A rotary detonation engine extracting power from a bladeless extraction shaft

Abstract

The application discloses a rotary detonation engine without blade extraction shaft power, comprising: an annular air inlet channel, an engine disc-shaped base, an outer ring wall surface, an inner ring hollow barrel wall surface, an igniter and a limiting streamline support. By orderly assembling each component and respectively connecting high-pressure air and fuel at the interface of the engine head and the outer wall surface, the igniter is used for single tangential ignition to generate a continuously circumferentially propagating detonation wave in the engine ring cavity. The high-pressure area behind the detonation wave acts on part of the non-circular inner ring hollow barrel wall surface to generate a tangential torque, so that the shaft connected with the inner ring wall surface rotates to output shaft power. The application does not have the traditional turbine blade structure, so that the viscosity and shock wave loss of the rotary detonation engine in the axial exhaust are reduced, the rotary detonation engine has the advantages of circumferential mechanical energy output while generating axial exhaust thrust, the obtained shaft power can be used for power generation, driving turboprop and fan and the like of the airborne equipment of a fighter, and the applicability of the rotary detonation engine under the low-speed flight condition is improved.

Description

Technical Field

[0001] This invention belongs to the field of rotary detonation engine design and manufacturing, specifically relating to a bladeless rotary detonation engine for extracting shaft power. Background Technology

[0002] Rotary detonation engines, as a new generation of aero-propulsion systems, possess advantages such as simple and compact structure, rapid heat release from the engine combustion chamber, high thermal cycle efficiency, and low entropy increase. Compared to traditional isobaric combustion, the detonation combustion process is similar to isochoric combustion. After the combustible mixture passes through the detonation wave, the pressure and temperature of the airflow increase significantly, resulting in higher power output and higher thermal efficiency. Traditional rotary detonation engines have a concentric annular cavity structure. The detonation wave propagates circumferentially along the cavity, inducing shock waves and shear layers at the three wave points, while the main exhaust flows axially. However, due to the spatial non-uniformity of the internal flow field structure of the rotary detonation engine, periodic lateral forces are generated on the inner and outer annular walls, causing unnecessary vibration problems. Simultaneously, the waveback regions of the circumferentially rotating detonation wave and shock wave impose high-frequency thermal loads on the engine walls, reducing the safety and reliability of the rotary detonation engine. To address the high-frequency vibration and thermal load problems of traditional rotary detonation engines, it is necessary to extract power from the engine and reduce the impact of non-uniform forces and thermal ablation.

[0003] Currently, rotating detonation engines are primarily used for flights at Mach numbers above 2.5, and are boosted by ramjet compressors. To enable rotating detonation engines to operate normally at Mach numbers below 2.5, additional shaft power is required to drive the booster equipment, such as axial compressors, centrifugal compressors, or electric superchargers. This ensures stable air intake into the combustion chamber, enabling the application of rotating detonation engines in low-speed aircraft such as helicopters, tiltrotor aircraft, and turboprop aircraft.

[0004] Therefore, this patent invention discloses a bladeless rotary detonation engine for extracting shaft power. The engine's inner ring wall is used as a rotating component around the shaft. The spatial non-uniformity of the rotary detonation wave and oblique shock wave generates a tangential torque, which outputs power through the shaft. This reduces engine vibration and thermal load to a certain extent and effectively extracts mechanical energy. Since there are no turbine blades intruding into the mains on the inner ring wall, it achieves both efficient exhaust of the rotary detonation engine and reduced exhaust temperature, thus improving the engine's stealth capabilities. Summary of the Invention

[0005] The purpose of this invention is to provide a bladeless rotating detonation engine that extracts shaft power. By using the inner ring wall of a non-circular cross-section of the engine as a rotating component around an axis, the non-uniformity of the rotating detonation wave and oblique shock wave in space generates a tangential torque, thereby outputting shaft power. This allows the rotating detonation engine to operate stably under low-speed flight conditions. The extracted shaft power can drive a generator, axial compressor, or centrifugal compressor to power airborne equipment or generate a stable constant-pressure air source. Since part of the internal energy of the high-temperature combustion gas is converted into mechanical energy through the inner ring wall of the non-circular cross-section, the vibration and thermal load problems of the rotating detonation engine are reduced. Furthermore, it can balance the efficient exhaust and stealth performance of the rotating detonation engine, making it a potential primary power source for helicopters, tiltrotor aircraft, and turboprop aircraft.

[0006] Technical solution: To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0007] A bladeless rotary detonation engine for extracting shaft power includes an inner ring cylinder. The right side of the inner ring cylinder is bolted to a first connecting shaft, which is bearing-connected to an engine disc-shaped base. An intake section is bolted to one side of the engine disc-shaped base. The left side of the inner ring cylinder is bolted to a second connecting shaft, which is bearing-connected to a limiting streamlined bracket. The limiting streamlined bracket is bolted to one end of an outer ring wall, and the other end of the outer ring wall is bolted to the engine disc-shaped base. An igniter is also connected to the outer ring wall.

[0008] The inner ring empty barrel is spindle-shaped with a non-circular cross-section in the middle and circular cross-sections on both sides;

[0009] An inertia wheel is also bolted to the first connecting shaft;

[0010] A U-shaped groove is also welded to one side of the engine disc base and the outer ring wall;

[0011] One side of the limiting streamlined bracket is also connected to a conical thin shell cover.

[0012] Preferably, the intake section includes an inner annular column wall and an outer annular column wall of the cavity. The inner and outer annular column walls are connected by a cavity cover plate. The first connecting shaft passes through the outer and inner annular column walls of the cavity in sequence and is connected to the inner annular cavity. Multiple intake channels are provided on the inner annular column wall, and the other side of the multiple intake channels is provided on the outer annular column wall. The intake section and the engine disc base are bolted together to form a cavity.

