Performance evaluation method and equipment for scramjet engine based on direct connection test

Abstract

The invention relates to a direct connection test-based performance evaluation method and equipment for a scramjet engine. The method comprises the following steps of: acquiring a first test bed thrust-time curve, a first flow parameter and a first pressure parameter of the scramjet engine under a free jet test working condition; the incoming flow condition of the scramjet engine in the ground direct connection type test is set based on the first airflow parameter, the first airflow parameter serves as the airflow parameter of the selected second engine characteristic section, and the second airflow parameter serves as the airflow parameter of the combustion chamber fuel inlet section of the scramjet engine; under the ground direct connection type test working condition, a second test bed thrust-time curve, a second flow parameter and a second pressure parameter of the scramjet engine after a second engine characteristic section are obtained; and evaluating the performance of the scramjet engine based on the second test bed thrust-time curve, the second flow parameter and the second pressure parameter.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and in particular to a performance evaluation method and device for a scramjet engine based on a direct-connection test. Background Art

[0002] Theoretical analysis and numerical simulation provide basic methods for engine design and performance analysis. However, experimental testing is still a key link in the engine development process, and the correctness of theoretical analysis and numerical simulation results also needs to be verified through engine tests. According to the purpose of the test, the ground test system can be divided into two types: free jet test system and direct connection test system, but both have certain defects.

[0003] The free jet test system, also known as a wind tunnel, places all test components (including the inlet, combustion chamber and tail nozzle) in a free jet nozzle to form a supersonic simulated flow field. It can fully simulate the inlet wave system state and truly reflect the coordinated working conditions between the various engine components. It is suitable for overall engine performance testing.

[0004] In the direct-connect test system, the test airflow provided by the equipment enters the engine through the connecting pipe. The actual flight state is simulated by controlling the total air pressure, total temperature and flow rate. It is usually used for performance testing of individual engine components.

[0005] Compared with the free jet test system, the direct-connection test system has a relatively simple structure, low cost, and is easy to implement. It is the simplest, most economical and more effective test method in the ground simulation test of ramjet engines, and it is the basis for ramjet engine research. However, the traditional direct-connection test system is generally used to carry out performance tests of individual engine components, such as thermal protection and combustion performance, and it is difficult to directly obtain engine thrust and specific impulse. The reason is that on the one hand, the thrust measured in the direct-connection test is the bench thrust, which is the thrust generated by the local components of the engine and the test system. It is difficult to convert it into engine thrust, and because the system error is large, it often exceeds 15%, and the measured thrust is difficult to apply directly; on the other hand, there is a certain difference between the airflow entering the combustion chamber in the direct-connection test system and the airflow entering the combustion chamber from the inlet duct-isolation section of the actual engine, and there is no strict processing. Summary of the invention

[0006] The object of the present invention is to provide a performance evaluation method and device for a scramjet engine based on a direct-connection test.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a performance evaluation method of a scramjet engine based on a direct-connection test, comprising the following steps: S1. Obtaining a first test bench thrust-time curve, a first flow parameter and a first pressure parameter of a scramjet engine under a free jet test condition; wherein the first flow parameter includes: a first airflow parameter of a simulated air flow of a selected first engine characteristic section, a second airflow parameter of a fuel gas flow of a combustion chamber fuel inlet section, and the first pressure parameter includes: a static pressure distribution of a simulated air flow of a selected first engine characteristic section; S2. setting the incoming flow condition of the scramjet engine during the ground direct-connection test based on the first airflow parameter, and using the first airflow parameter as the airflow parameter of the selected second engine characteristic section, and using the second airflow parameter as the airflow parameter of the fuel inlet section of the combustion chamber of the scramjet engine; S3. Under the ground direct-connection test condition, obtaining a second test bench thrust-time curve, a second flow parameter, and a second pressure parameter of the scramjet engine after the second engine characteristic section; S4. Evaluate the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter.

[0008] According to one aspect of the present invention, in step S1, the first airflow parameter includes: a first airflow mass flow rate, a first airflow pressure, and a first airflow temperature at the first engine characteristic cross section; The second airflow parameter includes: a second airflow mass flow rate at a fuel inlet section of the combustion chamber.

[0009] According to one aspect of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the performance evaluation result of the scramjet engine includes: internal thrust specific impulse, engine combustion chamber gas flow and equivalence ratio.

