An experimental device and method for the combustion characteristics of a gas-liquid nozzle under supercritical conditions

Abstract

The present invention provides an experimental device and method for studying the combustion characteristics of a gas-liquid nozzle under supercritical conditions, which are used to solve the technical problem that there is currently no experimental method for measuring the combustion characteristics of a gas-liquid nozzle under supercritical conditions. An experimental device for studying the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to the present invention includes an oxygen-rich gas generator, a gas-liquid injection unit, and an optical observation system. The oxygen-rich gas generator includes a liquid-liquid nozzle, a generator body, and a throttle orifice plate. By generating oxygen-rich gas with a given flow rate and thermal parameters through the oxygen-rich gas generator, the combustion characteristics of the gas-liquid nozzle under supercritical conditions can be experimentally simulated to a large extent. At the same time, introducing the optical observation system into the study of the high-pressure combustion of the gas-liquid nozzle is of great significance for understanding and recognizing the unsteady combustion characteristics of the gas-liquid nozzle under supercritical conditions.

Description

Technical Field

[0001] The present invention relates to a combustion characteristic test device and test method for a gas-liquid nozzle, and particularly to a combustion characteristic test device and test method for a gas-liquid nozzle under supercritical conditions. Background Art

[0002] The thrust chamber is the core component of a liquid rocket engine. In a high-pressure staged combustion engine thrust chamber, a gas-liquid injector is often used to supplement the combustion of the oxygen-rich gas generated by the gas generator. The interaction between gas and liquid can significantly improve the atomization performance of the nozzle and thus improve the combustion efficiency. The gas-liquid nozzle is the most basic combustion organization unit in the gas-liquid injector. Depending on the type of propellant, a dual centrifugal nozzle, a straight-through nozzle, or a straight-through / centrifugal nozzle can be selected. The gas-liquid nozzle injects a certain mass flow rate of gas and liquid propellants into the combustion chamber, where atomization, evaporation, mixing, and combustion occur to ensure the completeness and stability of combustion. The structural parameter design of the gas-liquid nozzle directly affects the atomization and combustion performance of the propellants, thus largely determining the performance of the thrust chamber. Therefore, during the development of liquid rocket engines, it is necessary to conduct screening hot tests on gas-liquid nozzles.

[0003] In the prior art, although there are studies on the atomization and combustion performance of gas-liquid nozzles, most of them are basic studies based on the atmospheric environment. In some high-pressure test studies, the gas propellants used are single-component gas oxidizers or gas fuels, which cannot simulate the pressure, temperature, and component characteristics of the oxygen-rich gas under the actual working conditions of the rocket engine thrust chamber. Therefore, there will be a large difference between the combustion characteristics of the gas-liquid nozzle and the actual thrust chamber state. The key reason for not using oxygen-rich gas in current studies is that it is difficult to obtain oxygen-rich gas under the conditions of a real thrust chamber (≥20 MPa), and it is difficult to simulate the high-temperature and high-pressure test conditions in the engine gas generator and thrust chamber in ground tests, and the test risk coefficient is relatively large. Chinese Patent with Publication No. CN113446133A discloses a ground screening test device and test method for an oxygen-rich and methane-rich gas injection unit, which provides two-way gas propellants for the gas-gas injection unit through an oxygen-rich / rich-fuel gas generator, and evaluates the combustion performance and structural reliability of the gas-gas injection unit based on the combustion chamber pulsating pressure data, but this technology cannot obtain the spatio-temporal distribution information of the flame of the gas-gas injection unit. Chinese Patent with Publication No. CN113790899A discloses a liquid rocket engine injector combustion state evaluation device and method, the injector of which can be a liquid-liquid injection unit or a gas-liquid injection unit, and obtains the heat flux distribution on the inner wall of the combustion chamber through the thermocouples on the body of the combustion chamber, so as to qualitatively evaluate the longitudinal length dimension of the flame, but this technology cannot restore the three-dimensional information of the flame and is difficult to be used for the study of the unsteady characteristics of the flame. There is currently no reported test method for measuring the combustion characteristics of gas-liquid nozzles under supercritical conditions. Summary of the Invention

[0004] The object of the present invention is to provide an experimental device and an experimental method for the combustion characteristics of a gas-liquid nozzle under supercritical conditions in view of the technical problem that there is currently no experimental method for studying the combustion characteristics of a gas-liquid nozzle under supercritical conditions.

[0005] An experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions is characterized in that it includes an oxygen-rich gas generator, a gas-liquid injection unit and an optical observation system;

[0006] The oxygen-rich gas generator includes a liquid-liquid nozzle, a generator body and an orifice plate; the generator body includes an upper part of the generator and a lower part of the generator, and the upper part of the generator, the orifice plate and the lower part of the generator are fixedly connected in sequence from top to bottom; a through hole is axially formed in the orifice plate for communicating the upper part of the generator and the lower part of the generator;

[0007] The outer side wall of the liquid-liquid nozzle is hermetically connected to the upper end of the upper part of the generator and extends into the upper part of the generator at the lower end; a first oxidant inlet and a first fuel inlet are formed on the side wall of the liquid-liquid nozzle; a first annular liquid collecting cavity is circumferentially arranged at a position corresponding to the lower part of the liquid-liquid nozzle on the inner side wall of the upper part of the generator, and a second oxidant inlet is formed on the side wall of the upper part of the generator corresponding to the first annular liquid collecting cavity; at least one pre-injection pressure monitoring device for oxygen-rich gas is installed on the side wall of the lower part of the generator.