[0013] Preferably, the middle part of the inner ring empty barrel has a non-circular cross section, and the non-circular cross section is a gradually changing elliptical cylinder or a gradually changing petal shape.

[0014] Preferably, a circular thick plate is bolted to one side of the engine disc base, the circular thick plate is bearing connected to the first connecting shaft, the circular thick plate and the left side of the inner ring empty barrel are dynamically sealed, and a sealing groove is also provided on the contact surface of the engine disc base and the air intake section and the outer ring wall, and a rubber gasket is installed in the sealing groove.

[0015] Preferably, the outer ring wall is a hollow circular thin-walled part, and the two ends of the outer ring wall are provided with threaded holes for connecting the engine disc base and the limiting streamlined bracket, respectively. The outer ring wall is also drilled with threaded holes along the tangential direction, and the size of the threaded holes matches the external thread interface of the igniter.

[0016] Preferably, the outer ring wall has multiple circular, elliptical, or horseshoe-shaped fuel injection holes along its circumference. The angle between the fuel injection holes and the radial direction of the outer ring wall is ±15°, ±30°, or ±45°, where a positive sign indicates that the axial component of the fuel injection velocity is in the same direction as the mainstream, and a negative sign indicates that the axial component of the fuel injection velocity is opposite to the mainstream. The outer ring wall is also welded with a U-shaped groove, which has threaded holes for connecting fuel supply pipelines.

[0017] Preferably, the igniter includes a straight tube, an ignition chamber, and a spark plug. One end of the straight tube is threaded to the outer ring wall, and the other end is threaded to the ignition chamber. The ignition chamber includes an ignition chamber shell and an ignition chamber end cap. The ignition chamber shell and the ignition chamber end cap are bolted together, and the ignition chamber end cap is threaded to the spark plug.

[0018] Preferably, the other side of the limiting streamlined bracket is bolted with a flow guide rib, which is triangular, symmetrical double arc, or single-sided offset double arc; the flow guide rib has an annular support frame around it, which is bolted to the outer ring wall, and the shape of the conical thin shell is a quadratic curve.

[0019] Preferably, the width of the inertia wheel is not greater than the length of the first connecting shaft extending out of the outer annular column wall of the cavity, and the diameter of the inertia wheel does not exceed the maximum diameter of the rotating detonation engine; circular thin plates are connected to both sides of the inner annular empty barrel, and the first connecting shaft and the second connecting shaft are respectively connected to the circular thin plates by bearings; the dynamic seal between the inner annular empty barrel and the engine disc base and the limiting streamlined bracket adopts a grate sealing method.

[0020] Preferred,

[0021] When the middle section of the inner ring empty barrel is a gradually changing elliptical cylinder, the torsion angles of adjacent elliptical annular surfaces that are equidistant along the axis of the rotating detonation engine are equal.

[0022] When the middle section of the inner ring empty barrel is a gradient petal shape, the direction of the boundary line between adjacent gradient protrusions of the gradient petal shape is consistent with the direction of the oblique shock wave emitted by the three wave points of the rotating detonation wave under the single-wave mode. The adjacent gradient protrusions are perpendicular to the injection ring seam plane near the combustion chamber inlet of the rotating detonation engine.

[0023] The fuel injection holes are distributed along the axial direction in a single row or a double row. The double row distribution includes staggered distribution and parallel distribution. The staggered distribution includes equal-angle staggered angle and offset staggered angle.

[0024] Beneficial effects: The rotating detonation engine provided by this invention can convert the non-uniform high-pressure distribution of rotating detonation waves into tangential torque through the inner ring wall of a partially non-circular cross section, thereby driving the power of the rotating shaft and the output shaft. While ensuring efficient exhaust of the rotating detonation engine, it reduces exhaust temperature, improves engine stealth, and can serve as an alternative power source for helicopters, tiltrotor aircraft, and turboprop aircraft, reducing fuel consumption and increasing the flight radius of the aircraft. Attached Figure Description

[0025] Figure 1 This is a three-dimensional assembly isometric drawing of a bladeless rotary detonation engine for extracting shaft power according to the present invention.

[0026] Figure 2 This is a cross-sectional view of a bladeless rotary detonation engine for extracting shaft power according to the present invention.

[0027] Figure 3 (a) is a front view of a bladeless rotary detonation engine for extracting shaft power according to the present invention;

[0028] Figure 3 (b) is a rear view of a bladeless rotary detonation engine for extracting shaft power according to the present invention;

[0029] Figure 4 This is a side view of a bladeless rotary detonation engine for extracting shaft power according to the present invention.

[0030] Figure 5 Three-view drawing of the air intake section;

[0031] Figure 6 Three views of the engine disc-shaped base;

[0032] Figure 7 Three views of the outer annular wall of the fuel injection holes with equal angles;

[0033] Figure 8 Three views of the inner ring of the hollow barrel wall, which is a non-circular cross-section that can rotate about an axis;

[0034] Figure 9 Three-view diagram of the igniter;

[0035] Figure 10 Three-view diagram of the assembly consisting of a streamlined limiting bracket, an annular support frame, and a cone arranged at the engine outlet;

[0036] Figure 11 Here are the three views of the first connecting axis;

[0037] Figure 12 Here are the three views of the inertia wheel;

[0038] Figure 13 Three-dimensional and cross-sectional views of the shapes of the three types of guide ribs;

[0039] Figure 14 These are three-dimensional images of two typical configurations—gradient elliptical cylinder and gradient petal—in the middle section of the inner ring of a partially non-circular cross-section of an empty barrel, viewed from different bottom angles:

[0040] in Figure 14 (a) is a three-dimensional view of the gradually elliptical cylinder in the middle section of the empty barrel wall from the rear side. Figure 14 (b) is a three-dimensional view of the gradually elliptical cylinder in the middle section of the empty barrel wall from the front side. Figure 14 (c) is a three-dimensional view of the gradient petal-shaped section of the middle section of the empty barrel wall from a rear perspective. Figure 14 (d) is a three-dimensional view of the gradient petal-shaped middle section of the empty barrel wall from the front side;

[0041] Figure 15 The three-view drawing and the three-dimensional view of the ring support frame are shown.

