Engine efficient mixing combustion test device based on oxidant porous jet flow and design method

Abstract

The invention provides an engine efficient mixing combustion test device based on oxidant porous jet flow. The engine efficient mixing combustion test device comprises a front end socket, a porous jet device, a combustion chamber shell, a front medicine baffle, an oxygen-poor propellant, a rear medicine baffle and a throat liner. According to the invention, the porous jet device is additionally arranged at the inlet of the combustion chamber, the front chemical baffle is additionally arranged in the pre-combustion chamber, and the rear chemical baffle is additionally arranged in the aftercombustion chamber, so that incoming flow characteristics of different oxygen-enriched gases and gas-solid mixed combustion pressure and combustion speed of the oxygen-enriched gases and oxygen-deficient propellants under the structures of the pre-combustion chamber and the aftercombustion chamber can be measured; therefore, the combustion chamber structure meeting the requirements of combustion performance and propulsive efficiency can be designed according to the pressure intensity and the combustion speed.

Description

Technical Field

[0001] The present invention relates to the technical field of solid rocket engine testing, and in particular to an engine high-efficiency mixed combustion test device and a design method based on an oxidizer porous jet, wherein the device is suitable for testing and studying the high-efficiency mixed combustion of an oxygen-rich fuel gas flow and an oxygen-depleted propellant. Background Art

[0002] In solid-liquid hybrid engines and solid ramjet engines, oxidants (such as fuel-rich gas or air) react with oxygen-depleted propellants to form a diffusion flame. In the current engine structure, due to the extremely fast flow rate of the oxidant, the residence time of the oxygen-rich gas or air in the combustion chamber is short, making it difficult to mix and burn with the pyrolysis gas of the oxygen-depleted propellant. In addition, the oxygen-depleted propellant is also affected by the flow of gas in the combustion chamber, the combustion temperature, the flame position, and the heat transfer of the flame to the combustion surface during the mixed combustion. Therefore, under the influence of multiple highly coupled factors, the current mixed combustion efficiency of oxygen-rich gas and oxygen-depleted propellant is low and the burning rate of oxygen-depleted propellant is low. How to optimize its combustion performance and improve propulsion efficiency has always been an important issue facing scientific researchers. Summary of the invention

[0003] Porous jets are widely used in the engineering field due to their high jet velocity and good heat and mass transfer effects, but are less used in fuel / oxygen separation rocket engines. In order to study the injection method of oxidant gas, especially the significant influence of porous jets on the three-dimensional flow and heat transfer performance inside the engine, the present invention proposes an engine high-efficiency mixed combustion test device and design method based on oxidant porous jets, which can meet the test requirements for different flow modes of oxygen-rich fuel gas, and can provide structural characteristics that affect factors such as gas flow, combustion temperature, flame position and flame combustion surface in the flow field in the combustion chamber. It is suitable for the test research of efficient mixed combustion of oxygen-rich fuel gas flow and oxygen-depleted propellant, and provides an experimental basis for revealing the influence of porous jets on the internal flow and heat transfer performance of solid rocket engines.

[0004] The technical solution of the present invention is:

[0005] An engine high-efficiency mixed combustion test device based on oxidant porous jet includes a front head, a porous ejector, a combustion chamber shell, a front baffle, an oxygen-depleted propellant, a rear baffle, and a throat liner;

[0006] The combustion chamber shell is a hollow cylindrical structure with an open front end and a closed rear end; a connecting flange is provided at the front opening for sealingly connecting with the front head; a through hole for installing the throat liner is provided at the center of the rear closed surface; a pressure measuring hole connected to a pressure measuring seat is provided on the rear side wall of the combustion chamber shell, and the pressure measuring seat is connected to the pressure sensor;

[0007] The front end cap is sealed and fixedly connected to the combustion chamber shell; a through hole for introducing oxygen-enriched fuel gas is provided in the center of the front end cap;

[0008] The multi-hole ejector is a detachable and replaceable module, which is coaxially sealed and fixed with the front end at the central through hole of the front end; the multi-hole ejector is provided with a plurality of ejection holes for introducing oxygen-enriched gas into the combustion chamber, so as to convert the input oxygen-enriched gas from one stream into multiple dispersed streams of oxygen-enriched gas;

[0009] The front baffle is a detachable and replaceable module, which is a cylindrical ring structure, and its outer diameter is consistent with the inner diameter of the combustion chamber shell. It is installed at the front end of the combustion chamber shell, and its two ends are constrained by the front head and the oxygen-depleted propellant;