[0008] The gas-liquid injection unit includes a injection flange, an optical observation combustion chamber and a throat which are fixedly connected in sequence from top to bottom; the upper end of the injection flange is fixedly connected to the lower end of the lower part of the generator, the gas-liquid nozzle to be tested is coaxially installed in the injection flange, a second annular liquid collecting cavity is formed between its outer side wall and the inner side wall of the injection flange, its upper end is communicated with the inner cavity of the lower part of the generator, and its lower end extends into the optical observation combustion chamber; a second fuel inlet is formed on the side wall of the injection flange corresponding to the second annular liquid collecting cavity;

[0009] At least one second chamber pressure monitoring device and at least one pulsating pressure monitoring device are installed on the side wall of the optical observation combustion chamber;

[0010] The optical observation system includes a schlieren system high-speed camera and a combustion field acquisition system high-speed camera, which are respectively used for photographing the characteristics of the flame schlieren field and the self-luminous images of the flame CH group and OH group in the optical observation combustion chamber.

[0011] Furthermore, a first oxidant pre-injection pressure monitoring device is installed on the annular channel corresponding to the first oxidant inlet of the liquid-liquid nozzle;

[0012] A first fuel pre-injection pressure monitoring device is installed on the annular channel corresponding to the first fuel inlet of the liquid-liquid nozzle;

[0013] A second oxidant pre-injection pressure monitoring device is installed on the channel of the second oxidant inlet;

[0014] A second fuel pre-injection pressure monitoring device is installed on the channel of the second fuel inlet;

[0015] A first chamber pressure monitoring device is installed on the upper side wall of the generator at a position corresponding to the lower part of the first annular liquid collection chamber.

[0016] Furthermore, the first annular liquid collection chamber includes a liquid injection ring; a circumferential annular groove is formed in the middle section of the outer side wall of the liquid injection ring, and the annular groove and the inner side wall at the corresponding position of the upper part of the generator form a secondary injection ring cavity; a plurality of downwardly inclined secondary injection holes are circumferentially arranged on the side wall of the liquid injection ring corresponding to the secondary injection ring cavity;

[0017] The first annular liquid collection chamber is installed on the inner side wall of the upper part of the generator by means of clearance fitting or welding.

[0018] Furthermore, at least one temperature monitoring device is installed on the lower side wall of the generator.

[0019] Furthermore, a first sealing flange is circumferentially arranged on the outer side wall near the lower end of the liquid-liquid nozzle, and a second sealing flange is arranged at the upper end of the upper part of the generator; a third sealing flange is arranged at the lower end of the upper part of the generator, and a fourth sealing flange is arranged at the upper end of the lower part of the generator;

[0020] The first sealing flange and the second sealing flange are axially fixed by a plurality of fixing screws;

[0021] The third sealing flange, the orifice plate, and the fourth sealing flange are axially fixed by a plurality of fixing screws.

[0022] Furthermore, the lower end of the injection flange and the upper end of the optical observation combustion chamber are fixedly connected by bolts;

[0023] The lower end of the optical observation combustion chamber and the upper end of the throat are fixedly connected by bolts.

[0024] Furthermore, the liquid-liquid nozzle is a liquid-liquid double centrifugal nozzle.

[0025] In addition, based on the above test device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions, the present invention also provides a test method for the combustion characteristics of a gas-liquid nozzle under supercritical conditions, which is characterized in that it includes the following steps:

[0026] Step 1, set the target chamber pressure of the generator body and the target chamber pressure of the optical observation combustion chamber;

[0027] Step 2: According to the principle of simulation test, analyze the flow rate, thermal parameters of the oxygen-rich gas required for the air-liquid injection unit to organize combustion, and the flow rate of the second fuel; according to the flow rate and thermal parameters of the oxygen-rich gas, obtain the flow rates of the first oxidant, second oxidant, and first fuel required for the oxygen-rich gas generator to organize combustion through thermodynamic calculations.

[0028] Step 3: According to the flow rate, thermal parameters of the oxygen-rich gas required for the air-liquid injection unit to organize combustion, and the flow rate of the second fuel, combined with the target chamber pressure of the optical observation combustion chamber, calculate the internal aperture of the throat; according to the target chamber pressure of the generator body, the target chamber pressure of the optical observation combustion chamber, and the flow rates of the first oxidant, second oxidant, and first fuel required for the oxygen-rich gas generator to organize combustion, calculate the aperture of the through-hole on the throttle orifice plate.

[0029] Step 4: According to the internal aperture of the throat and the aperture of the through-hole on the throttle orifice plate calculated in Step 3, select the corresponding throat and throttle orifice plate, and then build the combustion characteristic test device of the above air-liquid nozzle under supercritical conditions and install the air-liquid nozzle to be tested.

