Ultra-compact rotating detonation engine combustion chamber and design method

Abstract

The invention discloses an ultra-compact rotary detonation engine combustion chamber and a design method.The combustion chamber comprises a liquid collecting cavity, an oil injection rod, an annular combustion chamber and a plug type spray pipe, the annular combustion chamber is of a hexagonal star hollow structure, and rotary detonation waves are propagated downstream while rotating in an inner cavity of the annular combustion chamber; the liquid collecting cavity is matched with the front end face of the annular combustion chamber in shape and fixed to the front end face. The liquid collecting cavity is connected with a fuel oil storage tank and an oxidizing agent storage tank through pipelines; the oil injection rods are uniformly distributed along the front end face of the combustion chamber, are connected with the liquid collection cavity and the front end face of the annular combustion chamber, and are used for uniformly injecting the premixed combustibles in the liquid collection cavity into an inner cavity of the annular combustion chamber through the front end face of the annular combustion chamber; the plug type spray pipes are evenly distributed along the rear end face of the combustion chamber and used for spraying out fuel gas generated by combustion in the inner cavity of the annular combustion chamber, and therefore thrust is provided. The rotary detonation combustion efficiency can be effectively improved, and the working performance of the engine is improved.

Description

Technical Field

[0001] This invention belongs to the field of overall design technology of rotating detonation engines, specifically relating to an ultra-compact rotating detonation engine combustion chamber and its design method. Background Technology

[0002] A rotating detonation engine (RDE) is a novel power unit that utilizes one or more continuously rotating detonation waves propagating through an annular combustion chamber to sweep across a combustible mixture. The resulting high-temperature, high-pressure detonation products are discharged from the nozzle, generating thrust. Most RDE engines employ a coaxial annular detonation chamber, with one end closed for fuel injection. After initiation, the detonation wave propagates tangentially perpendicular to the fuel injection direction, ultimately resulting in high-speed ejection of the detonation combustion products from the outlet, generating thrust.

[0003] The performance of a rotary detonation engine largely depends on the combustion efficiency of the fuel. By increasing the residence time of the fuel in the combustion chamber, the fuel and oxidant can be mixed more thoroughly, ensuring that the fuel and oxidant react fully under the action of the detonation wave, further improving the overall heat release efficiency of the engine and promoting the overall performance of the engine.

[0004] Currently, the combustion chambers of rotary detonation engines are all standard annular or cylindrical shapes. How to design a more compact rotary detonation combustion chamber within a limited space and increase the residence time of fuel and oxidizer in the combustion chamber to improve engine performance is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-compact rotary detonation engine combustion chamber and its design method, which designs a more compact rotary detonation combustion chamber under limited space constraints, improves the combustion efficiency of rotary detonation, and enhances engine performance.

[0006] To achieve the above objectives, the present invention employs the following technical solution: An ultra-compact rotary detonation engine combustion chamber includes a liquid collection chamber, a fuel injector, an annular combustion chamber, and a plug-type nozzle, wherein: The annular combustion chamber has a hexagonal hollow structure, including an outer wall, an inner wall, a front end, and a rear end, which together form the inner cavity of the annular combustion chamber; the rotating detonation wave rotates and propagates downstream in the inner cavity of the annular combustion chamber. The shape of the liquid collection chamber is adapted to the shape of the front end face of the annular combustion chamber; the liquid collection chamber is a hollow structure and is fixed on the front end face; the liquid collection chamber is connected to the fuel tank and the oxidizer tank through pipelines. The fuel injection rods are evenly distributed along the front end face of the combustion chamber. The fuel injection rods connect the liquid collection chamber and the front end face of the annular combustion chamber, and are used to evenly inject the premixed combustible material in the liquid collection chamber into the inner cavity of the annular combustion chamber through the front end face of the annular combustion chamber. The plug-type nozzles are evenly distributed along the rear end face of the combustion chamber and are used to eject the gas generated by combustion in the inner cavity of the annular combustion chamber, thereby providing thrust.

