A combined pulse detonation engine ceramic matrix composite combustion chamber

Abstract

A combined pulse detonation engine ceramic matrix composite combustion chamber is composed of a high temperature alloy cylinder, bolts, nuts, CMC cylinder and sleeve. The combined structure of the high temperature alloy and ceramic matrix composite combustion chamber enables the pulse detonation engine combustion chamber to work for a long time in a high temperature environment. A cooling device is provided at the flange connection of the high temperature alloy cylinder and the CMC cylinder to reduce the temperature of the flange connection area and minimize the high temperature gap of the flange connection. At the same time, a sleeve is added to the bolts that tighten the flange connection. The sleeve has the characteristics of a large thermal expansion coefficient and can effectively offset the high temperature gap caused by the low thermal expansion coefficient of the CMC material in the bolt and nut connection, and prevent the combustion chamber flange connection structure from loosening due to the high temperature gap. The combined combustion chamber structure can increase the working durability of the pulse detonation engine combustion chamber and has a good application prospect in various pulse detonation engines of aerospace vehicles.

Description

Technical Field

[0001] The invention relates to a pulse detonation engine, in particular to a combined pulse detonation engine ceramic-based composite material combustion chamber. Background Art

[0002] The pulse detonation engine is a new engine that uses detonation waves to generate thrust. It is very different from the working mode of traditional gas turbine engines. The pulse detonation engine has the advantages of simple structure, small size, wide application range, low cost, can be used at zero speed, high combustion efficiency, and superior high-speed performance. However, the thermal environment of the pulse detonation engine combustion chamber is very complex and harsh, especially the high temperature environment, which puts higher requirements on the temperature resistance of the pulse detonation engine combustion chamber. The traditional ordinary combustion chamber can no longer meet the high temperature load of the pulse detonation engine combustion chamber. In order to meet the high temperature environment requirements of the pulse detonation engine combustion chamber, various active and passive cooling systems and composite combustion chamber structures have been proposed, but various structures face certain structural defects and challenges. Either the temperature resistance is poor, or the ablation rate is too high, resulting in damage after a long time. At present, there are few combustion chamber structures that can meet the long-term use requirements of the pulse detonation engine combustion chamber, and the weight of the pulse detonation engine combustion chamber that can achieve the temperature requirements will increase and the structure will be complex. Summary of the invention

[0003] In view of the various deficiencies existing in the pulse detonation engine combustion chamber in the above-mentioned prior art, the present invention provides a combined pulse detonation engine ceramic-based composite material combustion chamber, which has a simple structure, good sealing performance, and reliable flange connection. It can effectively improve the temperature resistance of the pulse detonation engine combustion chamber and improve the efficiency and durability of the pulse detonation engine.

[0004] To achieve the above technical objectives, the technical solution of the present invention is as follows:

[0005] A combined pulse detonation engine ceramic matrix composite combustion chamber, composed of a high-temperature alloy cylinder and a CMC cylinder, wherein one end of the high-temperature alloy cylinder is connected to flange plate one, and the other end is connected to flange plate two, wherein flange plate one is the inlet end of the combined pulse detonation engine ceramic matrix composite combustion chamber, wherein flange plate two is connected to a CMC flange plate at one end of the CMC cylinder, wherein flange plate two is fixedly connected to the CMC flange plate by bolts and nuts, wherein the high-temperature alloy cylinder is the inlet and middle area of ​​the combustion chamber, and wherein the CMC cylinder is the middle and outlet area of ​​the combined pulse detonation engine ceramic matrix composite combustion chamber.

[0006] To optimize the above technical solutions, the measures taken also include:

[0007] The flange plate 2 and the CMC flange plate are provided with corresponding bolt holes, the bolts are inserted into the bolt holes of the CMC flange plate, passed out from the bolt holes on the flange plate 2 and are screwed together with nuts, a sleeve is also provided between the nut and the flange plate 2, and the sleeve is sleeved on the bolt column of the bolt.

[0008] Both ends of the sleeve are provided with sleeve flanges. The thermal expansion coefficient of the sleeve is greater than that of the high-temperature alloy sleeve. The length of the sleeve is set to: when the pulse detonation engine is working, the axial elongation of the high-temperature expansion of the bolt is equal to the sum of the axial elongation of the high-temperature expansion of the flange plate 2, the CMC flange plate and the sleeve. The formula is as follows:

[0009]

[0010] Among them, x is the axial length of the sleeve, a0 is the thermal expansion coefficient of the bolt, x0 is the axial length of the bolt, a1 is the thermal expansion coefficient of flange two, x1 is the axial length of flange two, a2 is the thermal expansion coefficient of the CMC flange, x2 is the axial length of the CMC flange, and a3 is the thermal expansion coefficient of the sleeve.