[0030] Step 5: Input the first oxidant and first fuel with a given flow rate. After the first oxidant and first fuel are mixed in the liquid-liquid nozzle, they burn in the upper part of the generator; input the second oxidant with a given flow rate, which is mixed and burned with the first oxidant and first fuel to form oxygen-rich gas; the oxygen-rich gas flows into the air-liquid nozzle to be tested through the throttle orifice plate and the lower part of the generator; input the second fuel with a given flow rate to the air-liquid nozzle to be tested. After the second fuel interacts with the oxygen-rich gas, it is injected into the optical observation combustion chamber for atomization combustion; the high-temperature gas generated by combustion flows through the throat inside the optical observation combustion chamber to form supercritical conditions.

[0031] Step 6: According to the monitoring data of the second chamber pressure monitoring device, the internal aperture of the throat, and the actual flow rates of the first oxidant, first fuel, second oxidant, and second fuel, calculate the combustion efficiency of the air-liquid nozzle to be tested; according to the monitoring data of the oxygen-rich gas pre-injection pressure monitoring device and the second chamber pressure monitoring device, evaluate the pressure loss characteristics of the gas passage of the air-liquid nozzle to be tested; according to the monitoring data of the pulsating pressure monitoring device, analyze the combustion stability of the air-liquid nozzle to be tested; according to the imaging data of the schlieren system high-speed camera and the combustion field acquisition system high-speed camera, analyze the three-dimensional unsteady flow field characteristics of the air-liquid flame.

[0032] Step 7: According to the combustion efficiency of the air-liquid nozzle to be tested, the pressure loss characteristics of the gas passage of the air-liquid nozzle to be tested, the combustion stability of the air-liquid nozzle to be tested, and the three-dimensional unsteady flow field characteristics of the air-liquid flame, analyze the combustion characteristics of the air-liquid nozzle to be tested and complete the combustion characteristic test of the air-liquid nozzle to be tested under supercritical conditions.

[0033] Further, in step 6, the actual flow rates of the first oxidizer, the first fuel, and the second oxidizer are calculated based on the monitoring data of the first oxidizer pre-injection pressure monitoring device, the first fuel pre-injection pressure monitoring device, the second oxidizer pre-injection pressure monitoring device, and the first chamber pressure monitoring device; the actual flow rate of the second fuel is calculated based on the monitoring data of the second fuel pre-injection pressure monitoring device and the second chamber pressure monitoring device.

[0034] Further, in step 4, the installation of the gas-liquid nozzle to be tested is specifically as follows:

[0035] Install the gas-liquid nozzle to be tested in the injection flange, and check each connection through a pressure test to ensure there is no leakage in the seal;

[0036] In step 5, it also includes checking whether the actual temperature of the oxygen-rich gas deviates from the preset temperature value according to the monitoring data of the temperature monitoring device.

[0037] The beneficial effects of the present invention compared with the prior art are as follows:

[0038] 1. An experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions provided by the present invention includes an oxygen-rich gas generator, a gas-liquid injection unit, and an optical observation system. The oxygen-rich gas generator is composed of a liquid-liquid nozzle, a generator body, and a throttle orifice plate. By generating oxygen-rich gas with a given temperature, pressure, and composition through the oxygen-rich gas generator, the combustion characteristics of the gas-liquid nozzle under supercritical conditions can be experimentally simulated to a large extent. At the same time, introducing the optical observation system into the research on the high-pressure combustion of the gas-liquid nozzle is of great significance for understanding and recognizing the unsteady combustion characteristics of the gas-liquid nozzle under supercritical conditions.

[0039] 2. The present invention assembles the gas-liquid nozzle to be tested in the injection flange. During the test process, only the bolts between the injection flange and the optical observation combustion chamber need to be disassembled, without disassembling the oxygen-rich gas generator and the downstream throat, effectively improving the test efficiency.

[0040] 3. An experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions provided by the present invention determines the flow rates of the first oxidizer, the first fuel, and the second oxidizer through the first oxidizer pre-injection pressure monitoring device, the first fuel pre-injection pressure monitoring device, the second oxidizer pre-injection pressure monitoring device, and the first chamber pressure monitoring device, and determines the flow rate of the second fuel according to the second fuel pre-injection pressure monitoring device and the second chamber pressure monitoring device, which can achieve precise input of the propellant flow rate and ensure the accuracy of the test results.

[0041] 4. A test method for the combustion characteristics of a gas-liquid nozzle under supercritical conditions provided by the present invention. According to the high-pressure test simulation principle, the internal aperture of the throat and the aperture of the through holes on the throttle orifice plate are analyzed and calculated. An oxygen-rich gas generator is used to provide oxygen-rich gas with a set temperature, composition, and pressure as the propellant, so as to better simulate the combustion characteristics of the gas-liquid nozzle under the conditions of the thrust chamber (supercritical conditions) and screen out gas-liquid nozzles with excellent atomization and combustion performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic structural diagram of an embodiment of a test device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions of the present invention;

[0043] Figure 2 is a schematic structural diagram of the injection head in the embodiment of the present invention.

