Turboshaft engine complete machine surge boundary determination method, system and equipment

Abstract

The invention discloses a turboshaft engine complete machine surge boundary determination method, system and device, and belongs to the technical field of turboshaft engines, the turboshaft engine complete machine surge boundary determination method comprises the following steps: determining whether an engine power turbine overrotates; if the power turbine is over-rotating, over-rotating protection is carried out, and the fuel flow is adjusted to the set flow; and after the fuel flow is adjusted, power turbine over-rotation oil drainage reignition tests under different engine powers are carried out, and the engine surge boundary is determined according to test results. According to the method, the complete surge boundary of the whole engine state can be obtained through the dynamic fuel step method based on the over-running oil drainage reignition test, the engine and a test bed do not need to be greatly transformed, only the over-running oil drainage time sequence needs to be adjusted in the test process, and the method is easy to implement.

Description

Technical Field

[0001] The present invention belongs to the technical field of turboshaft engines, and in particular relates to a method, system and device for determining a surge boundary of a turboshaft engine. Background Art

[0002] Air intake distortion may cause compressor instability in the flight of an aircraft engine. To verify the aerodynamic stability of the compressor, it is necessary to determine the compressor surge boundary through compressor component characteristic tests. However, after the compressor is installed on the engine, the actual characteristics and component test characteristics may deviate to a certain extent. To verify the surge margin of the whole machine, the whole machine surge margin is usually determined through a whole machine forced surge test.

[0003] The existing fuel step forcing methods are divided into steady-state fuel step method and dynamic fuel step method, and the existing problems are:

[0004] Steady-state fuel step method: The surge margin of the engine in steady-state operation is large, and the amount of fuel to be injected is large, which may exceed the fuel limit that the engine fuel system can supply. The engine fuel system including the nozzle, fuel distribution device, and fuel main pipe needs to be redesigned, or fuel injection can be increased through an auxiliary fuel system independent of the engine. The test system is more complex and the test cost is higher.

[0005] Dynamic fuel step method: Only a few boundary points can be obtained, and it is difficult to obtain the complete surge boundary. Therefore, a method for determining the surge boundary of a turboshaft engine is urgently needed. Summary of the invention

[0006] In view of the above problems, the present invention discloses a method for determining the surge boundary of a turboshaft engine, comprising the following steps:

[0007] Determine whether the engine power turbine is over-rotating;

[0008] If the power turbine overspeeds, overspeed protection is performed and the fuel flow rate is adjusted to the set flow rate;

[0009] After the fuel flow rate is adjusted, the power turbine over-revving, oil discharge and re-ignition test is carried out at different engine powers, and the engine surge boundary is determined based on the test results.

[0010] Furthermore, the over-speed protection also includes lighting up an over-speed indicator light and connecting an ignition signal.

[0011] Furthermore, the specific steps of adjusting the fuel flow rate to the set flow rate are as follows:

[0012] Adjust the fuel flow rate to be 10-30% higher than the combustion chamber flameout boundary fuel flow rate.

[0013] Furthermore, the combustion chamber flameout boundary fuel flow rate is determined by the following steps:

[0014] Gradually reduce the fuel flow rate in the combustion chamber. If the temperature rise of the combustion chamber is 60-100°C, the fuel flow rate at this time is the flameout boundary fuel flow rate of the combustion chamber.

[0015] Furthermore, the above-mentioned conducting the power turbine over-revving oil discharge re-ignition test under different engine powers and determining the engine surge boundary according to the test results comprises the following steps:

[0016] Open the overrunning drain valve to drain the oil according to the set drain sequence, and at the same time, turn on the ignition signal for several seconds, then resume the fuel supply for re-ignition;

[0017] Check the engine's oil draining and re-ignition working conditions. If the engine does not surge, gradually reduce the oil draining time until the engine surges.

[0018] Carry out the power turbine over-speed oil discharge and re-ignition test at all state points in sequence;

[0019] According to the compressor inlet gauge pressure, compressor outlet gauge pressure and atmospheric pressure before surge in each state, the engine converted intake flow and pressure ratio are determined, and the surge boundary line is drawn on the flow-pressure ratio diagram.

[0020] Furthermore, the engine converted intake flow is determined by the following formula:

[0021]

[0022] Walc=-dMa 2 +eMa-f

[0023] Among them, Ma is the Mach number; PH is the atmospheric pressure; Ps1 is the compressor inlet gauge pressure; Walc is the engine converted intake flow; a, b, c, d, e, and f are set values.

