Method and apparatus for evaluating performance of a scramjet engine based on direct connection test

Abstract

The present application relates to the performance evaluation method and equipment of the super-combustion ramjet engine based on direct connection test, wherein the method comprises: obtaining the first test bench thrust-time curve, the first flow parameter and the first pressure parameter of the super-combustion ramjet engine under the free jet test working condition; setting the inflow condition of the super-combustion ramjet engine during the ground direct connection test based on the first airflow parameter, taking the first airflow parameter as the airflow parameter of the selected second engine characteristic section, and taking the second airflow parameter as the airflow parameter of the fuel inlet section of the combustion chamber of the super-combustion ramjet engine; obtaining the second test bench thrust-time curve, the second flow parameter and the second pressure parameter of the super-combustion ramjet engine after the second engine characteristic section under the ground direct connection test working condition; and evaluating the performance of the super-combustion ramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter.

Description

TECHNICAL FIELD

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

[0002] Theoretical analysis and numerical simulation provide a basic method for engine design and performance analysis, however, test test is still a key link in the engine development process, and the correctness of the results of theoretical analysis and numerical simulation also needs to be verified by engine test. According to the test purpose, the ground test system can be divided into two kinds of free jet test system and direct connection test system, but there are certain defects.

[0003] The free jet test system is also called wind tunnel, which places all test components (including inlet, combustion chamber and tail nozzle) in the supersonic simulation flow field formed by the free jet nozzle, can completely simulate the inlet wave system state, and truly reflect the cooperative working condition between each component of the engine, and is suitable for engine overall performance test.

[0004] In the direct connection test system, the test air flow provided by the equipment enters the engine through the connecting pipeline, and the actual flight state is simulated by controlling the total pressure, total temperature and flow rate, which is usually used for performance test of single component of the engine.

[0005] Compared with the free jet test system, the direct connection test system has relatively simple structure, low cost and easy implementation, and is the simplest, most economical and effective test method in the ground simulation test of ramjet engine, and it is the basis for the research of ramjet engine. However, the traditional direct connection test system is generally used for performance test of single component of the engine, such as thermal protection and combustion performance, and it is difficult to directly obtain the engine thrust and specific impulse. On the one hand, the measured thrust of the direct connection test is the bench thrust, which is the thrust generated by the local component of the engine and the test system, and it is difficult to convert into the engine thrust, and due to the large system error, the measured thrust is often more than 15%, which is difficult to be directly applied; on the other hand, there is a certain difference between the air flow entering the combustion chamber in the direct connection test system and the air flow entering the combustion chamber from the inlet-isolation section in the actual engine, which is not strictly handled. SUMMARY

[0006] The present application relates to the field of aerospace, in particular to a performance evaluation method and device of a scramjet engine based on direct connection test.

[0007] To achieve the above-mentioned application purpose, the present application provides a performance evaluation method of a scramjet engine based on direct connection test, comprising the following steps:

[0008] 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 comprises a first airflow parameter of a simulated air airflow at a selected first engine characteristic section, and a second airflow parameter of a fuel gas airflow at a combustion chamber fuel inlet section, and the first pressure parameter comprises a static pressure distribution of the simulated air airflow at the selected first engine characteristic section;

[0009] S2. setting a flow condition of the scramjet engine under a ground direct connection test based on the first airflow parameter, and taking the first airflow parameter as an airflow parameter at a selected second engine characteristic section, and taking the second airflow parameter as an airflow parameter at a combustion chamber fuel inlet section of the scramjet engine;

[0010] S3. 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 under a ground direct connection test condition;

[0011] S4. evaluating a performance of the scramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter.

[0012] According to an aspect of the present application, in step S1, the first airflow parameter comprises a first airflow mass flow, a first airflow pressure and a first airflow temperature at the first engine characteristic section.

[0013] The second airflow parameter comprises a second airflow mass flow at the combustion chamber fuel inlet section.

[0014] According to an aspect of the present application, in step S4, in the step of evaluating the performance of the scramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter, the performance evaluation results of the scramjet engine comprise an internal thrust specific impulse, an engine combustion chamber fuel gas flow and an equivalence ratio.

[0015] According to an aspect of the present application, in step S4, in the step of evaluating the performance of the scramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter, if the scramjet engine is a liquid fuel scramjet engine, the engine combustion chamber fuel gas flow is obtained based on a mass flow meter measurement.