[0044] The specific reference numerals are as follows:

[0045] 1 - oxygen-rich gas generator, 2 - liquid-liquid nozzle, 3 - first oxidant inlet, 4 - first fuel inlet, 5 - first pre-injection pressure monitoring device for oxidant, 6 - first pre-injection pressure monitoring device for fuel, 7 - body of the generator, 71 - upper part of the generator, 72 - lower part of the generator, 8 - first annular liquid collection chamber, 9 - second oxidant inlet, 10 - first chamber pressure monitoring device, 11 - pre-injection pressure monitoring device for oxygen-rich gas, 12 - temperature monitoring device, 13 - throttle orifice plate, 14 - second pre-injection pressure monitoring device for oxidant, 15 - injection head, 16 - optical observation combustion chamber, 17 - second chamber pressure monitoring device, 18 - pulsating pressure monitoring device, 19 - throat, 20 - injection flange, 21 - gas-liquid nozzle to be tested, 22 - second pre-injection pressure monitoring device for fuel, 23 - second fuel inlet, 24 - schlieren system high-speed camera, 25 - combustion field acquisition system high-speed camera, 26 - gas-liquid injection unit, 27 - optical observation system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] To make the advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] A test device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions, as Figure 1 shown, includes an oxygen-rich gas generator 1, a gas-liquid injection unit 26, and an optical observation system 27.

[0048] The oxygen-rich gas generator 1 is located upstream of the gas-liquid injection unit 26 and is used to supply oxygen-rich gas with a given flow rate and thermal parameters to the gas-liquid injection unit 26, where the thermal parameters include the temperature, density, and composition of the oxygen-rich gas. The oxygen-rich gas generator 1 includes a liquid-liquid nozzle 2, a generator body 7, and an orifice plate 13. The generator body 7 includes an upper part 71 and a lower part 72 of the generator. In this embodiment, the liquid-liquid nozzle 2 is a liquid-liquid double centrifugal nozzle.

[0049] The outer wall of the liquid-liquid nozzle 2 is hermetically connected to the upper end of the upper part 71 of the generator, and the lower end of the liquid-liquid nozzle 2 extends into the upper part 71 of the generator. Specifically, a first sealing flange is circumferentially arranged on the outer wall of the liquid-liquid nozzle 2 near the lower end, and a second sealing flange is arranged at the upper end of the upper part 71 of the generator. The first sealing flange and the second sealing flange are axially fixed by a plurality of fixing screws.

[0050] A first oxidant inlet 3 and a first fuel inlet 4 are provided on the side wall of the liquid-liquid nozzle 2; a first annular liquid collection chamber 8 is circumferentially arranged on the inner side wall of the upper part 71 of the generator at a position corresponding to the lower part of the liquid-liquid nozzle 2, and a second oxidant inlet 9 is provided on the side wall of the upper part 71 of the generator at a position corresponding to the first annular liquid collection chamber 8. Specifically, the first annular liquid collection chamber 8 in the present invention includes a liquid injection ring. An annular groove is circumferentially opened in the middle section of the outer side wall of the liquid injection ring, and the annular groove and the inner side wall of the corresponding position of the upper part 71 of the generator form a secondary injection ring cavity; a plurality of downwardly inclined secondary injection holes are circumferentially arranged on the side wall of the liquid injection ring at positions corresponding to the secondary injection ring cavity. Preferably, in this embodiment, the first annular liquid collection chamber 8 is installed on the inner side wall of the upper part 71 of the generator by means of clearance fitting, which can facilitate the rapid replacement of the first annular liquid collection chamber 8 with different geometric parameters. In other embodiments of the present invention, the first annular liquid collection chamber 8 can also be installed on the inner side wall of the upper part 71 of the generator by means of welding assembly.

[0051] The first oxidant and the first fuel with a given flow rate are respectively injected into the liquid-liquid nozzle 2 through the first oxidant inlet 3 and the first fuel inlet 4, and after mixing, they burn in the upper part 71 of the generator; the second oxidant with a given flow rate enters the upper part 71 of the generator through the second oxidant inlet 9, the secondary injection ring cavity of the first annular liquid collection chamber 8, and the secondary injection holes, and is mixed and burned with the first oxidant and the first fuel to form high-temperature and high-pressure oxygen-rich gas.

[0052] At the lower end of the upper part 71 of the generator, a third sealing flange is provided, and at the upper end of the lower part 72 of the generator, a fourth sealing flange is provided. The third sealing flange, the throttle orifice plate 13, and the fourth sealing flange are axially fixedly connected from top to bottom by a plurality of fixing screws. A through hole is axially formed in the throttle orifice plate 13. While connecting the upper part 71 and the lower part 72 of the generator, it can adjust the chamber pressure of the body part 7 of the generator, that is, adjust the chamber pressure of the upper part 71 of the generator by the aperture size of the through hole of the throttle orifice plate 13. In addition, the throttle orifice plate 13 can also rectify the oxygen-rich gas in the channel.