[0010] The rear baffle is a detachable and replaceable module, which is a cylindrical ring structure, and its outer diameter is consistent with the inner diameter of the combustion chamber shell. It is installed at the rear end of the combustion chamber shell, and its two ends are constrained by the rear end wall of the combustion chamber shell and the oxygen-depleted propellant;

[0011] The outlet of the rear end face of the combustion chamber shell is fixedly installed with a throat liner, and by changing the diameter of the throat liner, pressure condition tests of gas-solid mixed combustion of different oxygen-rich fuel gases and oxygen-poor propellants can be realized;

[0012] The oxygen-depleted propellant adopts an annular grain column, and a coating layer is applied on both sides of the oxygen-depleted propellant to prevent side combustion. The two ends of the oxygen-depleted propellant are restrained by a front grain baffle plate and a rear grain baffle plate.

[0013] Furthermore, the multi-hole ejector adopts a structure in which the front section is a hemispherical shell and the rear section is a cylindrical shell, and a plurality of ejection holes for introducing oxygen-rich combustion gas into the combustion chamber are opened on the hemispherical shell.

[0014] Furthermore, by setting a multi-hole ejector with different numbers of ejection holes and shapes of ejection holes, gas-solid mixed combustion tests of oxygen-rich fuel gas and oxygen-depleted propellant under different ejection holes were carried out.

[0015] Furthermore, by setting front baffles of different axial lengths, changing the distance from the oxygen-depleted propellant to the porous ejector, and adjusting the structure of the front pre-combustion chamber in the combustion chamber, gas-solid mixed combustion tests of oxygen-rich fuel gas and oxygen-depleted propellant with different pre-combustion chamber structures were carried out.

[0016] Furthermore, by setting rear baffles with different axial lengths and adjusting the aspect ratio of the afterburner in the combustion chamber, gas-solid mixed combustion tests of oxygen-rich fuel gas and oxygen-depleted propellant with different afterburner chamber structures were carried out.

[0017] Furthermore, a graphite gasket, a throat liner and a throat liner pressure screw are installed at the outlet of the rear end face of the combustion chamber shell; a graphite gasket is placed on the step surface of the inner small and outer large step hole at the rear end of the combustion chamber shell, sealing is achieved by the graphite gasket, a throat liner is placed on the graphite gasket, and fixed with a throat liner pressure screw.

[0018] The present invention also proposes a design method for the above-mentioned test device, comprising the following steps:

[0019] Step 1: Obtain the mass flow rate of the oxygen-rich fuel gas flowing into the combustion chamber, determine the mass flow rate of the oxygen-depleted propellant according to the O2 mass fraction of the oxygen-rich fuel gas and the theoretical equivalence ratio, and determine the inner diameter and length of the oxygen-depleted propellant according to the mass flow rate of the oxygen-depleted propellant;

[0020] Step 2: Obtain the working pressure range of the combustion chamber, determine the self-sustaining combustion rate of the oxygen-depleted propellant based on the minimum working pressure, and determine the radial thickness of the oxygen-depleted propellant in combination with the set combustion time, and then determine the outer diameter of the oxygen-depleted propellant and the inner diameter of the combustion chamber; determine the outer diameters of the front baffle plate and the rear baffle plate based on the inner diameter of the combustion chamber;

[0021] Step 3: According to the maximum design pressure of the combustion chamber and the selected combustion chamber shell material, the initial value of the combustion chamber shell wall thickness is determined according to the maximum stress intensity theoretical formula; and the design margin is determined in combination with the combustion time, combustion temperature and number of uses to obtain the final wall thickness of the combustion chamber shell;

[0022] Step 4: Determine the self-sustaining combustion rate range of the oxygen-poor propellant according to the working pressure range of the combustion chamber and the mass flow rate of the oxygen-rich gas flowing into the combustion chamber, and then determine the throat diameter range of the throat liner, and determine the size of the graphite gasket and the throat liner pressure screw according to the throat liner size;

[0023] Step 5: According to the test requirements, design the axial lengths of the front baffle plate and the rear baffle plate and the number and shape of the jet holes in the multi-hole ejector.