[0042] Figure 16 This is a schematic diagram showing the position of the annular column wall inside the cavity;

[0043] Figure 17 This is a three-dimensional diagram of the three-point aerodynamic structure of a rotating detonation wave.

[0044] The above figure includes (1) intake section, (101) inner annular column wall of cavity, (1011) intake passage, (102) outer annular column wall of cavity, (103) cavity cover plate, (2) engine disc base, (3) outer annular wall, (4) inner annular barrel, (5) igniter, (6) limiting streamlined bracket, (7) first connecting shaft, (8) second connecting shaft, (9) inertia wheel, (10) ignition chamber, (11) ignition chamber end cover, (12) U-shaped groove, (13) conical thin shell cover, (14) guide rib, (15) annular connecting section, (16) circular thick plate. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Combination Figure 1 and Figure 2 As shown, this invention discloses a bladeless rotary detonation engine for extracting power. In order for the rotary detonation engine to operate normally at Mach numbers less than 2.5, additional shaft power is required to drive the supercharging equipment, such as an axial compressor, a centrifugal compressor, or an electric supercharger, so as to ensure stable air intake in the combustion chamber and realize the application of the rotary detonation engine in low-speed aircraft such as helicopters, tiltrotor aircraft, and turboprop aircraft.

[0047] However, traditional turbine-based shaft power extraction methods often introduce additional disturbances to the flow field, disrupting the three-wave point structure of the rotating detonation combustion chamber and generating back-propagating reflected shock waves. This causes distortion in the air-fuel mixture triangle region ahead of the rotating detonation wave, affecting the continuity and stability of thrust. To minimize the impact of the turbine on engine aerodynamic performance, this invention proposes a bladeless rotating detonation engine mechanism for shaft power extraction.

[0048] The most important component in the bladeless rotary detonation engine for extracting shaft power proposed in this invention is the partially non-circular cross-section inner ring cylinder 4, which can rotate around the shaft. Because this type of inner ring cylinder 4 is not entirely oriented towards the shaft center when subjected to asymmetric aerodynamic forces from the wall, spatially distributed lever arms generate torque, thereby driving the first connecting shaft 7 and the second connecting shaft 8 to rotate and output shaft power. Since the first connecting shaft 7 is also connected to an inertia wheel, the rotational speeds of the first connecting shaft 7 and the partially non-circular cross-section inner ring cylinder 4 can be maintained in a relatively stable state.

[0049] In the rotary detonation engine for extracting shaft power without blades proposed in this invention, the first connecting shaft 7, the second connecting shaft 8, and the partially non-circular cross-section inner annular cylinder 4 are moving parts, and the movable connection gap at the head of the combustion chamber is subject to scouring by high-pressure, high-temperature combustion gases. To prevent combustion gases from leaking from the movable connection gap, the end face of the partially non-circular cross-section inner annular cylinder 4 has multiple annular sealing grates. To reduce the probability of collision between the inner annular end face grates and the grates of the engine disc-shaped base 16, the connection method of the first connecting shaft 7, the second connecting shaft 8, the partially non-circular cross-section inner annular cylinder 4, and the bearing is an interference fit.

[0050] In this invention, a bladeless rotary detonation engine for extracting shaft power features a downstream limiting streamlined support 6 and a partially non-circular cross-section inner annular cylinder 4 that rotate relative to each other, leading to potential gas leakage through their movable connection gaps. To confine the high-temperature, high-pressure gas within a non-circular channel, two grate-like structures, formed by the outer ring surface of a bearing and the inner ring surface of the support 4, are incorporated between the end faces of the limiting streamlined support 6 and 4. Because the airflow pressure gradually decreases along the axial direction, it is unnecessary to further machine the annular grate structure onto the limiting streamlined support 6.

[0051] This invention proposes a bladeless rotary detonation engine for extracting shaft power, employing a radial fuel intake and axial air intake supply scheme. Fuel and air meet within an annular supersonic nozzle at the head of the rotary detonation combustion chamber, interfering with each other through supersonic jets, thus improving downstream mixing efficiency. The cold-flow mixed gas generates an initial detonation wave for ignition via an igniter 5 tangentially connected to the outer annular wall 3. The ignition chamber 10 attached to the igniter 5 is a four-way pipe; one end of its axial main pipe is threaded to connect to the detonation tube, and the other end is threaded to connect to the spark plug. Internal threads on both sides of the main pipe are used to connect to hydrogen and oxygen supply lines. In the ignition sequence, mainstream air is supplied first, followed by fuel gas, with the supply time adjusted according to the total engine operating time. After the cold-flow mixed flow field has been established for 3 seconds, hydrogen / oxygen gas is simultaneously supplied and ignited via the spark plug.