[0024] Furthermore, the oil release timing is controlled at 0.15 to 1.0 s, and the ignition signal connection time is 4 to 10 s.

[0025] Furthermore, the time interval from when the combustion chamber is re-supplied with oil to when the gas turbine speed starts to recover does not exceed 0.2 s.

[0026] The present invention also discloses a turboshaft engine whole machine surge boundary determination system, comprising:

[0027] An electronic controller for determining whether the engine power turbine is overspeeding;

[0028] The test bench electrical system is used to provide over-speed protection if the power turbine over-speeds, adjust the fuel flow rate to the set flow rate, and conduct over-speed fuel discharge and re-ignition tests of the power turbine under different engine powers after the fuel flow rate is adjusted;

[0029] The test bench test system is used to determine the engine surge boundary based on the test results.

[0030] The present invention also discloses an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for determining the surge boundary of a turboshaft engine as a whole when executing the computer program.

[0031] Compared with the prior art, the embodiments of the present invention have at least the following advantages: the present invention utilizes the dynamic fuel step method, and based on the over-revving fuel release and re-ignition test, a relatively complete surge boundary of the whole engine state can be obtained, without a large number of modifications to the engine and the test bench. The test process only requires adjusting the over-revving fuel release timing (or the engine oil-to-gas ratio limit parameters), which is easy to implement.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A flow chart showing a method for determining a surge boundary of a turboshaft engine according to an embodiment of the present invention is shown;

[0035] Figure 2 A schematic diagram of super-rotation oil release according to an embodiment of the present invention is shown;

[0036] Figure 3 A schematic diagram of a super-rotation oil discharge machine of the prior art is shown;

[0037] Figure 4 A schematic diagram of fast re-ignition with slow over-speed fuel release according to an embodiment of the present invention is shown;

[0038] Figure 5 A schematic diagram of slow re-ignition at an empty, slow over-speed, oil-discharging, and slow re-ignition according to an embodiment of the present invention is shown;

[0039] Figure 6 A schematic diagram of an improved fuel dispensing device according to an embodiment of the present invention is shown;

[0040] Figure 7 The results of a 50% power over-revving oil discharge re-ignition test according to an embodiment of the present invention are shown;

[0041] Figure 8 The results of a 31% power over-revving oil discharge re-ignition test according to an embodiment of the present invention are shown;

[0042] Fig. 9 A schematic diagram of flow rate pressure ratio according to an embodiment of the present invention is shown;

[0043] Fig.10 A schematic diagram of a turboshaft engine whole machine surge boundary determination system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Figure 1 A flow chart of a method for determining the surge boundary of a turboshaft engine according to an embodiment of the present invention is shown. Figure 1 As shown, a method for determining the surge boundary of a turboshaft engine proposed in the present invention comprises the following steps:

[0046] Determine whether the engine power turbine is over-rotating;

[0047] If the power turbine overspeeds, overspeed protection is performed and the fuel flow rate is adjusted to the set flow rate;

[0048] After the fuel flow rate is adjusted, the power turbine over-revving, oil discharge and re-ignition test is carried out at different engine powers, and the engine surge boundary is determined based on the test results.

[0049] The present invention utilizes a dynamic fuel step method, and based on an over-revving fuel release and re-ignition test, a relatively complete surge boundary of the engine as a whole can be obtained, without requiring extensive modifications to the engine and the test bench. The test process only requires adjustment of the over-revving fuel release timing (or the engine oil-to-gas ratio limiting parameters), and is easy to implement.

[0050] The invention also provides a turboshaft engine power turbine over-rotation protection system.

[0051] Turboshaft engines are usually designed with a power turbine overspeed protection system. In order to conduct the power turbine overspeed protection and then ignition test, a power turbine overspeed protection system is required, including an overspeed drain valve, an improved fuel distribution device, an electronic controller, and a test bench electrical system.

[0052] Figure 2 FIG. 2 shows a schematic diagram of super-rotation oil release according to an embodiment of the present invention. Figure 2 As shown, the electronic controller determines whether the engine power turbine A channel and B channel are overspeeding; if the power turbine is overspeeding, the overspeed protection is executed after overspeeding, the overspeed drain valve is opened to cut off the oil supply to reduce the engine power turbine speed, and the ignition signal is turned on for several seconds, the overspeed indicator light is lit, and when the power turbine speed returns to the specified range, the overspeed drain valve is closed, and the oil supply is restored for re-ignition; in addition, when the engine test bench is tested, the overspeed protection function can be executed by the test bench electrical system through the lead wire.