[0024] Beneficial Effects

[0025] The present invention has the following beneficial effects:

[0026] 1. The separate design and processing of the porous ejector and the front head can realize the flexible combination of the porous ejector and the front head to meet the test requirements of different porous jet combustion conditions;

[0027] 2. By changing the front baffle, the structure of the pre-combustion chamber is changed, so that the flow and mixing of oxygen-enriched gas in the pre-combustion chamber can be optimized through experiments;

[0028] 3. By changing the rear baffle plate, the structure of the afterburner chamber is changed, so that the mixing and combustion of oxygen-rich fuel gas and oxygen-poor propellant pyrolysis gas can be optimized through experiments to improve the secondary combustion efficiency.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 It is a main sectional view, left sectional view and top sectional view of a porous jet high-efficiency mixing burner device;

[0032] Figure 2 It is a three-dimensional picture of the porous ejector from different viewing angles;

[0033] Figure 3 It is the main cross-sectional view and left view of the porous ejector;

[0034] Figure 4 It is the main sectional view and right view of the front head;

[0035] Figure 5 It is the main sectional view, left side view and top sectional view of the combustion chamber shell;

[0036] Figure 6 It is the main sectional view and left view of the sealing ring;

[0037] Figure 7 It is the main sectional view and left view of the front baffle plate;

[0038] Figure 8 It is the main sectional view and left view of the rear baffle;

[0039] Fig. 9 It is the main cross-sectional view and top view of the pressure measuring seat;

[0040] Fig.10 It is the main cross-sectional view and left view of the graphite gasket;

[0041] Fig.11 This is the main cross-sectional view of the throat liner pressure screw;

[0042] Fig.12 It is the main sectional view and left view of the throat liner.

[0043] In the figure: 1 porous ejector, 2 cylindrical head hexagon socket screw, 3 front head, 4 combustion chamber shell, 5 sealing ring, 6 front baffle plate, 7 oxygen-depleted propellant, 8 rear baffle plate, 9 pressure measuring seat, 10 graphite gasket, 11 throat liner, 12 throat liner pressure screw. DETAILED DESCRIPTION

[0044] In order to study the performance of efficient mixed combustion test of oxygen-rich fuel gas and oxygen-depleted propellant, the present invention proposes an efficient mixed combustion test device and design method for an engine based on oxidant porous jet. In theory, the oxidant porous jet device can change the flow mode of oxygen-rich fuel gas and increase the residence time of oxygen-rich fuel gas, thereby affecting the flow of fuel gas in the combustion chamber flow field and the heat transfer to the combustion surface. Therefore, by adding a porous ejector at the inlet of the combustion chamber, adding a front baffle plate in the pre-combustion chamber, and adding a rear baffle plate in the after-combustion chamber, the flow characteristics of oxygen-rich fuel gas, the gas-solid mixed combustion pressure and burning rate of oxygen-rich fuel gas and oxygen-depleted propellant under different pre-combustion chamber and after-combustion chamber structures can be measured, and then the combustion chamber structure design that meets the requirements of combustion performance and propulsion efficiency can be carried out according to the pressure and burning rate.

[0045] like Figure 1 As shown, the test device consists of a front head, a porous ejector, a sealing ring, a combustion chamber shell, a front baffle plate, an oxygen-depleted propellant, a rear baffle plate, a pressure measuring seat, a graphite gasket, a throat liner, and a throat liner pressure screw.

[0046] like Figure 1 and Figure 5 As shown, the combustion chamber shell is a hollow cylindrical structure with an open front end and a closed rear end; a connecting flange is provided at the front opening for sealing connection with the front head; a through hole for installing the throat liner is provided in the center of the rear closed surface. A pressure measuring hole connected to a pressure measuring seat is provided on the rear side wall of the combustion chamber shell. The pressure measuring seat is connected to a pressure sensor and can measure the pressure change when the oxygen-rich and fuel-rich gas is mixed and burned inside the combustion chamber.

[0047] like Figure 1 and Figure 4 As shown, the front end cap is connected to the combustion chamber shell and fixed by cylindrical head hexagon socket screws. A sealing ring groove is provided on the matching surface of the combustion chamber shell and the front end cap, and the combustion chamber is sealed by the sealing ring. A through hole is opened in the center of the front end cap for introducing oxygen-enriched fuel gas.