[0053] A monitoring device 11 for the pre-injection pressure of oxygen-rich gas and a temperature monitoring device 12 are installed on the side wall of the lower part 72 of the generator to monitor the state parameters of the oxygen-rich gas, that is, the pre-injection pressure and temperature.

[0054] At the positions corresponding to the first oxidant inlet 3 and the first fuel inlet 4 in the liquid-liquid nozzle 2, there are two annular channels respectively; a first oxidant pre-injection pressure monitoring device 5 and a first fuel pre-injection pressure monitoring device 6 are correspondingly installed in the two annular channels, and a second oxidant pre-injection pressure monitoring device 14 is installed on the channel of the second oxidant inlet 9. The first oxidant pre-injection pressure monitoring device 5, the first fuel pre-injection pressure monitoring device 6, and the second oxidant inlet 9 are respectively used to monitor the pre-injection pressures of the first oxidant, the first fuel, and the second oxidant. A first chamber pressure monitoring device 10 is installed on the side wall of the upper part 71 of the generator at the position corresponding to the lower part of the first annular liquid collection cavity 8 to monitor the chamber pressure of the upper part 71 of the generator.

[0055] The gas-liquid injection unit 26 includes a injection flange 20, an optical observation combustion chamber 16, and a throat 19 fixedly connected in sequence from top to bottom. Specifically, the lower end of the injection flange 20 and the upper end of the optical observation combustion chamber 16 are fixedly connected by bolts, and the lower end of the optical observation combustion chamber 16 and the upper end of the throat 19 are fixedly connected by bolts.

[0056] As Figure 2 shown, the upper end of the injection flange 20 is fixedly connected to the lower end of the lower part 72 of the generator. The gas-liquid nozzle 21 to be tested can be any type of gas-liquid nozzle, such as an internal mixing type direct current nozzle or a double centrifugal nozzle, which is coaxially installed in the injection flange 20 to form an injection head 15. At the same time, the upper end of the gas-liquid nozzle 21 to be tested is communicated with the internal cavity of the lower part 72 of the generator, and the lower end extends into the optical observation combustion chamber 16. A second annular liquid collection cavity is formed between the outer side wall of the gas-liquid nozzle 21 to be tested and the inner side wall of the injection flange 20, and a second fuel inlet 23 is opened on the side wall of the injection flange 20 corresponding to the second annular liquid collection cavity.

[0057] The oxygen-rich gas passes through the orifice plate 13 and enters the gas-liquid nozzle to be tested 21 from the lower part 72 of the generator. The second fuel passes through the second fuel inlet 23 and the second annular liquid collecting chamber and enters the gas-liquid nozzle to be tested 21. After the oxygen-rich gas and the second fuel interact in the gas-liquid nozzle to be tested 21, they are injected into the optical observation combustion chamber 16 for atomization combustion. The high-temperature gas generated by combustion flows through the throat 19 inside the optical observation combustion chamber 16. By selecting a throat 19 with an appropriate internal aperture, the chamber pressure inside the optical observation combustion chamber 16 can be changed to form supercritical conditions.

[0058] In the present invention, the first oxidant and the second oxidant usually adopt the same oxidant, and the first fuel and the second fuel usually adopt the same fuel. In this embodiment, both the first oxidant and the second oxidant are liquid oxygen, and the first fuel and the second fuel are liquid kerosene. In other embodiments of the present invention, the first oxidant and the second oxidant can also adopt oxidants such as dinitrogen tetroxide, and the first fuel and the second fuel can also adopt fuels such as hydrazine. Among them, the first oxidant, the second oxidant, the first fuel, and the second fuel can be normal-temperature propellants or cryogenic propellants.

[0059] A second chamber pressure monitoring device 17 and a pulsating pressure monitoring device 18 are installed on the side wall of the optical observation combustion chamber 16 to monitor the combustion characteristic parameters inside the optical observation combustion chamber 16, namely the chamber pressure and the pulsating pressure. A second fuel pre-injection pressure monitoring device 22 is installed on the channel of the second fuel inlet 23 to monitor the pre-injection pressure of the second fuel.

[0060] The optical observation system 27 is used for optical imaging monitoring, and it includes a schlieren system high-speed camera 24 and a combustion field acquisition system high-speed camera 25. The schlieren system high-speed camera 24 is used to photograph the flame schlieren field characteristics inside the optical observation combustion chamber 16, and the combustion field acquisition system high-speed camera 25 is used to photograph the self-luminous images of the flame CH group and OH group inside the optical observation combustion chamber 16.

[0061] Meanwhile, the present invention also provides a test method for the combustion characteristics of a gas-liquid nozzle under supercritical conditions, which specifically includes the following steps:

[0062] Step 1, set the target chamber pressure of the generator body 7 and the target chamber pressure of the optical observation combustion chamber 16.

[0063] Step 2, according to the simulation test principle, analyze the flow rate, temperature, density, and composition of the oxygen-rich gas required for the gas-liquid injection unit 26 to organize combustion, as well as the flow rate of the second fuel; according to the flow rate, temperature, density, and composition of the oxygen-rich gas, calculate the flow rates of the first oxidant, the second oxidant, and the first fuel required for the oxygen-rich gas generator 1 to organize combustion through thermodynamic calculations.

