A method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine

Abstract

The present application belongs to the field of aviation turbofan engine control technology, and specifically relates to a method for controlling the outer inner pressure ratio of the right boundary of the flight envelope of an aviation turbofan engine. The method is designed to control the outer inner pressure ratio by adjusting the outer area based on the optimal outer inner pressure ratio of the corresponding operating point when the engine flight envelope enters the right boundary, so as to maintain the outer inner pressure ratio at the optimal outer inner pressure ratio. While meeting the exhaust temperature requirements, the mixing loss in the afterburner and the nozzle can be reduced, thereby improving the thrust, optimizing the engine performance, reducing the aerodynamic load of the heat shield in the afterburner and the nozzle, and improving the reliability of the structure.

Description

Technical Field

[0001] The present application belongs to the field of aviation turbofan engine control technology, and specifically relates to a method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine. Background Art

[0002] In order to reduce the detectability of aviation turbofan engines, part of the external bypass air is usually used for afterburner combustion chamber and nozzle cooling. This part of the external bypass air flows out from the afterburner heat shield and the nozzle heat shield to form a cooling air film, which will eventually mix with the internal airflow and flow out of the engine.

[0003] At the right boundary of the flight envelope of an aviation turbofan engine, the inlet pressure is relatively high, and the thrust is usually increased by expanding the nozzle throat area and increasing the inlet air flow.

[0004] At the right boundary of the flight envelope of aviation turbofan engines, as the nozzle throat area expands, the outer duct pressure will increase sharply, causing the outer duct gas to cool the afterburner, the mixing loss of the nozzle and the inner duct airflow to increase, reducing the engine thrust, and increasing the pressure difference with the inner duct, resulting in an increase in the outer-to-inner duct pressure ratio, which will greatly increase the aerodynamic load on the afterburner and the heat shield in the nozzle and reduce the structural reliability.

[0005] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0006] The purpose of this application is to provide a method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine, so as to overcome or alleviate at least one of the known technical defects.

[0007] The technical solution of this application is:

[0008] A method for controlling the internal pressure ratio outside the right boundary of a flight envelope of an aviation turbofan engine, comprising:

[0009] Step 1: According to the engine flight envelope and control plan, the altitude and Mach number corresponding to the nozzle throat area at each operating point on the right boundary of the flight envelope are obtained after the area is enlarged;

[0010] Step 2: Calculate the engine performance parameters based on the height and Mach number corresponding to the nozzle throat area at each operating point on the right boundary of the engine flight envelope after the nozzle throat area is enlarged to obtain the inherent pressure;

[0011] Step 3: Based on the enlarged internal pressure of the nozzle throat area at each operating point on the right boundary of the engine flight envelope, calculate the minimum external pressure that can meet the cooling of the afterburner and nozzle, and obtain the minimum external-to-internal pressure ratio;

[0012] Step 4: Based on the height and Mach number corresponding to the nozzle throat area enlarged at each operating point on the right boundary of the engine flight envelope, the outer envelope area is adjusted to the minimum value, and the maximum outer-to-inner pressure ratio is calculated;

[0013] Step 5: Based on the height and Mach number corresponding to the enlarged nozzle throat area at each operating point on the right boundary of the engine flight envelope, the thrust under different external and internal pressure ratios is calculated between the minimum external and internal pressure ratio and the maximum external and internal pressure ratio, and the external and internal pressure ratio corresponding to the maximum thrust that meets the exhaust temperature requirement is taken as the optimal external and internal pressure ratio;

[0014] Step 6: When the engine flight envelope enters the right boundary, based on the optimal outer-to-inner pressure ratio of the corresponding operating point, the outer-to-inner pressure ratio is closed-loop controlled by adjusting the outer-to-inner pressure ratio.

[0015] Optionally, in the above-mentioned method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine, in step two, the engine performance parameters are calculated based on the overall performance calculation model of the engine to obtain the internal pressure.

[0016] Optionally, in the above-mentioned method for controlling the external internal pressure ratio of the right boundary of the flight envelope of an aviation turbofan engine, in step three, a simulation is performed to calculate the minimum external internal pressure ratio that can meet the cooling of the afterburner and the nozzle.