[0052] After a bladeless rotary detonation engine successfully starts, a stable rotating detonation wave is generated in the rotary detonation combustion chamber. The flow field structure of the rotating detonation wave includes a contact discontinuity between combusted and uncombustible gases, a detonation wave tilted towards the mainstream, an oblique shock wave emanating from the apex of the mixture triangle, and a shear layer. The pressure in the circumferential region behind the rotating detonation wave gradually decreases, generating a torque on the non-circular cross-section inner annular cylinder 4. After engine ignition, the rotational speeds of the partially non-circular cross-section inner annular cylinder 4 and the first connecting shaft 7 and second connecting shaft 8 gradually increase. After a certain period, the difference between the propagation speed of the detonation wave and the rotational speed of the inner annular cylinder approaches a constant value, at which point the bladeless rotary detonation engine reaches a stable operating state.

[0053] After the bladeless rotary detonation engine successfully starts, some of the mechanical energy is transmitted to the corresponding onboard equipment through the rotating non-circular cross-section inner ring cylinder 4 and the first connecting shaft 7 and the second connecting shaft 8, driving the compressor or generator to compress gas or generate electricity. The remaining mechanical energy is used to expand and accelerate the airflow through the downstream plug nozzle, generating a reaction force to propel the engine forward.

[0054] High-temperature and high-pressure gas flows through the downstream limiting streamlined bracket 6. The thin side of the limiting streamlined bracket 6 faces the incoming flow, which can effectively reduce fluid resistance and keep the exhaust velocity at a high level.

[0055] The second connecting shaft 8 inside the tapered thin shell cover 13 attached to the limiting streamlined bracket 6 at the engine outlet acts as a fulcrum on one side of the inner ring empty barrel 4, and the extended section of the shaft can effectively reduce the vibration of rotating parts caused by excessive counterweight deviation on both sides.

[0056] Engine shutdown can be achieved by reducing the fuel gas supply, which involves two main steps:

[0057] Step 1: Close the fuel supply valve, while maintaining a continuous gas supply.

[0058] Step 2: When the engine temperature drops to ambient temperature, close the main valve.

[0059] Depending on the required output shaft power, the elliptical gradient surface of the inner ring of the non-circular cross-section can be replaced with a gradient petal shape.

[0060] Based on the airtightness requirements of the bladeless rotary detonation engine for extracting shaft power, the rectangular annular sealing grates can be replaced with isosceles triangles, semicircles, and semi-ellipses.

[0061] Figure 17 This demonstrates the non-uniform distribution of flow field parameters in space. In the annular space enclosed by the inner and outer toroidal surfaces, the detonation wave propagates circumferentially. There is an inclined contact discontinuity on the wavefront. Oblique shock waves and shear layers are emitted from the upper apex of the detonation wave. The upper apex of the detonation wave is the three-wave point aerodynamic structure.

[0062] A bladeless rotary detonation engine for extracting shaft power includes the following main components:

[0063] The main component 1 is the intake section, which plays a role in stabilizing the high-pressure air source. The intake section 1 consists of an inner annular wall 101, an outer annular wall 102, and a cover plate 103, which are connected to the engine disc base 2 to form a cavity structure. The outer annular wall 102 of the intake section 1 has multiple air passage threaded hole interfaces evenly distributed circumferentially. The number of radial interfaces of the air passages and the circumferential gap of the engine combustion chamber inlet are determined by the air flow rate, the diameter of the radial threaded holes, and the air pressure. The end faces of the inner annular wall 101 and the outer annular wall 102 of the cavity are drilled with an equal number of bolt through holes. The bolts pass through the inner annular wall 101 and the outer annular wall 102 of the cavity in sequence to connect with the engine disc base 2.

[0064] The main component 2 is the engine disc base, which is responsible for the interference fit with the bearing, centering with the intake section 1, positioning with the outer annular cylindrical wall 102 of the cavity, static sealing with the intake section 1 and the outer annular cylindrical wall 102 of the cavity, and dynamic sealing with the end face of the inner annular barrel 4, which has a partial non-circular cross section. The engine disc base 2 has multiple annular steps, and the mating surfaces of the engine disc base 2, the intake section 1, and the outer annular cylindrical wall 102 of the cavity also have sealing grooves. Rubber gaskets are installed in the grooves to improve the airtightness of the upstream of the rotating detonation engine.

[0065] The main component 3 is the outer ring wall of the fuel injection holes distributed at equal angles, which is responsible for confining the rotating detonation wave within a limited space and for effectively mixing fuel and air. The outer ring wall 3 is a circular thin-walled component with corresponding threaded holes at both ends, which are used to connect the engine disc base 2 and the limiting streamlined bracket 6, respectively. The outer ring wall 3 also has threaded holes drilled tangentially, the size of which matches the external thread interface of the igniter 5. The axial position of the threaded hole connecting to the igniter 5 can be close to the head or the middle of the rotating detonation engine.

[0066] The main component 4 is a partially non-circular cross-section inner ring barrel that can rotate around an axis, and it is responsible for converting the non-uniformly distributed force of the rotating detonation wave into shaft power. The middle section of the partially non-circular cross-section inner ring barrel 4 has two typical configurations: a gradually changing elliptical cylinder or a gradually changing petal shape. The eccentricity of the gradually changing elliptical cylinder inner ring barrel 4 is set according to the output shaft power and the design speed, and the number of petals and the ratio of the protrusion height of the gradually changing petal shape inner ring barrel 4 are also set according to the output shaft power and the design speed.

