A method for designing a corrosion sensitivity test procedure for a turbofan engine

Abstract

The application belongs to the field of aero-engine design and is a kind of turbofan engine corrosion sensitivity test procedure design method, wherein first, the relationship between the high-pressure relative conversion speed and the engine turbine temperature drop ratio from the slow state to the intermediate state is obtained according to the engine overall performance calculation model, then the relationship between the high-pressure relative conversion speed from the slow state to the intermediate state and the actually measured low-pressure turbine rear exhaust total temperature in the test process is obtained, and then the high-pressure turbine front gas total temperature difference value converted from the engine intermediate state and the slow state is calculated; and according to the relationship between the high-pressure conversion speed and the low-pressure conversion speed, the low-pressure conversion speed value corresponding to the temperature under different throttle states is accurately obtained, so as to perform the corrosion sensitivity test procedure design. The throttle state steady state step is set by the engine low-pressure rotor conversion speed, which is beneficial to improve the accuracy of the engine inlet salt mist flow control in the corrosion sensitivity test process.

Description

Technical Field

[0001] This application belongs to the field of aero-engine design, and specifically relates to a method for designing a corrosion sensitivity test procedure for a turbofan engine. Background Technology

[0002] For aero engines serving on aircraft carriers or in coastal areas, the long-term exposure to the marine atmosphere, high temperature, high humidity, and salt spray results in a highly corrosive marine environment. To assess the engine's corrosion resistance, a whole-engine corrosion sensitivity test is typically conducted during the engine development phase. GJB 241A-2010 outlines the general requirements for corrosion sensitivity testing; however, due to the limited number of corrosion sensitivity tests conducted on turbofan engines in China, there is a lack of relevant experience in test procedure design.

[0003] GJB 241A-2010 stipulates that when developing a corrosion sensitivity test procedure, four steady-state steps with equal intervals should be set based on the total temperature difference of the turbine inlet gas between the slow-speed and intermediate states. Current corrosion sensitivity test procedure design methods have the following drawbacks:

[0004] 1) Currently, when designing corrosion sensitivity test programs, the steady-state step of throttling is usually calculated only based on the engine's overall performance simulation program. The actual performance of the engine during testing usually differs from the theoretical calculation results, which can lead to deviations in the setting of the steady-state step of throttling in the corrosion sensitivity test program, affecting the test evaluation results.

[0005] 2) For high-thrust turbofan engines, corrosion sensitivity testing equipment is typically open-type. To ensure that the test environment parameters meet national military standards, the salt spray atomization flow rate needs to be dynamically adjusted according to changes in the engine inlet flow rate during the test. In test program design, it is common practice to set a steady-state step for throttling based on the engine's high-pressure rotor relative equivalent speed. However, the relationship between the high-pressure rotor relative equivalent speed and the engine intake flow rate is affected by engine slip, which is detrimental to controlling the inlet conditions during corrosion sensitivity testing.

[0006] Therefore, how to achieve the accuracy of the corrosion sensitivity test procedure design for turbofan engines is a problem that needs to be solved. Summary of the Invention

[0007] The purpose of this application is to provide a method for designing a corrosion sensitivity test procedure for turbofan engines, in order to solve the problem of deviations in the existing corrosion sensitivity test procedures for turbofan engines.

[0008] The technical solution of this application is: a method for designing a corrosion sensitivity test procedure for a turbofan engine, comprising:

[0009] A simulation model of the engine's overall performance is selected to calculate the steady-state performance of the engine from idle to intermediate state under standard atmospheric conditions at sea level, obtaining the high-pressure relative equivalent speed n from idle to intermediate state. 2r Compared with engine turbine temperature drop ratio τ T The relationship curve, where τ T =T4 / T6, where T4 is the total gas temperature before the high-pressure turbine and T6 is the total exhaust temperature after the low-pressure turbine of the engine;

[0010] Based on the bench test data of the engine, the high-pressure relative conversion speed n from the idle state to the intermediate state during the actual test was obtained. 2r The measured total exhaust temperature T after the low-pressure turbocharger during the test drive 6k The relationship curve, and the engine low-pressure converted speed n 1r Converted speed n with high pressure 2r Relationship curve;

[0011] High voltage relative conversion speed n from idle state to intermediate state 2r Compared with engine turbine temperature drop ratio τ T The relationship curve, and the high pressure relative conversion speed n during the actual test run from slow to intermediate state. 2r The measured total exhaust temperature T after the low-pressure turbocharger during the test drive 6k The relationship curve was obtained by using the linear interpolation method to obtain the relative equivalent speed n under different high pressures during the actual test run. 2r The engine turbo temperature drop ratio τ T The value of n is then used to obtain the high-pressure converted speed n during the actual test run. 2r Total high-pressure turbine inlet gas temperature T converted to engine specifications 4k The relationship curve was then used to calculate the total gas temperature T before the high-pressure turbine based on the engine idle state. 4k_MC Total high-pressure turbine inlet gas temperature T, converted from engine intermediate state 4k_ZJ Calculate the total temperature difference ΔT between the high-pressure turbine inlet gas and the engine in intermediate and idle states.

