to sealingly contact the rotor housing body52, thereby forming three separate working chambers78of variable volume between the rotor48and the rotor housing body52.

In operation of the engine12, the fuel system50is configured to effect rotation of the rotor48by directing a fuel into the rotor cavity60and igniting the fuel in a defined sequence. During each orbital revolution of the rotor48, each working chamber78varies in volume and moves about the rotor cavity60to undergo four phases of intake, compression, expansion, and exhaust.

Referring toFIGS.4-7, the rotor housing46will be described in greater detail. In particular, the side housing assemblies54(e.g., each of the side housing assemblies54A,54B) includes a side plate80, a side housing body82, and a rail84.FIG.4illustrates a perspective view of the side plate80.FIG.5illustrates a side view of the side housing body82and the rail84.FIG.6illustrates a perspective view of the side housing body82and the rail84.FIG.7illustrates a cutaway view of the assembled rotor housing46including the rotor housing body52and the components80,82,84of one of the side housing assemblies54.

The side plate80extends (e.g., axially extends relative to the rotational axis28) between and to an inner side86of the side plate80and an outer side88of the side plate80. The side plate80includes a perimeter edge90circumscribing the inner side86and the outer side88. The side plate80(e.g., the perimeter edge90) may have an epitrochoid shape similar to that of the rotor cavity60. As shown inFIG.7, for example, the inner side86forms a portion of the rotor cavity60. The side plate80forms a shaft aperture92for the engine shaft26(seeFIGS.1-3). The shaft aperture92extends through the side plate80from the inner side86to the outer side88. The side plate80includes a side plate material. The side plate material may form all or a substantial portion of the side plate80. The side plate material may be metal such as alloy steel, aluminum, or the like. The side plate material may alternatively be a composite material such as, but not limited to, silicon carbide (SIC). The present disclosure, however, is not limited to the use of a particular material or combination of materials for the side plate material.

The side housing body82extends (e.g., axially extends relative to the rotational axis28) between and to an inner side94of the side housing body82and an outer side96of the side housing body82. The side housing body82includes a perimeter edge98circumscribing the inner side94. The inner side includes a first side portion100and a second side portion102. The first side portion100is disposed at (e.g., on, adjacent, or proximate) the perimeter edge98. The second side portion102is disposed inward (e.g., radially inward) of the first side portion100. The second side portion102is recessed (e.g., axially spaced) relative to the first side portion100to accommodate the side plate80(seeFIG.7). The second side portion102is positioned in contact with or is otherwise disposed at (e.g., on, adjacent, or proximate) the side plate80(e.g., the outer side88). The side housing body82forms a shaft aperture104for the engine shaft26(seeFIGS.1-3). The shaft aperture104extends through the side housing body82from the inner side94(e.g., the second side portion102) to the outer side96. The side housing body82includes a side housing body material. The side housing body material may form all or a substantial portion of the side housing body82. The side housing body material may be different than the side plate material. For example, the side housing body material may be a softer material relative to the side plate material (i.e., the side plate material may be harder than the side housing body material). The side housing body material may be metal such as, but not limited to aluminum. The present disclosure, however, is not limited to the use of a particular material or combination of materials for the side housing body material.

The side housing body82forms a fluid cooling passage106on the inner side94. The fluid cooling passage106is disposed between and separates the first side portion100and the second side portion102. The fluid cooling passage106extends about (e.g., completely around) the rotational axis38. The fluid cooling passage106may have an epitrochoid shape similar to that of the side plate80. The fluid cooling passage106is formed by a portion of the side housing body82recessed from the inner side94(e.g., the first side portion100and the second side portion102). For example, the fluid cooling passage106ofFIGS.5-7includes an outer radial side108, an inner radial side110, and an outer axial side112formed by the side housing body82. The outer radial side108, the inner radial side110, and the outer axial side112extend about (e.g., completely around) the rotational axis38. The outer radial side108and the inner radial side110extend (e.g., axially extend) between the inner side94and the outer axial side112. For example, the outer radial side108ofFIGS.5-7extends between and to the first side portion100and the outer axial side112and the inner radial side110ofFIGS.5-7extends between and to the second side portion102and the outer axial side112. The fluid cooling passage106is further formed by the outer side88(seeFIG.7). The fluid cooling passage106may be connected in fluid communication with a fluid inlet and a fluid outlet (not shown) for the rotor housing46. For example, the first side housing assembly54A (seeFIG.2) may include or otherwise form a fluid inlet for the fluid cooling passage106and the second side housing assembly54B (seeFIG.2) may include or otherwise form a fluid outlet for the fluid cooling passage106. A fluid cooling system (not shown) may direct a cooling fluid through the rotor housing46(e.g., through the first side housing assembly54A, the rotor housing body52and the second side housing assembly54B) from the fluid inlet to the fluid outlet. The present disclosure, however, is not limited to any particular suitable configuration of the fluid inlet, the fluid outlet, or the fluid supply system, which suitable configuration may be selected or determined by a person of ordinary skill in the art in accordance with and as informed by one or more aspects of the present disclosure.