[0067] The main component 5 is the igniter, which is tangentially connected to the opening on the outer wall surface. It is responsible for generating a tangential hot jet after the ignition command is issued. The igniter 5, which is tangentially connected to the opening on the outer ring wall surface 3, mainly consists of a straight tube, an ignition chamber 10, and a spark plug. The length of the straight tube is determined by the fuel slow combustion to detonation distance and the height of the protrusion inside the tube. One end of the internally threaded tube is connected to the tangential threaded hole on the outer ring wall surface 3, and the other end is connected to the internally threaded hole in the ignition chamber 10. The components that make up the ignition chamber 10 are the ignition chamber thin shell and the ignition chamber end cap 11. One bottom side of the ignition chamber 10 has an internally threaded hole, and the other side has a flange that mates with the ignition chamber end cap 11. The ignition chamber thin shell and the ignition chamber end cap 11 are connected by bolts and nuts, and the ignition chamber end cap 11 is connected to the spark plug through the internally threaded hole.

[0068] The main component 6 is a streamlined limiting bracket located at the engine outlet. This bracket limits the axial and radial sway of the non-circular cross-section inner annular barrel 4 and forms a simply supported beam. The three typical shapes of the guide ribs in the streamlined limiting bracket are triangular, symmetrical double-circular arc, and single-sided offset double-circular arc. The angle of the guide ribs 14 relative to the axial direction is determined by the length of the rotating detonation engine combustion chamber, the three-point aerodynamic structure of the rotating detonation wave, and the average width of the annular groove. The number of guide ribs 14 is determined by the average Mach number at the outlet of the rotating detonation engine combustion chamber. The streamlined limiting bracket 6 has a tapered thin-shell cover 13 with a streamlined transition at the outlet end along the axis; its typical profile is a quadratic curve. The annular connecting section 15 is fastened to the outer annular wall of the rotating detonation engine through a ring of bolt holes. The cone mainly guides the airflow to accelerate expansion.

[0069] The main component 7 is the first connecting shaft, which serves to connect the bearings of the engine disc base 2, as well as external mechanical equipment and power generation equipment. The first connecting shaft 7 is connected to the end face of the inner ring barrel 4 with a partial non-circular cross-section by bolts. Both the bearing mounting part and the transmission part have keyways to prevent circumferential relative sliding.

[0070] The main component 8 is the second connecting shaft, which serves to connect the bearing of the streamlined bracket 6 at the outlet limit. The second connecting shaft 8 is connected to the end face of the inner ring barrel 4, which has a partial non-circular cross-section, by bolts. Both the bearing mounting part and the transmission part have keyways to prevent circumferential relative sliding.

[0071] The main component 9 is the inertia wheel, which is responsible for preventing the rotating shaft from idling and reversing. The width of the inertia wheel 9 is no greater than the length of the first connecting shaft 7 extending out, and its diameter does not exceed the maximum diameter of the rotating detonation engine.

[0072] Main components 1, 2, and 3 are connected sequentially along the axial direction and fastened with bolts. Main components 9, 7, 2, 4, 6, and 8 are connected sequentially along the axial direction, and bearings limit the rotation of main component 4 to ensure that it can only rotate around the axis.

[0073] The axial area of ​​the intake passage in intake section 1 changes slowly and smoothly to ensure that the total pressure loss is not too large when the high-pressure air source enters the combustion chamber through the annular gap. The radial area of ​​the fuel injection hole on the outer annular wall 3 also changes slowly and smoothly.

[0074] The multiple annular grates on the engine disc base 2 and the multiple annular grates at the bottom of the inner ring empty barrel are arranged alternately to form a microchannel with high total pressure loss, which hinders the overflow gas. The radial cross section of the grates can be an isosceles triangle, rectangle, semicircle, or semiellipse.

[0075] The dynamic seal of the inner ring empty barrel 4 end face and the limiting streamlined bracket 6 adopts the grate sealing method. Multiple annular grates are arranged alternately between the two planes to form a microchannel with high total pressure loss to block the overflow gas. The radial section of the grate can be an isosceles triangle, rectangle, semicircle, or semiellipse.

[0076] The gradient of the inner ring empty barrel 4 is mainly affected by the detonation wave dip angle, the oblique shock wave dip angle and the shear layer dip angle, while the flow field structure of the detonation wave / shock wave system is mainly affected by the fuel / air chemical equivalence ratio and the mainstream air flow rate.

[0077] The percentage of the total length of the non-circular cross-section of the inner ring empty barrel 4 is determined by the power required by the airborne power generation equipment, axial compressor, and centrifugal compressor, and is usually greater than 2 / 3 of the total length of the inner ring empty barrel 4.

[0078] The streamlined tail cone of the engine outlet limiting streamline bracket 6 is a conical thin-shell cover 13, which effectively reduces the overall weight of the limiting streamline bracket 6 and also accommodates the extended section of the second connecting shaft 8. The connection between the conical thin-shell cover 13 and the main body of the limiting streamline bracket 6 is achieved by bolts, and the centering and positioning between the conical thin-shell cover 13 and the main body of the limiting streamline bracket 6 are achieved by an annular step on the limiting streamline bracket 6. The guide ribs of the limiting streamline bracket 6 are also hollow thin shells, which can also effectively reduce the overall weight of the limiting streamline bracket 6. In order to improve the deformation resistance of the guide ribs, a series of annular connecting sections 15 are arranged inside the thin shell layer of the guide ribs. The annular connecting sections and the thin wall of the guide ribs are connected and fastened by welding.

[0079] The central cylinder of the limiting streamlined bracket 6 has stacked stepped holes and threaded holes evenly distributed circumferentially on the outer ring wall 3. The stepped holes are mainly used for bearing interference fits, and the minimum diameter of the stepped holes is larger than the diameter of the connecting shaft. The threaded holes on the outer wall of the central cylinder are used to connect the guide ribs.

[0080] Since the first connecting shaft 7 and the second connecting shaft 8, as well as the intake section 1, are not completely exposed to the high-temperature combustion gas, the materials used are generally 45 steel or stainless steel.