[0016] If the scramjet engine is a solid fuel scramjet engine, the engine combustion chamber fuel gas flow is obtained based on the following steps, which comprise:

[0017] obtaining a mass flow rate of engine fuel in the scramjet engine;

[0018] obtaining a fuel theoretical consumption mass of the scramjet engine before and after the ground direct-connected test based on the mass flow rate;

[0019] obtaining a fuel actual consumption mass of the propellant in the scramjet engine before and after the ground direct-connected test;

[0020] obtaining an engine combustion chamber fuel gas flow of the scramjet engine based on the fuel theoretical consumption mass and the fuel actual consumption mass.

[0021] According to one aspect of the present application, in the step of obtaining a mass flow rate of engine fuel in the scramjet engine, the step comprises:

[0022] obtaining a first mass of a solid propellant grain in a fuel gas generator of the scramjet engine before the test m 1and a second mass of the solid propellant grain in the fuel gas generator of the scramjet engine after the test m 2, and obtaining a mass difference Δ m 1between the first mass m 2and the second mass m ;

[0023] calculating a fuel gas flow in a test time period by using a burning rate formula, and obtaining a mass flow rate of fuel at each time of the test at an engine combustion chamber fuel inlet section of the scramjet engine; wherein the mass flow rate is expressed as:

[0024]

[0025] wherein, the mass flow rate is represented by, a propellant burning rate coefficient is represented by, a pressure coefficient is represented by, a density is represented by, a burning area is represented by, and is a constant value, and the pressure of the fuel gas generator is represented by.

[0026] According to one aspect of the present application, in the step of obtaining a fuel theoretical consumption mass of the scramjet engine before and after the ground direct-connected test based on the mass flow rate, the fuel theoretical consumption mass is obtained based on an integral of the mass flow rate, and is expressed as:

[0027]

[0028] wherein, the fuel theoretical consumption mass is represented by, t 1represents a start time of the test, t2 represents the time when the test is terminated.

[0029] According to an aspect of the present application, in the step of obtaining the engine combustion chamber gas flow of the scramjet engine based on the fuel theoretical consumption mass and the fuel actual consumption mass, the engine combustion chamber gas flow is expressed as:

[0030]

[0031] wherein, represents the mass flow, i.e. the engine combustion chamber gas flow.

[0032] According to an aspect of the present application, in the step S4, in the step of evaluating the performance of the scramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter, the specific impulse of the internal thrust is expressed as:

[0033]

[0034]

[0035] wherein, I is the specific impulse of the internal thrust, is the test bench thrust gain under the test condition, is the gas flow, is the internal resistance of the combustion chamber, is the hot thrust of the engine combustion chamber under the test condition, is the cold thrust of the test bench under the test condition.

[0036] According to an aspect of the present application, in the step S4, in the step of evaluating the performance of the scramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter, the equivalence ratio is expressed as:

[0037]

[0038] wherein, E is the equivalence ratio, is the theoretical equivalence ratio of the fuel, is the gas flow, is the air flow.

[0039] To achieve the above-mentioned purposes, the present application provides an apparatus applied to the performance evaluation method, comprising at least one processor, at least one memory and a data bus;

[0040] The processor and the memory complete mutual communication through the data bus;

[0041] The memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the performance evaluation method.

[0042] According to one scheme of the present application, the present application can directly use a ground direct connection test to replace a free jet test to obtain engine thrust performance. Compared with the free jet test, the scheme only needs an engine part after a second engine characteristic section, the test product is simple, and no additional free jet aircraft and other accompanying test pieces are needed; the direct connection test system used has low cost, is one order of magnitude lower than the free jet test system, and has equivalent test effect; and the direct connection test time is significantly shortened, is easy to organize, and can quickly obtain engine thrust data and evaluate engine performance. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a schematic block diagram illustrating steps of a performance evaluation method according to one embodiment of the present application;

[0044] Figure 2 is a structural schematic diagram of a free jet test system;

[0045] Figure 3 is a structural schematic diagram of a ground direct connection test system;

[0046] Figure 4 is a first test stand thrust-time curve diagram under a free jet test working condition;

[0047] Figure 5 is a second test stand thrust-time curve diagram under a ground direct connection test working condition. DETAILED DESCRIPTION

[0048] The present application will be described in detail below in combination with the drawings and specific embodiments. The embodiments cannot be exhaustively described here, but the embodiments of the present application are not limited to the following embodiments.