[0053] Figure 3 FIG. 2 shows a schematic diagram of a super-rotation oil discharge machine in the prior art. Figure 3 As shown, when the engine is working normally, the main oil circuit valve and the auxiliary oil circuit valve of the fuel distribution device are in the open state, and the fuel enters the fuel main pipe through the annular cavity between the two valve core valve sleeves of the selection valve. When the over-turn oil drain valve is connected, the selection valve moves, and the oil supply to the auxiliary oil circuit valve is cut off. All the fuel flows from the main oil circuit valve into the selection valve and then flows to the fuel pump inlet, cutting off the fuel supply to the combustion chamber.

[0054] The present invention also provides an improved fuel distribution device for over-revving fuel release and stable re-ignition.

[0055] Figure 4 A schematic diagram of fast re-ignition with slow over-speed fuel release according to an embodiment of the present invention is shown. Figure 5 The schematic diagram of slow re-ignition at idle slow over-speed oil discharge according to an embodiment of the present invention is shown. Since the fuel inlet of the combustion chamber is cut off when the over-speed oil discharge valve is opened, causing flameout, re-ignition will be performed when the over-speed oil discharge valve is closed to resume fuel supply. There is randomness in the ignition time ( Figure 4 , Figure 5 The results of two tests under the same conditions of over-revving, fuel-draining and re-ignition are given. The parameters of the two tests are consistent, but the ignition timing is very different. This results in the surge boundary point state determined by the test being low and having a large discreteness. Therefore, it is necessary to provide an improved fuel distribution device for over-revving, fuel-draining and stable re-ignition.

[0056] Figure 6 FIG. 2 shows a schematic diagram of an improved fuel dispensing device according to an embodiment of the present invention. Figure 6 As shown, in Figure 3On the basis of the selection valve sleeve, an additional inclined hole is added on the valve sleeve. When the valve sleeve is in the over-turn oil return state, part of the fuel can still flow to the auxiliary oil outlet. When the engine is working normally, the additionally processed inclined hole will supply oil together with a circle of oil holes on the valve sleeve, so it will not have any effect on the engine performance during normal operation. The size of the inclined hole is determined according to the lean oil flameout test of the combustion chamber:

[0057] The combustion chamber hot state performance test is carried out according to the specified combustion chamber inlet parameters, and the performance of the combustion chamber in various states is recorded. After the performance recording is completed, the combustion chamber inlet air parameters are kept unchanged in various states. When the engine is from the ground slow state to the maximum state of the engine (the maximum state refers to the working state where the engine can produce the maximum power or thrust under the set conditions. It is usually not allowed to exceed this state during flight or testing, and there are running time regulations), the combustion chamber flameout test is carried out on the combustion chamber component stand, and the fuel flow rate of the combustion chamber is gradually reduced. If the temperature rise of the combustion chamber is 60-100℃ (or the flame detector cannot detect the flame), it indicates that the combustion chamber flameout limit has been reached. The fuel flow rate at this time is the flameout boundary fuel flow rate of the combustion chamber. During the test, the parameters such as the combustion chamber inlet air flow and pressure, fuel flow rate, and combustion chamber outlet temperature need to be recorded. In order to ensure that the combustion chamber does not flame out during over-turning and oil discharge, the fuel flow rate of the over-turning and oil discharge of the inclined hole of the improved fuel distribution device should be 10-30% higher than the flameout boundary fuel flow rate of each state of the combustion chamber. Preferably, when the temperature rise of the combustion chamber is lower than 80°C, it indicates that the combustion chamber flameout limit has been reached, and the fuel flow rate at this time is the flameout boundary fuel flow rate of the combustion chamber. Preferably, the fuel flow rate of the inclined hole super-discharge oil flowing out of the improved fuel distribution device should be 20% higher than the flameout boundary fuel flow rate of each state of the combustion chamber.

[0058] The over-speed oil discharge valve cuts off and supplies fuel by selecting the movement of the valve, controls the fuel independently of the parking solenoid valve, and has the function of retaining a portion of the fuel during over-speed oil discharge, so that the time interval from resuming fuel supply after oil cut-off to the start of the gas turbine speed Ng to recover is no more than 0.2s.

