A method for designing a test load for an engine thermal management capability

Abstract

The application belongs to the field of gas turbine engine, and is a kind of engine thermal management capability test load design method, first determine the duration of different inlet fuel temperature Tin and engine speed N state, then respectively segment the engine speed N and inlet fuel temperature Tin is summarized, the proportion of each state duration is obtained The proportion of operating time;According to the engine inlet fuel temperature promotion demand, the test state temperature of engine thermal management segment interval is corrected, the corrected engine thermal management test state is connected in series to form a test load spectrum, and a cycle verification test is carried out, on the basis of meeting the temperature resistance capability verification test, the engine thermal management whole machine test is carried out, and the accessory inlet fuel temperature is corrected. It can be used to verify the long-time working ability of the engine under the condition of the increase of the inlet fuel temperature, and solves the problem that the existing test method can only verify single state point or over-checking verification.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of gas turbine engines, and particularly relates to a method for designing a test load for engine thermal management capability. BACKGROUND

[0002] With the improvement of aircraft performance, the heat dissipation of its electromechanical system increases significantly. The heat sinks on the aircraft include fuel and ram air. However, due to the requirement of improving the performance of the aircraft, the introduction of ram air from outside the aircraft is limited, and the application of composite materials on the aircraft reduces the ability of the fuel to dissipate heat outward through the structure of the fuel tank. Therefore, the aircraft can only use more heat sinks of the fuel, which causes the inlet fuel temperature of the engine to continuously increase. With the increase of the inlet fuel temperature of the engine, the temperature of the entire fuel system also increases, which may exceed the maximum tolerance temperature of the fuel accessories such as pumps and regulators, and further affect the safe operation of the engine. Therefore, it is necessary to carry out a verification test of the thermal management capability of the engine, and the test load needs to be determined for the verification test of the thermal management capability. At present, there are few studies on the verification test of the thermal management capability, and there is no method for designing a test load that can be referred to.

[0003] Figure 1 A schematic diagram of the flow path of a typical engine fuel system is given. The fuel from the fuel tank first cools the heat-generating components of the aircraft, then enters the engine and mixes with the return oil inside the engine, then enters the low-pressure pump to complete the first step of pressure increase, then enters the high-pressure pump to complete the second step of pressure increase, and the high-pressure fuel finally enters the combustion chamber after passing through the regulating device and the fuel-oil radiator. The regulating device measures the fuel entering the combustion chamber according to the demand of the combustion chamber, and the remaining fuel returns to the low-pressure pump through the actuator mechanism. The fuel-oil radiator can cool the oil to ensure that the engine oil does not overheat.

[0004] When carrying out a verification test of the thermal management capability of the engine, the inlet fuel temperature Tin of the engine needs to be simulated. Usually, only the highest inlet fuel temperature of the engine is simulated to verify the thermal management capability of the engine at a typical state point. Considering that the engine will not always work at the highest inlet fuel temperature, if the long-time working capability of the engine to withstand the increase of the inlet fuel temperature is to be evaluated, only simulating the highest inlet fuel temperature of the engine will result in over-evaluation and cannot achieve the verification purpose.

[0005] Therefore, how to effectively verify the thermal management capability of the engine is a problem to be solved. SUMMARY

[0006] The purpose of the present application is to provide a method for designing a test load for the thermal management capability of an engine to solve the problem that there is no effective verification test of the thermal management capability of the engine.

[0007] The technical solution of the present application is: a method for designing a test load for the thermal management capability of an engine, comprising:

[0008] statistical existing engine import fuel temperature flight test data, to carry out the flight mission profile under the simulation calculation of the engine heat management, analyze the calculation results and obtain the duration of the engine under different import fuel temperature Tin and different engine speed N state, form the first statistical data;

[0009] The first statistical data is segmented according to the engine speed N, the maximum speed is set, and the set speed difference of the engine heat management state segmentation interval is taken as the interval, the import fuel temperature and the duration of the engine in different speed range are segmented and counted; Then, according to the import fuel temperature Tin, each engine speed segment is segmented and counted, and the second statistical data is formed;

[0010] Combined with the second statistical data, the engine heat management state segmentation time is converted, the proportion of each state duration in the running time is obtained, and the third statistical data is formed combined with the corresponding engine speed and temperature data;

