Total Temperature Regulation Method at the Inlet of a Turbofan Engine for Intake Air Heating Simulation Tests

Abstract

The present application provides a method for regulating the total inlet temperature of a turbofan engine for an intake air heating simulation test. The method includes: Step 1: Divide the process of regulating the total inlet temperature of the engine for the intake air heating simulation test into a lift stage and a descent stage; Step 2: In the lift stage, divide the target value of the total inlet temperature of the engine into three temperature increase adjustment stages, determine the relationship between the target value of the total inlet temperature regulation of the engine and the adjustment stage, and increase the total inlet temperature of the engine according to the adjustment stage in which the target value is located; Step 3: In the descent stage, divide the target value of the total inlet temperature of the engine into two temperature decrease adjustment stages, determine the relationship between the target value of the total inlet temperature regulation of the engine and the adjustment stage, and decrease the total inlet temperature of the engine according to the adjustment stage in which the target value is located. The method of the present application can truly simulate the actual working conditions of the engine in flight, reduce the risk of rubbing between the engine rotor blades and the casing, and at the same time shorten the test time.

Description

Technical Field

[0001] This application belongs to the technical field of aero-engine test technology, and particularly relates to a total inlet temperature regulation method for a turbofan engine used in an intake air heating simulation test. Background Technique

[0002] The intake air heating simulation test of a turbofan engine refers to only simulating the engine inlet temperature during the intake air heating test, without simulating the inlet pressure. It is an important test for endurance running to assess the reliability of the engine. During the intake air heating simulation test run of the engine, the regulation of the engine inlet temperature is an important link to meet the test requirements and safety.

[0003] Currently, with the increasingly high design indicators of turbofan engines, more advanced test equipment, and more refined matching technology between engine rotor blades and the casing, the atmospheric pressure during the intake air heating test is the ground-state atmospheric pressure. At this time, the intake air conditions are non-standard intake air conditions. Therefore, the total temperature regulation of the engine is related to the safety of the engine.

[0004] Currently, the method for regulating the total inlet temperature of the engine follows the way of "first increasing the engine state and then raising the temperature during the lift process, and first reducing the temperature and then reducing the state during the descent process", that is, when the engine state rises in steps, first conduct a test under normal temperature gas supply conditions. After the engine state rises and stabilizes, start to adjust the opening of the intake air heating gas supply valve to adjust to the intake air heating target temperature. After meeting the time requirement of the heating program, when the engine descends in steps, first close the gas supply regulating valve. After the engine inlet drops to normal temperature gas supply, then conduct the operation of reducing the engine state, as shown in Figure 1 shown.

[0005] This operation method has a relatively high technical maturity and is applicable to the early intake air heating test run of the engine. This operation method requires the engine to first rise to the target state and then adjust the total inlet temperature. Since the intake air heating equipment heats up and cools down slowly, the engine needs to wait a relatively long time for heating up and cooling down at a high state. According to the statistics of the previous test situation, the time for the engine to wait for heating up and cooling down accounts for about 40% of the heating time, wasting the engine service life, increasing the test run cost, and resulting in low efficiency of the intake air heating test run. At the same time, during the heating up and cooling down process of the engine inlet total temperature, due to the large amplitude of increase and decrease of the inlet total temperature, the engine speed changes greatly at the same state, which does not conform to the engine operating conditions during flight, resulting in the phenomenon of "cold casing, hot rotor", increasing the risk of rubbing between the engine rotor blades and the casing, and being unfavorable to the test safety. Summary of the Invention

[0006] The purpose of this application is to provide a total inlet temperature regulation method for a turbofan engine used in an intake air heating simulation test to solve or alleviate at least one problem in the background technique.

[0007] The technical solution of this application is: a method for adjusting the total inlet temperature of a turbofan engine for an intake air heating simulation test, and the method includes:

[0008] Step 1: Divide the process of adjusting the total inlet temperature of the engine for the intake air heating simulation test into a rising stage and a falling stage;

[0009] Step 2: In the rising stage, divide the target value of the total inlet temperature of the engine into three temperature-rising adjustment stages, determine the relationship between the target value of the total inlet temperature adjustment of the engine and the temperature-rising adjustment stage, and increase the total inlet temperature of the engine according to the temperature-rising adjustment stage where the target value is located;

[0010] Step 3: In the falling stage, divide the target value of the total inlet temperature of the engine into two temperature-lowering adjustment stages, determine the relationship between the target value of the total inlet temperature adjustment of the engine and the temperature-lowering adjustment stage, and decrease the total inlet temperature of the engine according to the temperature-lowering adjustment stage where the target value is located.