[0049] As shown in Figure 1 , according to one embodiment of the present application, a performance evaluation method of a scramjet engine based on a direct connection test of the present application includes the following steps:

[0050] S1. Obtain a first test stand thrust-time curve of a scramjet engine under a free jet test working condition, a first flow parameter, and a first pressure parameter; wherein the first flow parameter includes a first airflow parameter of a simulated air airflow of a selected first engine characteristic section, and a second airflow parameter of a fuel gas airflow of a combustion chamber fuel inlet section, and the first pressure parameter includes a static pressure distribution of the simulated air airflow of the selected first engine characteristic section;

[0051] S2. Setting the incoming flow conditions for the scramjet engine during a ground direct-connection test based on the first airflow parameter, using the first airflow parameter as the airflow parameter for the selected second engine characteristic cross-section, and using the second airflow parameter as the airflow parameter for the fuel inlet cross-section of the scramjet engine's combustion chamber;

[0052] S3. Under ground-based direct-connect test conditions, obtain a second test bench thrust-time curve, a second flow parameter, and a second pressure parameter for the scramjet engine after the second engine characteristic section;

[0053] 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.

[0054] 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. The aircraft is installed in the test section so that the air inlet, combustion chamber, and tail nozzle of the scramjet engine are all located 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, thereby fully simulating the air inlet wave system state, truly reflecting the coordinated working conditions between the various components of the first test component, and being suitable for overall engine performance testing.

[0055] 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 characteristic, which is convenient for 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 scramjet engine combustion chamber inlet cross section or the inlet throat cross section, see Figure 2 .

[0056] 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.

[0057] like Figure 3As shown, according to an embodiment of the present application, in step S2, the ground direct connection test is performed based on the constructed ground direct connection test system, wherein the ground direct connection test system comprises: a second high-pressure air source 21, a second heater system 22, a connecting pipe 23, a collector 24 and a second ejector exhaust system 25 connected in sequence, wherein the second test component is arranged between the connecting pipe 23 and the collector 24, so as to realize that the test air flow provided by the front device 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 usually adopts the scramjet engine in the first test component for performance test, and of course, the single component of the scramjet engine in the first test component can also be tested for performance.

[0058] In this embodiment, the second engine characteristic section is determined based on the first engine characteristic section, as shown in Figure 3 The second engine characteristic section is determined from the position of 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 located at the same position as the first engine characteristic section. Further, the inflow condition of the scramjet engine in the ground direct connection test is set based on the first air flow parameter, and the first air flow parameter is taken as the air flow parameter of the selected second engine characteristic section, and the second air flow parameter is taken as the air flow parameter of the combustion chamber fuel inlet section of the scramjet engine.

[0059] According to an embodiment of the present application, in step S4, in the step of evaluating the performance of the scramjet engine based on the second test bench thrust-time curve, the second flow parameter and the second pressure parameter, the performance evaluation results of the scramjet engine include: the specific impulse of the internal thrust, the engine combustion chamber gas flow and the equivalence ratio.

[0060] According to an embodiment of the present application, in step S4, in the step of evaluating the performance of the scramjet engine based on the second test bench thrust-time curve, 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 is obtained based on the mass flow meter measurement;

[0061] If the scramjet engine is a solid fuel scramjet engine, the engine combustion chamber gas flow is obtained based on the following steps, which include:

[0062] Obtaining the mass flow rate of the engine fuel in the 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:

[0063] Obtaining a first mass of a solid propellant grain in a gas generator of a scramjet engine before a ground test m 1and a second mass of the solid propellant grain in the gas generator of the scramjet engine after the ground test m 2, and obtaining a mass difference Δ between the first mass m 1and the second mass m 2 m ;

[0064] The fuel flow rate in the test period is calculated by using the burning rate formula, and 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 is obtained; wherein the mass flow rate is represented as:

[0065]

[0066] wherein, the mass flow rate is represented as, the propellant burning rate coefficient is represented as, the pressure coefficient is represented as, the density is represented as, the burning area is represented as, and it is a constant value (i.e. the propellant is ignited to burn at a constant area), the pressure of the gas generator is represented as.

[0067] Obtaining the fuel theoretical consumption mass of the scramjet engine before and after the ground test based on the mass flow rate; wherein if the scramjet engine is a solid fuel scramjet engine, the fuel theoretical consumption mass is obtained based on the integral of the mass flow rate, and is represented as:

[0068]

[0069] wherein, the fuel theoretical consumption mass is represented as, t 1represents the start time of the test, t 2represents the end time of the test.

[0070] Obtaining the fuel actual consumption mass of the propellant in the scramjet engine before and after the ground test; in this embodiment, the fuel actual consumption mass can be obtained by weighing the difference between the fuel before and after the test.