[0010] According to one aspect of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, if the scramjet engine is a liquid fuel scramjet engine, the engine combustion chamber gas flow rate is obtained based on mass flow meter measurement; If the scramjet engine is a solid fuel scramjet engine, the engine combustion chamber gas flow rate is obtained based on the following steps, which include: Obtaining a mass flow rate of engine fuel in the scramjet engine; Obtaining theoretical fuel consumption mass of the scramjet engine before and after a ground direct-connection test based on the mass flow rate; Obtaining the actual fuel consumption mass of the propellant in the scramjet engine before and after the ground direct-connection test; The fuel flow rate of the engine combustion chamber of the scramjet engine is obtained based on the theoretical fuel consumption mass and the actual fuel consumption mass.

[0011] According to one aspect of the present invention, the step of obtaining the mass flow rate of the engine fuel in the scramjet engine comprises: Obtain the first mass of the solid propellant grain in the gas generator of the scramjet engine before the test m 1 The second mass of the solid propellant grain in the gas generator after the test m 2 , and get the first mass m 1 With the second quality m 2 Poor quality m ; The combustion rate formula is used to calculate the gas flow rate during the test period to obtain the mass flow rate of the fuel at the fuel inlet section of the combustion chamber of the scramjet engine at each time of the test; wherein the mass flow rate is expressed as:

[0012] in, represents the mass flow rate, represents the propellant burning rate coefficient, represents the pressure coefficient, represents density, Represents the burning area, and it is a constant value. is the gas generator pressure.

[0013] According to one aspect of the present invention, in the step of obtaining the theoretical fuel consumption mass of the scramjet engine before and after the ground direct-connection test based on the mass flow rate, the theoretical fuel consumption mass is obtained based on the integral of the mass flow rate and is expressed as:

[0014] in, Indicates the theoretical fuel consumption mass, t 1 Indicates the start time of the test. t 2 Indicates the end time of the test.

[0015] According to one aspect of the present invention, in the step of obtaining the gas flow rate of the engine combustion chamber of the scramjet engine based on the theoretical fuel consumption mass and the actual fuel consumption mass, the gas flow rate of the engine combustion chamber is expressed as:

[0016] in, Indicates mass flow, that is, the gas flow in the engine combustion chamber.

[0017] According to one aspect of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the internal thrust specific impulse is expressed as:

[0018]

[0019] in, I is the internal thrust specific impulse, is the thrust gain of the test bench under the test conditions, is the gas flow rate, The combustion chamber resistance is is the thermal thrust of the engine combustion chamber under test conditions, It is the cold thrust of the test bench under the test conditions.

[0020] According to one aspect of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the equivalence ratio is expressed as:

[0021] in, E is the equivalent ratio, is the theoretical equivalent ratio of the fuel, is the gas flow rate, is the air flow rate.

[0022] To achieve the above-mentioned object of the invention, the present invention provides a device applied to the above-mentioned performance evaluation method, comprising at least one processor, at least one memory and a data bus; The processor and the memory communicate with each other via the data bus; The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the performance evaluation method.

[0023] According to one solution of the present invention, the present invention can directly use a ground direct-connection test to replace the free jet test to obtain the engine thrust performance. Compared with the free jet test, this solution only requires the engine part after the second engine characteristic section, the test product is simple, and no additional free jet aircraft or other accompanying test pieces are required; the direct-connection test system used is low-cost, one order of magnitude lower than the free jet test system, and the test effect is equivalent; and the direct-connection test time is significantly shortened, easy to organize, and the engine thrust data can be quickly obtained to evaluate the engine performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flowchart schematically showing a performance evaluation method according to an embodiment of the present invention; Figure 2 It is a schematic diagram showing the structure principle of a free jet test system; Figure 3 It is a schematic diagram showing the structure principle of a ground direct-connection test system; Figure 4 is a diagram schematically showing the thrust-time curve of the first test bench under the free jet test condition; Figure 5 It schematically shows the thrust-time curve of the second test bench under the ground direct-connection test condition. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0026] like Figure 1 As shown, according to one embodiment of the present invention, a performance evaluation method of a scramjet engine based on a direct-connection test of the present invention comprises the following steps: S1. Obtaining a first test bench thrust-time curve, a first flow parameter and a first pressure parameter of a scramjet engine under a free jet test condition; wherein the first flow parameter includes: a first airflow parameter of a simulated air flow of a selected first engine characteristic section, a second airflow parameter of a fuel gas flow of a combustion chamber fuel inlet section, and the first pressure parameter includes: a static pressure distribution of a simulated air flow of a selected first engine characteristic section; S2. setting the incoming flow condition of the scramjet engine during the ground direct-connection test based on the first airflow parameter, and using the first airflow parameter as the airflow parameter of the selected second engine characteristic section, and using the second airflow parameter as the airflow parameter of the fuel inlet section of the combustion chamber of the scramjet engine; S3. Under the ground direct-connection test condition, obtain a second test bench thrust-time curve, a second flow parameter, and a second pressure parameter of the scramjet engine after the second engine characteristic section; S4. Evaluate the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter, and the second pressure parameter.