[0011] Further, the three temperature-rising adjustment stages of the target value of the total inlet temperature of the engine in the rising stage include below the first temperature value, between the first temperature value and the second temperature, and above the second temperature value.

[0012] Further, when the target value of the total inlet temperature adjustment of the engine is below the first temperature value, the total inlet temperature of the engine is simulated by the synchronous increase of the engine speed and the inlet total temperature. During the process of increasing the engine speed, the engine state is adjusted in real time, and the opening of the air supply valve of the test equipment is adjusted to adjust the total inlet temperature of the engine in real time, so that the target temperature of the inlet total temperature and the engine state reach simultaneously.

[0013] Further, when the target value of the total inlet temperature adjustment of the engine is between the first temperature value and the second temperature, the engine state and the total inlet temperature of the engine are first adjusted to a predetermined state by the synchronous increase of the engine speed and the total inlet temperature of the engine. After that, the engine speed is kept unchanged, and the total inlet temperature of the engine is increased according to a predetermined temperature step. After the engine speed / state is stable, the engine state is increased according to a first predetermined speed step, and the above process is alternated until the engine state and the total inlet temperature of the engine meet the requirements of the test run procedure.

[0014] Further, when the target value of the total inlet temperature adjustment of the engine is above the second temperature value, the engine speed and the total inlet temperature of the engine are first adjusted to a predetermined state by the synchronous increase of the engine speed and the total inlet temperature of the engine. After that, the engine speed is kept unchanged, and the total inlet temperature of the engine is increased according to the same predetermined temperature step as in step 2.2. After the engine state is stable, the engine state is increased according to a second predetermined speed step, and the above process is alternated until the engine state and the total inlet temperature of the engine meet the requirements of the test run procedure.

[0015] Further, the two temperature reduction adjustment stages of the engine inlet total temperature target value in the descending stage include below the third temperature value and above the third temperature value.

[0016] Further, when the engine inlet total temperature target value is below the third temperature value, the engine inlet total temperature and the engine speed are simultaneously and matchedly reduced to reduce the engine inlet total temperature to the target state and normal temperature.

[0017] Further, when the engine inlet total temperature target value is above the third temperature value, at the maximum engine speed state, first keep the engine inlet total temperature unchanged, reduce the engine state according to the third predetermined speed step, and then reduce the engine inlet total temperature according to the predetermined temperature step, and gradually alternate. When the engine state and the engine inlet total temperature are reduced to the predetermined state, reduce the engine inlet total temperature and the engine speed simultaneously and matchedly.

[0018] The method for synchronously adjusting the engine inlet total temperature and the engine speed provided by this application has been verified by test runs. The matching of the inlet total temperature and the engine state is good, and it can truly simulate the actual working conditions of the engine in flight, reducing the risk of rubbing between the engine rotor blades and the casing. At the same time, the waiting time for heating and cooling during the heating test adjustment process can be shortened to less than 25% of the test time, improving the test efficiency and saving the test cost. Description of the Drawings

[0019] To more clearly illustrate the technical solutions provided by this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0020] Figure 1 It is a schematic diagram of the engine inlet total temperature adjustment in the prior art.

[0021] Figure 2 It is a general schematic diagram of the engine inlet total temperature adjustment of this application.

[0022] Figure 3 It is a schematic diagram of the engine inlet total temperature adjustment below the first temperature value in the lift stage of an embodiment of this application.

[0023] Figure 4 It is a schematic diagram of the engine inlet total temperature adjustment between the first temperature value and the second temperature value or above the second temperature value in the lift stage of an embodiment of this application.

[0024] Figure 5 It is a schematic diagram of the engine inlet total temperature adjustment below the first temperature value in the descending stage of an embodiment of this application.

