阅读说明：本技术 一种涡扇发动机轴承腔封严的引气参数控制方法及系统 (Method and system for controlling air entraining parameters of turbofan engine bearing cavity seal ) 是由 阮文博 姜繁生 张雪冬 邴连喜 范静 袁继来 张志舒 陈仲光 唐明智 吕安琪 于 2019-10-11 设计创作，主要内容包括：本申请属于发动机控制技术领域,涉及一种涡扇发动机轴承腔封严的引气参数控制方法及系统,所述方法包括确定高压压气机中间级引气温度以及外涵气压力；进而控制轴承封严引气流路上的活门开度,包括在所述外涵气压力超过第一阈值时,使用外涵气对发动机轴承进行封严,否则判断当所述高压压气机中间级引气温度低于第二阈值时,使用高压压气机中间级引气对发动机轴承进行封严。本申请对发动机的封严引气参数实现了直接或间接的控制,可有效满足发动机在全包线范围、不同发动机工作状态下轴承腔的封严要求,保证发动机工作安全和可靠性。(The application belongs to the technical field of engine control, and relates to a bleed air parameter control method and a bleed air parameter control system for sealing a bearing cavity of a turbofan engine, wherein the method comprises the steps of determining the bleed air temperature of the middle stage of a high-pressure compressor and the pressure of the bypass air; and further controlling the opening degree of a valve on a bearing sealing air-entraining flow path, wherein when the external bypass air pressure exceeds a first threshold value, the engine bearing is sealed by using the external bypass air, otherwise, when the intermediate stage air-entraining temperature of the high-pressure compressor is lower than a second threshold value, the engine bearing is sealed by using the intermediate stage air-entraining of the high-pressure compressor. The sealing air-entraining parameter of the engine is directly or indirectly controlled, the sealing requirements of the bearing cavity of the engine in a full-envelope range and different engine working states can be effectively met, and the working safety and reliability of the engine are ensured.)

1. A method for controlling a bleed air parameter of a turbofan engine bearing cavity seal is characterized by comprising the following steps:

step S1, determining the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor;

and step S2, controlling the opening degree of a valve on a bearing sealing bleed air flow path, wherein when the pressure of the outside bypass air exceeds a first threshold value, the outside bypass air is used for sealing the engine bearing, otherwise, when the temperature of the intermediate bleed air of the high-pressure compressor is lower than a second threshold value, the intermediate bleed air of the high-pressure compressor is used for sealing the engine bearing.

2. The method for controlling the bleed air parameters of the turbofan engine bearing cavity seal according to claim 1 wherein the determining the intermediate stage bleed air temperature of the high pressure compressor in step S1 comprises:

step S11, in a ground test, obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the outlet temperature of the compressor;

and step S12, calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured outlet temperature of the compressor and the actually measured low-pressure converted rotating speed of the engine.

3. The method for controlling the bleed air parameters of the turbofan engine bearing cavity seal according to claim 1 wherein the determining the intermediate stage bleed air temperature of the high pressure compressor in step S1 comprises:

step S13, in a ground test, obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the total temperature of the inlet of the engine;

and step S14, calculating the intermediate-stage bleed air temperature of the high-pressure compressor according to the measured total temperature of the inlet of the engine and the measured low-pressure conversion rotating speed of the engine.

4. The turbofan engine bearing cavity seal bleed air parameter control method according to claim 1 wherein in step S2, when the intermediate stage bleed air of the high pressure compressor is over-temperature and the outside bypass air pressure is insufficient, the seal bleed air parameter is made lower than the second threshold value by adjusting the engine state.

5. The turbofan engine bearing cavity sealed bleed air parameter control method of claim 2 further comprising performing ground debugging after step S11, and performing a correction to the relationship determined in step S11 based on the test result; and carrying out high-altitude simulation verification, and carrying out secondary correction on the relationship after primary correction according to the test result.

6. A bleed air parameter control system for sealing a bearing cavity of a turbofan engine is characterized by comprising:

the parameter acquisition module is used for determining the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor;

and the control module is used for controlling the opening degree of a valve on the bearing sealing air-entraining flow path, wherein when the external bypass air pressure exceeds a first threshold value, the engine bearing is sealed by using the external bypass air, otherwise, when the intermediate stage air-entraining temperature of the high-pressure compressor is lower than a second threshold value, the engine bearing is sealed by using the intermediate stage air-entraining of the high-pressure compressor.