[0064] Step 3: Calculate the internal aperture diameter of the throat 19 based on the flow rate, temperature, density, and composition of the oxygen-rich gas required for combustion by the gas-liquid injection unit 26, and the flow rate of the second fuel, in combination with the target chamber pressure of the optical observation combustion chamber 16. Calculate the aperture diameter of the through-hole on the throttle orifice plate 13 based on the target chamber pressure of the generator body 7, the target chamber pressure of the optical observation combustion chamber 16, and the flow rates of the first oxidant, second oxidant, and first fuel required for combustion by the oxygen-rich gas generator 1.

[0065] Step 4: Select the corresponding throat 19 and throttle orifice plate 13 according to the internal aperture diameter of the throat 19 and the aperture diameter of the through-hole on the throttle orifice plate 13 calculated in Step 3, and then build the combustion characteristics test device of the above gas-liquid nozzle under supercritical conditions. Install the gas-liquid nozzle 21 to be tested in the injection flange 20, and check each connection through a pressure test to ensure there is no leakage. Then, simultaneously turn on the oxygen-rich gas pre-injection pressure monitoring device 11, the second chamber pressure monitoring device 17, the pulsating pressure monitoring device 18, the schlieren system high-speed camera 24, the combustion field acquisition system high-speed camera 25, the first oxidant pre-injection pressure monitoring device 5, the first fuel pre-injection pressure monitoring device 6, the second oxidant pre-injection pressure monitoring device 14, the first chamber pressure monitoring device 10, the second fuel pre-injection pressure monitoring device 22, and the temperature monitoring device 12 for data monitoring and acquisition.

[0066] Step 5: Input the first oxidant and the first fuel with a given flow rate. After the first oxidant and the first fuel are mixed in the liquid-liquid nozzle 2, they burn in the upper part 71 of the generator. Input the second oxidant with a given flow rate, which is mixed and burned with the first oxidant and the first fuel to form oxygen-rich gas. The oxygen-rich gas flows through the throttle orifice plate 13 and the lower part 72 of the generator into the gas-liquid nozzle 21 to be tested. Input the second fuel with a given flow rate into the gas-liquid nozzle 21 to be tested. After the second fuel interacts with the oxygen-rich gas, it is injected into the optical observation combustion chamber 16 for atomization combustion. The high-temperature gas generated by combustion flows through the throat 19 inside the optical observation combustion chamber 16 to establish the corresponding combustion chamber pressure and form supercritical conditions. At the same time, check whether the actual temperature of the oxygen-rich gas deviates from the preset temperature value according to the monitoring data of the temperature monitoring device 12. The preset temperature value of the oxygen-rich gas is the temperature of the oxygen-rich gas required for combustion by the gas-liquid injection unit 26 analyzed in Step 2.

[0067] Step 6: Calculate the actual flow rates of the first oxidizer, the first fuel, and the second oxidizer based on the monitoring data of the first oxidizer pre-injection pressure monitoring device 5, the first fuel pre-injection pressure monitoring device 6, the second oxidizer pre-injection pressure monitoring device 14, and the first chamber pressure monitoring device 10; calculate the actual flow rate of the second fuel based on the monitoring data of the second fuel pre-injection pressure monitoring device 22 and the second chamber pressure monitoring device 17; then calculate the combustion efficiency of the gas-liquid nozzle 21 to be measured based on the monitoring data of the second chamber pressure monitoring device 17, the internal aperture of the throat 19, and the actual flow rates of the first oxidizer, the first fuel, the second oxidizer, and the second fuel.

[0068] Evaluate the pressure loss characteristics of the gas passage of the gas-liquid nozzle 21 to be measured based on the monitoring data of the oxygen-rich gas pre-injection pressure monitoring device 11 and the second chamber pressure monitoring device 17.

[0069] Analyze the combustion stability of the gas-liquid nozzle 21 to be measured based on the monitoring data of the pulsating pressure monitoring device 18.

[0070] Based on the imaging data of the high-speed camera 25 of the combustion field acquisition system, self-luminous images of the flame CH group and OH group can be obtained. Based on the imaging data of the high-speed camera 24 of the schlieren system, the characteristics of the flame schlieren field can be obtained; combining the above synchronous shooting data, the three-dimensional unsteady flow field characteristics of the gas-liquid flame can be obtained.

[0071] Step 7: Analyze the combustion characteristics of the gas-liquid nozzle 21 to be measured based on the combustion efficiency of the gas-liquid nozzle 21 to be measured, the pressure loss characteristics of the gas passage of the gas-liquid nozzle 21 to be measured, the combustion stability of the gas-liquid nozzle 21 to be measured, and the three-dimensional unsteady flow field characteristics of the gas-liquid flame, and complete the rapid test of the combustion characteristics of the gas-liquid nozzle 21 to be measured under supercritical conditions. The present invention can screen out gas-liquid nozzles with excellent atomization and combustion performance according to the rapid test of the combustion characteristics of the gas-liquid nozzle 21 to be measured under supercritical conditions.