[0025] Figure 6 It is a schematic diagram of the engine inlet total temperature adjustment above the first temperature value in the descending stage of an embodiment of this application. Detailed implementation manners

[0026] 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 with reference to the accompanying drawings in the embodiments of this application.

[0027] In order to ensure, as much as possible, that the total inlet temperature of the engine is synchronously adjusted with the engine, simulate the operating conditions of the engine during flight to the greatest extent, reduce the risk of rubbing between the engine rotor blades and the casing, shorten the waiting time for heating and cooling during the adjustment of the total inlet temperature, improve the test efficiency, and reduce the test cost, this application provides a method for instantaneously adjusting the total inlet temperature of a turbofan engine for an intake air heating simulation test.

[0028] Since the total inlet temperature at the engine inlet varies widely during the actual flight of an aircraft, but the change in the total inlet temperature at the engine inlet during the flight condition is matched with the change in the engine state (speed), and there is no fixed engine state, for the operating condition of the total inlet temperature of the engine changing drastically, the temperature matching of each component of the engine can maintain relative balance, and the possibility of rubbing between the rotor and the casing is small. The method of this application aims to simulate the operating conditions of the engine during flight to the greatest extent when conducting a total inlet temperature simulation test in the ground state of the engine, and achieve the matching of the total inlet temperature of the engine with the engine state.

[0029] As Figure 2 shown, the method for instantaneously adjusting the total inlet temperature of a turbofan engine for an intake air heating simulation test provided by this application includes:

[0030] Step 1: Divide the adjustment process of the total inlet temperature of the engine for the intake air heating simulation test into a rising stage and a falling stage;

[0031] Step 2: In the rising stage, determine the target value or target total temperature for adjusting the total inlet temperature of the engine;

[0032] 2.1) When the target value T1 for adjusting the total inlet temperature of the engine * is below the first temperature value, the total inlet temperature of the engine is simulated by synchronously increasing the engine speed and the total inlet temperature. During the process of increasing the engine speed, the engine state is adjusted in real time, and the opening degree of the air supply valve of the test equipment is adjusted in real time to adjust the total inlet temperature of the engine, so that the target temperature of the total inlet temperature and the engine state reach simultaneously.

[0033] For example Figure 3In the illustrated embodiment, taking the first temperature value as 80°C as an example, when the target value of the total inlet temperature of the engine is below 80°C, due to the control law of the engine itself, the change in the total inlet temperature of the engine results in little change in the engine state and does not affect the test safety of the engine. Therefore, below this target total temperature, the total inlet temperature is simulated by synchronously increasing the engine speed and the engine inlet temperature. During the process of increasing the engine speed, the engine state is adjusted in real time, and the opening of the air supply valve of the test equipment is adjusted to regulate the engine inlet temperature. The rising rate of the total inlet temperature of the engine is 8 - 10°C / s, which can ensure that the target temperature of the total inlet temperature regulation of the engine and the engine state (intermediate state) reach simultaneously.

[0034] 2.2) When the target value of the total inlet temperature of the engine is between the first temperature value and the second temperature, the engine state and the total inlet temperature of the engine are adjusted to a predetermined state by synchronously increasing the engine speed and the total inlet temperature of the engine. Then, the engine speed is kept unchanged, and the total inlet temperature of the engine is increased according to a predetermined temperature step. After the engine speed / state is stable, the engine state is increased according to the first predetermined speed step. The above process is alternately carried out until the engine state and the total inlet temperature of the engine meet the requirements of the test procedure.

[0035] For example Figure 4 In the illustrated embodiment, the first temperature value is 80°C and the second temperature value is 120°C. When the target value of the total inlet temperature of the engine is between 80°C and 120°C, first, the method of synchronously increasing the engine speed and the inlet total temperature in step 2.1 is adopted to increase the engine speed to the position of (n 2max - 10)% and the inlet total temperature to the range of (80 ± 5)°C. Then, the engine speed is kept unchanged, and the engine inlet temperature is increased according to a fixed temperature step until the engine state is stable. Then, the engine speed is increased according to a fixed speed step Δn2 = (2% - 3%)n 2max After the engine speed is stable, the inlet total temperature is continuously increased according to a fixed temperature step, and the process is alternately carried out until the engine state and the total inlet temperature of the engine meet the requirements of the test procedure.

