Single-nozzle combustion stability evaluation method and test system

Abstract

The invention discloses a single-nozzle combustion stability evaluation method and a test system, and relates to the technical field of engines, and the method comprises the steps: determining the working time t1 of the single ignition operation of a single-nozzle combustion stability test device according to the moment when the combustion of an engine is unstable; determining a single ignition time sequence according to the working time t1; a plurality of groups of mixing percentages with different percentage values are set, a plurality of groups of working condition percentages with different percentage values are set, the group number of the mixing percentages and the group number of the working condition percentages are the same, and under the condition that one group is selected from the plurality of groups of mixing percentages and the plurality of groups of working condition percentages, a combustion stability test is carried out according to a single ignition time sequence. And testing the combustion stability until each group of the mixing percentage and the working condition percentage is subjected to the combustion stability test, and recording the percentage of the number of times of generating the excitation combustion instability in the number of times of all the combustion stability tests. And transversely comparing the stability of different nozzles by taking the percentage of the combustion instability problem in the test matrix as a quantitative index.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine, in particular to a single-nozzle combustion stability evaluation method and test system. BACKGROUND

[0002] Combustion instability problem is almost encountered in the development process of every rocket engine, which seriously affects the reliable work of the engine and even the rocket system. Many researchers have carried out a lot of exploration work on combustion instability problem. Stability test is an important means to study combustion stability. So far, various devices have been used to study the combustion instability phenomenon of liquid rocket engine. Nozzle is the smallest organizational unit of injector, which is closely related to combustion stability. The simulation piece with single nozzle is one of the devices for studying combustion stability, which has the advantages of simple structure, low cost and good effectiveness, and helps to more comprehensively study the basic mechanism and process of combustion instability.

[0003] Liquid rocket engine generally adopts normal temperature self-ignition propellant combination (such as dinitrogen tetroxide / hydrazine) and low temperature propellant combination (such as liquid oxygen / kerosene propellant). At the design initial stage, the first order tangential high frequency combustion instability which is the most dangerous is generally paid attention to and control measures are taken, which leads to the difficulty in considering the inhibition of longitudinal high frequency combustion instability. Therefore, single-nozzle combustion stability test is carried out to solve the problem of longitudinal high frequency combustion instability. However, the single-nozzle combustion test in the prior art is only a single working condition test for different structural nozzles to study the influence of different structural sizes on combustion stability, which leads to the inability to more comprehensively study the mechanism of single-nozzle combustion instability. SUMMARY

[0004] The purpose of the present application is to provide a single-nozzle combustion stability evaluation method and test system. The single-nozzle combustion stability evaluation method provided by the present application is used to more comprehensively study the mechanism of single-nozzle combustion instability.

[0005] In order to achieve the above purpose, the present application provides the following technical solutions: In the first aspect, the present application provides a single-nozzle combustion stability evaluation method, comprising: determining the working time t1 of single ignition operation of the single-nozzle combustion stability test device according to the time when the engine appears combustion instability; determining the single ignition timing according to the working time t1; The mixing percentage of multiple groups of different percentage values is set, the working condition percentage of multiple groups of different percentage values is set, and the number of groups of the mixing percentage and the number of groups of the working condition percentage are the same. From the conditions of each optional group of the multiple groups of the mixing percentage and the multiple groups of the working condition percentage, respectively, the combustion stability test is carried out according to the single ignition timing, until each group of the mixing percentage and the working condition percentage has carried out the combustion stability test, and the percentage of the number of times of generating excited combustion instability to the total number of combustion stability test times is recorded.

[0006] Optionally, in the single nozzle combustion stability evaluation method described above, the single ignition timing includes: At -t0, the electric shut-off valves on the oxidant supply pipeline and the fuel supply pipeline are opened at the same time, and fuel and oxidant are supplied; At 0s, the electric valve of the single nozzle combustion stability test device is opened, fuel and oxidant are supplied to the single nozzle combustion stability test device for combustion stability test, and the working time t1 is run; At t1, the electric shut-off valves on the oxidant supply pipeline and the fuel supply pipeline are closed at the same time, and the fuel supply pipeline and the oxidant supply pipeline stop supplying fuel and oxidant to the single nozzle combustion stability test device.