7. The turbofan engine bearing cavity sealed bleed air parameter control system of claim 1 wherein the parameter acquisition module comprises:

the first relation determining module is used for obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the outlet temperature of the compressor in a ground test;

the first calculation module is used for calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured outlet temperature of the compressor and the actually measured low-pressure conversion rotating speed of the engine.

8. The turbofan engine bearing cavity sealed bleed air parameter control system of claim 1 wherein the parameter acquisition module comprises:

the second relation determination module is used for obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the total temperature of the inlet of the engine in a ground test;

and the second calculation module is used for calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured total temperature of the inlet of the engine and the actually measured low-pressure conversion rotating speed of the engine.

9. The turbofan engine bearing cavity sealed bleed air parameter control system of claim 1 further comprising an engine state adjustment module for adjusting an engine state to cause the sealed bleed air parameter to be below the second threshold when intermediate stage bleed air of the high pressure compressor is over-temperature while ambient bleed air pressure is insufficient.

10. The turbofan engine bearing cavity sealed bleed air parameter control system of claim 7 wherein the first relationship determination module further comprises a correction module comprising:

the ground debugging and correcting unit is used for carrying out ground debugging and correcting the relation determined by the first relation determining module for one time according to the test result;

and the high-altitude debugging and correcting unit is used for carrying out high-altitude simulation verification and carrying out secondary correction on the relationship after primary correction according to the test result.

Technical Field

The application belongs to the technical field of engine control, and particularly relates to a method and a system for controlling a gas-entraining parameter of a turbofan engine bearing cavity seal.

Background

For pressurization and sealing of an aeroengine bearing cavity, one or more pressurization air sources (air-entraining positions) in an engine compression system are selected through the design of an air system flow path, and air with proper temperature and pressure is introduced into the bearing cavity by switching to different air sources according to the condition changes such as height, speed, rotating speed and the like, so that the lubricating oil can be reliably prevented from leaking under various working states of the engine.

The method is characterized in that a culvert and intermediate bleed air of a high-pressure compressor are used as air sources for sealing a bearing of a certain turbofan engine, an air system conversion valve is arranged on a flow path of an air system, the conversion valve is switched according to control parameters including throttle lever angles, engine physical rotating speeds and intake air temperatures, and the control valve is used for selecting the culvert or intermediate pressurized air sources when the engine is in different working states, so that sealing of a bearing cavity is realized. In the debugging process of the ground and the high-altitude platform, the problems of valve conversion alarm, improper air-entraining parameters before and after valve switching under different atmospheric conditions or large variation range cause that the sealing requirement cannot be met occur, and the reliability and the working safety of an engine are influenced.

Under the prior art scheme, when the control is carried out according to the throttle lever instead of the engine state, the condition that the controller outputs a valve switching instruction according to the position of the throttle lever in advance and the engine speed and the sealed air-entraining pressure cannot reach the valve hardware conversion condition occurs in the process that the engine is rapidly pushed to accelerate on the throttle, so that the valve conversion time exceeds an alarm threshold value to cause an alarm; meanwhile, when the valve is controlled to switch according to the air inlet temperature and the physical rotating speed of the engine, the sealing air pressure after the hot day switching is lower, the sealing air pressure before the cold day switching is higher, and the air entraining pressure of the high-altitude small gauge speed part state is lower, so that the sealing requirement cannot be met. The sealing pressure is low, so that lubricating oil leaks to the main runner to influence the environment control bleed air safety of an aircraft, the lubricating oil consumption greatly influences the implementation of tactical and technical indexes such as long endurance time, the service life of a sealing material is influenced by high pressure, and the reliability and the safety of an engine are adversely influenced.

Disclosure of Invention

In order to solve at least one of the technical problems, the application provides a method and a system for controlling a bleed air parameter of a turbofan engine bearing cavity seal, and solves the technical problem that the adaptability of the original valve switching control parameter is poor.

The application provides in a first aspect a bleed air parameter control method of turbofan engine bearing cavity obturage, mainly includes:

step S1, determining the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor;

and step S2, controlling the opening degree of a valve on a bearing sealing bleed air flow path, wherein when the pressure of the outside bypass air exceeds a first threshold value, the outside bypass air is used for sealing the engine bearing, otherwise, when the temperature of the intermediate bleed air of the high-pressure compressor is lower than a second threshold value, the intermediate bleed air of the high-pressure compressor is used for sealing the engine bearing.