[0012] Based on high pressure, the rotational speed n 2r Total high-pressure turbine inlet gas temperature T converted to engine specifications 4k Relationship curve, interpolation calculation T 4k For (T) 4k_MC +0.2×ΔT), (T 4k_MC +0.4×ΔT), (T 4k_MC +0.6×ΔT) and (T 4k_MC The corresponding high-pressure equivalent speed n at +0.8×ΔT) 2r value n 2r_1 n 2r_2 n2r_3 and n 2r_4 ;

[0013] According to n 2r_1 n 2r_2 n 2r_3 and n 2r_4 Converting speed n to high pressure 2r Low-pressure conversion speed n 1r The corresponding low-pressure equivalent speed n is obtained by interpolation calculation of the relationship curve. 1r_1 n 1r_2 n 1r_3 and n 1r_4 value;

[0014] Based on low pressure, the rotational speed n is calculated. 1r_1 n 1r_2 n 1r_3 and n 1r_4 By combining the engine's large-state time ratio and cycle number, an engine corrosion sensitivity program was designed.

[0015] Preferably, the total exhaust temperature T after the low-pressure turbine is... 6k =T 6m ×(288.15 / (T1+273.15)) k k = 0.000048499 × T1 2 -0.0021T1+0.7041, where T 6m This is the total exhaust temperature after the low-pressure turbocharger of the engine, measured during the test run.

[0016] Preferably, the total gas temperature T before the high-pressure turbine is... 4k =T 6k ×τ T ,ΔT=T 4k_ZJ -T 4k_MC .

[0017] This application discloses a corrosion sensitivity test procedure design method for a turbofan engine. First, based on the engine's overall performance calculation model, the steady-state performance of the engine from idle to intermediate states is calculated. The relationship between the high-pressure relative equivalent speed and the turbine temperature drop ratio from idle to intermediate states is obtained. Then, the relationship between the high-pressure relative equivalent speed from idle to intermediate states and the measured low-pressure turbine exhaust total temperature during actual testing is obtained. Next, the difference in high-pressure turbine exhaust total temperature between the intermediate and idle states is calculated based on the high-pressure turbine inlet total temperature converted from the idle state and the high-pressure turbine inlet total temperature converted from the intermediate state. The high-pressure equivalent speed values ​​corresponding to different throttling conditions are calculated, and the low-pressure equivalent speed values ​​corresponding to different throttling conditions are accurately obtained based on the relationship between high and low-pressure equivalent speeds, thus enabling the design of the corrosion sensitivity test procedure. Using the engine's low-pressure rotor equivalent speed to set the steady-state step in the throttling state is beneficial for improving the accuracy of engine inlet salt spray flow control during the corrosion sensitivity test. Attached Figure Description

[0018] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0019] Figure 1 This is a schematic diagram of the overall process of this application;

[0020] Figure 2 n is the value obtained from the calculation of the overall engine performance of this application. 2r With τ T Relationship diagram;

[0021] Figure 3 During the actual test run of the engine in this application, n 2r With T 6k Relationship diagram;

[0022] Figure 4 During the actual test run of the engine in this application, n 2r With n 1r Relationship diagram;

[0023] Figure 5 During the actual test run of the engine in this application, n 2r With T 4k Relationship diagram. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0025] A method for designing a corrosion sensitivity test procedure for a turbofan engine, such as Figure 1 As shown, it includes the following steps:

[0026] Step S100: Select an engine whole-machine performance simulation calculation model, calculate the steady-state performance of the engine from idle state to intermediate state under standard atmospheric conditions at sea level, and obtain the high-pressure relative equivalent speed n from idle state to intermediate state. 2r Compared with engine turbine temperature drop ratio τ T Relationship curves, such as Figure 2 As shown, where τ T =T4 / T6, where T4 is the total gas temperature before the high-pressure turbine and T6 is the total exhaust temperature after the low-pressure turbine of the engine;

[0027] By establishing the correspondence between the high-pressure relative conversion speed and the engine turbine temperature drop ratio, the temperature change relationship between the total gas temperature before the high-pressure turbine and the total exhaust temperature after the low-pressure turbine in different engine states was obtained, thereby further obtaining the temperature correspondence between the high-pressure and low-pressure turbines in different states.