[0027] like Figure 2 As shown, according to one embodiment of the present invention, in step S1, in the step of obtaining the first test bench thrust-time curve, the first flow parameter and the first pressure parameter of the scramjet engine under the free jet test condition, the free jet test system for realizing the free jet test condition includes: a first high-pressure gas source 11, a first heater system 12, a free jet nozzle 13, a test section 14 and a first ejection exhaust system 15 connected in sequence, wherein the test section 14 is a hollow structure to facilitate the installation of the first test component. In this embodiment, the first test component is an aircraft with an engine, which includes: an aircraft body and a scramjet engine, and the scramjet engine includes: an air inlet, a combustion chamber and a tail nozzle, wherein the aircraft is installed in the test section so that the air inlet, the combustion chamber and the tail nozzle of the scramjet engine are all in the test section, so that the first test component is completely in the supersonic simulated flow field formed by the free jet nozzle 13, so as to fully simulate the air inlet wave system state, truly reflect the coordinated working conditions between the various components of the first test component, and is suitable for the overall performance test of the engine.

[0028] In this embodiment, the first engine characteristic cross section is determined based on the structural characteristics of the scramjet engine in the first test component, and has a uniform parameter distribution feature, which is conducive to the simulation in the ground direct connection test in the subsequent steps. In this embodiment, the first engine characteristic cross section is generally selected from the combustion chamber inlet cross section or the intake throat cross section of the scramjet engine, see Figure 2 .

[0029] Furthermore, in step S1, the first airflow parameters include: a first airflow mass flow rate, a first airflow pressure, and a first airflow temperature at a first engine characteristic section; the second airflow parameters include: a second airflow mass flow rate at a combustion chamber fuel inlet section.

[0030] like Figure 3As shown, according to an embodiment of the present invention, in step S2, a ground direct connection test is performed based on the constructed ground direct connection test system, wherein the ground direct connection test system includes: a second high-pressure gas source 21, a second heater system 22, a connecting pipe 23, a collector 24, and a second ejection exhaust system 25 connected in sequence, wherein a second test component is arranged between the connecting pipe 23 and the collector 24, so that the test airflow provided by the front equipment enters the engine through the connecting pipe 23, and the actual flight state is simulated by controlling the total air pressure, total temperature and flow rate. In this embodiment, the second test component is usually tested for performance using the scramjet engine in the first test component, and of course, a single component of the scramjet engine in the first test component can also be tested for performance.

[0031] In this embodiment, the second engine characteristic cross section is determined based on the first engine characteristic cross section. Figure 3 As shown, the second engine characteristic section is determined by the position on the second test component corresponding to the first engine characteristic section in the first test component. In this embodiment, the second engine characteristic section is at the same position as the first engine characteristic section. Furthermore, the incoming flow condition of the scramjet engine during the ground direct-connection test is set based on the first airflow parameter, and the first airflow parameter is used as the airflow parameter of the selected second engine characteristic section, and the second airflow parameter is used as the airflow parameter of the fuel inlet section of the combustion chamber of the scramjet engine.

[0032] According to one embodiment of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the performance evaluation results of the scramjet engine include: internal thrust specific impulse, engine combustion chamber gas flow and equivalence ratio.