[0007] Optionally, in the single nozzle combustion stability evaluation method described above, the single ignition timing includes: At t1, the electric shut-off valves on the oxidant supply pipeline and the fuel supply pipeline are opened at the same time, and the fuel supply pipeline and the oxidant supply pipeline stop supplying fuel and oxidant to the single nozzle combustion stability test device.

[0008] Optionally, in the single nozzle combustion stability evaluation method described above, before -t0, the electric shut-off valves on the oxidant supply pipeline and the fuel supply pipeline are opened at the same time, the method further includes: The cooling pipeline is opened to supply cooling liquid, and the single nozzle combustion stability test device is cooled by cooling liquid circulation.

[0009] The single-nozzle combustion stability evaluation method provided by the application first determines the single ignition operation working time t1 of the single-nozzle combustion stability test device according to the time when the engine occurs combustion instability, then plans the ignition timing according to the determined single ignition operation working time t1 of the single-nozzle combustion stability test device, then sets multiple groups of different percentage values for the mixture percentage and the working condition percentage, respectively selects one group from the multiple groups of mixture percentage and working condition percentage, and performs combustion stability test according to the ignition timing, until each group of the mixture percentage and the working condition percentage has been tested for combustion stability, records the number of groups that produce excited combustion instability in the whole test process, and then calculates the percentage of the number of groups that produce excited combustion instability in the total number of combustion stability test groups. Compared with the prior art, the single-nozzle combustion stability evaluation method provided by the application is not only suitable for combustion stability test of different propellant combinations and different nozzle types, but also uses the percentage of combustion instability in the test matrix as a quantitative index to compare the stability of different nozzles horizontally, and further comprehensively study the mechanism of single-nozzle combustion instability.

[0010] In a second aspect, the application further provides a test system for implementing the single-nozzle combustion stability evaluation method, wherein the single-nozzle combustion stability evaluation method is the single-nozzle combustion stability evaluation method according to any one of the preceding items. The test system comprises a fuel tank, a fuel control valve, an oxidizer tank, an oxidizer control valve, a single-nozzle combustion stability test device, a blowing system, a cooling system and a measurement system. The fuel tank is connected to the single-nozzle combustion stability test device through a fuel supply pipeline. The fuel control valve is arranged on the fuel supply pipeline to control the supply of fuel. The oxidizer tank is connected to the single-nozzle combustion stability test device through an oxidizer supply pipeline. The oxidizer control valve is arranged on the oxidizer supply pipeline to control the supply of oxidizer. The measurement system is used to measure the parameters of the ignition process of the single-nozzle combustion stability test device. The blowing system is connected to the single-nozzle combustion stability test device to perform blowing treatment. The cooling system is connected to the single-nozzle combustion stability test device to perform cooling by cooling liquid.

[0011] Optionally, in the test system, the fuel control valve comprises a manual valve, a check valve and an electric shut-off valve, which are sequentially and spaced apart along the supply direction of the fuel, and / or The oxidizer control valve comprises a manual valve, a check valve and an electric shut-off valve, which are sequentially and spaced apart along the supply direction of the oxidizer.

[0012] Optionally, in the above-mentioned test system, a flow meter and a filter are arranged on the fuel supply pipeline, the filter is arranged between the manual valve and the electric cut-off valve, and the flow meter is arranged between the manual valve and the filter.

[0013] Optionally, in the above-mentioned test system, the test system further comprises a high-pressure nitrogen gas cylinder, which is communicated with the fuel storage tank and the oxidant storage tank through pipelines respectively, so as to pressurize the fuel storage tank and the oxidant storage tank through the high-pressure nitrogen gas cylinder.

[0014] Optionally, in the above-mentioned test system, the blowing system comprises a fuel blowing gas cylinder and an oxidant blowing gas cylinder, the fuel blowing gas cylinder is communicated with one end of the fuel supply pipeline close to the single-nozzle combustion stability test device through a first pipeline, the oxidant blowing gas cylinder is communicated with one end of the oxidant supply pipeline close to the single-nozzle combustion stability test device through a second pipeline, and the first pipeline and the second pipeline are both provided with a control valve and a check valve.