[0028] Step S200: Based on the bench test data of the engine, obtain the high-pressure relative conversion speed n from the idle state to the intermediate state during the actual test. 2r The measured total exhaust temperature T after the low-pressure turbocharger during the test drive 6k The relationship curve, and the engine low-pressure converted speed n 1r Converted speed n with high pressure 2r Relationship curves, such as Figure 3-4 As shown,;

[0029] Low-pressure turbocharger exhaust total temperature:

[0030] T 6k =T 6m ×(288.15 / (T1+273.15)) k

[0031] k = 0.000048499 × T1 2 -0.0021T1+0.7041

[0032] Where T 6m This is the total exhaust temperature after the low-pressure turbocharger of the engine, measured during the test run.

[0033] Since there is a direct conversion relationship between the exhaust total temperature after the low-pressure turbine and the low-pressure converted speed, a correspondence between the high-pressure and low-pressure converted speeds is established, thus providing a basis for further matching between the high-pressure shaft system and the low-pressure shaft system data.

[0034] Step S300, high-pressure relative conversion speed n from idle state to intermediate state2r Compared with engine turbine temperature drop ratio τ T The relationship curve, and the high pressure relative conversion speed n during the actual test run from slow to intermediate state. 2r The measured total exhaust temperature T after the low-pressure turbocharger during the test drive 6k The relationship curve was obtained by using the linear interpolation method to obtain the relative equivalent speed n under different high pressures during the actual test run. 2r The engine turbo temperature drop ratio τ T The value of n is then used to obtain the high-pressure converted speed n during the actual test run. 2r Total high-pressure turbine inlet gas temperature T converted to engine specifications 4k Relationship curves, such as Figure 5 As shown, the total temperature T of the high-pressure turbine inlet gas is then calculated based on the engine idle state. 4k_MC Total high-pressure turbine inlet gas temperature T, converted from engine intermediate state 4k_ZJ Calculate the total temperature difference ΔT between the high-pressure turbine inlet gas and the engine in intermediate and idle states.

[0035] High-pressure turbine inlet gas total temperature:

[0036] T 4k =T 6k ×τ T

[0037] ΔT=T 4k_ZJ -T 4k_MC .

[0038] This step establishes the difference relationship between the total gas temperature before the high-pressure turbine under different engine conditions. The state between the engine's intermediate state and idle state is the throttling state, determined by T... 4k_MC and T 4k_ZJ It can accurately locate the temperature range corresponding to the throttling state.

[0039] Step S400: Calculate the rotational speed n based on the high pressure. 2r Total high-pressure turbine inlet gas temperature T converted to engine specifications 4k Relationship curve, interpolation calculation T 4k For (T) 4k_MC +0.2×ΔT), (T 4k_MC +0.4×ΔT), (T 4k_MC +0.6×ΔT) and (T 4k_MC The corresponding high-pressure equivalent speed n at +0.8×ΔT) 2r value n 2r_1 n 2r_2 n 2r_3 and n 2r_4 ;

[0040] By dividing the temperature range corresponding to the throttling state into equal proportions, it is possible to calibrate and find the high-pressure converted speed value corresponding to the total temperature of the high-pressure turbine inlet gas under different throttling states.

[0041] Step S500, according to n 2r_1 n 2r_2 n 2r_3 and n 2r_4 Converting speed n to high pressure 2r Low-pressure conversion speed n 1r The corresponding low-pressure equivalent speed n is obtained by interpolation calculation of the relationship curve. 1r_1 n 1r_2 n 1r_3 and n 1r_4 The value; the correspondence between the high and low pressure converted speeds obtained through step S200 can accurately obtain the low pressure converted speed value corresponding to the throttling state.

[0042] Step S600, calculate the rotational speed n based on the low pressure. 1r_1 n 1r_2 n 1r_3 and n 1r_4 By combining the engine's large-state time ratio and cycle number, an engine corrosion sensitivity program was designed. Since the low-pressure converted speed values ​​corresponding to different throttling states were accurately found, the specific program can be designed according to existing methods, and will not be elaborated further.