[0048] The porous ejector is a detachable and replaceable module, such as Figure 1 and Figure 2 As shown, the front section is a hemispherical shell and the rear section is a cylindrical shell structure, which is coaxially sealed and fixed with the front head at the central through hole of the front head. Several jet holes are opened on the hemispherical shell for introducing oxygen-rich gas into the combustion chamber. When the oxygen-rich gas is ejected from the multi-hole ejector, the oxygen-rich gas changes from one stream to multiple dispersed streams of oxygen-rich gas. The multi-hole jet has a significant effect on the internal flow performance of the engine. By setting different numbers of jet holes and jet hole shapes, gas-solid mixed combustion tests of oxygen-rich gas and oxygen-poor propellant under different jet holes can be carried out.

[0049] The front baffle is a detachable and replaceable module, such as Figure 1 and Figure 7As shown, it is a cylindrical ring structure, the outer diameter of which is consistent with the inner diameter of the combustion chamber shell, installed at the front end of the combustion chamber shell, and constrained by the front head and the oxygen-depleted propellant at both ends. By setting the front baffle plates with different axial lengths, the distance from the oxygen-depleted propellant to the porous ejector can be changed, thereby adjusting the structure of the front pre-combustion chamber in the combustion chamber, which can be used to study the gas-solid mixed combustion of oxygen-rich gas and oxygen-depleted propellant with different pre-combustion chamber structures.

[0050] The rear baffle is a detachable and replaceable module, such as Figure 1 and Figure 8 As shown, it is a cylindrical ring structure, the outer diameter of which is consistent with the inner diameter of the combustion chamber shell, installed at the rear end of the combustion chamber shell, and constrained by the rear end wall of the combustion chamber shell and the oxygen-depleted propellant at both ends. By setting the rear baffle plates with different axial lengths, the aspect ratio of the afterburner in the combustion chamber can be adjusted, affecting the secondary combustion of oxygen-rich gas and combustible gas, and can be used to study the gas-solid mixed combustion of oxygen-rich gas and oxygen-depleted propellant with different afterburner structures.

[0051] The outlet of the rear end face of the combustion chamber shell is equipped with a graphite gasket, a throat liner, and a throat liner pressure screw. A graphite gasket is placed on the step surface of the inner small and outer large step hole at the rear end of the combustion chamber shell, and the sealing is achieved through the graphite gasket. A throat liner is placed on the graphite gasket and fixed with a throat liner pressure screw. By changing the diameter of the throat liner, pressure condition tests of different oxygen-rich fuel gas and oxygen-poor propellant gas-solid mixed combustion are achieved.

[0052] The oxygen-depleted propellant uses an annular grain column, the outer diameter of which is consistent with the inner diameter of the combustion chamber shell. The oxygen-depleted propellant is coated on both sides to prevent side combustion and achieve a parallel layer combustion effect. The two ends of the oxygen-depleted propellant are restrained by the front baffle plate and the rear baffle plate.

[0053] During installation, put the graphite gasket into the outlet of the closed section of the combustion chamber housing, then place the throat liner on the graphite gasket, and finally use the throat liner pressure screw to fix the throat liner and graphite gasket to achieve a sealed state. Put the rear baffle plate into the combustion chamber housing from the inlet of the combustion chamber housing, then put the oxygen-depleted propellant into the combustion chamber housing from the inlet, and then put the front baffle plate into the combustion chamber housing from the inlet of the combustion chamber. Rotate the porous ejector into the front head, then put the sealing ring into the sealing groove, and then fix and seal the front head that has fixed the porous ejector with the combustion chamber housing with a cylindrical head hexagon screw, and finally connect the pressure sensor to the pressure measuring seat to obtain an engine high-efficiency mixing combustion test device based on oxidant porous jet.

[0054] In addition, the present invention also proposes a corresponding design method for the above-mentioned test device, comprising the following steps:

[0055] Step 1: Obtain the mass flow rate of the oxygen-rich fuel gas flowing into the combustion chamber, determine the mass flow rate of the oxygen-depleted propellant according to the O2 mass fraction of the oxygen-rich fuel gas and the theoretical equivalence ratio, and determine the inner diameter and length of the oxygen-depleted propellant according to the mass flow rate of the oxygen-depleted propellant;

[0056] Step 2: Obtain the working pressure range of the combustion chamber, determine the self-sustaining combustion rate of the oxygen-depleted propellant based on the minimum working pressure, and determine the radial thickness of the oxygen-depleted propellant in combination with the set combustion time, and then determine the outer diameter of the oxygen-depleted propellant and the inner diameter of the combustion chamber; determine the outer diameters of the front baffle plate and the rear baffle plate based on the inner diameter of the combustion chamber;