[0007] Furthermore, when the rotary detonation engine is working, fuel and oxidizer are injected together into the liquid collection chamber for premixing.

[0008] Furthermore, the liquid collection chamber, the fuel injection rod, and the plug-type nozzle are made of metal, and the annular combustion chamber is made of high-temperature alloy.

[0009] A design method for an ultra-compact rotating detonation engine combustion chamber includes: A preliminary model of the annular combustion chamber is constructed based on a hexagonal star structure. The maximum outer diameter and minimum inner diameter of the outer wall of the annular combustion chamber, as well as the apex of each star in the hexagonal star structure, are determined to form the star skeleton. The width of the annular combustion chamber is set, and the inner wall of the annular combustion chamber is constructed by offsetting the dimensions. The liquid collection chamber is designed so that its shape is adapted to the shape of the front end face of the annular combustion chamber; Based on the flow rate, density, and injection speed of the premixed combustible material injected into the annular combustion chamber, the diameter and number of injection rods between the liquid collection chamber and the front end face of the annular combustion chamber are determined. Based on the design thrust, the working pressure of the annular combustion chamber, and the outlet pressure of the plug nozzle, the throat area, outlet Mach number, and expansion ratio of the plug nozzle are determined, thereby completing the design of the entire rotary detonation engine combustion chamber.

[0010] Furthermore, the outer wall of the annular combustion chamber is initially modeled as a hexagonal star structure with six starbursts; based on the dimensional design constraints of the rotating detonation engine, the maximum outer diameter of the annular combustion chamber's outer wall is set. ; Determine the minimum inner diameter of the outer wall of the annular combustion chamber 3. The 60° sector area is used as the design constraint for each star ray of the hexagonal star structure. The smaller the value, the longer the straight side of the starburst. The longer, the sharper the star's rays. The smaller the value, the following relationship applies: ; ; Under the premise of satisfying the above relationship, it should be that As small as possible, while reducing At the same time ensure ; Determining the maximum outer diameter , minimum inner diameter and star-shaped tips Then, the framework of the starburst is formed; the straight edges of the starburst are transformed into arcs, and the sharp corners of the starburst are... Convert to rounded corners to achieve a smooth transition design and complete the modeling of the outer wall surface.

[0011] Furthermore, the width of the annular combustion chamber is set. Then the outer wall of the annular combustion chamber is offset inward. The inner wall surface of the annular combustion chamber is obtained; the axial length of the combustion chamber is determined based on the dimensional design constraints of the rotating detonation engine. The outer wall and the front and rear ends of the inner wall are sealed to form the front end face and the rear end face, thus obtaining the model of the annular combustion chamber.

[0012] Furthermore, when the rotary detonation engine is operating, the flow rate of premixed combustible material injected into the annular combustion chamber 3... With the diameter of the fuel injector rod Number of fuel injectors It has the following relationship: ; In the formula, This refers to the density of the premixed combustible material. The injection rate of the premixed combustible material; The diameter of the fuel injector is determined based on the above relationship. and quantity .

[0013] Furthermore, the throat area of ​​the plug nozzle The following requirements should be met: ; in, For the design thrust of the plug nozzle, The working pressure of the annular combustion chamber, This is the thrust coefficient; Exit Mach number of plug nozzle and expansion ratio The following requirements should be met: ; ; in, The specific heat ratio of the fuel gas. This refers to the outlet pressure of the plug nozzle. This represents the nozzle exit area.

[0014] Furthermore, after completing the design of the rotary detonation engine combustion chamber, the design parameters were adjusted through model simulation optimization to achieve injection matching optimization of the liquid collection chamber, injection rod and annular combustion chamber, as well as thrust matching optimization of the annular combustion chamber and plug nozzle.