[0059] The power turbine over-revving oil discharge and re-ignition test under different engine powers (different states) is carried out. The test results under each state are obtained by adjusting the over-revving oil discharge timing (or the engine oil-air ratio limit parameter). The specific steps for determining the engine surge boundary according to the test results are as follows:

[0060] Based on the characteristic that the engine surge margin is small during the over-revving and oil-draining process, the combustion chamber temperature rise caused by resuming oil supply at the moment of closing the over-revving and oil-draining valve is used to cause the engine to surge. Before the test, the connection and debugging between the test bench electrical system and the engine over-speed oil drain valve are completed. The engine adopts high oil-gas ratio limit parameters. The test bench uses a high-speed dynamic recorder to collect the engine compressor outlet gauge pressure Ps3, compressor intake gauge pressure Ps1, gas turbine speed, power turbine speed, etc. After the engine is successfully started, the PMS (flight status switch) switch is turned to the "flight" state. After several minutes of air slow stability, the test bench electrical system connects the over-speed oil drain valve, and opens the over-speed oil drain valve according to the set oil drain timing (adjustable) for oil draining. At the same time, the ignition signal is connected for several seconds, and then the fuel supply is restored for re-ignition. Check the engine oil drain and re-ignition working conditions. If the engine does not surge, the oil drain time is gradually reduced (or the oil-gas ratio limit parameters are increased) as appropriate, and repeated until the engine surges (which can be judged by the sound of blasting and the violent fluctuation of the intake gauge pressure), and then push the load rod to the next state, and perform the over-speed oil drain and re-ignition test to make the engine surge, and repeat in sequence until the test of all state points is completed. Among them, the oil release timing (the time to set the flow rate to a specified value, which is equal to the time the overrun oil release valve is opened) is controlled at 0.15 to 1.0 s, and the ignition signal connection time is 4 to 10 s.

[0061] Figure 7 The results of the 50% power over-revving oil discharge re-ignition test according to an embodiment of the present invention are shown. Figure 7 As shown in the test results, 50% of the maximum engine power, the oil-to-air ratio is the oil-to-air ratio that meets the engine acceleration, the fuel supply is continuously restored after over-revving and releasing the oil for 0.15s, and the time from the resumption of fuel supply to the start of the gas turbine speed rising is 0.1s for re-ignition. It can be seen that the combustion chamber is not extinguished when the engine is over-revved and released. In this state, the intake gauge pressure Ps1 fluctuates violently when the engine is re-ignited, indicating that the engine has surged. Figure 8 The results of the 31% power overrun fuel discharge re-ignition test according to an embodiment of the present invention are shown. Figure 8 As shown, 31% of the maximum engine power, the oil-to-air ratio is the oil-to-air ratio that meets the engine acceleration, the over-revving oil is released for 0.5s, and then the oil supply is continuously restored. The time from the resumption of oil supply to the start of the gas turbine speed rising is 0.1s for re-ignition test results. It can be seen that the combustion chamber is not flameout when the engine is over-revving and the intake gauge pressure Ps1 does not fluctuate when the engine is re-ignited in this state, indicating that the engine does not surge.

[0062] After the test, the engine converted intake flow Walc and pressure ratio are calculated according to the pre-surge parameters of each state, namely, the compressor inlet gauge pressure Ps1, the compressor outlet gauge pressure Ps3, and the atmospheric pressure PH, and the surge boundary line is drawn on the flow-pressure ratio diagram.

[0063]

[0064] Walc=-dMa 2 +eMa-f (2)

[0065] Pressure ratio = (Ps3 + PH) / PH (3)

[0066] Wherein, Ma is the Mach number; a, b, c, d, e, and f are set values. For example, a is 5; b is 0.2857; c is 1; d is 5.7049; e is 20.33; and f is 0.0921.

[0067] Fig. 9 The flow pressure ratio diagram according to the embodiment of the present invention is shown. In a certain type of turboshaft engine, the method for determining the surge boundary of the turboshaft engine of the present invention is used to conduct an oil release and re-ignition test with different oil release timings from idle slow to 62.5% of the maximum engine power state. During the test, after the engine is released and the oil supply is restored, the gas turbine speed Ng speed quickly recovers (such as Figure 8 ), after the test, the engine surge boundary point is determined as follows Fig. 9 As shown, the data are well consistent with the theoretical surge boundary, which proves the feasibility of the method for determining the surge boundary of the turboshaft engine of the present invention.