[0057] Step 3: According to the maximum design pressure of the combustion chamber and the selected combustion chamber shell material, the initial value of the combustion chamber shell wall thickness is determined according to the maximum stress intensity theoretical formula; and the design margin is determined in combination with the combustion time, combustion temperature and number of uses to obtain the final wall thickness of the combustion chamber shell;

[0058] Step 4: Determine the self-sustaining combustion rate range of the oxygen-poor propellant according to the working pressure range of the combustion chamber and the mass flow rate of the oxygen-rich gas flowing into the combustion chamber, and then determine the throat diameter range of the throat liner, and determine the size of the graphite gasket and the throat liner pressure screw according to the throat liner size;

[0059] Step 5: According to the test requirements, design the axial lengths of the front baffle plate and the rear baffle plate and the number and shape of the jet holes in the multi-hole ejector.

[0060] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0061] The experimental device design process in this embodiment is as follows:

[0062] Step 1: Obtain the oxygen-rich gas mass flow rate flowing into the combustion chamber as 50 g·s -1 According to the O2 mass fraction of the oxygen-rich fuel gas and the theoretical equivalence ratio, the mass flow rate of the oxygen-depleted propellant is determined to be 36 g·s -1 According to the mass flow rate of the oxygen-depleted propellant, the inner diameter and length of the oxygen-depleted propellant are determined to be 30mm×100mm.

[0063] Step 2: Obtain the working pressure range of the combustion chamber from 2 to 10 MPa. Based on the minimum working pressure of 2 MPa, determine the self-sustaining combustion rate of the oxygen-poor propellant to be 3.34 mm·s -1 , and combined with the set combustion time of 3s, the radial thickness of the oxygen-depleted propellant is determined to be 10mm, and then the outer diameter of the oxygen-depleted propellant and the inner diameter of the combustion chamber are determined to be 50mm; therefore, the size of the oxygen-depleted propellant is outer diameter × inner diameter × length 50mm × 30mm × 100mm. And the outer diameter of the front baffle and the rear baffle is determined to be 50mm.

[0064] Step 3: The maximum design pressure of the combustion chamber is 15 MPa. The selected combustion chamber shell material is ultra-high strength alloy steel 30CrMnSiA. The strength limit σ of ultra-high strength alloy steel 30CrMnSiA is b is 1079MPa, and the yield limit σ s It is 883MPa. According to the maximum stress strength theoretical formula, the initial value of the combustion chamber shell wall thickness is determined to be 0.825mm. Combined with the combustion time, combustion temperature and number of uses, the design margin is determined, and the final wall thickness of the combustion chamber shell is 10mm. The inner diameter of the combustion chamber shell is determined to be 50mm, the outer diameter is 70mm, and the length is determined to be 210mm based on the aspect ratio.

[0065] An outlet with a diameter of 10 mm is opened in the closed section of the combustion chamber casing for connection with the throat liner, and a groove with a diameter × length of 24 mm × 16 mm is opened to place the graphite gasket, throat liner and throat liner pressure screw.

[0066] A sealing groove is designed at the front end of the combustion chamber casing. The outer diameter × inner diameter × thickness of the sealing groove is 66mm × 58mm × 5mm. The sealing ring is made of graphite gasket with a compression rate of 0.3-0.5 and a size of 66mm × 58mm × 3mm.

[0067] A hole with a diameter of 2 mm is opened on the side wall 171 mm away from the front end of the combustion chamber shell for welding the pressure measuring seat, which is connected to the pressure sensor to measure the pressure of the combustion chamber during the test.

[0068] Step 4: Based on the working pressure range of the combustion chamber (2-10 MPa) and the mass flow rate of the oxygen-enriched gas flowing into the combustion chamber (50 g·s) -1 , determine the self-sustaining burning rate range of oxygen-poor propellant 3-7mm·s -1 , and then determined that the throat diameter range of the throat liner is 4-10mm, the outer diameter of the throat liner is 16mm, it is made of graphite, the convergence section is 45 degrees, there is no expansion section, and the length is 15mm.

[0069] According to the size of the throat liner, determine the size of the graphite gasket and the throat liner screw: the graphite gasket is used for sealing, and the compression rate is 0.3-0.5, so the outer diameter × inner diameter × length of the graphite gasket is 24mm × 10mm × 3mm; the throat liner screw is used to fix the throat liner and graphite gasket, the thickness of the graphite gasket is 3mm and the length of the throat liner is 15mm, so the length of the throat liner screw is 16mm. The outer diameter of the throat liner screw is 24mm, and the inner diameter is 16.2mm.