[0011] A cooling groove is provided on the second flange in a circumferential direction, a cooling pipe is provided in the cooling groove, the cooling pipe has a cooling pipe inlet and a cooling pipe outlet, a coolant flows into the cooling pipe through the cooling pipe inlet, and is discharged through the cooling pipe outlet, and the coolant cools the high-temperature alloy tube and the CMC tube when flowing in the cooling pipe.

[0012] The coolant is liquid fuel of the pulse detonation engine or external cooling water.

[0013] The CMC tube is made of ceramic-based composite material, and a chamfer is provided at a structural mutation area where the cylindrical structure of the CMC tube is connected to the CMC flange, and the chamfer is greater than or equal to R5.

[0014] The ceramic-based composite material of the CMC tube is woven in a 2.5D or 3D manner, the warp direction of the woven structure is the same as the axial direction of the ceramic-based composite material combustion chamber of the combined pulse detonation engine, and the weft direction is the same as the circumferential direction of the ceramic-based composite material combustion chamber of the combined pulse detonation engine. The thickness of the CMC tube is 5mm-10mm.

[0015] A graphite gasket is also arranged between the second flange and the CMC flange, and the graphite gasket is provided with the same bolt holes as those of the second flange and the CMC flange.

[0016] The material of the high-temperature alloy tube is high-temperature alloy material GH3536.

[0017] The ceramic-based composite material is specifically C / SiC material.

[0018] The beneficial effects of the present invention are:

[0019] 1. The coolant of the present invention can use the liquid fuel of the pulse detonation engine, such as kerosene, gasoline, etc. On the one hand, it can reduce the temperature of the flange connection area, help reduce the excessive gap caused by the mismatch of the bolt and nut connection due to high-temperature thermal expansion, and improve the connection strength of the flange; on the other hand, no additional coolant is required, which reduces the weight of the pulse detonation engine.

[0020] 2. The CMC tube of the present invention is designed with chamfers in the structural mutation area, so that the woven structure arrangement of the ceramic-based composite material is more reasonable. Therefore, the overall structural strength of the CMC tube will not be reduced due to excessive corners, which can effectively improve the overall structural strength of the present invention.

[0021] 3. The present invention utilizes the high temperature resistance of the graphite gasket, which effectively improves the sealing connection effect between the high-temperature high-gold cylinder and the CMC cylinder, ensuring that the combustion chamber of the present invention can operate for a long time.

[0022] 4. The present invention provides a sleeve at the bolts and nuts connecting the flange, which helps to reduce the gap caused by high-temperature expansion of the bolt and nut connection, and improves the reliability and stability of the bolt and nut connection; at the same time, sleeve flanges are provided at both ends of the sleeve, and the sleeve flanges not only increase the contact area at both ends of the sleeve to reduce stress concentration, but also increase the sealing of the flange connection.

[0023] 5. The high-temperature, high-gold cylinder and the CMC cylinder of the present invention can adjust the length ratio according to the temperature of the pulse detonation engine combustion chamber to achieve better results.

[0024] 6. The present invention uses CMC materials to reduce the weight of the engine, which has a good beneficial effect on improving the performance of the pulse detonation engine. The pulse detonation engine has a very high application value when applied to various aircraft in the aerospace industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is the connection diagram between flange 2 and CMC flange;

[0027] Figure 3 This is a schematic diagram of the high temperature and high gold cylinder structure;

[0028] Figure 4 It is a schematic diagram of the CMC tube structure;

[0029] Figure 5 Schematic diagram of 2.5D weaving of C / SiC material;

[0030] Among them: 1-high temperature alloy cylinder, 101-flange one, 102-flange two, 103-bolt hole, 104-cooling groove, 105-cooling pipe, 106-cooling pipe inlet, 107-cooling pipe outlet, 2-CMC cylinder, 3-bolt, 4-nut, 201-CMC flange, 202-chamfer, 203-graphite gasket, 5-sleeve. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to the accompanying drawings and embodiments:

[0032] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , the embodiment of the present invention includes:

[0033] A combined pulse detonation engine ceramic matrix composite combustion chamber comprises a high temperature alloy cylinder 1, a bolt 3, a nut 4, a CMC cylinder 2, and a sleeve 5. A flange 101 is connected to a combustion chamber inlet device, a flange 202 is connected to a CMC flange 201 at one end of the CMC cylinder 2, and the high temperature alloy cylinder 1 and the CMC cylinder 2 are connected by flanges to form a combined pulse detonation engine ceramic matrix composite combustion chamber, which has a very high temperature resistance.