[0015] Optionally, in the above-mentioned test system, the cooling system comprises a water storage tank, a high-pressure water pump, a cooling supply pipeline and a cooling return pipeline, the high-pressure water pump supplies cooling liquid to the single-nozzle combustion stability test device through the cooling supply pipeline for cooling and temperature reduction, and the cooling liquid after cooling and temperature reduction is returned to the water storage tank through the cooling return pipeline.

[0016] The test system provided by the present application has all the technical effects of the single-nozzle combustion stability evaluation method, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and together with the description serve to explain the present application. In the drawings: Figure 1 A flow chart of the single-nozzle combustion stability evaluation method disclosed by the embodiments of the present application; Figure 2 A flow chart of the single-time ignition timing in the single-nozzle combustion stability evaluation method disclosed by the embodiments of the present application; Figure 3 A flow chart of the single-time ignition timing disclosed by the embodiments of the present application; Figure 4 A structural schematic diagram of the test system disclosed by the embodiments of the present application; Figure 5The matrix diagram obtained by the single-nozzle combustion stability evaluation method disclosed by the embodiment of the present application to the A-nozzle experiment; Figure 6 The matrix diagram obtained by the single-nozzle combustion stability evaluation method disclosed by the embodiment of the present application to the B-nozzle experiment; Figure 7 The matrix diagram obtained by the single-nozzle combustion stability evaluation method disclosed by the embodiment of the present application to the B-nozzle experiment.

[0018] Reference signs: 100 is a fuel tank; 200 is an oxidant tank; 300 is a single-nozzle combustion stability test device; 400 is a blowing system, 410 is a fuel blowing gas cylinder, and 420 is an oxidant blowing gas cylinder; 500 is a cooling system, 510 is a water tank, and 520 is a high-pressure water pump; 600 is a high-pressure nitrogen cylinder; 10 is a manual valve, 20 is a check valve, 30 is an electric shut-off valve, 40 is a flowmeter, and 50 is a filter. DETAILED DESCRIPTION

[0019] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0021] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more than two, unless otherwise specifically limited. The meaning of "several" is one or more than one, unless otherwise specifically limited.

[0022] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0023] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0024] As shown in Figure 1 The single-nozzle combustion stability evaluation method disclosed by the embodiment of the present application is used to more comprehensively study the mechanism of single-nozzle combustion instability, and the single-nozzle combustion stability evaluation method comprises: Step 101: determining the working time t1 of single ignition operation of the single-nozzle combustion stability test device according to the time when the engine appears combustion instability; At present, the time when most of the engine appears combustion instability is recorded during the operation of the engine, and the working time t1 of single ignition operation of the single-nozzle combustion stability test device is determined according to the recorded time of combustion instability.

[0025] Step 102: determining single ignition timing according to the working time t1; According to the determined working time t1 of single ignition operation of the single-nozzle combustion stability test device, the single ignition timing is planned.

[0026] Step 103: setting a plurality of groups of different percentage values of mixing percentage and a plurality of groups of different percentage values of working condition percentage, and the number of groups of mixing percentage and the number of groups of working condition percentage are the same, and under the condition that each group is selected from the plurality of groups of mixing percentage and the plurality of groups of working condition percentage, respectively, the combustion stability test is carried out according to the single ignition timing, until each group of mixing percentage and working condition percentage has carried out the combustion stability test, and the percentage of the number of times of excited combustion instability to the total number of combustion stability test is recorded. The mixing percentage refers to the percentage relationship of the actual ratio of fuel to oxidant and the rated ratio of fuel to oxidant; the working condition percentage refers to the percentage relationship of the actual total flow of fuel and oxidant and the rated total flow of fuel and oxidant.

[0027] While setting multiple sets of mixed percentages with different percentage values, multiple sets of operating condition percentages with different percentage values ​​are also set, with the number of mixed percentage sets being the same as the number of operating condition percentage sets. Then, each set of mixed percentages and operating condition percentages is randomly selected as the test requirement, and combustion stability tests are performed according to the single ignition sequence until each set of mixed percentages and operating condition percentages has been tested for combustion stability. The number of times initiation combustion instability occurs during the test is recorded. At this point, the test results are presented as an experimental matrix, and then the percentage of combustion instability out of all combustion stability test counts is calculated.

