A test method for testing the thermal fatigue performance of flame tube

Abstract

The present application discloses a test method for testing the thermal fatigue performance of a flame tube, comprising: constructing a control process logic for a flame tube thermal fatigue test, wherein the control process logic comprises: a first stage in which a fuel flow rate rises from a flow rate value corresponding to a low temperature state to a flow rate value corresponding to a high temperature state within a predetermined time, a second stage in which the fuel flow rate is maintained at a flow rate value corresponding to a high temperature state for a predetermined time, a third stage in which the fuel flow rate drops from a flow rate value corresponding to a high temperature state to a flow rate value corresponding to a low temperature state within a predetermined time, and a third stage in which the fuel flow rate is maintained at a flow rate value corresponding to a low temperature state for a predetermined time; determining whether to use a high temperature state or a low temperature state as a reference, adjusting the test state of the flame tube to a reference state, and then adjusting the fuel flow rate to another state, and inputting the inverter frequency values ​​of the two states into a control program; starting a thermal fatigue cycle test of the flame tube, cycling for a predetermined number of times, and recording the values ​​of parameters of each test state and the wall temperature and effective flow area.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine testing, and in particular to a testing method for testing the thermal fatigue performance of a flame tube. Background Art

[0002] The flame tube is an important hot end component of an aircraft engine. It is very easy to crack in the structure due to thermal fatigue, thus affecting the performance and flight safety of the aircraft engine. However, it is very difficult to analyze the fatigue problem of the flame tube, especially it is difficult to obtain accurate data through experiments, and sometimes it has to be judged by experience and estimation. The causes of cracks in the flame tube are mostly described in a general way, which is difficult to use for safety assessment and life prediction.

[0003] Therefore, a method is needed to test the thermal fatigue performance of the flame tube. Summary of the invention

[0004] The purpose of the present application is to provide a test method for testing the thermal fatigue performance of a flame tube, so as to solve or alleviate at least one problem in the background technology.

[0005] The technical solution of the present application is: a test method for testing the thermal fatigue performance of a flame tube, the test method comprising:

[0006] Construct the control process logic of the flame tube thermal fatigue test, the control process logic includes:

[0007] a first stage in which the fuel flow rate increases from the flow rate value corresponding to the low temperature state to the flow rate value corresponding to the high temperature state over a predetermined time, a second stage in which the fuel flow rate is maintained at the flow rate value corresponding to the high temperature state for a predetermined time, a third stage in which the fuel flow rate decreases from the flow rate value corresponding to the high temperature state to the flow rate value corresponding to the low temperature state over a predetermined time, and a third stage in which the fuel flow rate is maintained at the flow rate value corresponding to the low temperature state for a predetermined time;

[0008] Determine whether the high temperature state or the low temperature state is used as the reference, adjust the test state of the flame tube to the reference state, input the frequency value of the inverter that controls the fuel flow into the control program, keep other control parameters unchanged, manually adjust the fuel flow to another state, and input the frequency value of the inverter that controls the fuel flow into the control program again;

[0009] Start the thermal fatigue cycle test of the flame tube, cycle the preset number of times, and record the values ​​of each test state parameter, wall temperature, and effective flow area;

[0010] Furthermore, the control process logic of the flame tube thermal fatigue test is implemented through configuration software.

[0011] Furthermore, in the first stage, the frequency of the frequency converter for controlling the fuel flow rate increases from the low temperature state frequency value to the high temperature state frequency value with a fixed frequency step size, and the fixed frequency step size of the frequency converter frequency is:

[0012] Δf 1 =T R (f H -f L ) / T C1

[0013] Where, T R It is the operating cycle of the fuel control function of the configuration software;

[0014] f L is the low temperature state frequency;

[0015] f H is the high temperature state frequency;

[0016] T C1 It is the time from low temperature state to high temperature state.

[0017] Furthermore, in the second stage, it is determined whether the difference between the high temperature state flow rate and the current flow rate is within the allowable range ΔG. That is, if G H -G>ΔG, then calculate the inverter frequency per unit flow And the frequency adjustment of the inverter And update the inverter frequency f in high temperature state H =f H +Δf 2 ;

[0018] When the difference between the high temperature flow rate and the current flow rate G'=|G L No adjustment is made when -G|≤ΔG;

[0019] Where ΔG is the threshold value;

[0020] G is the actual fuel flow rate;

[0021] G L The fuel flow rate is at low temperature;

[0022] G H It is the fuel parameter at high temperature;

[0023] k is the adjustment coefficient.