[0036] 2.3) When the target value of the total inlet temperature of the engine is above the second temperature value, the engine speed and the total inlet temperature of the engine are adjusted to a predetermined state by synchronously increasing the engine speed and the total inlet temperature of the engine. Then, the engine speed is kept unchanged, and the total inlet temperature of the engine is increased according to the same predetermined temperature step as in step 2.2. After the engine state is stable, the engine state is increased according to the second predetermined speed step. The above process is alternately carried out until the engine state and the total inlet temperature of the engine meet the requirements of the test procedure.

[0037] For example Figure 4In the illustrated embodiment, the second temperature value is 120°C. When the target value of the total temperature at the engine inlet is above 120°C, first, the method of synchronously increasing the engine speed and the total temperature at the engine inlet in step 2.1 is adopted to increase the engine speed to the position of (n 2max -10)% and increase the total temperature at the inlet to the range of (80±5)°C. Then, keep the engine speed unchanged, and the total temperature at the engine inlet also increases by a fixed temperature step . After the engine state is stable, increase the engine speed by a fixed speed step Δn2=(1% - 1.5%)n 2max . After the engine speed is stable, continue to increase the total temperature at the inlet by a fixed temperature step, and alternate until the engine state and the total temperature at the engine inlet meet the requirements of the test run procedure.

[0038] Step 3: During the lift phase, judge the target value or the target total temperature of the total temperature regulation at the engine inlet;

[0039] 3.1) When the target value of the total temperature at the engine inlet is below the third temperature value, adopt the method of simultaneously and proportionally reducing the total temperature at the engine inlet and the engine speed to reduce the total temperature at the engine inlet to the target state and normal temperature;

[0040] For example Figure 5 In the illustrated embodiment, the third temperature value is 100°C. When the target value of the total temperature at the engine inlet is below 100°C, adopt the method of simultaneously and proportionally reducing the total temperature at the engine inlet and the engine speed to reduce the total temperature at the engine inlet to the target state and normal temperature. A total temperature reduction rate of 5 - 7°C / s can meet the requirements of simultaneously reducing the total temperature at the engine inlet and the engine speed.

[0041] 3.2) When the target value of the total temperature at the engine inlet is above the third temperature value, at the maximum engine speed state, first keep the total temperature at the engine inlet unchanged, reduce the engine state according to the third predetermined speed step, and then reduce the total temperature at the engine inlet according to the predetermined temperature step, and gradually alternate. When the engine state and the total temperature at the engine inlet are reduced to the predetermined state, reduce the total temperature at the engine inlet and the engine speed simultaneously and proportionally according to the method of step 3.1.

[0042] For example Figure 6 In the illustrated embodiment, the third temperature value is 100°C. When the total temperature at the engine inlet is above 100°C, at the engine speed of n 2max state, first keep the total temperature at the engine inlet T1 unchanged, and adopt a fixed speed step Δn2=(1% - 1.5%)n 2max to reduce the engine state. After the generator state is stable, reduce the total temperature at the engine inlet according to the fixed temperature step . Gradually and alternately reduce the engine speed to (n 2max-10)%, the total inlet temperature of the engine drops to (100 ± 5) °C, and finally, in the same way as simultaneously matching the reduction of the total inlet temperature of the engine and the engine speed in step 3.1, the total inlet temperature of the engine is reduced to the target state and normal temperature.

[0043] Due to factors such as the engine control law and the slow change of equipment warming compared to cooling, in this application, the warming process of the total inlet temperature of the engine is divided into three states, and the cooling process is divided into two states. At the same time, since the rotor and the casing are in the cooling process during the engine cooling process, in order to avoid the phenomenon of "cold casing and hot rotor" caused by too rapid reduction of temperature and speed, resulting in rubbing, the relative step size of the cooling process is smaller.

[0044] The method for synchronously adjusting the total inlet temperature of the engine and the engine speed provided by this application has been verified by test runs. The matching of the inlet temperature and the engine state is good, which can truly simulate the actual working conditions of the engine under flight conditions, reduce the risk of rubbing between the engine rotor blades and the casing. At the same time, the waiting time for warming and cooling during the heating test adjustment process can be shortened to within 25% of the test time, improving the test efficiency and saving the test cost.