[0028] The single-nozzle combustion stability assessment method provided by this invention is not only applicable to combustion stability tests of different propellant combinations and different nozzle types, but also uses the percentage of combustion instability problems occurring within the test matrix as a quantitative indicator to compare the stability of different nozzles horizontally, thereby enabling a more comprehensive study of the mechanism of single-nozzle combustion instability.

[0029] In one specific embodiment, the single-nozzle combustion stability assessment method provided in this embodiment is used to conduct combustion instability tests on three different types of nozzles: nozzle A, nozzle B, and nozzle C. Figure 5 The test results for nozzle A show that there were 0 cases where nozzle A caused unstable combustion, and the calculated percentage of unstable combustion for nozzle A is 0. Figure 6 Based on the test results for nozzle B, 24 operating conditions showed unstable combustion when nozzle B was used, with a calculated percentage of 29.6%. Figure 7 The test results for nozzle C show that there were 54 cases where combustion was unstable when nozzle C was used to ignite the system, and the percentage was calculated to be 66.7%. Based on this, it can be concluded that nozzle A has the best combustion stability performance, followed by nozzle B, and nozzle C has the worst performance.

[0030] In one specific embodiment, such as Figure 2 Hehe Figure 3 As shown, the single ignition timing sequence includes the following steps: Step 102-1: At time -t0, simultaneously open the electric shut-off valves on the oxidizer supply line and the fuel supply line to supply fuel and oxidizer; where -t0 refers to a time before time 0s.

[0031] At time -t0, the electric shut-off valves on both the oxidizer supply line and the fuel supply line are opened simultaneously. Oxidizer is supplied to the oxidizer supply line until it is full of oxidizer, and fuel is supplied to the fuel supply line until it is full of fuel. This prepares the necessary fuel and oxidizer for the combustion stability test.

[0032] Step 102-2: At 0s, open the electric valve of the single-nozzle combustion stability test device, supply fuel and oxidant into the single-nozzle combustion stability test device for combustion stability test, and run for a working time t1. After the electric stop valves on the oxidant supply pipeline and the fuel supply pipeline are both opened, at 0s, open the electric valve of the single-nozzle combustion stability test device, supply fuel and oxidant into the single-nozzle combustion stability test device and ignite at the same time, until the combustion stability test runs for a working time t1.

[0033] Step 102-3: At t1, close the electric stop valves on the oxidant supply pipeline and the fuel supply pipeline at the same time, and stop supplying fuel and oxidant. After the combustion stability test runs for a time t1 in the single-nozzle combustion stability test device, at t1, the electric stop valves on the oxidant supply pipeline and the fuel supply pipeline are closed at the same time, and the single-nozzle combustion stability test device stops the combustion stability test.

[0034] In another specific embodiment, the single ignition timing further includes Step 102-4: At t1, open the electric stop valves on the oxidant blowing pipeline and the fuel blowing pipeline for blowing, and the blowing time is t2. After the combustion stability test runs for a time t1 in the single-nozzle combustion stability test device, at t1, the electric stop valves on the oxidant supply pipeline and the fuel supply pipeline are closed at the same time, and the electric stop valves on the oxidant blowing pipeline and the fuel blowing pipeline are opened for blowing to blow away the residual liquid and gas in the single-nozzle combustion stability test device, so as to avoid the interference of the residual gas in the single-nozzle combustion stability test device on the next combustion stability test, and the blowing time is set to t2, that is, the blowing system is closed at t1+t2.

[0035] In a specific embodiment, before Step 102-1, that is, before opening the electric stop valves on the oxidant supply pipeline and the fuel supply pipeline at -t0, it further includes: Step 102-0: Open the cooling pipeline to supply cooling liquid, and cool the single-nozzle combustion stability test device through the circulation of the cooling liquid.