[0072] The above is only used to illustrate the technical solution of the present invention, rather than to limit it. For those of ordinary professional skills in the art, the specific technical solutions recorded in the above embodiments can be modified, or some of the technical features can be equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions protected by the present invention.

Claims

1. An experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions, characterized in that: It includes an oxygen-rich gas generator (1), a gas-liquid injection unit (26), and an optical observation system (27); The oxygen-rich gas generator (1) includes a liquid-liquid nozzle (2), a generator body (7), and a throttle orifice plate (13); the generator body (7) includes an upper part of the generator (71) and a lower part of the generator (72), and the upper part of the generator (71), the throttle orifice plate (13), and the lower part of the generator (72) are fixedly connected in sequence from top to bottom; a through hole is axially provided on the throttle orifice plate (13) for communicating the upper part of the generator (71) and the lower part of the generator (72) and regulating the chamber pressure of the upper part of the generator (71); The outer side wall of the liquid-liquid nozzle (2) is hermetically connected to the upper end of the upper part of the generator (71), and the lower end extends into the upper part of the generator (71); a first oxidant inlet (3) and a first fuel inlet (4) are provided on the side wall of the liquid-liquid nozzle (2); a first annular liquid collection chamber (8) is circumferentially arranged at a position corresponding to the lower part of the liquid-liquid nozzle (2) on the inner side wall of the upper part of the generator (71), and a second oxidant inlet (9) is provided on the side wall of the upper part of the generator (71) corresponding to the first annular liquid collection chamber (8); at least one oxygen-rich gas pre-injection pressure monitoring device (11) is installed on the side wall of the lower part of the generator (72); The gas-liquid injection unit (26) includes a injection flange (20), an optical observation combustion chamber (16), and a throat (19) fixedly connected in sequence from top to bottom; the upper end of the injection flange (20) is fixedly connected to the lower end of the lower part of the generator (72), and the gas-liquid nozzle to be tested (21) is coaxially installed in the injection flange (20), and a second annular liquid collection chamber is formed between its outer side wall and the inner side wall of the injection flange (20), its upper end is communicated with the inner cavity of the lower part of the generator (72), and the lower end extends into the optical observation combustion chamber (16); a second fuel inlet (23) is provided on the side wall of the injection flange (20) corresponding to the second annular liquid collection chamber; At least one second chamber pressure monitoring device (17) and at least one pulsating pressure monitoring device (18) are installed on the side wall of the optical observation combustion chamber (16); The optical observation system (27) includes a schlieren system high-speed camera (24) and a combustion field acquisition system high-speed camera (25), which are respectively used to photograph the characteristics of the flame schlieren field and the self-luminous images of the flame CH group and OH group in the optical observation combustion chamber (16).

2. The experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to claim 1, characterized in that: A first oxidant pre-injection pressure monitoring device (5) is installed on the annular channel of the liquid-liquid nozzle (2) corresponding to the first oxidant inlet (3); A first fuel pre-injection pressure monitoring device (6) is installed on the annular channel of the liquid-liquid nozzle (2) corresponding to the first fuel inlet (4); A second oxidant pre-injection pressure monitoring device (14) is installed on the channel of the second oxidant inlet (9); A second fuel pre-injection pressure monitoring device (22) is installed on the channel of the second fuel inlet (23); A first chamber pressure monitoring device (10) is installed at a position on the side wall of the upper part (71) of the generator corresponding to the lower part of the first annular liquid collection chamber (8).

3. The experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to claim 1 or 2, characterized in that: The first annular liquid collection chamber (8) includes a liquid injection ring; an annular groove is circumferentially formed in the middle section of the outer side wall of the liquid injection ring, and the annular groove and the inner side wall of the corresponding position of the upper part (71) of the generator form a secondary injection ring cavity; a plurality of downwardly inclined secondary injection holes are circumferentially arranged on the side wall of the liquid injection ring corresponding to the secondary injection ring cavity; The first annular liquid collection chamber (8) is installed on the inner side wall of the upper part (71) of the generator by means of clearance fitting or welding.

4. The experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to claim 3, characterized in that: At least one temperature monitoring device (12) is installed on the side wall of the lower part (72) of the generator.

5. The experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to claim 4, characterized in that: A first sealing flange is circumferentially arranged on the outer side wall of the liquid-liquid nozzle (2) near the lower end, and a second sealing flange is arranged at the upper end of the upper part (71) of the generator; a third sealing flange is arranged at the lower end of the upper part (71) of the generator, and a fourth sealing flange is arranged at the upper end of the lower part (72) of the generator; The first sealing flange and the second sealing flange are axially fixed by a plurality of fixing screws; The third sealing flange, the orifice plate (13), and the fourth sealing flange are axially fixed by a plurality of fixing screws.

6. The experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to claim 1, characterized in that: The lower end of the injection flange (20) and the upper end of the optical observation combustion chamber (16) are fixedly connected by bolts; The lower end of the optical observation combustion chamber (16) and the upper end of the throat (19) are fixedly connected by bolts.