[0011] The upper limit value of the engine heat management state segmentation interval in the third statistical data is taken as the test state value; Then, according to the engine import fuel temperature improvement requirement, the test state temperature of the engine heat management segmentation interval is corrected to obtain the corrected engine heat management test state;

[0012] The corrected engine heat management test state is connected in series to form a test load spectrum, and the length of each test load spectrum is determined, and then the cycle number is determined according to the engine temperature resistance capacity requirement, and then the cycle verification test is carried out according to the test load spectrum to obtain the test result data;

[0013] According to the test result data of the cycle verification test, the engine import fuel temperature is determined, the highest value of the import fuel temperature of each accessory is judged by heat management simulation calculation; The temperature resistance capacity verification test of each accessory of the fuel system is carried out, the import fuel temperature of each accessory is obtained, whether the import fuel temperature of each accessory exceeds the corresponding fuel temperature highest value is judged, if yes, the corresponding accessory is found and the accessory is optimized and designed, until the import fuel temperature is less than the fuel temperature highest value; If not, the engine heat management whole machine test is carried out.

[0014] Preferably, the set speed difference and the set test state temperature difference are 5% or 10%.

[0015] Preferably, the length of a single basic test load spectrum is 1-2h.

[0016] Preferably, the method of the engine thermal management test state series is: obtaining the inlet fuel temperature, the maximum engine speed and the minimum engine speed of all test load spectrum; first, according to the inlet fuel temperature, sorting from small to large to obtain the test load spectrum corresponding to different inlet fuel temperatures, and then sorting the test load spectrum at the same inlet fuel temperature according to the minimum engine speed from small to large, and sorting according to the speed from small to large; in the second temperature interval, sorting according to the speed from large to small, and then in the third temperature interval, sorting according to the speed from small to large, and so on, until all the test is completed.

[0017] The engine thermal management capability test load design method of the present application first determines the duration of the engine at different inlet fuel temperatures Tin and different engine speeds N, and then respectively segments and collects the engine speed N and the inlet fuel temperature Tin to obtain the proportion of the running time of each state duration; then, according to the engine inlet fuel temperature improvement requirement, the test state temperature of the engine thermal management segmented interval is corrected, the corrected engine thermal management test state is connected in series to form a test load spectrum, a cycle verification test is carried out to obtain test result data, on the basis of meeting the temperature resistance capability verification test, an engine thermal management whole machine test is carried out to correct the accessory inlet fuel temperature, and an engine thermal management capability verification test load spectrum is obtained. It can be used to verify the long-time working capability of the engine under the condition of the inlet fuel temperature improvement, and solves the problem that the existing test method can only verify or over-check a single state point. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions provided by the present application, the following will briefly introduce the drawings. Obviously, the drawings described below are only some embodiments of the present application.

[0019] Figure 1 A typical engine fuel system flow path schematic diagram in the background art;

[0020] Figure 2 A whole process schematic diagram of the present application;

[0021] Figure 3 An engine thermal management test load spectrum schematic diagram of the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] A method for designing a test load of an engine thermal management capability, as shown in Figure 2 includes the following steps:

[0024] Step S100, count the existing engine inlet fuel temperature flight test data, if there is no flight test data, the flight mission profile can be carried out under the flight thermal management simulation calculation, the flight mission profile under the flight thermal management simulation calculation, analysis and calculation results and obtain the duration of engine at different inlet fuel temperature Tin And different engine speed N State, form the first statistical data, get the statistics as shown in table 1:

[0025] Table 1 engine thermal management state statistics

[0026] Serial number Inlet fuel temperature Tin Engine speed N Duration 1 43℃ 80％ 5 min 2 45℃ 86％ 1 min 3 55℃ 92％ 2 min 4 60℃ 96％ 3 min

[0027] Step S200, the first statistical data is segmented according to the engine speed N It is summarized, the maximum speed is set, such as 100%, and the set speed difference of the engine thermal management state segmentation interval is taken as the interval, the inlet fuel temperature and the duration of the engine in different speed range are segmented and counted; Then according to the set test state temperature difference of the engine thermal management state segmentation interval, the inlet fuel temperature Tin In each engine speed section, it is summarized and formed into the second statistical data.

[0028] The set speed difference and the set test state temperature difference are 5% or 10%, usually the smaller the set speed difference interval, the more conducive to develop the thermal management test load spectrum close to the real state, usually the smaller the set test state temperature difference interval, the more conducive to develop the thermal management test load spectrum close to the real state.