[0036] The cooling pipeline is opened to supply cooling liquid to the single-nozzle combustion stability test device, and the single-nozzle combustion stability test device is cooled in time through the circulation of the cooling liquid in the cooling channel of the single-nozzle combustion stability test device during the combustion test, so as to avoid the damage of high temperature to the single-nozzle combustion stability test device, thereby improving the reliability of the experiment.

[0037] As Figure 4As shown, the embodiment of the present application further discloses a test system, which comprises a fuel storage tank 100, a fuel control valve, an oxidant storage tank 200, an oxidant control valve, a single-nozzle combustion stability test device 300, a blowing system 400, a cooling system 500 and a measuring system. The fuel storage tank 100 for storing fuel is communicated with the single-nozzle combustion stability test device 300 through a fuel supply pipeline, and the fuel control valve arranged on the fuel supply pipeline controls the supply and closing of the fuel supply pipeline to supply fuel to the single-nozzle combustion stability test device 300 in time. The oxidant storage tank 200 for storing oxidant is communicated with the single-nozzle combustion stability test device 300 through an oxidant supply pipeline, and the oxidant control valve arranged on the oxidant supply pipeline controls the supply and closing of the oxidant supply pipeline to supply oxidant to the single-nozzle combustion stability test device 300 in time. The blowing system 400 is communicated with the single-nozzle combustion stability test device 300 to blow away the residual gas after the combustion stability test, the cooling system 500 is connected with the single-nozzle combustion stability test device 300 to supply cooling liquid to the single-nozzle combustion stability test device 300 for cooling, and the measuring system is used to measure and record the parameters of the single-nozzle combustion stability test device 300 during the ignition operation. Since the test system is used for the implementation of the single-nozzle combustion stability evaluation method, it has all the technical effects of the single-nozzle combustion stability evaluation method, which will not be described here.

[0038] In a specific embodiment, the fuel control valve comprises a manual valve 10, a one-way valve 20 and an electric shut-off valve 30, wherein the manual valve 10, the one-way valve 20 and the electric shut-off valve 30 are sequentially and spacedly arranged along the fuel supply direction. By arranging multiple control valves in the fuel supply pipeline, not only the fuel supply is controlled, but also the reliability of fuel supply is improved, avoiding the problem of fuel supply caused by the failure of a single valve, and improving the safety of the operation of the test system. Similarly, the oxidant control valve can also comprise a manual valve 10, a one-way valve 20 and an electric shut-off valve 30, wherein the manual valve 10, the one-way valve 20 and the electric shut-off valve 30 are sequentially and spacedly arranged along the oxidant supply direction, and have the same effect as the fuel control valve on the fuel supply pipeline.

[0039] Further, the fuel supply pipeline is also provided with a flow meter 40 and a filter 50, the filter 50 is located between the manual valve 10 and the electric cut-off valve 30, and the flow meter 40 is arranged between the manual valve 10 and the filter 50, so that the fuel supply amount in the fuel supply pipeline can be monitored through the flow meter 40, so as to control the amount of fuel entering the single nozzle combustion stability test device 300 in time and accurately, and the filter 50 filters the fuel in the fuel supply pipeline, reduces the impurities in the fuel, and then reduces the occurrence of the single nozzle blockage problem. Similarly, the oxidant supply pipeline is also provided with a flow meter 40 and a filter 50, and the filter 50 is located between the manual valve 10 and the electric cut-off valve 30, and the flow meter 40 is arranged between the manual valve 10 and the filter 50.

[0040] As shown in Figure 4 The test system provided by the present example also includes a high-pressure nitrogen cylinder 600, which is communicated with the fuel storage tank 100 and the oxidant storage tank 200 through pipelines, and supplies high-pressure nitrogen to the fuel storage tank 100 and the oxidant storage tank 200 through the pipelines, so as to increase the internal pressure of the fuel storage tank 100 and the oxidant storage tank 200, and press the fuel in the fuel storage tank 100 and the oxidant in the oxidant storage tank 200 respectively, so as to ensure that the fuel and the oxidant can be stably and quickly supplied to the single nozzle combustion stability test device 300.