[0068] Fig.10 A schematic diagram of a turboshaft engine whole machine surge boundary determination system according to an embodiment of the present invention is shown. Fig.10 As shown, based on the above-mentioned method for determining the surge boundary of a turboshaft engine as a whole, this embodiment proposes a system for determining the surge boundary of a turboshaft engine as a whole, including:

[0069] An electronic controller for determining whether the engine power turbine is overspeeding;

[0070] The test bench electrical system is used to provide over-speed protection if the power turbine over-speeds, adjust the fuel flow rate to the set flow rate, and conduct over-speed fuel discharge and re-ignition tests of the power turbine under different engine powers after the fuel flow rate is adjusted;

[0071] The test bench test system is used to determine the engine surge boundary based on the test results.

[0072] The present invention also proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for determining the surge boundary of the entire turboshaft engine when executing the computer program.

[0073] The present invention also proposes a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for determining the surge boundary of a turboshaft engine is implemented.

[0074] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.

[0075] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the surge boundary of a turboshaft engine, characterized in that: The following steps are involved: Determine whether the engine power turbine is over-rotating; If the power turbine overspeeds, overspeed protection is performed and the fuel flow rate is adjusted to the set flow rate; After the fuel flow rate is adjusted, the power turbine over-revving, oil discharge and re-ignition test is carried out at different engine powers, and the engine surge boundary is determined based on the test results.

2. The method for determining the surge boundary of a turboshaft engine according to claim 1, characterized in that: The over-rotation protection also includes lighting up an over-rotation indicator light and connecting an ignition signal.

3. The method for determining the surge boundary of a turboshaft engine according to claim 1, characterized in that: The specific steps of adjusting the fuel flow rate to the set flow rate are as follows: Adjust the fuel flow rate to be 10-30% higher than the combustion chamber flameout boundary fuel flow rate.

4. The method for determining the surge boundary of a turboshaft engine according to claim 3, characterized in that: The combustion chamber extinction boundary fuel flow rate is determined by the following steps: Gradually reduce the fuel flow rate in the combustion chamber. If the temperature rise of the combustion chamber is 60-100°C, the fuel flow rate at this time is the flameout boundary fuel flow rate of the combustion chamber.

5. The method for determining the surge boundary of a turboshaft engine according to claim 1, characterized in that: The method of conducting a power turbine over-revving oil discharge and re-ignition test under different engine powers and determining the engine surge boundary according to the test results comprises the following steps: Open the overrunning drain valve to drain the oil according to the set drain sequence, and at the same time, turn on the ignition signal for several seconds, then resume the fuel supply for re-ignition; Check the engine's oil draining and re-ignition working conditions. If the engine does not surge, gradually reduce the oil draining time until the engine surges. Carry out the power turbine over-speed oil discharge and re-ignition test at all state points in sequence; According to the compressor inlet gauge pressure, compressor outlet gauge pressure and atmospheric pressure before surge in each state, the engine converted intake flow and pressure ratio are determined, and the surge boundary line is drawn on the flow-pressure ratio diagram.

6. The method for determining the surge boundary of a turboshaft engine according to claim 5, characterized in that: The engine converted intake flow rate is determined by the following formula: Waltz=-dMa 2 +eMa-f Among them, Ma is the Mach number; PH is the atmospheric pressure; Ps1 is the compressor inlet gauge pressure; Walc is the engine converted intake flow; a, b, c, d, e, and f are set values.

7. The method for determining the surge boundary of a turboshaft engine according to claim 5, characterized in that: The oil release timing is controlled at 0.15 to 1.0 s, and the ignition signal connection time is 4 to 10 s.

8. The method for determining the surge boundary of a turboshaft engine according to claim 4, characterized in that: The time interval from when the combustion chamber is re-supplied with oil to when the speed of the gas turbine starts to recover is no more than 0.2s.

9. A turboshaft engine whole machine surge boundary determination system, characterized in that: include: An electronic controller for determining whether the engine power turbine is overspeeding; The test bench electrical system is used to provide over-speed protection if the power turbine over-speeds, adjust the fuel flow rate to the set flow rate, and conduct over-speed fuel discharge and re-ignition tests of the power turbine under different engine powers after the fuel flow rate is adjusted; The test bench test system is used to determine the engine surge boundary based on the test results.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for determining the surge boundary of the whole turboshaft engine according to any one of claims 1-8 is implemented.

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