[0029] The segmented statistical table corresponding to the second statistical data is shown in table 2:

[0030] Table 2 engine thermal management state segmentation statistics

[0031]

[0032] Step S300, combined with the second statistical data, the engine thermal management state segmentation statistical time is converted, the proportion of the running time occupied by the duration of each state is obtained, and the corresponding engine speed and temperature data are combined to form the third statistical data. If the total statistical time is 20h, the statistical time of a certain state is 1h, then the time proportion of the state is 1 / 20, that is, 5%, and the time proportion statistical sample table is shown in table 3.

[0033] Table 3 engine thermal management state segmentation statistical time proportion

[0034]

[0035]

[0036] Step S400, the upper limit value of the engine thermal management state in the third statistical data is segmented into the speed and temperature of the test state value; then according to the engine inlet fuel temperature promotion demand, the test state temperature of the engine thermal management segmented interval is corrected. The corrected engine thermal management test state is obtained. If the engine inlet fuel temperature statistical interval is 20-30℃, the test temperature is 30℃; if the engine inlet fuel temperature speed statistical interval is 80-85%, the test speed is 85%, and the engine thermal management test state preliminary planning table is shown in Table 4.

[0037] Table 4 Engine thermal management state preliminary planning table

[0038]

[0039] Step S500, the corrected engine thermal management test state is connected in series to form a test load spectrum, and the time length of each test load spectrum is determined, and the time length of a single load spectrum is 1-2 hours, and then according to the engine temperature resistance capacity demand, the cycle number is determined, and then the cycle verification test is carried out according to the test load spectrum, and the test result data is obtained. If the engine inlet fuel temperature is increased by 10℃, the test state temperature is increased by 10℃, and the corrected engine thermal management test state planning table is shown in Table 5.

[0040] Table 5 Engine thermal management test state planning table

[0041]

[0042] Taking the test state and time proportion planned in Table 5 as an example, the engine thermal management test load spectrum with a design time length of 2 hours is shown in Table 6. Figure 3 If the engine is tested for 200 hours under the condition of increased inlet fuel temperature, the load spectrum needs to be repeated 100 times.

[0043] Preferably, the method for connecting the engine thermal management test state in series is: obtaining the inlet fuel temperature, the maximum engine speed and the minimum engine speed of all test load spectrums; first, according to the inlet fuel temperature, sorting from small to large, obtaining the test load spectrum corresponding to different inlet fuel temperatures, in the first temperature interval, first, according to the minimum engine speed, sorting from small to large, and according to the speed, sorting from small to large; in the second temperature interval, according to the speed, sorting from large to small, and then in the third temperature interval, according to the speed, sorting from small to large, and so on, until all the tests are completed. The cycle lifting type test method is realized, the time length of a single load spectrum is 1-2 hours, and through this test method, the smooth transition of the speed can be realized, and the sudden increase and decrease of the speed can be prevented.

[0044] In step S600, the engine inlet fuel temperature is determined according to the test result data of the cycle verification test, the highest value of the inlet fuel temperature of each accessory is judged through thermal management simulation calculation, the temperature resistance verification test of each accessory of the fuel system is performed, the inlet fuel temperature of each accessory is obtained, whether the inlet fuel temperature of each accessory exceeds the corresponding highest value of the fuel temperature is judged, if yes, the corresponding accessory is found out and the accessory is optimized and designed until the inlet fuel temperature thereof is less than the highest value of the fuel temperature, and if no, the engine thermal management whole machine test is performed. If the engine inlet fuel temperature is 50 DEG C, the inlet temperature of the low-pressure pump and the high-pressure pump under the corresponding engine speed is obtained through thermal management simulation calculation as the temperature resistance test temperature of the low-pressure pump and the high-pressure pump, if the low-pressure pump exceeds the calculated inlet temperature, the low-pressure pump is optimized and designed again to reduce the inlet temperature requirement thereof until the corresponding inlet temperature is met.