[0034] The high-temperature alloy cylinder 1 is made of high-temperature alloy material, and GH3536 can be selected, which has good high-temperature mechanical stability. A cooling groove 104 is processed on the flange plate 102 on the high-temperature alloy cylinder 1, and a cooling pipe 105 is buried in the cooling groove 104. The coolant is introduced into the cooling pipe inlet 106, passes through the cooling pipe 105 in the cooling groove 104, and flows out from the cooling pipe outlet 107. The coolant uses the liquid fuel of the pulse detonation engine. The introduction of the coolant can effectively reduce the temperature of the flange connection area, thereby effectively reducing the gap between the bolts 3 and the nuts 4 caused by the different high-temperature thermal expansion properties, effectively improving the stability and sealing of the flange connection of the pulse detonation engine combined combustion chamber, and improving the structural strength of the flange connection.

[0035] The connection structure of the sleeve 5, bolt 3 and nut 4: Due to the different high-temperature expansion coefficients of the materials of the CMC cylinder 2, the high-temperature alloy cylinder 1 and the bolt 3, the elongations of the flange 2 102, the CMC flange 201 and the bolt 3 are different when the pulse detonation engine is working. The high-temperature expansion coefficients of the high-temperature alloy cylinder 1 and the bolt 3 are large, and the high-temperature expansion coefficient of the CMC cylinder 2 is small, which will cause the axial elongation of the bolt 3 to be greater than the axial elongation of the flange 2 102 and the CMC flange 201. A gap will be generated in the flange connection, resulting in poor sealing of the combustion chamber. In order to minimize the generation of the gap, a sleeve 5 with a larger material expansion rate is designed and placed between the nut 4 and the flange 2 102. Sleeve flanges are set at both ends of the sleeve 5 to increase the contact area at both ends of the sleeve, thereby reducing stress concentration and increasing the sealing of the flange 2 102. The length of the sleeve 5 can be determined in the following manner: when the pulse detonation engine is working, the axial elongation of the bolt 3 due to high-temperature expansion is equal to the sum of the axial elongations of the flange 202, the CMC flange 201 and the sleeve 5, which can effectively reduce the gap of the flange connection and improve the sealing and stability of the flange connection of the combustion chamber of the present invention.

[0036] The structure of the CMC tube 2 includes a CMC flange 201 and a chamfer 202. The CMC tube 2 is made of a ceramic-based composite material and is woven in a 2.5D or 3D manner. The warp direction of the woven structure is the same as the axial direction of the combustion chamber, and the weft direction is the same as the circumferential direction of the combustion chamber. The material has good high temperature resistance and mechanical properties. The thickness of the CMC tube 2 is between 5mm and 10mm, and it has good anti-ablation performance. When used in a pulse detonation engine combustion chamber, it can greatly improve the temperature resistance of the combustion chamber, reduce the amount of cooling air, reduce the weight of the detonation engine, and improve the efficiency and thrust-to-weight ratio of the detonation engine.

[0037] A graphite gasket 203 is placed between the CMC flange 201 and the second flange 102, and then the flanges are connected and fixed by bolts 3 and nuts 4. The graphite gasket 203 has good high-temperature stability, so that the flange connection part of the combustion chamber has good temperature resistance and sealing.

[0038] The structural mutation area between the cylindrical structure on the CMC tube 2 and the CMC flange 201 is designed as a chamfer 202, and the chamfer 202 is set to be greater than or equal to R5, so that the braided structure arrangement of the CMC tube 2 can be more reasonable, so that the overall structural strength of the CMC tube 2 is not reduced due to excessive turning angles, and the overall structural strength of the pulse detonation combustion chamber can be effectively improved.

[0039] The flange 101 on the high-temperature alloy tube 1 is the inlet end of the pulse detonation combustion chamber, and the CMC tube 2 is close to the outlet end of the combustion chamber. This design makes the high-temperature alloy tube 1 located in the inlet and middle area of ​​the combustion chamber, and the CMC tube 2 located in the middle and outlet area of ​​the combustion chamber. Corresponding to the characteristics of low temperature in the inlet area of ​​the combustion chamber and high temperature in the outlet area, the length ratio of the high-temperature alloy tube 1 and the CMC tube 2 can be determined according to the temperature of the combustion chamber.