[0015] An ultra-compact rotary detonation engine, wherein the combustion chamber is provided.

[0016] Compared with the prior art, the present invention has the following technical features: 1. The engine combustion chamber configuration proposed in this invention replaces the existing standard circular or cylindrical shape with a hexagonal star structure. Under the same spatial constraints, the propagation path of the rotating detonation wave is increased by about 22%, and the residence time of the rotating detonation wave is extended by about 22% when the speed of the rotating detonation wave is constant. This effectively improves the combustion efficiency in the combustion chamber and enhances the working performance of the engine.

[0017] 2. The ultra-compact rotating detonation engine combustion chamber configuration proposed in this invention is simple and reliable. Under the premise of unchanged spatial constraints, the performance of the rotating detonation engine can be improved by changing the configuration of the combustion chamber, thus promoting the improvement of the design level of rotating detonation engines. Attached Figure Description

[0018] Figure 1 An overall view of the combustion chamber of an ultra-compact rotary detonation engine; Figure 2 A cross-sectional view of an ultra-compact rotating detonation combustion chamber; Figure 3 Left and right views of an ultra-compact rotating detonation combustion chamber; Figure 4 This is a schematic diagram of the annular combustion chamber structure; Figure 5 This is a schematic diagram of the design parameters for an annular combustion chamber.

[0019] Explanation of reference numerals in the attached drawings: 1. Liquid collection chamber; 2. Injection rod; 3. Annular combustion chamber; 4. Plug nozzle; 31. Outer wall surface; 32. Inner wall surface; 33. Front end surface; 34. Rear end surface. Detailed Implementation

[0020] This invention first provides an ultra-compact rotary detonation engine combustion chamber. Under the premise of unchanged spatial constraints, the performance of the rotary detonation engine is improved by changing the configuration of the combustion chamber; for example... Figures 1 to 3 As shown, the ultra-compact rotating detonation engine combustion chamber is installed inside the aircraft cabin and includes a liquid collection chamber 1, a fuel injector 2, an annular combustion chamber 3, and a plug-type nozzle 4, wherein: The annular combustion chamber 3 has a hexagonal hollow structure, including an outer wall surface 31, an inner wall surface 32, a front end surface 33, and a rear end surface 34, which together form the inner cavity of the annular combustion chamber 3. The rotating detonation wave rotates and propagates downstream in the inner cavity of the annular combustion chamber 3, and the fuel and oxidizer are fully combusted under the action of the rotating detonation wave.

[0021] The shape of the liquid collection chamber 1 is adapted to the shape of the front end face 33 of the annular combustion chamber 3, both being hexagonal star structures; the liquid collection chamber 1 is a hollow structure and is fixed on the front end face 33; the liquid collection chamber 1 is connected to the fuel tank and the oxidizer tank through pipelines; when the rotary detonation engine is working, the fuel and oxidizer are injected together into the liquid collection chamber 1 for premixing.

[0022] The fuel injection rod 2 is evenly distributed along the front end face 33 of the combustion chamber. The fuel injection rod 2 connects the liquid collection chamber 1 and the front end face 33 of the annular combustion chamber, and is used to evenly inject the premixed combustible material in the liquid collection chamber 1 into the inner cavity of the annular combustion chamber 3 through the front end face 33 of the annular combustion chamber 3. The plug nozzle 4 is evenly distributed along the rear end face 34 of the combustion chamber and is used to spray out the gas generated by combustion in the inner cavity of the annular combustion chamber 3, thereby providing thrust.

[0023] To withstand the extreme temperatures of detonation combustion within the combustion chamber, the liquid collection chamber 1, the fuel injection rod 2, and the plug-type nozzle 4 are made of metal, while the annular combustion chamber 3 is made of a high-temperature alloy.