Preferably, in step S1, the determining the intermediate stage bleed air temperature of the high-pressure compressor includes:

step S11, in a ground test, obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the outlet temperature of the compressor;

and step S12, calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured outlet temperature of the compressor and the actually measured low-pressure converted rotating speed of the engine.

Preferably, in step S1, the determining the intermediate stage bleed air temperature of the high-pressure compressor includes:

step S13, in a ground test, obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the total temperature of the inlet of the engine;

and step S14, calculating the intermediate-stage bleed air temperature of the high-pressure compressor according to the measured total temperature of the inlet of the engine and the measured low-pressure conversion rotating speed of the engine.

Preferably, in step S2, when the intermediate stage bleed air of the high-pressure compressor is over-temperature and the bypass air pressure is insufficient, the sealed bleed air parameter is made lower than the second threshold value by adjusting the engine state.

Preferably, after the step S11, the method further includes performing ground debugging, and performing a correction on the relationship determined in the step S11 according to the test result; and carrying out high-altitude simulation verification, and carrying out secondary correction on the relationship after primary correction according to the test result.

This application second aspect provides a bleed parameter control system that turbofan engine bearing chamber was obturaged, includes:

the parameter acquisition module is used for determining the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor;

and the control module is used for controlling the opening degree of a valve on the bearing sealing air-entraining flow path, wherein when the external bypass air pressure exceeds a first threshold value, the engine bearing is sealed by using the external bypass air, otherwise, when the intermediate stage air-entraining temperature of the high-pressure compressor is lower than a second threshold value, the engine bearing is sealed by using the intermediate stage air-entraining of the high-pressure compressor.

Preferably, the parameter acquiring module includes:

the first relation determining module is used for obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the outlet temperature of the compressor in a ground test;

the first calculation module is used for calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured outlet temperature of the compressor and the actually measured low-pressure conversion rotating speed of the engine.

Preferably, the parameter acquiring module includes:

the second relation determination module is used for obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the total temperature of the inlet of the engine in a ground test;

and the second calculation module is used for calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured total temperature of the inlet of the engine and the actually measured low-pressure conversion rotating speed of the engine.

Preferably, the system further comprises an engine state adjusting module, which is used for adjusting the engine state to enable the sealed bleed air parameter to be lower than the second threshold value when the bleed air of the middle stage of the high-pressure compressor is over-temperature and the bypass air pressure is insufficient.

Preferably, the first relationship determination module further comprises a modification module, the modification module comprising:

the ground debugging and correcting unit is used for carrying out ground debugging and correcting the relation determined by the first relation determining module for one time according to the test result;

and the high-altitude debugging and correcting unit is used for carrying out high-altitude simulation verification and carrying out secondary correction on the relationship after primary correction according to the test result.

The invention obtains the relation between the sealed air-entraining parameter and the conversion state of the engine, the inlet parameter of the engine or the outlet parameter of the compressor through the performance calculation of the mathematical model of the engine, and simultaneously corrects the calculated sealed air-entraining parameter through a ground test so as to obtain the more accurate relation between the sealed air-entraining parameter and the rotating speed and the air intake condition of the engine.

Drawings

FIG. 1 is a flow chart of a preferred embodiment of the method for controlling bleed air parameters for turbofan engine bearing cavity seal according to the present application.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application, and should not be construed as limiting the present application. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application. Embodiments of the present application will be described in detail below with reference to the drawings.

The application provides in a first aspect a bleed air parameter control method of turbofan engine bearing cavity obturage, mainly includes:

step S1, determining the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor;

step S2, as shown in FIG. 1, controlling the opening degree of a valve on a bearing sealing bleed air flow path, wherein the step comprises sealing the engine bearing by using external bypass air when the external bypass air pressure exceeds a first threshold, and otherwise, when the intermediate bleed air temperature of the high-pressure compressor is judged to be lower than a second threshold, sealing the engine bearing by using the intermediate bleed air of the high-pressure compressor.

Wherein the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor in the step S1 pass through n_1r、T_t2、P_t2、T_t3And calculating and obtaining the control input parameter.