[0081] Since the engine disc base 2 faces the combustion chamber inlet end face, the inner side of the outer ring wall 3 faces the combustion chamber cavity, the outer side of the inner ring empty barrel 4 with a part of the non-circular cross section faces the combustion chamber cavity, and the limiting streamlined bracket 6 is exposed to the high temperature exhaust, the materials are generally high temperature alloy steel.

[0082] To prevent severe deformation of the inner ring cylinder 4, which has a partially non-circular cross-section, from being impacted by moving detonation waves and shock waves, the inner ring cylinder 4 also has hub-shaped support bars radially distributed along its axis. Each set of support bars in the inner ring cylinder 4 is manufactured by machining. There are three sets of hub-shaped support bars, located at 1 / 4, 1 / 2, and 3 / 4 of the total axial length of the inner ring cylinder 4, respectively.

[0083] Typical fuel injection orifice shapes on the outer ring wall 3 include circular, elliptical, and horseshoe shapes. Typical included angles between the injection orifice and the radial direction are ±15°, ±30°, and ±45°, where a positive sign indicates that the axial component of the fuel injection velocity is aligned with the mainstream direction, and a negative sign indicates that the axial component of the fuel injection velocity is opposite to the mainstream direction. The number of fuel injection orifices on the outer ring wall 3 is mainly determined by the fuel type, mass flow rate at the equivalence ratio, diameter of a single fuel injection orifice, and fuel pressure. A U-shaped groove 12 is welded to the outer side of the axial position where the injection orifices are located on the outer ring wall 3. The bottom of the U-shaped groove 12 has a threaded hole for connecting the fuel supply pipeline. The U-shaped groove 12 fits snugly against the outer ring wall 3, forming a fuel pressure stabilizing chamber to prevent excessive back pressure during detonation wave propagation, which could cause excessive pressure oscillations upstream of the fuel supply pipeline.

[0084] The rotational speed of the inner ring empty barrel 4 relative to the outer ring wall 3 in the non-circular cross-section is determined by the air flow, the knock wave boost ratio, and the actual working fuel equivalence ratio. Compared to the traditional concentric ring cavity engine structure, the rotating knock wave, oblique shock wave, and shear layer in the non-circular cavity exhibit lateral compression and expansion effects along the radial direction. To prevent the rotating shaft from idling or even reversing, the first connecting shaft 7 is connected to the inner ring empty barrel 4 on one side and to the inertia wheel 9 on the other side.

[0085] The outer ring wall 3 forms an internal double-cone truncated cone on the side near the engine disc-shaped base 2, which, together with the partially non-circular cross-section inner ring empty barrel 4, forms an annular Laval nozzle at the head of the combustion chamber, capable of efficiently generating a combustible gas mist mixture. After passing through the Laval nozzle, the high-pressure air is continuously accelerated to supersonic speed, interacting with the injected combustible liquid to produce small-diameter combustible droplets, increasing the contact area between the air and the combustible liquid.

[0086] Check valves are installed in the threaded holes of the U-shaped groove 12 welded to the outer ring wall 3 to prevent backfire from occurring in the fuel delivery pipe. The intake section 1 is also equipped with a check flow channel to prevent high-pressure gas from backfireing into the main air supply line after the knock wave.

[0087] Extracting shaft power primarily reduces the thermal load on the inner ring empty barrel 4. The stationary outer ring wall 3 mainly dissipates engine heat through heat sinks and external heat radiation. The limiting streamlined bracket 6 mainly draws air from the outer ring wall 3 through the hollow guide ribs 14 and discharges it from the cooling holes distributed on the guide ribs 14, forming a cooling air film.

[0088] The size of the ignition chamber 10 in the igniter 5, which is tangentially connected to the opening on the outer ring wall 3, is determined according to the required initial detonation wave pressure ratio.

[0089] In the partially non-circular cross-section inner ring hollow barrel 4, a derivative configuration exists in the middle section of the gradually changing petal-shaped section. This configuration involves alternating protrusions of different heights and different petal shapes within the cross-section. The purpose is to improve the adaptability of the bladeless rotary detonation engine, which extracts shaft power, to multiple modes. Typical petal shapes include semicircular, isosceles triangular, and parabolic.

[0090] The overall length and maximum diameter of a bladeless rotary detonation engine for extracting shaft power are adjusted accordingly based on the suitable aircraft. For unmanned helicopters, unmanned tiltrotor aircraft, and unmanned turboprop aircraft, the typical overall length of the engine is between 50mm and 2mm, and the typical maximum diameter is between 2mm and 1mm. For manned helicopters, manned tiltrotor aircraft, and manned turboprop aircraft, the typical overall length of the engine is between 10mm and 30mm, and the typical maximum diameter is between 2mm and 6mm.

[0091] When the fuel injection holes on the outer ring wall are in a double row, the staggered equal-angled small holes and the drilling angle work together to produce an atomization effect through gas-liquid interaction, and generate an atomized combustible mixture through high-speed collision between liquids.

[0092] The outer ring wall 3 and the inner ring empty barrel 4, which is part of the non-circular cross section, form the annular Laval nozzle. The contraction section is shorter than the expansion section. The area ratio of the expansion section is selected according to the physical properties of the liquid fuel to be atomized and the critical Mach number.

[0093] Multiple pressure measurement holes are drilled along the axial direction on the outer ring wall 3 for connecting high-frequency pressure sensors to monitor changes in combustion chamber pressure.

[0094] The outer ring wall 3 has multiple temperature measuring holes drilled around its circumference to connect high-frequency thermocouples and monitor changes in combustion chamber temperature.