[0070] Step 5: According to the test requirements, design the axial lengths of the front baffle plate and the rear baffle plate and the number and shape of the jet holes in the multi-hole ejector.

[0071] The front baffle is used to fix the position of the oxygen-depleted propellant in the pre-combustion chamber and to change the structure of the pre-combustion chamber. The outer diameter of the front baffle is 50 mm, and the inner diameter and axial length are determined according to the test requirements;

[0072] The rear baffle is used to fix the position of the oxygen-depleted propellant in the afterburner and to change the structure of the afterburner. The outer diameter of the rear baffle is 50 mm, and the inner diameter and axial length are determined according to the test requirements.

[0073] The front head is used to seal the combustion chamber. A hole with a diameter × length of 14mm × 15mm is opened at the center of the front head, and an external threaded hole with an outer diameter × inner diameter × length of 24mm × 18mm × 8mm is opened on the side close to the combustion chamber to fix the multi-hole ejector. At the same time, the outer diameter × inner diameter × length of the sealing groove is designed to be 66mm × 58mm × 4mm to fix the sealing ring, and 6 holes with a diameter × length of 8.2 × 15mm are opened at a distance of 45mm from the center to connect the front head and the combustion chamber shell.

[0074] The cylindrical shell part of the porous ejector has an internal threaded hole with an outer diameter × inner diameter × length of 24mm × 18mm × 8mm, which is used to fix the front head; the other part is a hemispherical shell with an outer diameter × inner diameter of 22mm × 14mm, and holes are opened on the hemispherical shell to form a porous ejector with different numbers of holes. The diameter of one hole is 5mm, the diameter of three holes is 2.88mm, the diameter of four holes is 2.5mm, and the diameter of five holes is 2.24mm. The total area of ​​one hole, three holes, four holes and five holes remains constant and is 19.625mm 2 .

[0075] Two examples of test devices are given below:

[0076] Embodiment 1:

[0077] For the gas-solid mixed combustion test of oxygen-rich gas and oxygen-poor propellant, the oxygen-poor propellant is made into a grain column with an outer diameter × inner diameter × length of 50mm × 30mm × 100mm. A glass rod is used to apply the coating liquid on both sides of the oxygen-poor propellant to prevent it from burning on the side and achieve a parallel layer combustion effect. Then a graphite gasket with an outer diameter × inner diameter × length of 24mm × 8mm × 3mm is placed at the outlet of the combustion chamber, a throat liner with a throat diameter of 5mm is placed on the graphite gasket, and then the throat liner and graphite gasket are fixed with a M24 × 1.5 throat liner screw. Then a rear baffle with an outer diameter × inner diameter × length of 50mm × 35mm × 70mm is placed in the combustion chamber, the coated oxygen-poor propellant with an outer diameter × inner diameter × length of 50mm × 30mm × 100mm is placed in the combustion chamber, and then a front baffle with an outer diameter × inner diameter × length of 50mm × 35mm × 10mm is placed in the combustion chamber. Then fix the porous ejector with two ejection holes to the front head, and then put the sealing ring with an outer diameter × inner diameter × length of 66mm × 58mm × 3mm into the sealing groove, and then fix the front head with the porous ejector to the combustion chamber shell with 6 M8 × 1 screws, connect the pressure sensor to the M20 × 1.5 pressure measuring seat, and the oxygen-enriched mass flow rate is 50g·s -1 Entering the combustion chamber and burning with the oxygen-poor propellant, the pressure sensor records the pressure change in the combustion chamber. The combustion time is 3s, the maximum pressure is 2.4MPa, and the burning rate is 3.33mm·s -1 .