7. The experimental device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to claim 1, characterized in that: The liquid-liquid nozzle (2) is a liquid-liquid double centrifugal nozzle.

8. A test method for the combustion characteristics of a gas-liquid nozzle under supercritical conditions, based on the test device for the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to any one of claims 1-7, characterized in that, It includes the following steps: Step 1, set the target chamber pressure of the generator body (7) and the target chamber pressure of the optical observation combustion chamber (16); Step 2, according to the principle of simulation test, analyze the flow rate, thermal parameters of the oxygen-rich gas required for the combustion of the gas-liquid injection unit (26), and the flow rate of the second fuel; according to the flow rate and thermal parameters of the oxygen-rich gas, calculate the flow rates of the first oxidant, the second oxidant, and the first fuel required for the combustion of the oxygen-rich gas generator (1) through thermodynamic calculations; Step 3, according to the flow rate, thermal parameters of the oxygen-rich gas required for the combustion of the gas-liquid injection unit (26), and the flow rate of the second fuel, combined with the target chamber pressure of the optical observation combustion chamber (16), calculate the inner diameter of the throat (19); according to the target chamber pressure of the generator body (7), the target chamber pressure of the optical observation combustion chamber (16), and the flow rates of the first oxidant, the second oxidant, and the first fuel required for the combustion of the oxygen-rich gas generator (1), calculate the aperture of the through hole on the orifice plate (13); Step 4: According to the internal aperture diameter of the throat (19) calculated in Step 3 and the aperture diameter of the through-hole on the throttle orifice plate (13), select the corresponding throat (19) and throttle orifice plate (13), and then build an experimental device for the combustion characteristics of the gas-liquid nozzle under supercritical conditions as described in any one of Claims 1-7, and install the gas-liquid nozzle to be tested (21). Step 5: Input the first oxidant and the first fuel with a given flow rate. After the first oxidant and the first fuel are mixed in the liquid-liquid nozzle (2), they burn in the upper part (71) of the generator; input the second oxidant with a given flow rate, which is mixed and burned with the first oxidant and the first fuel to form oxygen-rich gas; the oxygen-rich gas flows into the gas-liquid nozzle to be tested (21) via the throttle orifice plate (13) and the lower part (72) of the generator; input the second fuel with a given flow rate to the gas-liquid nozzle to be tested (21). After the second fuel interacts with the oxygen-rich gas, it is injected into the optical observation combustion chamber (16) for atomization combustion; the high-temperature gas generated by combustion flows through the throat (19) inside the optical observation combustion chamber (16) to form supercritical conditions. Step 6: Calculate the combustion efficiency of the gas-liquid nozzle to be tested (21) according to the monitoring data of the second chamber pressure monitoring device (17), the internal aperture diameter of the throat (19), and the actual flow rates of the first oxidant, the first fuel, the second oxidant, and the second fuel; evaluate the pressure loss characteristics of the gas passage of the gas-liquid nozzle to be tested (21) according to the monitoring data of the oxygen-rich gas pre-injection pressure monitoring device (11) and the second chamber pressure monitoring device (17); analyze the combustion stability of the gas-liquid nozzle to be tested (21) according to the monitoring data of the pulsating pressure monitoring device (18); analyze the three-dimensional unsteady flow field characteristics of the gas-liquid flame according to the imaging data of the schlieren system high-speed camera (24) and the combustion field acquisition system high-speed camera (25). Step 7: Analyze the combustion characteristics of the gas-liquid nozzle to be tested (21) according to the combustion efficiency of the gas-liquid nozzle to be tested (21), the pressure loss characteristics of the gas passage of the gas-liquid nozzle to be tested (21), the combustion stability of the gas-liquid nozzle to be tested (21), and the three-dimensional unsteady flow field characteristics of the gas-liquid flame, and complete the experimental study on the combustion characteristics of the gas-liquid nozzle to be tested (21) under supercritical conditions.

9. The method for testing the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to Claim 8, wherein:[[]]END]] In Step 6, the actual flow rates of the first oxidant, the first fuel, and the second oxidant are calculated according to the monitoring data of the first oxidant pre-injection pressure monitoring device (5), the first fuel pre-injection pressure monitoring device (6), the second oxidant pre-injection pressure monitoring device (14), and the first chamber pressure monitoring device (10); the actual flow rate of the second fuel is calculated according to the monitoring data of the second fuel pre-injection pressure monitoring device (22) and the second chamber pressure monitoring device (17).

10. The method for testing the combustion characteristics of a gas-liquid nozzle under supercritical conditions according to Claim 9, wherein:[[]]END]] In Step 4, the installation of the gas-liquid nozzle to be tested (21) specifically is:[[]]END]] Install the gas-liquid nozzle to be tested (21) in the injection flange (20), and check each connection through a pressure test to ensure that there is no leakage in the seal. In step 5, it also includes checking whether the actual temperature of the oxygen-rich gas deviates from the preset temperature value according to the monitoring data of the temperature monitoring device (12).

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