[0024] This invention also provides a design method for an ultra-compact rotating detonation engine combustion chamber, comprising the following steps: Step 1: A preliminary model of the annular combustion chamber 3 is created based on the hexagonal star structure. The maximum outer diameter and minimum inner diameter of the outer wall surface 31 of the annular combustion chamber 3, as well as the apex angle of each star ray in the hexagonal star structure, are determined to form the star ray skeleton. The width of the annular combustion chamber is set, and the inner wall surface 32 of the annular combustion chamber 3 is constructed by offsetting the model. This ensures that the rotating detonation wave can propagate smoothly downstream during engine operation.

[0025] To better illustrate the shape of the annular combustion chamber 3, the design parameters are as follows: Figure 5 As shown; including: Step 1.1: Initially model the outer wall 31 of the annular combustion chamber 3 as a hexagonal star structure with six starbursts; based on the size design constraints of the rotating detonation engine, set the maximum outer diameter of the outer wall 31 of the annular combustion chamber 3. The maximum outer diameter This refers to the maximum distance on the outer wall surface 31 from the axis of the annular combustion chamber 3, that is, the distance from the endpoint of each ray of the hexagon (one ray is one point of the hexagon) to the axis; the maximum outer diameter is defined as the maximum dimension that satisfies the dimensional design constraints of the rotating detonation engine. .

[0026] Step 1.2, determine the minimum inner diameter of the outer wall surface 31 of the annular combustion chamber 3. The minimum inner diameter refers to the distance from the junction of adjacent starbursts to the axis; the annular combustion chamber 3 has a hexagonal star structure, therefore a 60° sector area is used as the design constraint for each starburst of the hexagonal star structure; whereby... The smaller the value, the longer the straight side of the starburst. The longer, the sharper the star's rays. The smaller the value, the following relationship applies: (1) (2) When the rotary detonation engine is working, The longer the rotational detonation wave propagation path, the better the combustion performance. The smaller the diameter, the sharper the starburst, and the more difficult it is for the rotating detonation wave to propagate. Therefore, a reasonable trade-off must be made between the two. Generally, in design... To be as small as possible, in order to ensure combustion chamber performance, while reducing At the same time, ensure: (3) Step 1.3, after determining the maximum outer diameter , minimum inner diameter and star-shaped tips Then, the framework of the starburst is formed; based on this, the design is optimized, transforming the straight edges of the starburst into arcs and reducing the sharp corners of the starburst. The corners are converted to rounded corners; in other words, the outer wall 31 of the entire annular combustion chamber 3 is designed to have a smooth transition to ensure that the rotational detonation propagates smoothly along the wall. At this point, the modeling design of the outer wall 31 of the annular combustion chamber 3 is complete. Step 1.4, set the width of the annular combustion chamber 3 ;like If it is too small, the propagation of the rotating detonation wave will be blocked; if... If the width is too large, the rotating detonation wave may not be able to form; combustion chamber width The setting should be based on the operating flow rate of the rotary detonation engine; the outer wall 31 of the annular combustion chamber 3 is offset inward. The inner wall surface 32 of the annular combustion chamber 3 is obtained.

[0027] Step 1.5: Determine the axial length of the combustion chamber based on the dimensional design constraints of the rotating detonation engine. Complete the shape design of the annular combustion chamber 3; that is, set the length within the allowable size range of the rotary detonation engine. .

[0028] Step 1.6: Close the front and rear ends of the outer wall surface 31 and the inner wall surface 32 to form the front end surface 33 and the rear end surface 34, thus obtaining the model of the annular combustion chamber 3.

[0029] Step 2: Design the liquid collection chamber 1, the shape of which is adapted to the shape of the front end face 33 of the annular combustion chamber 3.

[0030] Step 3: Based on the flow rate, density, and injection speed of the premixed combustible material injected into the annular combustion chamber 3, determine the diameter and number of injection rods 2 between the liquid collection chamber 1 and the front end face 33 of the annular combustion chamber 3.