The side housing body82further forms a plurality of ribs114coincident with the fluid cooling passage106. Each of the ribs114extends (e.g., radially extends) into the fluid cooling passage106from the outer radial side108to a distal end116of the respective rib114. Each of the ribs114extends from the outer radial side108toward the inner radial side110with the distal end116spaced (e.g., radially spaced) from the inner radial side110. Each of the ribs114extends along the outer axial side112. Each of the ribs114may extend along and form a portion of the inner side94(e.g., the first side portion100). The ribs114may extend about (e.g., completely around) the fluid cooling passage106. For example, the ribs114may be distributed about the fluid cooling passage106as an array (e.g., an epitrochoid array) of the ribs114. Each rib114may be spaced (e.g., circumferentially spaced) from each adjacent rib114to form a fluid cooling channel118(collectively a plurality of fluid cooling channels118) between the adjacent ribs114. The side housing body82and its plurality of ribs114form a channel inlet120and a channel outlet122of each fluid cooling channel118. The channel inlet120may be disposed at (e.g., on, adjacent, or proximate) the distal ends116of adjacent ribs114. The channel inlet120may be disposed coincident with the fluid cooling passage106. The channel outlet122may be disposed at (e.g., on, adjacent, or proximate) the inner side94(e.g., the first side portion100). Each fluid cooling channel118may be disposed in fluid communication with the fluid cooling passage106to direct a fluid (e.g., water) from the fluid cooling passage106through each fluid cooling channel118from the channel inlet120to the channel outlet122.

The rail84extends about (e.g., completely around) the rotational axis38coincident with the fluid cooling passage106. The rail84may be mounted to, formed with, or otherwise disposed at (e.g., on, adjacent, or proximate) each of the plurality of ribs114. The rail84forms a portion of each of the fluid cooling channels118. The rail84includes an axially-extending portion124and a radially-extending portion126. Each of the axially-extending portion124and the radially-extending portion126extend about (e.g., completely around) the rotational axis38. The axially-extending portion124intersects the radially-extending portion126at a rail interface128. The rail interface128may form an orthogonal or substantially orthogonal intersection of the axially-extending portion124and the radially-extending portion126. The axially-extending portion124extends (e.g., axially extends) from the rail interface128to an axial end130at (e.g., on, adjacent, or proximate) the inner side86(e.g., the first side portion100). In other words, the axially-extending portion124may extend from the radially-extending portion126to the axial end130. Accordingly, the radially-extending portion126is recessed (e.g., axially spaced) relative to the first side portion100to accommodate the side plate80(seeFIG.7). The axial end130may form a portion of the channel outlet122for each fluid cooling channel118. The radially-extending portion126extends (e.g., radially extends) from the rail interface128to a radial end132at (e.g., on, adjacent, or proximate) the distal end116for each of the plurality of ribs114. In other words, the radially-extending portion126may extend from the axially-extending portion124to the radial end132. The radial end132may form a portion of the channel inlet120for each fluid cooling channel118.

Referring toFIG.7, the rotor housing body52and the components80,82,84of one of the side housing assemblies54are shown. The side plate80is disposed with the outer side88at (e.g., on, adjacent, or proximate) the radially-extending portion126, the perimeter edge90at (e.g., on, adjacent, or proximate) the axially-extending portion124, and the inner side86at (e.g., on, adjacent, or proximate) the rotor housing body52. Fluid (e.g., water)134is directed through the fluid cooling passage106and the fluid cooling channels118to facilitate cooling of the side plate80and the side housing body82. The rotor housing body52may form a fluid cooling passage136connected in fluid communication with the fluid cooling channels118(e.g., the channel outlets122). Accordingly, the fluid134may further facilitate cooling of the rotor housing body52.

The rotor housing46may include one or more seals (e.g., annular seals, O-rings, etc.) between the side plate80and the rail84and/or between the side plate80and the rotor housing body52. For example, the rotor housing46may include a seal138between the outer side88and the radially-extending portion126, a seal140between the perimeter edge90and the axially-extending portion124, and/or a seal142between the inner side86and the rotor housing body52. The present disclosure, however, is not limited to the particular configuration of the seals138,140,142illustrated inFIG.7. The rail84provides a continuous support surface of the side plate80about the epitrochoid rotor cavity60while facilitating cooling fluid134flow through the rotor housing46. The rail84facilitates improved sealing between the fluid cooling passage106and the rotor cavity60by providing a continuous sealing surface, for example, for the seals138and/or140ofFIG.7. The continuous sealing surface formed by the rail84for the seals138and/or140allows the seals138and/or140to be positioned further from the hot combustion gases of the rotor cavity60(e.g., in comparison to the seal142) while still allowing the seals138and/or140to form a continuous seal (e.g., completely around the side plate80) between the side plate80and the side housing body82. Accordingly, the continuous sealing surface formed by the rail84may facilitate a reduction in the likelihood of seal138,140degradation and/or failure due to exposure to hot combustion gases. The continuous support and sealing surface formed by the rail84may additionally facilitate a reduction in wear which may be caused by movement of the side plate80against a relatively softer side housing body82(e.g., wear which may be caused by a relatively harder side plate80material to a relatively softer side housing body82material).

While various inventive aspects, concepts and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the disclosures—such as alternative materials, structures, configurations, methods, devices, and components, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein. For example, in the exemplary embodiments described above within the Detailed Description portion of the present specification, elements may be described as individual units and shown as independent of one another to facilitate the description. In alternative embodiments, such elements may be configured as combined elements.