[0078] Embodiment 2:

[0079] For the gas-solid mixed combustion test of oxygen-rich gas and oxygen-poor propellant, the oxygen-poor propellant was made into a grain column with an outer diameter × inner diameter × length of 50mm × 30mm × 100mm, and a coating layer was applied on both sides of the oxygen-poor propellant with a glass rod to prevent it from burning on the side and achieve a parallel layer combustion effect. Then a graphite gasket with an outer diameter × inner diameter × length of 24mm × 10mm × 3mm was placed at the outlet of the combustion chamber, a throat liner with a throat diameter of 5mm was placed on the graphite gasket, and the throat liner and graphite gasket were fixed with a throat liner pressure screw of M24 × 1.5. Then a rear baffle with an outer diameter × inner diameter × length of 50mm × 35mm × 70mm was placed in the combustion chamber, and the coated oxygen-poor propellant with an outer diameter × inner diameter × length of 50mm × 30mm × 100mm was placed in the combustion chamber, and then a front baffle with an outer diameter × inner diameter × length of 50mm × 35mm × 10mm was placed in the combustion chamber. Then fix the porous ejector with 4 ejection holes to the front head, and then put the sealing ring with an outer diameter × inner diameter × length of 66mm × 58mm × 3mm into the sealing groove, and then fix the front head with the porous ejector to the combustion chamber shell with 6 M8 × 1 screws, connect the pressure sensor to the M20 × 1.5 pressure measuring seat, and the oxygen-enriched mass flow rate is 50g·s -1Entering the combustion chamber and burning with the oxygen-poor propellant, the pressure sensor records the pressure change in the combustion chamber. The combustion time is 2.4s, the maximum pressure is 3.2MPa, and the burning rate is 4.17mm·s -1 .

[0080] In the gas-solid mixed combustion test of oxygen-rich gas and oxygen-depleted propellant, when the oxygen-rich gas is ejected from the porous ejector, the oxygen-rich gas changes from one stream to multiple dispersed streams of oxygen-rich gas. The porous jet has a significant effect on the internal flow performance of the engine. As the number of porous jet holes increases, the aperture of each hole gradually decreases, so the flow rate of the oxygen-rich gas entering the combustion chamber increases and the flow uniformity is improved. In particular, when the number of porous jet holes increases to a certain extent, the flow inside the engine shows obvious three-dimensional characteristics, and the flow structure is more complex. In addition, each dispersed oxygen-rich combustion gas in the combustion chamber interacts with each other to form multiple recirculation zones. The existence of the recirculation zone will strengthen the flow, mixing and combustion of the oxygen-rich combustion gas, enhance the heat transfer to the upstream of the oxygen-depleted propellant, and make the combustion close to the combustion surface, thereby promoting heat transfer to the combustion surface and increasing the combustion temperature. At the same time, the existence of the recirculation zone reduces the speed of the flow field in the combustion chamber, causing the residence time of the oxygen-rich combustion gas to increase, thereby gradually increasing the heat transfer coefficient inside the engine, improving the heat transfer efficiency, and gradually improving the combustion performance and propulsion efficiency of the engine. Through experiments conducted with the test device proposed by the present invention, it was found that when the number of porous jet holes increased to 4 holes, the heat transfer coefficient reached a maximum value, and the combustion performance and propulsion efficiency of the engine reached an optimal value, but when the number of porous jet holes continued to increase, the heat transfer coefficient, combustion performance and propulsion efficiency began to show a downward trend, which shows that too many porous jet holes will lead to deterioration of heat transfer performance, resulting in insufficient combustion and reduced propulsion efficiency.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. An engine high-efficiency mixed combustion test device based on oxidant porous jet, characterized in that: It includes front head, porous ejector, combustion chamber shell, front baffle, oxygen-depleted propellant, rear baffle, and throat liner; The combustion chamber shell is a hollow cylindrical structure with an open front end and a closed rear end; a connecting flange is provided at the front opening for sealingly connecting with the front head; a through hole for installing the throat liner is provided at the center of the rear closed surface; a pressure measuring hole connected to a pressure measuring seat is provided on the rear side wall of the combustion chamber shell, and the pressure measuring seat is connected to the pressure sensor; The front end cap is sealed and fixedly connected to the combustion chamber shell; a through hole for introducing oxygen-enriched fuel gas is provided in the center of the front end cap; The multi-hole ejector is a detachable and replaceable module, which is coaxially sealed and fixed with the front end at the central through hole of the front end; the multi-hole ejector is provided with a plurality of ejection holes for introducing oxygen-enriched gas into the combustion chamber, so as to convert the input oxygen-enriched gas from one stream into multiple dispersed streams of oxygen-enriched gas; The front baffle is a detachable and replaceable module, which is a cylindrical ring structure, and its outer diameter is consistent with the inner diameter of the combustion chamber shell. It is installed at the front end of the combustion chamber shell, and its two ends are constrained by the front head and the oxygen-depleted propellant; The rear baffle is a detachable and replaceable module, which is a cylindrical ring structure, and its outer diameter is consistent with the inner diameter of the combustion chamber shell. It is installed at the rear end of the combustion chamber shell, and its two ends are constrained by the rear end wall of the combustion chamber shell and the oxygen-depleted propellant; The outlet of the rear end face of the combustion chamber shell is fixedly installed with a throat liner, and by changing the diameter of the throat liner, pressure condition tests of gas-solid mixed combustion of different oxygen-rich fuel gases and oxygen-poor propellants can be realized; The oxygen-depleted propellant adopts an annular grain column, and a coating layer is applied on both sides of the oxygen-depleted propellant to prevent side combustion. The two ends of the oxygen-depleted propellant are restrained by a front grain baffle plate and a rear grain baffle plate.