[0031] Determine the diameter of fuel injector 2 and quantity The selection of the diameter and number of the fuel injector rods 2 ensures that their atomization characteristics, penetration depth, and smoothness meet design requirements, and the fuel injector rods 2 are evenly distributed; when the rotary detonation engine is working, the flow rate of the premixed combustible material injected into the annular combustion chamber 3 is... With the diameter of the fuel injector rod 2 Quantity of fuel injector 2 It has the following relationship: (4) In the formula, This refers to the density of the premixed combustible material. The injection speed of the premixed combustible material.

[0032] Step 4: Based on the design thrust, the operating pressure of the annular combustion chamber, and the outlet pressure of the plug nozzle 4, determine the throat area of ​​the plug nozzle 4. Export Mach number and expansion ratio This completes the design of the entire combustion chamber.

[0033] Step 4.1, determine the throat area of ​​the plug nozzle 4. ; throat area The following requirements should be met: (5) in, The design thrust of the plug nozzle 4, The working pressure of the annular combustion chamber 3, This is the thrust coefficient.

[0034] Step 4.2, determine the exit Mach number of the plug nozzle 4. and expansion ratio Export Mach number and expansion ratio The following requirements should be met: (6) (7) in, The specific heat ratio of the fuel gas. The outlet pressure of the plug nozzle 4 This represents the nozzle exit area.

[0035] Finally, the global matching optimization of the ultra-compact rotating detonation engine combustion chamber is carried out, including: first, the injection matching optimization of the liquid collection chamber 1, the fuel injector 2 and the annular combustion chamber 3; second, the thrust matching optimization of the annular combustion chamber 3 and the plug nozzle 4. This process can be optimized through model simulation, and the design parameters of each part can be optimized and adjusted.

[0036] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An ultra-compact rotary detonation engine combustion chamber, characterized in that, It includes a liquid collection chamber (1), an injection rod (2), an annular combustion chamber (3), and a plug-type nozzle (4), wherein: The annular combustion chamber (3) has a hexagonal hollow structure, including an outer wall surface (31), an inner wall surface (32), a front end surface (33), and a rear end surface (34), which together form the inner cavity of the annular combustion chamber (3); the rotating detonation wave rotates and propagates downstream in the inner cavity of the annular combustion chamber (3); The shape of the liquid collection chamber (1) is adapted to the shape of the front end face (33) of the annular combustion chamber (3); the liquid collection chamber (1) is a hollow structure and is fixed on the front end face (33); the liquid collection chamber (1) is connected to the fuel tank and the oxidizer tank through pipelines; The fuel injection rod (2) is evenly distributed along the front end face (33) of the combustion chamber. The fuel injection rod (2) connects the liquid collection chamber (1) and the front end face (33) of the annular combustion chamber. It is used to evenly inject the premixed combustible material in the liquid collection chamber (1) into the inner cavity of the annular combustion chamber (3) through the front end face (33) of the annular combustion chamber (3). The plug nozzle (4) is evenly distributed along the rear end face (34) of the combustion chamber and is used to spray out the gas generated by combustion in the inner cavity of the annular combustion chamber (3) to provide thrust.

2. The ultra-compact rotary detonation engine combustion chamber according to claim 1, characterized in that, When the rotary detonation engine is working, fuel and oxidizer are injected together into the liquid collection chamber (1) for premixing.

3. The ultra-compact rotary detonation engine combustion chamber according to claim 1, characterized in that, The liquid collection chamber (1), the fuel injection rod (2), and the plug nozzle (4) are made of metal, while the annular combustion chamber (3) is made of high-temperature alloy.