[0095] The depth of the bearing mounting hole of the engine disc base 2 is slightly less than the bearing thickness, so that the end face of the inner ring empty barrel 4 with part of the non-circular cross section does not contact the engine disc base, ensuring that the resistance is minimized when the inner ring empty barrel 4 with part of the non-circular cross section rotates circumferentially.

[0096] The depth of the bearing mounting hole of the limiting streamlined bracket 6 is slightly less than the bearing thickness, so that the other end face of the inner ring empty barrel 4 with part of the non-circular cross section does not contact the limiting streamlined bracket 6, ensuring that the resistance is minimized when the inner ring empty barrel 4 with part of the non-circular cross section rotates circumferentially.

[0097] The following is also a working sequence of a bladeless rotary detonation engine for extracting shaft power, as follows:

[0098] Step 1: High-pressure air enters the annular cavity through the intake section. The gas in the cavity passes through the contraction and expansion sections of the annular Laval nozzle in sequence and enters the combustion chamber of the rotary detonation engine. Then it flows through the downstream limiting streamlined support 6, establishing a steady-state cold flow field in a very short time.

[0099] Step 2: The combustible liquid is pumped into the U-shaped groove 12 welded on the outer side of the outer ring wall 3 by a high-pressure gas pump, and then enters the rotating detonation combustion chamber through the micropores uniformly distributed along the circumference covered by the U-shaped groove 12.

[0100] Step 3: The combustible liquid entering the combustion chamber through the micropores is impacted by the supersonic mainstream at the outlet of the annular Laval nozzle, breaking it into discrete droplets. As the combustible droplets continue to move downstream, they continue to interact with the mainstream gas, ultimately creating a cold atomization effect.

[0101] Step 4: Hydrogen / oxygen is introduced into the left and right sides of the igniter 5. The mixing ratio adopts the chemical equivalence ratio. The gas introduction time is generally about 1 second, so that the straight pipe and the ignition chamber 10 are filled with combustible gas.

[0102] Step 5: The spark plug at the top of the igniter 5 generates an electric spark the instant the high-voltage power is switched on. The high temperature and high pressure of the electric spark trigger the combustible gas in the ignition chamber, generating a slow-burning wave.

[0103] Step 6: After the slow-burning wave passes through the raised structure inside the straight pipe, the flame front will undergo a slow-burning to detonation process, and a detonation wave will be transmitted at the other end of the straight pipe.

[0104] Step 7: The detonation wave transmitted from the straight pipe enters the rotating detonation combustion chamber through the tangential inlet of the outer ring wall 3, and the detonation wave begins to propagate circumferentially within the annular cavity of the rotating detonation combustion chamber.

[0105] Step 8: When the detonation wave sweeps across the atomized combustible mixture, it further breaks the combustible droplets into smaller particles. At the same time, the high-temperature and high-pressure zone behind the detonation wave also plays a role in the disintegration of combustible droplets and triggering the ignition of the atomized mixture.

[0106] Step 9: After the detonation wave propagates through the combustion chamber for multiple cycles, it will form a stable dynamic mixture triangle on the wavefront. The top of the triangle will induce the generation of a shear layer and an oblique shock wave.

[0107] Step 10: The high-pressure zone behind the detonation wave and the oblique shock wave acts on the inner ring empty barrel 4 of the part of the non-circular cross section. Since the high-pressure zone behind the wave decays rapidly along the circumference, the integral force on the inner ring empty barrel 4 has a lever arm relative to the axis of rotation, thus generating a tangential torque.

[0108] Step 11: The tangential torque drives the inner ring empty barrel 4, which has a part of a non-circular cross section, to rotate. The inner ring empty barrel 4 rotates around the first connecting shaft 7 and the second connecting shaft 8, thereby driving the inertial wheel 9 to rotate.

[0109] In step 12, the inert wheel 9, the inner ring empty barrel 4 around the first connecting shaft 7, the second connecting shaft 8, and part of the non-circular cross section finally rotate at a constant speed, with a fixed difference between the rotation speed and the propagation speed of the detonation wave.

[0110] Step 13: After the high-temperature airflow after output shaft power passes through the knock wave, oblique shock wave and shear layer in the combustion chamber along the axial direction, it is discharged after being guided by the guide ribs 14 of the limiting streamlined bracket 6, generating a certain degree of axial thrust.

[0111] Step 14: The connecting shaft on the side equipped with the inertial wheel 9 transmits mechanical energy to the airborne power generation equipment, axial compressor or centrifugal compressor, thereby realizing the effective extraction of shaft power.

[0112] When the total incoming pressure increases or decreases, the flow rate of the bladeless rotary detonation engine that extracts shaft power will also increase or decrease accordingly, and the rotational speed of the inner ring empty barrel 4 of the non-circular wall and the first connecting shaft 7 and the second connecting shaft 8 will also increase or decrease accordingly.

[0113] As the fuel injection equivalence ratio continues to increase from lean to rich, the rotational speed of the inner ring empty barrel 4 and the first connecting shaft 7 and the second connecting shaft 8 of the non-circular wall of the rotary detonation engine without blades for extracting shaft power will first increase and then decrease.

[0114] The following is a shutdown sequence for a bladeless rotary detonation engine that extracts shaft power:

[0115] Step 1: Close the fuel line valve, while maintaining a continuous gas supply.