[0041] In a specific embodiment, the blowing system 400 includes a fuel blowing cylinder 410 and an oxidant blowing cylinder 420, the fuel blowing cylinder 410 is communicated with the fuel supply pipeline through a first pipeline, and the connection end of the first pipeline with the fuel supply pipeline is close to one end of the single nozzle combustion stability test device 300, that is, the connection end of the first pipeline with the fuel supply pipeline is located downstream of the one-way valve 20, and the oxidant blowing cylinder 420 is communicated with the oxidant supply pipeline through a second pipeline, and the connection end of the second pipeline with the oxidant supply pipeline is also close to one end of the single nozzle combustion stability test device 300, that is, the connection end of the second pipeline with the fuel supply pipeline is located downstream of the one-way valve 20, and the first pipeline and the second pipeline are both provided with the electric cut-off valve 30 and the one-way valve 20, so as to control the one-way flow direction of the blowing gas to the single nozzle combustion stability test device 300, so as to blow away the residual fuel, oxidant and other waste gas generated in the single nozzle combustion stability test device 300.

[0042] As shown in Figure 4As shown, the cooling system 500 includes a water tank 510, a high-pressure water pump 520, a cooling supply pipeline and a cooling return pipeline. The high-pressure water pump 520 is located in the water tank 510 for containing the cooling liquid. The high-pressure water pump 520 is in communication with the cooling channel in the single-nozzle combustion stability test device 300 through the cooling supply pipeline. The cooling liquid is supplied into the cooling channel through the high-pressure water pump 520. The cooling liquid flowing in the cooling channel cools and lowers the temperature of the single-nozzle combustion stability test device 300. The cooling liquid after absorbing heat returns to the water tank 510 through the cooling return pipeline, thereby realizing the circulating cooling and temperature lowering of the cooling liquid. In a specific embodiment, the cooling liquid can be water.

[0043] In a specific embodiment, the measurement system includes a pressure sensor, a pressure fluctuation sensor, a temperature measuring thermocouple and a vibration measurement sensor. The pressure sensor is used to measure the tank pressure, the combustion chamber pressure, the cooling water inlet pressure and the blow-off gas pressure. The pressure fluctuation sensor is mainly used to measure the pressure fluctuation of the oxidizer and the fuel before injection and the combustion chamber pressure fluctuation. The temperature measuring thermocouple is used to measure the wall temperature of the single-nozzle combustion stability test device 300 and the gas temperature. The vibration measurement sensor is installed on the vibration measurement platform and is used to measure the vibration of the single-nozzle combustion stability test device 300 at different positions. The structure of the single-nozzle combustion stability test device 300 mainly includes an electric valve, a head and a body. The electric valve is used to control the propellant into the combustion chamber. In the single ignition timing step, the electric valve is opened at 0s to make the fuel and the oxidizer enter the single-nozzle combustion stability test device 300. The electric valve in the single-nozzle combustion stability test device 300 is closed at the end of t3, i.e. at t1+ t2+ t3, to prepare for the next single ignition for combustion stability experiment.

[0044] The nozzle to be tested is brazed on the head, so that the verification of different nozzle schemes can be realized by replacing the head. The body can be integrally formed by 3D printing and has a cooling jacket for the flow of the cooling liquid. The head and the body are connected by bolts and have a graphite sealing ring therebetween for sealing. The number and length of the cylindrical body sections can be adjusted. The principle is to ensure that the total length of the combustion chamber is consistent with the actual length of the combustion assembly, so as to ensure the consistency of the acoustic frequency. The single-nozzle combustion stability test device 300 has a temperature measuring connector, a pressure measuring connector, a chamber pressure fluctuation connector and a vibration measurement platform, which correspond to the installation of the temperature measuring thermocouple, the pressure sensor, the pressure fluctuation sensor and the vibration measurement sensor.

[0045] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0046] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for evaluating the combustion stability of a single nozzle, characterized in that, include: Based on the moment when combustion instability occurs in the engine, determine the working time t1 of a single ignition operation of the single-nozzle combustion stability test device. The single ignition sequence is determined based on the working time t1; Multiple sets of mixed percentages with different percentage values ​​and multiple sets of operating condition percentages with different percentage values ​​are set, and the number of mixed percentages and the number of operating condition percentages are the same. Under the condition of randomly selecting one set from each of the multiple mixed percentages and multiple operating condition percentages, combustion stability tests are performed according to the single ignition sequence until each set of mixed percentages and operating condition percentages has been tested for combustion stability, and the percentage of times that ignition instability occurs out of the total number of combustion stability tests is recorded.