4. A design method for an ultra-compact rotating detonation engine combustion chamber, characterized in that, include: A preliminary model of the annular combustion chamber (3) is performed based on the hexagonal star structure; The maximum outer diameter and minimum inner diameter of the outer wall surface (31) of the annular combustion chamber (3) and the star tip of each star of the hexagonal structure are determined to form a star skeleton; the width of the annular combustion chamber is set and the inner wall surface (32) of the annular combustion chamber (3) is constructed by offsetting. The liquid collection chamber (1) is designed so that its shape is adapted to the shape of the front end face (33) of the annular combustion chamber (3); Based on the flow rate, density and injection speed of the premixed combustible injected into the annular combustion chamber (3), the diameter and number of the injection rods (2) between the liquid collection chamber (1) and the front end face (33) of the annular combustion chamber (3) are determined. Based on the design thrust, the working pressure of the annular combustion chamber, and the outlet pressure of the plug nozzle (4), the throat area, outlet Mach number, and expansion ratio of the plug nozzle (4) are determined, thereby completing the design of the entire rotary detonation engine combustion chamber.

5. The design method for the ultra-compact rotating detonation engine combustion chamber according to claim 4, characterized in that, The outer wall (31) of the annular combustion chamber (3) is initially modeled as a hexagonal star structure with six starbursts; based on the size design constraints of the rotating detonation engine, the maximum outer diameter of the outer wall (31) of the annular combustion chamber (3) is set. ; Determine the minimum inner diameter of the outer wall surface (31) of the annular combustion chamber (3). The 60° sector area is used as the design constraint for each star ray of the hexagonal star structure. The smaller the value, the longer the straight side of the starburst. The longer, the sharper the star's rays. The smaller the value, the following relationship applies: ； ； Under the premise of satisfying the above relationship, it should be that As small as possible, while reducing At the same time ensure ; Determining the maximum outer diameter , minimum inner diameter and star-shaped tips Then, the framework of the starburst is formed; the straight edges of the starburst are transformed into arcs, and the sharp corners of the starburst are... Convert to rounded corners to achieve a smooth transition design and complete the modeling of the outer wall surface (31).

6. The design method for the ultra-compact rotating detonation engine combustion chamber according to claim 4, characterized in that, Set the width of the annular combustion chamber (3) Then the outer wall (31) of the annular combustion chamber (3) is offset inward. The inner wall surface (32) of the annular combustion chamber (3) is obtained; the axial length of the combustion chamber is determined according to the dimensional design constraints of the rotating detonation engine. The front and rear ends of the outer wall (31) and inner wall (32) are sealed to form the front end face (33) and rear end face (34), thus obtaining the model of the annular combustion chamber (3).

7. The design method for the ultra-compact rotating detonation engine combustion chamber according to claim 4, characterized in that, When the rotary detonation engine is operating, the flow rate of premixed combustible material injected into the annular combustion chamber 3 is... With the diameter of the fuel injector (2) Quantity of fuel injector (2) It has the following relationship: ； In the formula, This refers to the density of the premixed combustible material. The injection rate of the premixed combustible material; The diameter of the fuel injector (2) is determined based on the above relationship. and quantity .

8. The design method for the ultra-compact rotating detonation engine combustion chamber according to claim 4, characterized in that, throat area of ​​plug nozzle (4) The following requirements should be met: ； in, For the design thrust of the plug nozzle (4), The working pressure of the annular combustion chamber (3) This is the thrust coefficient; Exit Mach number of plug nozzle (4) and expansion ratio The following requirements should be met: ； ； in, The specific heat ratio of the fuel gas. For the outlet pressure of the plug nozzle (4), This represents the nozzle exit area.

9. The design method for the ultra-compact rotating detonation engine combustion chamber according to claim 4, characterized in that, After completing the design of the rotary detonation engine combustion chamber, the design parameters were adjusted through model simulation optimization to achieve injection matching optimization of the liquid collection chamber (1), the fuel injector (2) and the annular combustion chamber (3), as well as thrust matching optimization of the annular combustion chamber (3) and the plug nozzle (4).

10. An ultra-compact rotary detonation engine, characterized in that, The engine is provided with the combustion chamber as described in claim 1.

Images