[0040] The pulse detonation engine generates thrust by using high-temperature, high-pressure combustion gas generated by intermittent detonation waves. When the pulse detonation combustion chamber is in operation, the explosive fuel and oxidant are mixed and filled into the combustion chamber, that is, the entrance of the high-temperature alloy cylinder 1. After ignition and detonation, the generated detonation wave propagates to the open end and is discharged from the combustion chamber. After most of the gas is discharged, the expansion wave reflected from the closed end is discharged from the combustion chamber. After the expansion wave is discharged, the combustion chamber is in a low-pressure state, and the isolation gas is filled in to blow out the remaining gas, and then the explosive mixture is replenished to start a new cycle. The entire working process is intermittent and periodic, that is, the pulse detonation engine is non-steady-state operation. When the detonation frequency is very high, it can be approximately considered that the working process is continuous, and continuous thrust can be provided to propel the aircraft forward. The average temperature of the high-temperature gas in the combustion chamber is different. The temperature at the inlet is the lowest, and the temperature is higher as it is closer to the outlet. Therefore, the present invention adopts a combined combustion chamber structure, and the high-temperature alloy cylinder 1 is placed in the inlet area, and the CMC cylinder 2 is placed in the combustion chamber outlet area, which can effectively resist the high-temperature impact and ablation of the gas in the combustion chamber.

[0041] In order to ensure the sealing of the flange connection area of ​​the pulse detonation combustion chamber, a graphite gasket 203 is added to the connection between the CMC flange 201 and the flange 2 102. Since graphite has good high-temperature stability, it can effectively improve the sealing and temperature resistance of the flange connection. When the combustion chamber starts working, the coolant is introduced from the cooling pipe inlet 106. The coolant is a liquid fuel required by the pulse detonation engine combustion chamber, such as kerosene, gasoline, etc. No additional coolant is needed, which reduces the weight of the pulse detonation engine. The coolant flows into the cooling pipe 105 from the cooling pipe inlet 106, passes through the flange 2 102, and then flows out from the cooling pipe outlet 107. The outflowing coolant is introduced into the fuel inlet of the pulse detonation engine and sprayed into the combustion chamber. While effectively reducing the expansion gap problem caused by high temperature in the flange connection and improving the flange strength, no additional coolant is needed, which reduces the overall quality of the engine.

[0042] The length of sleeve 5 is selected based on the following: when the pulse detonation engine is working, the axial elongation of the high temperature expansion of bolt 3 is equal to the sum of the axial elongation of the high temperature expansion of flange 202, CMC flange 201 and sleeve 5, which can effectively reduce the gap of flange connection and improve the sealing and stability of the flange connection of the pulse detonation engine combined combustion chamber. The length of sleeve 5 is x, and the calculation process is as follows:

[0043]

[0044] In the formula: a0 is the thermal expansion coefficient of the bolt 3, x0 is the axial length of the bolt 3, a1 is the thermal expansion coefficient of the flange 102, x1 is the axial length of the flange 102, a2 ​​is the thermal expansion coefficient of the CMC flange 201, x2 is the axial length of the CMC flange 201, and a3 is the thermal expansion coefficient of the sleeve 5.

[0045] The lengths of the high-temperature alloy tube 1 and the CMC tube 2 are determined according to the temperature distribution of the pulse detonation combustion chamber. The temperature of the combustion chamber is the lowest in the inlet area and the highest in the outlet area. Ensure that the temperature of all areas of the combustion chamber is lower than the temperature resistance temperature of the high-temperature alloy tube 1 and the CMC tube 2. If the temperature is too high, lengthen the length of the CMC tube 2. If the temperature is not high, lengthen the length of the high-temperature alloy tube 1.

[0046] The CMC tube 2 is made of ceramic-based composite materials. There are many kinds of ceramic-based composite materials. Here, 2.5-dimensional woven C / SiC material is selected, which can have good mechanical properties in ultra-high temperature environment, can work for a short time at 2500K temperature, and can work for a long time below 1932K temperature. It can reduce the amount of cooling air of the pulse detonation engine, reduce the weight of the detonation engine, and improve the efficiency and thrust-to-weight ratio of the detonation engine.