[0043] This application first calculates the steady-state performance of the engine from idle to intermediate state based on the overall engine performance calculation model, and obtains the relationship between the high-pressure relative equivalent speed and the engine turbine temperature drop ratio from idle to intermediate state. Then, it obtains the relationship between the high-pressure relative equivalent speed from idle to intermediate state and the measured low-pressure turbine exhaust total temperature during the actual test. Then, it calculates the high-pressure turbine inlet total temperature difference between the intermediate state and the idle state based on the high-pressure turbine inlet total temperature converted from the engine idle state and the high-pressure turbine inlet total temperature converted from the engine intermediate state. It calculates the high-pressure equivalent speed value corresponding to the temperature under different throttling conditions, and accurately obtains the low-pressure equivalent speed value corresponding to the temperature under different throttling conditions based on the relationship between high and low pressure equivalent speeds, thereby designing a corrosion sensitivity test program. The actual performance of the engine under different intake air temperatures was taken into consideration to ensure that the total gas temperature of the turbine inlet can meet the requirements of GJB241A-2010 under the set steady-state speed steps of each throttling state. The compatibility with the intake air salt spraying equipment for corrosion sensitivity testing was also taken into consideration. The steady-state steps of the throttling state were set by using the converted speed of the engine's low-pressure rotor, which is beneficial to improving the accuracy of the control of the engine inlet salt spray flow during the corrosion sensitivity test.

[0044] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for designing a corrosion sensitivity test procedure for a turbofan engine, characterized in that, include: A simulation model of the engine's overall performance is selected to calculate the steady-state performance of the engine from idle to intermediate state under standard atmospheric conditions at sea level, obtaining the high-pressure equivalent speed n from idle to intermediate state. 2r Compared with engine turbine temperature drop ratio τ T The relationship curve, where τ T =T4 / T6, where T4 is the total gas temperature before the high-pressure turbine and T6 is the total exhaust temperature after the low-pressure turbine of the engine; Based on the bench test data of the engine, the high-pressure converted speed n from the idle state to the intermediate state during the actual test was obtained. 2r The measured total exhaust temperature T after the low-pressure turbocharger during the test drive 6k The relationship curve, and the engine low-pressure converted speed n 1r Converted speed n with high pressure 2r Relationship curve; High-voltage conversion speed n from idle to intermediate state 2r Compared with engine turbine temperature drop ratio τ T The relationship curve, and the high-pressure converted speed n from the slow state to the intermediate state during the actual test run. 2r The measured total exhaust temperature T after the low-pressure turbocharger during the test drive 6k The relationship curve was obtained using the linear interpolation method to obtain the converted speed n under different high pressures during the actual test run. 2r The engine turbo temperature drop ratio τ T The value of n is then used to obtain the high-pressure converted speed n during the actual test run. 2r Total high-pressure turbine inlet gas temperature T converted to engine specifications 4k The relationship curve was then used to calculate the total gas temperature T before the high-pressure turbine based on the engine idle state. 4k_MC Total high-pressure turbine inlet gas temperature T, converted from engine intermediate state 4k_ZJ Calculate the total temperature difference ΔT between the high-pressure turbine inlet gas and the engine in intermediate and idle states. Based on high pressure, the rotational speed n 2r Total high-pressure turbine inlet gas temperature T converted to engine specifications 4k Relationship curve, interpolation calculation T 4k For (T) 4k_MC +0.2×ΔT), (T) 4k_MC +0.4×ΔT), (T) 4k_MC +0.6×ΔT) and (T 4k_MC The corresponding high-pressure equivalent speed n at +0.8×ΔT) 2r value n 2r_1 n 2r_2 n 2r_3 and n 2r_4 ; According to n 2r_1 n 2r_2 n 2r_3 and n 2r_4 Converting speed n to high pressure 2r Low-pressure conversion speed n 1r The corresponding low-pressure equivalent speed n is obtained by interpolation calculation of the relationship curve. 1r_1 n 1r_2 n 1r_3 and n 1r_4 value; Based on low pressure, the rotational speed n is calculated. 1r_1 n 1r_2 n 1r_3 and n 1r_4 By combining the engine's large-state time ratio and cycle number, an engine corrosion sensitivity program was designed.

2. The method for designing a corrosion sensitivity test procedure for a turbofan engine as described in claim 1, characterized in that: The total exhaust temperature after the low-pressure turbine was measured during the test run. , T 6m This is the total exhaust temperature after the low-pressure turbocharger of the engine, measured during the test run.

3. The method for designing a corrosion sensitivity test procedure for a turbofan engine as described in claim 1, characterized in that: The engine's calculated total gas temperature before the high-pressure turbine is... , .

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