[0033] According to an embodiment of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, if the scramjet engine is a liquid fuel scramjet engine, the gas flow rate of the engine combustion chamber is obtained based on the measurement of the mass flow meter; If the scramjet engine is a solid fuel scramjet engine, the engine combustion chamber gas flow rate is obtained based on the following steps, which include: Obtaining a mass flow rate of engine fuel in a scramjet engine; wherein, if the scramjet engine is a solid fuel scramjet engine, the mass flow rate is obtained by the following steps, which include: Obtaining the first mass of the solid propellant grain in the gas generator of the scramjet engine before the test m 1The second mass of the solid propellant grain in the gas generator after the test m 2 , and get the first quality m 1 With the second mass m 2 Poor quality m ; The combustion rate formula is used to calculate the gas flow rate during the test period to obtain the mass flow rate of the fuel at the fuel inlet section of the scramjet combustion chamber at each moment of the test; the mass flow rate is expressed as:

[0034] in, represents the mass flow rate, represents the propellant burning rate coefficient, represents the pressure coefficient, represents density, represents the burning area, and it is a constant value (i.e., the propellant burns at a constant area after ignition). is the gas generator pressure.

[0035] The theoretical fuel consumption mass of the scramjet engine before and after the ground direct-connection test is obtained based on the mass flow rate; if the scramjet engine is a solid fuel scramjet engine, the theoretical fuel consumption mass is obtained based on the integral of the mass flow rate and is expressed as:

[0036] in, Indicates the theoretical fuel consumption mass, t 1 Indicates the start time of the test. t 2 Indicates the end time of the test.

[0037] Obtain the actual fuel consumption mass of the propellant in the scramjet engine before and after the ground direct-connection test; in this embodiment, weighing can be used to obtain the fuel difference before and after the test to obtain the corresponding actual fuel consumption mass.

[0038] The gas flow rate of the engine combustion chamber of the scramjet engine is obtained based on the theoretical fuel consumption mass and the actual fuel consumption mass; wherein, if the scramjet engine is a solid fuel scramjet engine, the gas flow rate of the engine combustion chamber is expressed as:

[0039] in, Indicates mass flow, that is, the gas flow in the engine combustion chamber.

[0040] According to an embodiment of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the internal thrust specific impulse is expressed as:

[0041]

[0042] in, I is the internal thrust specific impulse, is the thrust gain of the test bench under the test conditions, is the gas flow rate, The combustion chamber resistance is is the thermal thrust of the engine combustion chamber under test conditions, It is the cold thrust of the test bench under the test conditions.

[0043] According to an embodiment of the present invention, in step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the equivalence ratio is expressed as:

[0044] in, E is the equivalent ratio, is the theoretical equivalent ratio of the fuel, is the gas flow rate, is the air flow rate.

[0045] According to one embodiment of the present invention, the present invention provides an electronic device applied to the aforementioned performance evaluation method, comprising at least one processor, at least one memory and a data bus; wherein the processor and the memory communicate with each other via the data bus; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the performance evaluation method.

[0046] In this embodiment, the memory can be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), etc.

[0047] In this embodiment, the processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0048] According to one embodiment of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, and the computer program implements the aforementioned design method when executed by a processor.

[0049] To further illustrate this solution, further examples are given.

[0050] Example 1 The same combustion chamber model was subjected to a ground direct-connection test and a free jet test. The comparison of the engine performance parameters under the two working conditions is shown in the following table. It can be seen that the overall engine performance ground direct-connection test and the free jet test results are basically consistent. Among them, the overall engine performance ground direct-connection test and the free jet test results are shown in Table 1.

[0051] Table 1

[0052] Figure 4 The thrust-time curve of the first test bench under free jet test conditions is shown. Figure 5 The thrust-time curve of the second test bench under the ground direct test condition is shown. Figure 4 and Figure 5 Comparison of the results shows that the two methods are equally effective in thrust measurement and evaluation.

[0053] The above contents are merely examples of specific solutions of the present invention. For devices and structures not described in detail therein, it should be understood that they can be implemented by adopting general devices and general methods available in the art.