[0047] The present invention can improve the durability of the pulse detonation engine combustion chamber, improve the temperature resistance of the combustion chamber, has a simple overall structure, good sealing and high-temperature stability, can effectively increase the operating temperature of the detonation engine, has a good beneficial effect on improving various performances of the pulse detonation engine, and has a good application prospect in various types of aerospace aircraft.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A combined pulse detonation engine ceramic matrix composite combustion chamber, characterized in that: The invention is composed of a high-temperature alloy cylinder (1) and a CMC cylinder (2), wherein one end of the high-temperature alloy cylinder (1) is connected to a flange plate one (101), and the other end is connected to a flange plate two (102), wherein the flange plate one (101) is the inlet end of the ceramic-based composite combustion chamber of the combined pulse detonation engine, the flange plate two (102) is connected to a CMC flange plate (201) at one end of the CMC cylinder (2), and the flange plate two (102) and the CMC flange plate (201) are fixedly connected by bolts (3) and nuts (4), wherein the high-temperature alloy cylinder (1) is the inlet and middle area of ​​the combustion chamber, and the CMC cylinder (2) is the middle and outlet area of ​​the ceramic-based composite combustion chamber of the combined pulse detonation engine; The second flange (102) and the CMC flange (201) are provided with corresponding bolt holes (103); the bolts (3) are inserted into the bolt holes (103) of the CMC flange (201), and are passed out from the bolt holes (103) on the second flange (102) and are screwed together with the nuts (4); a sleeve (5) is further provided between the nut (4) and the second flange (102); the sleeve (5) is sleeved on the bolt column of the bolt (3); Both ends of the sleeve (5) are provided with sleeve flanges. The thermal expansion coefficient of the sleeve (5) is greater than that of the high-temperature alloy sleeve (1). The length of the sleeve (5) is set so that when the pulse detonation engine is working, the axial elongation of the bolt (3) due to high-temperature expansion is equal to the sum of the axial elongations of the flange plate 2 (102), the CMC flange plate (201) and the sleeve (5). The formula is as follows: Wherein, x is the axial length of the sleeve (5), a0 is the thermal expansion coefficient of the bolt (3), x0 is the axial length of the bolt (3), a1 is the thermal expansion coefficient of the second flange (102), x1 is the axial length of the second flange (102), a2 is the thermal expansion coefficient of the CMC flange (201), x2 is the axial length of the CMC flange (201), and a3 is the thermal expansion coefficient of the sleeve (5); A cooling groove (104) is provided on the flange plate (102) in a circumferential direction. A cooling pipe (105) is provided in the cooling groove (104). The cooling pipe (105) has a cooling pipe inlet (106) and a cooling pipe outlet (107). Coolant flows into the cooling pipe (105) through the cooling pipe inlet (106) and is discharged through the cooling pipe outlet (107). When the coolant flows in the cooling pipe (105), the high-temperature alloy cylinder (1) and the CMC cylinder (2) are cooled. The length ratio of the high-temperature high-metal cylinder (1) and the CMC cylinder (2) can be adjusted according to the temperature of the pulse detonation engine combustion chamber.

2. A combined pulse detonation engine ceramic matrix composite combustion chamber as claimed in claim 1, characterized in that: The coolant is liquid fuel of the pulse detonation engine or external cooling water.

3. A combined pulse detonation engine ceramic matrix composite combustion chamber as claimed in claim 1, characterized in that: The CMC tube (2) is made of a ceramic-based composite material, and a chamfer (202) is provided at a structural mutation area where the cylindrical structure of the CMC tube (2) is connected to the CMC flange (201), and the chamfer (202) is greater than or equal to R5.

4. A combined pulse detonation engine ceramic matrix composite combustion chamber as claimed in claim 1, characterized in that: The ceramic matrix composite material of the CMC tube (2) is woven in a 2.5D or 3D manner, the warp direction of the woven structure is the same as the axial direction of the ceramic matrix composite material combustion chamber of the combined pulse detonation engine, and the weft direction is the same as the circumferential direction of the ceramic matrix composite material combustion chamber of the combined pulse detonation engine, and the thickness of the CMC tube (2) is 5 mm-10 mm.

5. The combined pulse detonation engine ceramic matrix composite combustion chamber according to claim 1, characterized in that: A graphite gasket (203) is also arranged between the second flange (102) and the CMC flange (201), and the graphite gasket (203) is provided with bolt holes (103) which are the same as those of the second flange (102) and the CMC flange (201).

6. A combined pulse detonation engine ceramic matrix composite combustion chamber as claimed in claim 1, characterized in that: The material of the high-temperature alloy cylinder (1) is the high-temperature alloy material GH3536.

7. A combined pulse detonation engine ceramic matrix composite combustion chamber as claimed in claim 1, characterized in that: The ceramic-based composite material is specifically C / SiC material.

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