The parameters related to the present application mainly include:

h is the flying height, n_1rFor measured low-pressure conversion of the engine speed, T_t2Is the measured total temperature of the inlet of the engine, P_t2For measured total pressure at the inlet of the engine, T_{Height of}For the measured intermediate stage bleed air temperature, T, of the high-pressure compressor_{High js}For calculating the intermediate bleed air temperature, P, of the high-pressure compressor_{Is low in}Is the measured pressure of the culvert air, P_{Low js}For calculating the pressure of the culvert gases, T_t3The measured outlet temperature of the compressor.

(1) When P is present_{Is low in}At fault, according to P_{Low js}As a control value;

(2) when n is_1rAt fault, according to T_t3Calculating to obtain T_{High js}；

(3) When T is_t3At fault, according to n_1r、T_t2Calculating to obtain T_{High js}。

The invention is characterized in that the prediction is carried out (by theoretical calculation), the debugging and correction are carried out based on the prediction, and the process of the iterative validation is repeated. The method specifically comprises the following steps:

(1) for the engine under study, a mathematical model is established based on component characteristics, engine principles and the like, and the ground T is obtained through numerical simulation_{High js}And n_1r、T_t3Relation of (1), T_{High js}And n_1r、T_t2A relationship of (A) and P_{Low js}And n_1r、P_t2The relationship (2) provides a basis for developing a ground test;

(2) starting ground debugging on the basis of the parameter relationship, and correcting the relationship ground calculation result according to the test result;

(3) and carrying out high-altitude simulation verification on the basis of the work, further correcting the relation according to a test result, and ensuring that the sealing air entraining parameters of the engine bearing cavity meet the requirements under different working conditions and different working states during ground test and high-altitude simulation verification.

Under certain special conditions (such as the condition of high-altitude small surface speed hot days), when the intermediate stage bleed air of the high-pressure compressor is over-temperature and the bypass air pressure is insufficient according to the designed engine state control rule, the sealed bleed air parameters meet the requirements by adjusting the engine state, namely the temperature of the bleed air meets the set value by adjusting the engine state.

The invention obtains the relation between the sealed air-entraining parameter and the conversion state of the engine, the inlet parameter of the engine or the outlet parameter of the compressor through the performance calculation of the mathematical model of the engine, and simultaneously corrects the calculated sealed air-entraining parameter through a ground test so as to obtain the more accurate relation between the sealed air-entraining parameter and the rotating speed and the air intake condition of the engine.

The second aspect of the present application provides a bleed air parameter control system for sealing a bearing cavity of a turbofan engine, which corresponds to the above method, and includes:

the parameter acquisition module is used for determining the intermediate stage bleed air temperature and the bypass air pressure of the high-pressure compressor;

and the control module is used for controlling the opening degree of a valve on the bearing sealing air-entraining flow path, wherein when the external bypass air pressure exceeds a first threshold value, the engine bearing is sealed by using the external bypass air, otherwise, when the intermediate stage air-entraining temperature of the high-pressure compressor is lower than a second threshold value, the engine bearing is sealed by using the intermediate stage air-entraining of the high-pressure compressor.

In some optional embodiments, the parameter obtaining module comprises:

the first relation determining module is used for obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the outlet temperature of the compressor in a ground test;

the first calculation module is used for calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured outlet temperature of the compressor and the actually measured low-pressure conversion rotating speed of the engine.

In some optional embodiments, the parameter obtaining module comprises:

the second relation determination module is used for obtaining the relation between the intermediate stage bleed air temperature of the high-pressure compressor and the low-pressure conversion rotating speed of the engine and the total temperature of the inlet of the engine in a ground test;

and the second calculation module is used for calculating the intermediate stage bleed air temperature of the high-pressure compressor according to the actually measured total temperature of the inlet of the engine and the actually measured low-pressure conversion rotating speed of the engine.

In some optional embodiments, the system further comprises an engine state adjusting module, configured to adjust an engine state to make the sealed bleed air parameter lower than the second threshold when the bleed air of the middle stage of the high-pressure compressor is over-temperature and the bypass air pressure is insufficient.

In some optional embodiments, the first relationship determination module further comprises a correction module, the correction module comprising:

the ground debugging and correcting unit is used for carrying out ground debugging and correcting the relation determined by the first relation determining module for one time according to the test result;

and the high-altitude debugging and correcting unit is used for carrying out high-altitude simulation verification and carrying out secondary correction on the relationship after primary correction according to the test result.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.