[0071] Obtaining the engine combustion chamber gas flow of the scramjet engine based on the fuel theoretical consumption mass and the fuel actual consumption mass; wherein if the scramjet engine is a solid fuel scramjet engine, the engine combustion chamber gas flow is represented as:

[0072]

[0073] wherein, Indicates mass flow, that is, the gas flow in the engine combustion chamber.

[0074] 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 internal thrust specific impulse is expressed as:

[0075]

[0076]

[0077] 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 internal resistance of the combustion chamber, is the thermal thrust of the engine combustion chamber under test conditions, is the cold thrust of the test bench under test conditions.

[0078] 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 equivalence ratio is expressed as:

[0079]

[0080] in, E is the equivalence ratio, is the theoretical equivalence ratio of the fuel, is the gas flow rate, is the air flow rate.

[0081] 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.

[0082] 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.

[0083] In this embodiment, the processor can be an integrated circuit chip with signal processing capability. The processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; or can be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component.

[0084] According to an embodiment of the present application, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the design method.

[0085] To further illustrate the present application, further examples are provided.

[0086] Example 1

[0087] The same kind of combustion chamber model is respectively subjected to ground direct connection test and free jet test, and the engine performance parameters under the two working conditions are compared as shown in the following table. It can be seen that the overall engine performance of the ground direct connection test is basically consistent with that of the free jet test. Among them, the overall engine performance of the ground direct connection test and the free jet test is shown in Table 1.

[0088] Table 1

[0089]

[0090] Figure 4 A first test bench thrust-time curve diagram under the free jet test working condition is shown,Figure 5 The second test bench thrust-time curve under the ground direct connection test condition is shown, and the results are compared with Figure 4 and Figure 5 It can be seen that the effects of the two in the thrust measurement evaluation are equivalent.

[0091] The above only is the example of the specific scheme of the present application, and for the equipment and structure not described in detail, it should be understood that the general equipment and general method in the art are adopted to implement.

[0092] The above only is one scheme of the present application, and is not used to limit the present application, and for the person skilled in the art, the present application can have various changes and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

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 free jet test conditions; wherein the first flow parameter includes: a first flow parameter of a simulated air flow at a selected first engine characteristic cross section, and a second flow parameter of a fuel gas flow at a combustion chamber fuel inlet cross section; and the first pressure parameter includes: a static pressure distribution of the simulated air flow at the selected first engine characteristic cross section; S2. Setting an incoming flow condition for the scramjet engine during a ground direct-connection test based on the first airflow parameter, using the first airflow parameter as an airflow parameter for a selected second engine characteristic cross-section, and using the second airflow parameter as an airflow parameter for a fuel inlet cross-section of a combustion chamber of the scramjet engine; S3. Under ground direct-connect test conditions, 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, the second flow parameter, and the second pressure parameter of the second test bench; wherein the scramjet engine performance evaluation results include: internal thrust specific impulse, engine combustion chamber gas flow rate, and equivalence ratio; If the scramjet engine is a liquid fuel scramjet engine, the engine combustion chamber gas flow rate is obtained based on measurement by a 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 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; Obtaining a gas flow rate of an engine combustion chamber of the scramjet engine based on the theoretical fuel consumption mass and the actual fuel consumption mass; The internal thrust specific impulse is expressed as: in, I is the internal thrust specific impulse, Δ F is the thrust gain of the test bench under the test conditions, x f The internal resistance of the combustion chamber, F hot is the thermal thrust of the engine combustion chamber under test conditions, F cold is the cold thrust of the test bench under test conditions, Indicates mass flow, i.e. the gas flow in the engine combustion chamber; The equivalence ratio is expressed as: in, E is the equivalence ratio, is the theoretical equivalence ratio of the fuel, is the air flow rate.

2. The performance evaluation method according to claim 1, wherein: In step S1, the first airflow parameters include: 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, wherein: 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 get 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 cross section of the scramjet combustion chamber at each time of the test; wherein the mass flow rate is expressed as: in, m fuel_1 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, p g is the gas generator pressure.

4. The performance evaluation method according to claim 3, wherein: 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: Among them, Δ m s Indicates the theoretical fuel consumption mass, t 1 indicates the start time of the test, t 2 indicates the end time of the test.

5. The performance evaluation method according to claim 4, 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.

6. A device applied to the performance evaluation method according to any one of claims 1 to 5, 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 executed by the processor, and the processor calls the program instructions to execute the performance evaluation method.

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