[0024] Furthermore, in the third stage, the frequency of the frequency converter for controlling the fuel flow rate is reduced from the high temperature state frequency value to the low temperature state frequency value with a fixed frequency step size, and the fixed frequency step size of the frequency converter frequency is:

[0025] Δf 3 =T R (fH -f L ) / T C3

[0026] Where, T C3 It is the time from high temperature state to low temperature state.

[0027] Furthermore, in the fourth stage, it is determined whether the difference between the low temperature fuel flow rate and the current fuel flow rate is within the allowable range. L -G>ΔG, calculate the inverter frequency per unit flow Frequency adjustment And update the low temperature state inverter frequency f L =f L +Δf 4 ;

[0028] When G'=|G L No adjustment is made when -G|≤ΔG.

[0029] Furthermore, the coefficient k is set to 1 by default.

[0030] The method of the present application realizes automatic control of fuel flow, can meet the requirements of flame tube thermal fatigue test, determines the test flow of flame tube thermal fatigue and the processing process of test results, and can complete the flame tube thermal fatigue performance test more comprehensively. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0032] Figure 1 This is the fuel cycle control timing diagram in this application.

[0033] Figure 2 This is the oil circuit control system structure in this application.

[0034] Figure 3 This is a block diagram of the oil circuit control system in this application.

[0035] Figure 4 This is the fuel control flow chart in this application.

[0036] Figure 5 It is the control program interface in this application.

[0037] Figure 6 Schematic diagram of the flame tube wall temperature and ACd values ​​monitored during the test process in this application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0039] Aiming at the characteristics of flame tube thermal fatigue test, this application proposes a test method that can comprehensively complete the flame tube thermal fatigue performance test by stipulating the fuel flow control, test process and data processing required for the flame tube thermal fatigue test.

[0040] The method of this application mainly includes fuel flow automatic control, flame tube thermal fatigue test process and test result data processing, and the specific steps are as follows:

[0041] 1) Automatic fuel flow control

[0042] like Figure 1 The fuel cycle control sequence of the flame tube thermal fatigue test shown in the figure includes the fuel supply rate from the low temperature state to the high temperature state and from the high temperature state to the low temperature state, as well as the holding time of the high temperature state and the low temperature state.

[0043] The original fuel system control method is to manually adjust the potentiometer to change the output frequency of the inverter, thereby changing the speed of the oil pump motor to achieve fuel flow control. However, in the flame tube thermal fatigue test, the timing requirements of fuel circulation control cannot be met by manual operation. Therefore, this application proposes to use computer control technology to replace manual operation through control programs to achieve automatic control of fuel circulation. The control system structure is as follows Figure 2 shown.

[0044] The control computer compares and judges the test parameters obtained by the acquisition computer, and according to different engine state requirements, uses the network bus and serial port server to coordinate and control the output of the inverter of the main / auxiliary fuel circuit, and changes the speed of the oil pump of the main / auxiliary fuel circuit to adjust the fuel flow. The change of fuel flow can make the test parameters change according to the state required by the test, thus forming a typical closed-loop control system. The block diagram of the oil circuit control system is shown in the figure below. Figure 3 shown.

[0045] Configuration software is a software platform tool with user-customizable functions. It can be connected to a variety of input / output devices and is widely used in fieldbus control systems. This application uses the "Configuration King" program, which can be modularly designed, has a large number of library elements, and is equipped with a serial communication protocol with the inverter, reducing the programming of the communication part.

[0046] Under the test state, manually adjust and explore the inverter frequency corresponding to the fuel flow rate in the low temperature state and the high temperature state. The fuel flow rate is adjusted to the low temperature state, and its fuel flow rate G LThe corresponding frequency converter Hertz number is f L , manually adjust the fuel flow to high temperature state G H , its fuel flow G H The corresponding frequency converter Hertz number is f H , get the inverter frequency corresponding to the unit flow As a reference for frequency adjustment during the flow maintenance phase.