[0054] The above is only one solution of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A performance evaluation method for a scramjet engine based on a direct-connection test, characterized in that: The following steps are involved: S1. Obtaining a first test bench thrust-time curve, a first flow parameter and a first pressure parameter of a scramjet engine under a free jet test condition; wherein the first flow parameter includes: a first airflow parameter of a simulated air flow of a selected first engine characteristic section, a second airflow parameter of a fuel gas flow of a combustion chamber fuel inlet section, and the first pressure parameter includes: a static pressure distribution of a simulated air flow of a selected first engine characteristic section; S2. setting the incoming flow condition of the scramjet engine during the ground direct-connection test based on the first airflow parameter, and using the first airflow parameter as the airflow parameter of the selected second engine characteristic section, and using the second airflow parameter as the airflow parameter of the fuel inlet section of the combustion chamber of the scramjet engine; S3. Under the ground direct-connection test condition, obtaining a second test bench thrust-time curve, a second flow parameter, and a second pressure parameter of the scramjet engine after the second engine characteristic section; S4. Evaluate the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter.

2. The performance evaluation method according to claim 1, characterized in that: In step S1, the first airflow parameter includes: a first airflow mass flow rate and a first airflow temperature at the first engine characteristic cross section; The second airflow parameter includes: a second airflow mass flow rate at a fuel inlet section of the combustion chamber.

3. The performance evaluation method according to claim 2, characterized in that: In step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the performance evaluation result of the scramjet engine includes: internal thrust specific impulse, engine combustion chamber gas flow and equivalence ratio.

4. The performance evaluation method according to claim 3, characterized in that: In step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, if the scramjet engine is a liquid fuel scramjet engine, the engine combustion chamber gas flow rate is obtained based on mass flow meter measurement; If the scramjet engine is a solid fuel scramjet engine, the engine combustion chamber gas flow rate is obtained based on the following steps, which include: Obtaining a mass flow rate of engine fuel in the scramjet engine; Obtaining theoretical fuel consumption mass of the scramjet engine before and after a ground direct-connection test based on the mass flow rate; Obtaining the actual fuel consumption mass of the propellant in the scramjet engine before and after the ground direct-connection test; The fuel flow rate of the engine combustion chamber of the scramjet engine is obtained based on the theoretical fuel consumption mass and the actual fuel consumption mass.

5. The performance evaluation method according to claim 4, characterized in that: The step of obtaining the mass flow rate of the engine fuel in the scramjet engine comprises: Obtain the first mass of the solid propellant grain in the gas generator of the scramjet engine before the test m 1 and the second mass of the solid propellant grain in the gas generator after the test m 2, and obtain the first mass m 1 with the second mass m 2 quality difference △ m ; The combustion rate formula is used to calculate the gas flow rate during the test period to obtain the mass flow rate of the fuel at the fuel inlet section of the combustion chamber of the scramjet engine at each time of the test; wherein the mass flow rate is expressed as: in, represents the mass flow rate, represents the propellant burning rate coefficient, represents the pressure coefficient, represents density, Represents the burning area, and it is a constant value. is the gas generator pressure.

6. The performance evaluation method according to claim 5, characterized in that: In the step of obtaining the theoretical fuel consumption mass of the scramjet engine before and after the ground direct-connection test based on the mass flow rate, the theoretical fuel consumption mass is obtained based on the integration of the mass flow rate and is expressed as: in, Indicates the theoretical fuel consumption mass, t 1 indicates the start time of the test, t 2 indicates the end time of the test.

7. The performance evaluation method according to claim 6, characterized in that: In the step of obtaining the gas flow rate of the engine combustion chamber of the scramjet engine based on the theoretical fuel consumption mass and the actual fuel consumption mass, the gas flow rate of the engine combustion chamber is expressed as: in, Indicates mass flow, that is, the gas flow in the engine combustion chamber.

8. The performance evaluation method according to claim 7, characterized in that: In step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the internal thrust specific impulse is expressed as: in, I is the internal thrust specific impulse, is the thrust gain of the test bench under the test conditions, The combustion chamber resistance is is the thermal thrust of the engine combustion chamber under test conditions, It is the cold thrust of the test bench under the test conditions.

9. The performance evaluation method according to claim 8, characterized in that: In step S4, in the step of evaluating the performance of the scramjet engine based on the thrust-time curve of the second test bench, the second flow parameter and the second pressure parameter, the equivalence ratio is expressed as: in, E is the equivalent ratio, is the theoretical equivalent ratio of the fuel, is the air flow rate.

10. A device applied to the performance evaluation method according to any one of claims 1 to 9, characterized in that: comprising at least one processor, at least one memory and a data bus; The processor and the memory communicate with each other via the data bus; The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the performance evaluation method.

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