2. The engine high-efficiency mixed combustion test device based on oxidant porous jet according to claim 1 is characterized by: The multi-hole ejector adopts a structure in which the front section is a hemispherical shell and the rear section is a cylindrical shell. The hemispherical shell is provided with a plurality of ejection holes for introducing oxygen-rich combustion gas into the combustion chamber.

3. The engine high-efficiency mixed combustion test device based on oxidant porous jet according to claim 1 or 2, characterized in that: By setting a multi-hole ejector with different numbers of ejection holes and shapes of ejection holes, gas-solid mixed combustion tests of oxygen-rich fuel gas and oxygen-depleted propellant were carried out under different ejection holes.

4. The engine high-efficiency mixed combustion test device based on oxidant porous jet according to claim 1 is characterized in that: By setting front baffles of different axial lengths, changing the distance from the oxygen-depleted propellant to the porous ejector, and adjusting the structure of the front pre-combustion chamber in the combustion chamber, gas-solid mixed combustion tests of oxygen-rich fuel gas and oxygen-depleted propellant with different pre-combustion chamber structures were carried out.

5. The engine high-efficiency mixed combustion test device based on oxidant porous jet according to claim 1 is characterized in that: By setting rear baffles with different axial lengths and adjusting the aspect ratio of the afterburner in the combustion chamber, gas-solid mixed combustion tests of oxygen-rich fuel gas and oxygen-depleted propellant with different afterburner chamber structures were carried out.

6. The engine high-efficiency mixed combustion test device based on oxidant porous jet according to claim 1 is characterized by: A graphite gasket, a throat liner and a throat liner pressing screw are installed at the outlet of the rear end face of the combustion chamber shell; a graphite gasket is placed on the step surface of the inner small and outer large step hole at the rear end of the combustion chamber shell, and sealing is achieved by the graphite gasket. A throat liner is placed on the graphite gasket and fixed with a throat liner pressing screw.

7. A method for designing a test device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Obtain the mass flow rate of the oxygen-rich fuel gas flowing into the combustion chamber, determine the mass flow rate of the oxygen-depleted propellant according to the O2 mass fraction of the oxygen-rich fuel gas and the theoretical equivalence ratio, and determine the inner diameter and length of the oxygen-depleted propellant according to the mass flow rate of the oxygen-depleted propellant; Step 2: Obtain the working pressure range of the combustion chamber, determine the self-sustaining combustion rate of the oxygen-depleted propellant based on the minimum working pressure, and determine the radial thickness of the oxygen-depleted propellant in combination with the set combustion time, and then determine the outer diameter of the oxygen-depleted propellant and the inner diameter of the combustion chamber; determine the outer diameters of the front baffle plate and the rear baffle plate based on the inner diameter of the combustion chamber; Step 3: According to the maximum design pressure of the combustion chamber and the selected combustion chamber shell material, the initial value of the combustion chamber shell wall thickness is determined according to the maximum stress intensity theoretical formula; The design margin is determined by combining the combustion time, combustion temperature and number of uses to obtain the final wall thickness of the combustion chamber shell; Step 4: Determine the self-sustaining combustion rate range of the oxygen-poor propellant according to the working pressure range of the combustion chamber and the mass flow rate of the oxygen-rich gas flowing into the combustion chamber, and then determine the throat diameter range of the throat liner, and determine the size of the graphite gasket and the throat liner pressure screw according to the throat liner size; Step 5: According to the test requirements, design the axial lengths of the front baffle plate and the rear baffle plate and the number and shape of the jet holes in the multi-hole ejector.

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