[0047] In this application, the fuel control process is divided into four stages, such as Figure 4 As shown:

[0048] In the first stage, the fuel flow rate is from the flow value corresponding to the low temperature state for a predetermined time T C1 The flow rate value corresponding to the high temperature state.

[0049] This stage is the rising stage. The frequency of the fuel inverter increases from the low temperature state frequency value to the high temperature state frequency value with a fixed frequency step length. The fixed frequency adjustment value Δf 1 =T R (f H -f L ) / T C1 , control the fuel inverter frequency to increase Δf per operation cycle 1 , experience about T C1 = Actual frequency of the inverter after 30 seconds f = f H .

[0050] The increase value of the inverter frequency is determined through the above process.

[0051] In the second stage, the fuel flow rate is maintained at a corresponding flow value in a high temperature state for a predetermined time.

[0052] This stage is the inverter frequency holding stage, which can realize the switching between automatic adjustment and manual adjustment.

[0053] During automatic adjustment, after the first stage of adjustment is completed, it is determined whether the difference between the high temperature state flow rate and the current flow rate is within the allowable range ΔG, that is, if G'=G H -G>ΔG, then calculate the inverter frequency per unit flow And the frequency adjustment of the inverter And update the high temperature state inverter frequency f H =f H +Δf 2 , k is the adjustment coefficient, which is adjusted according to the actual debugging situation. The default k=1. When G'=|G H No adjustment is made when -G|≤ΔG.

[0054] During manual adjustment, the operator will make manual adjustments based on their judgment. The program only counts time, and manual adjustment will be prohibited when the second stage time ends.

[0055] In the third stage, the fuel flow rate is from the fuel flow rate value corresponding to the high temperature state for a predetermined time T C3 = The fuel flow value corresponding to the drop to low temperature state in 30 seconds.

[0056] This stage is the inverter frequency reduction stage. The fuel inverter frequency is reduced to the low temperature state frequency value with a fixed frequency step length. The fixed frequency adjustment value Δf 3 =T R (f H -f L ) / T C3 , the inverter frequency decreases by Δf in each control function operation cycle 3 , update f L =f L +Δf 2 After about 30 seconds, f = f L ;

[0057] In the fourth stage, the fuel flow rate is maintained at the corresponding flow value in the low temperature state for 30 seconds.

[0058] This stage is the inverter frequency holding stage, which can realize the switching between automatic adjustment and manual adjustment.

[0059] During automatic adjustment, after the third stage adjustment is completed, determine whether the difference between the low temperature fuel flow rate and the current fuel flow rate is within the allowable range, that is, if G' = G L -G>ΔG, calculate the inverter frequency per unit flow Frequency adjustment And update the low temperature state inverter frequency f L =f L +Δf 4 , k is the adjustment coefficient, which is adjusted according to the actual debugging situation. The default k=1. When G'=G L No adjustment is made when -G≤ΔG.

[0060] During manual adjustment, the operator will make manual adjustments based on his own judgment. The program only counts time, and manual adjustment will be prohibited when the second stage time ends.

[0061] Parameter Description:

[0062] T R It is the operation cycle of the fuel control function of KingView;

[0063] △G is the threshold value (flow control accuracy);

[0064] G L The fuel flow rate is at low temperature;

[0065] G HIt is the fuel parameter at high temperature;

[0066] G is the actual fuel flow rate;

[0067] f L is the low temperature state frequency;

[0068] f H is the high temperature state frequency;

[0069] f is the actual frequency of the inverter;

[0070] k is the adjustment coefficient.

[0071] 2) Test process

[0072] 2.1) First determine whether to use the high temperature state or the low temperature state as the reference, adjust the test state to the reference state, input the inverter frequency value of the fuel flow at this time into the control program, keep other control parameters unchanged, manually adjust the fuel flow to another state, input the inverter frequency value of the fuel flow at this time into the control program, and determine the adjustment accuracy according to the actual situation of the test state;

[0073] 2.2) If Figure 5 As shown in the figure, after all parameters are input, the thermal fatigue cycle test begins. During the cycle, try not to adjust the test parameters. If the test parameters deviate too much from the required test state, adjust them according to the situation;

[0074] 2.3) If multiple cycles (e.g. 100 cycles) are completed or a fault occurs that cannot be eliminated on the spot, stop the machine according to the operating procedures;

[0075] 2.4) After the test, check the status of the flame tube and the tester, and decide whether to carry out the next stage of flame tube thermal fatigue test. If any problems are found, deal with them in time.