2. The single-nozzle combustion stability evaluation method according to claim 1, characterized in that, The single ignition timing sequence includes: At time -t0, the electric shut-off valves on both the oxidizer supply line and the fuel supply line are opened simultaneously to supply fuel and oxidizer. At time 0s, the electric gas valve of the single-nozzle combustion stability test device is opened to supply fuel and oxidant to the single-nozzle combustion stability test device for combustion stability testing, and the working time t1 is run. At time t1, the electric shut-off valves of the oxidant supply line and the fuel supply line are simultaneously closed, and the fuel supply line and the oxidant supply line stop supplying fuel and oxidant to the single-nozzle combustion stability test device.

3. The single-nozzle combustion stability evaluation method according to claim 2, characterized in that, The single ignition timing sequence includes: At time t1, the electric shut-off valves of the oxidizer purge line and the fuel purge line are opened for purging, and the purging time is t2.

4. The single-nozzle combustion stability evaluation method according to claim 2, characterized in that, Before simultaneously opening the electrically operated shut-off valves on both the oxidizer supply line and the fuel supply line at time -t0, the following steps are also included: The cooling pipes are turned on to supply coolant, and the single-nozzle combustion stability test device is cooled down by circulating the coolant.

5. A testing system, characterized in that, The test system is used for the single-nozzle combustion stability assessment method as described in any one of claims 1-4; The test system includes a fuel tank, a fuel control valve, an oxidizer tank, an oxidizer control valve, a single-nozzle combustion stability test device, a purging system, a cooling system, and a measurement system. The fuel tank is connected to the single-nozzle combustion stability test device via a fuel supply pipeline. The fuel control valve is located in the fuel supply pipeline to control the fuel supply. The oxidizer tank is connected to the single-nozzle combustion stability test device via an oxidizer supply pipeline. The oxidizer control valve is located in the oxidizer supply pipeline to control the oxidizer supply. The measurement system is used to measure the parameters of the ignition process of the single-nozzle combustion stability test device. The purging system is connected to the single-nozzle combustion stability test device for purging treatment. The cooling system is connected to the single-nozzle combustion stability test device to cool it down with coolant.

6. The testing system according to claim 5, characterized in that, The fuel control valve includes a manual valve, a check valve, and an electric shut-off valve, wherein the manual valve, the check valve, and the electric shut-off valve are arranged sequentially at intervals along the fuel supply direction, and / or; The oxidant control valve includes a manual valve, a check valve, and an electric shut-off valve, which are arranged sequentially at intervals along the oxidant supply direction.

7. The testing system according to claim 6, characterized in that, The fuel supply line is equipped with a flow meter and a filter. The filter is arranged between the manual valve and the electric shut-off valve, and the flow meter is arranged between the manual valve and the filter.

8. The testing system according to claim 5, characterized in that, The test system also includes a high-pressure nitrogen cylinder, which is connected to the fuel tank and the oxidant tank via pipelines to pressurize the fuel tank and the oxidant tank.

9. The testing system according to claim 5, characterized in that, The purging system includes a fuel purging cylinder and an oxidizer purging cylinder. The fuel purging cylinder is connected to one end of the fuel supply pipeline near the single-nozzle combustion stability test device via a first pipeline. The oxidizer purging cylinder is connected to one end of the oxidizer supply pipeline near the single-nozzle combustion stability test device via a second pipeline. Both the first pipeline and the second pipeline are equipped with an electric control valve and a one-way valve.

10. The testing system according to claim 5, characterized in that, The cooling system includes a water tank, a high-pressure water pump, a cooling supply pipeline, and a cooling return pipeline. The high-pressure water pump supplies coolant to the single-nozzle combustion stability test device through the cooling supply pipeline for cooling. The cooled coolant is then returned to the water tank through the cooling return pipeline.

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