[0045] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claimed rights.

Claims

1. A method for adjusting the total inlet temperature of a turbofan engine for intake air heating simulation tests, characterized in that, The method includes: Step 1: Divide the engine inlet total temperature adjustment process of the intake air heating simulation test into a rising stage and a falling stage; Step 2: In the rising stage, divide the target value of the engine inlet total temperature into three heating adjustment stages, including below the first temperature value, between the first temperature value and the second temperature, and above the second temperature value. The second temperature value is higher than the first temperature value. Among them: When the target value of the engine inlet total temperature adjustment is below the first temperature value, the engine inlet total temperature is simulated by synchronously increasing the engine speed and the inlet total temperature, so that the target temperature of the inlet total temperature and the engine state reach simultaneously; When the target value of the engine inlet total temperature adjustment is above the first temperature value, first adjust the engine state and the engine inlet total temperature to a predetermined state by synchronously increasing the engine speed and the engine inlet total temperature. Then, keep the engine speed unchanged and increase the engine inlet total temperature, and then increase the engine state alternately. Repeat the above process until the engine state and the engine inlet total temperature meet the requirements of the test procedure; Step 3: In the falling stage, divide the target value of the engine inlet total temperature into two cooling adjustment stages, judge the relationship between the target value of the engine inlet total temperature adjustment and the cooling adjustment stage, and reduce the engine inlet total temperature according to the cooling adjustment stage where the target value is located; Among them, the two cooling adjustment stages of the engine inlet total temperature target value in the falling stage include below the third temperature value and above the third temperature value. When the target value of the engine inlet total temperature is below the third temperature value, the engine inlet total temperature and the engine speed are simultaneously and matchedly reduced to reduce the engine inlet total temperature to the target state and normal temperature; when the target value of the engine inlet total temperature is above the third temperature value, at the maximum engine speed state, first keep the engine inlet total temperature unchanged, reduce the engine state according to the third predetermined speed step, and then reduce the engine inlet total temperature according to the predetermined temperature step, and gradually alternate. When the engine state and the engine inlet total temperature are reduced to the predetermined state, reduce the engine inlet total temperature and the engine speed simultaneously and matchedly.

2. The method for adjusting the total inlet temperature of a turbofan engine for intake air heating simulation tests according to claim 1, characterized in that, The said Step 2 further includes: Step 2.1: When the target value of the engine inlet total temperature adjustment is below the first temperature value, the engine inlet total temperature is simulated by synchronously increasing the engine speed and the inlet total temperature. During the process of increasing the engine speed, the engine state is adjusted in real time, and the opening degree of the air supply valve of the test equipment is adjusted to adjust the engine inlet total temperature in real time, so that the target temperature of the inlet total temperature and the engine state reach simultaneously.

3. The method for adjusting the total inlet temperature of a turbofan engine for intake air heating simulation tests according to claim 2, characterized in that, The said Step 2 further includes: Step 2.2: When the target value of the engine inlet total temperature adjustment is between the first temperature value and the second temperature, first adjust the engine state and the engine inlet total temperature to a predetermined state by synchronously increasing the engine speed and the engine inlet total temperature. Then, keep the engine speed unchanged and increase the engine inlet total temperature according to the predetermined temperature step. After the engine speed / state is stable, increase the engine state according to the first predetermined speed step, and alternate the above process until the engine state and the engine inlet total temperature meet the requirements of the test procedure.

4. The method for adjusting the total inlet temperature of a turbofan engine for intake air heating simulation tests according to claim 3, characterized in that, The said Step 2 further includes: Step 2.3: When the target value of the total temperature at the engine inlet is above the second temperature value, first adjust the engine speed and the total temperature at the engine inlet to a predetermined state by increasing the engine speed and the total temperature at the engine inlet synchronously. After that, keep the engine speed unchanged, increase the total temperature at the engine inlet according to the same predetermined temperature step in Step 2.

2. After the engine state is stable, then increase the engine state according to the second predetermined speed step, and alternate the above processes until the engine state and the total temperature at the engine inlet meet the requirements of the test run procedure.

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