[0076] 3) Experimental data processing

[0077] 3.1) During the flame tube thermal cycle, record the values ​​of each test state parameter, wall temperature, and effective flow area ACd to ensure the validity of the test, such as Figure 6 During the test, there was no situation where the wall temperature at more than multiple points (e.g. 5 points) changed simultaneously in the same state, and the temperature range exceeded 30K or the change rate of the effective flow area ACd value exceeded 5%;

[0078] 3.2) Draw the loop control timing diagram of the actual state to check whether it meets the test requirements.

[0079] The method of the present application realizes automatic control of fuel flow, can meet the requirements of flame tube thermal fatigue test, determines the test flow of flame tube thermal fatigue and the processing process of test results, and can complete the flame tube thermal fatigue performance test more comprehensively.

[0080] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A test method for testing the thermal fatigue performance of a flame tube, characterized in that: The test method includes: Construct the control process logic of the flame tube thermal fatigue test, the control process logic includes: The first stage is that the fuel flow rate rises from the flow value corresponding to the low temperature state to the flow value corresponding to the high temperature state within a predetermined time, the second stage is that the fuel flow rate is maintained at the flow value corresponding to the high temperature state for a predetermined time, the third stage is that the fuel flow rate decreases from the flow value corresponding to the high temperature state to the flow value corresponding to the low temperature state within a predetermined time, and the fourth stage is that the fuel flow rate is maintained at the flow value corresponding to the low temperature state for a predetermined time; wherein, in the second stage, it is determined whether the difference between the flow rate at the high temperature state and the current flow rate is within the allowable range ΔG, that is, if |G H -G|>ΔG, where ΔG is the threshold, G is the actual fuel flow, G H For high temperature fuel parameters, calculate the inverter frequency per unit flow And the frequency adjustment of the inverter Where G L is the fuel flow rate at low temperature, k is the adjustment coefficient, and the inverter frequency f is updated at high temperature. H =f H +Δf2; when the difference between the high temperature state flow and the current flow G'=|G L -G|≤ΔG, no adjustment is made; in the fourth stage, it is determined whether the difference between the low temperature fuel flow rate and the current fuel flow rate is within the allowable range, that is, if |G L -G|>ΔG, calculate the inverter frequency per unit flow Frequency adjustment And update the low temperature state inverter frequency f L =f L +Δf4; when |G L No adjustment is made when -G|≤ΔG; Determine whether the high temperature state or the low temperature state is used as the reference, adjust the test state of the flame tube to the reference state, input the frequency value of the inverter that controls the fuel flow into the control program, keep other control parameters unchanged, manually adjust the fuel flow to another state, and input the frequency value of the inverter that controls the fuel flow into the control program again; Start the thermal fatigue cycle test of the flame tube, cycle a predetermined number of times, and record the values ​​of each test state parameter, wall temperature, and effective flow area.

2. The test method for testing the thermal fatigue performance of the flame tube according to claim 1, characterized in that: The control process logic of the flame tube thermal fatigue test is realized through configuration software.

3. The test method for testing the thermal fatigue performance of the flame tube according to claim 2, characterized in that: In the first stage, the frequency of the frequency converter controlling the fuel flow is increased from the low temperature state frequency value to the high temperature state frequency value with a fixed frequency step size, and the fixed frequency step size of the frequency converter frequency is: Δf1=T R (f H -f L ) / T C1 Where, T R It is the operating cycle of the fuel control function of the configuration software; f L is the low temperature state frequency; f H is the high temperature state frequency; T C1 It is the time from low temperature state to high temperature state.

4. The test method for testing the thermal fatigue performance of the flame tube according to claim 3, characterized in that: In the third stage, the frequency of the frequency converter controlling the fuel flow is reduced from the high temperature state frequency value to the low temperature state frequency value with a fixed frequency step size, and the fixed frequency step size of the frequency converter frequency is: Δf3=T R (f H -f L ) / T C3 Where, T C3 It is the time from high temperature state to low temperature state.

5. The test method for testing the thermal fatigue performance of the flame tube according to claim 4, characterized in that: The coefficient k defaults to 1.

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