[0045] The present application firstly determines the duration of the engine under different inlet fuel temperatures Tin and different engine speeds N, then respectively collects the engine speed N and the inlet fuel temperature Tin in segments to obtain the proportion of the duration of each state in the running time, then according to the requirement of the engine inlet fuel temperature improvement, the test state temperature of the engine thermal management segmented interval is corrected, the corrected engine thermal management test states are connected in series to form a test load spectrum, the cycle verification test is carried out to obtain the test result data, the engine thermal management whole machine test is performed on the basis of meeting the temperature resistance verification test, the accessory inlet fuel temperature is corrected, and the engine thermal management capability verification test load spectrum is obtained. The engine thermal management capability verification test load spectrum can be used to verify the long-time working capability of the engine under the condition of the improved inlet fuel temperature by comprehensively considering the thermal load and the mechanical load of the engine fuel system under the real working state, and the problem that the existing test method can only verify a single state point or over-verification is solved.

[0046] Finally, it should be pointed out that: first, in the description of the present application, it should be pointed out that unless otherwise specified and limited, the terms "installation", "connection", "connection" should be understood broadly, which can be mechanical connection or electrical connection, or the communication between two elements, or direct connection, "up", "down", "left", "right" and the like are only used to represent the relative positional relationship, when the absolute position of the described object changes, the relative positional relationship may change;

[0047] Secondly: the present application discloses the structure involved in the embodiment of the present application, other structures can refer to the general design, and the same embodiment and different embodiments of the present application can be combined with each other under the condition of no conflict;

[0048] Finally: the above only for the preferred embodiments of the present application, and not for limiting the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, should be included in the scope of protection of the present application.

Claims

1. A method for designing test loads for engine thermal management capability, characterized in that, include: We statistically analyzed existing test data on engine inlet fuel temperature, conducted flight heat management simulation calculations under flight mission profiles, analyzed the calculation results, and obtained the duration of engine operation under different inlet fuel temperatures (Tin) and different engine speeds (N), thus forming the first statistical data. The first statistical data is segmented and summarized according to the engine speed N. The maximum speed is set, and the inlet fuel temperature and duration of the engine in different speed ranges are statistically summarized in segments with the set speed difference of the engine thermal management state segment interval as the interval. Then, the inlet fuel temperature Tin is segmented and summarized in each engine speed segment with the set test state temperature difference of the engine thermal management state segment interval as the interval to form the second statistical data. Combining the second statistical data, the segmented statistical time of the engine thermal management state is converted to obtain the proportion of the running time of each state duration, and the third statistical data is formed by combining the corresponding engine speed and temperature data. The upper limits of the engine speed and temperature within the engine thermal management state segment interval in the third statistical data are used as the test state values; then, based on the engine inlet fuel temperature increase requirement, the test state temperature of the engine thermal management segment interval is corrected to obtain the corrected engine thermal management test state. The modified engine thermal management test states are connected in series to form a test load spectrum, and the duration of each test load spectrum is determined. Then, based on the engine temperature resistance requirements, the number of cycles is determined, and then a cyclic verification test is carried out according to the test load spectrum to obtain test result data. The engine inlet fuel temperature is determined based on the test results data from the cyclic verification test. The maximum inlet fuel temperature of each accessory is determined through thermal management simulation calculation. The temperature resistance verification test of each accessory of the fuel system is carried out to obtain the inlet fuel temperature of each accessory. It is determined whether the inlet fuel temperature of each accessory exceeds the corresponding maximum fuel temperature. If so, the corresponding accessory is identified and its design is optimized until its inlet fuel temperature is less than the maximum fuel temperature. Otherwise, the engine thermal management whole machine test is carried out.

2. The test load design method for engine thermal management capability as described in claim 1, characterized in that: The set speed difference and the set test temperature difference are both 5% or 10%.

3. The test load design method for engine thermal management capability as described in claim 1, characterized in that: The duration of a single basic test load spectrum is 1-2 hours.

4. The test load design method for engine thermal management capability as described in claim 1, characterized in that: The method for cascading the engine thermal management test states is as follows: obtain the inlet fuel temperature, maximum engine speed, and minimum engine speed of all test load spectra; first, sort the test load spectra from smallest to largest according to the inlet fuel temperature to obtain the test load spectra corresponding to different inlet fuel temperatures; within the first temperature range, sort the test load spectra at the same inlet fuel temperature from smallest to largest according to the minimum engine speed, and then conduct tests from smallest to largest according to the engine speed; within the second temperature range, conduct tests from largest to smallest according to the engine speed; then, in the third temperature range, conduct tests from smallest to largest according to the engine speed, and so on, until all tests are completed.

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