[0116] Step 2: When the rotary detonation engine cools to room temperature, close the main valve.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bladeless rotary detonation engine for extracting shaft power, characterized in that, The device includes an inner ring empty barrel (4), the right side of which is bolted to a first connecting shaft (7), the first connecting shaft (7) is bearing connected to an engine disc base (2), one side of which is bolted to an intake section (1), the left side of which is bolted to a second connecting shaft (8), the second connecting shaft (8) is bearing connected to a limiting streamline bracket (6), the limiting streamline bracket (6) is bolted to one end of an outer ring wall (3), the other end of which is bolted to the engine disc base (2), and an igniter (5) is also connected to the outer ring wall (3). The inner ring empty barrel (4) is a spindle shape with a non-circular cross section in the middle and circular cross sections on both sides; An inertia wheel (9) is also bolted to the first connecting shaft (7); A U-shaped groove (12) is also welded to one side of the engine disc base (2) and the outer ring wall (3); One side of the limiting streamlined bracket (6) is also connected to a conical thin shell cover (13).

2. The rotary detonation engine for extracting shaft power without blades according to claim 1, characterized in that, The intake section (1) includes an inner annular column wall (101) and an outer annular column wall (102) of the cavity. The inner annular column wall (101) and the outer annular column wall (102) of the cavity are connected by a cavity cover plate (103). The first connecting shaft (7) passes through the outer annular column wall (102) and the inner annular column wall (101) of the cavity in sequence and is connected to the inner annular barrel (4). Multiple intake channels (1011) are provided on the inner annular column wall (101). The other side of the multiple intake channels is provided on the outer annular column wall (102) of the cavity. The intake section (1) and the engine disc base (2) are bolted together to form a cavity.

3. A bladeless rotary detonation engine for extracting shaft power according to claim 1, characterized in that, The middle part of the inner ring empty barrel (4) has a non-circular cross section, and the non-circular cross section is a gradually changing elliptical cylinder or a gradually changing petal shape.

4. A bladeless rotary detonation engine for extracting shaft power according to claim 1, characterized in that, One side of the engine disc base (2) is bolted to a circular thick plate (16), and the circular thick plate (16) is bearing connected to the first connecting shaft (7). The left side of the circular thick plate (16) and the inner ring empty barrel (4) are dynamically sealed. The mating surfaces of the engine disc base (2), the air intake section (1), and the outer ring wall (3) are also provided with sealing grooves, and rubber gaskets are installed in the sealing grooves.

5. A bladeless rotary detonation engine for extracting shaft power according to claim 1, characterized in that, The outer ring wall (3) is a hollow circular thin-walled part. The two ends of the outer ring wall (3) are provided with threaded holes, which are used to connect the engine disc base (2) and the limiting streamline bracket (6) respectively. The outer ring wall (3) is also drilled with threaded holes along the tangential direction. The size of the threaded holes matches the external thread interface of the igniter (5).

6. A bladeless rotary detonation engine for extracting shaft power according to claim 3, characterized in that, The outer ring wall (3) has multiple circular, elliptical or horseshoe-shaped fuel injection holes along its circumference. The angle between the fuel injection holes and the radial direction of the outer ring wall (3) is ±15°, ±30° or ±45°. The positive sign indicates that the axial component of the fuel injection speed is consistent with the mainstream direction, and the negative sign indicates that the axial component of the fuel injection speed is opposite to the mainstream direction. The outer ring wall (3) is also welded with the U-shaped groove (12). The U-shaped groove (12) has threaded holes for connecting the fuel supply pipeline.

7. A bladeless rotary detonation engine for extracting shaft power according to claim 1, characterized in that, The igniter (5) includes a straight tube, an ignition chamber (10), and a spark plug. One end of the straight tube is threaded to the outer ring wall (3), and the other end is threaded to the ignition chamber (10). The ignition chamber (10) includes an ignition chamber shell and an ignition chamber end cap (11). The ignition chamber shell and the ignition chamber end cap (11) are bolted together, and the ignition chamber end cap (11) is threaded to the spark plug.

8. A bladeless rotary detonation engine for extracting shaft power according to claim 1, characterized in that, The other side of the limiting streamlined bracket (6) is also bolted with a flow guide rib (14), which is triangular, symmetrical double arc or single-sided offset double arc; the outer periphery of the flow guide rib (14) is a ring support frame, which is bolted to the outer ring wall (3), and the shape of the conical thin shell cover (13) is a quadratic curve.

9. A bladeless rotary detonation engine for extracting shaft power according to claim 1, characterized in that, The width of the inertia wheel (9) is not greater than the length of the first connecting shaft (7) extending out of the outer annular column wall of the cavity, and the diameter of the inertia wheel (9) does not exceed the maximum diameter of the rotating detonation engine; the inner annular empty barrel (4) is connected to two circular thin plates on both sides, and the circular thin plates are respectively connected to the first connecting shaft (7) and the second connecting shaft (8) by bearings; the dynamic seal between the inner annular empty barrel (4) and the engine disc base (2) and the limiting streamlined bracket (6) adopts the toothed sealing method.

10. A bladeless rotary detonation engine for extracting shaft power according to claim 6, characterized in that, When the middle section of the inner ring empty barrel (4) is a gradually changing elliptical cylinder, the torsion angles of adjacent elliptical annular surfaces that are equidistant along the axis of the rotating detonation engine are equal. When the middle section of the inner ring empty barrel (4) is a gradient petal shape, the direction of the boundary line between the adjacent gradient protrusions of the gradient petal shape is consistent with the direction of the oblique shock wave emitted by the three wave points of the rotating detonation wave under the single wave mode. The adjacent gradient protrusions are perpendicular to the injection ring seam plane near the combustion chamber inlet of the rotating detonation engine. The fuel injection holes are distributed along the axial direction in a single row or a double row. The double row distribution includes staggered distribution and parallel distribution. The staggered distribution includes equal-angle staggered angle and offset staggered angle.

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