[0017] Optionally, in the above-mentioned method for controlling the external internal pressure ratio at the right boundary of the flight envelope of an aviation turbofan engine, in step four, the maximum external internal pressure ratio is calculated using the engine overall performance calculation model.

[0018] Optionally, in the above-mentioned method for controlling the external internal pressure ratio of the right boundary of the flight envelope of an aviation turbofan engine, in step five, the thrust under different external internal pressure ratios is calculated based on the engine overall performance calculation model, and the difference between adjacent different external internal pressure ratios is 1%.

[0019] Optionally, in the above-mentioned method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine, step six is ​​specifically as follows:

[0020] The optimal external and internal pressure ratios of each operating point at the right boundary of the engine flight envelope are saved in the engine controller. When the engine flight envelope enters the right boundary, the external and internal pressure ratios are closed-loop controlled through the external area based on the optimal external and internal pressure ratios of the corresponding operating point, including:

[0021] S1. Calculate the deviation between the external and internal pressure ratio of the engine and the optimal external and internal pressure ratio ,in, is the optimal external-to-internal pressure ratio of the engine; is the external-to-internal pressure ratio of the engine, , is the external pressure, For the connotation pressure;

[0022] S2. Calculate the control current of the electro-hydraulic servo valve of the outer area adjustment mechanism actuator using the PI control algorithm ,in, is the proportional control parameter, which is a constant; The balance current of the electro-hydraulic servo valve of the outer area adjustment mechanism actuator is a constant; is the integral control parameter, which is a constant; Indicates the integral link;

[0023] S3, the outer area adjustment mechanism actuator electro-hydraulic servo valve control current , which is transmitted to the electro-hydraulic servo valve of the outer circumference area adjustment mechanism actuator to drive the outer circumference area adjustment mechanism actuator, and the outer circumference area adjustment mechanism adjusts the outer circumference area to make the deviation of the outer circumference pressure ratio of the engine from the optimal outer circumference pressure ratio Tends to zero.

[0024] This application has at least the following beneficial technical effects:

[0025] A method for controlling the outer inner pressure ratio at the right boundary of the flight envelope of an aviation turbofan engine is provided. The method is designed to control the outer inner pressure ratio by adjusting the outer area based on the optimal outer inner pressure ratio of the corresponding operating point when the flight envelope of the engine enters the right boundary, so that the outer inner pressure ratio is kept at the optimal outer inner pressure ratio. While meeting the exhaust temperature requirement, the mixing loss in the afterburner and the nozzle can be reduced, thereby improving the thrust, optimizing the engine performance, reducing the aerodynamic load of the afterburner and the heat shield in the nozzle, and improving the reliability of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine provided in an embodiment of the present application;

[0027] Figure 2 It is a schematic diagram of closed-loop control of the external-to-internal pressure ratio through the external-to-internal pressure ratio based on the optimal external-to-internal pressure ratio of the corresponding operating point when the engine flight envelope enters the right boundary provided by an embodiment of the present application.

[0028] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0029] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0030] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0031] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0032] In order to improve the operability of aviation turbofan engines, some aviation turbofan engines are equipped with an outer envelope area adjustment mechanism for adjusting the outer envelope area. Therefore, the present application provides a method for controlling the outer envelope pressure ratio of the right boundary of the flight envelope of an aviation turbofan engine, such as Figure 1 shown.

[0033] Step 1: According to the engine flight envelope and control plan, obtain the altitude and Mach number corresponding to the nozzle throat area at each operating point on the right boundary of the flight envelope after it is enlarged.

[0034] Step 2: Calculate the engine performance parameters based on the altitude and Mach number corresponding to the nozzle throat area at each operating point on the right boundary of the engine flight envelope to obtain the intrinsic pressure.

[0035] Specifically, the overall engine performance calculation model can be used to calculate engine performance parameters and obtain the intrinsic pressure.

[0036] Step 3: Based on the enlarged internal pressure of the nozzle throat area at each operating point on the right boundary of the engine flight envelope, calculate the minimum external pressure that can meet the cooling of the afterburner and nozzle, and obtain the minimum external-to-internal pressure ratio.

[0037] Specifically, the minimum external pressure that can meet the cooling of the afterburner and nozzle can be simulated and calculated to obtain the minimum external-to-internal pressure ratio.

[0038] Step 4: Based on the altitude and Mach number corresponding to the enlarged nozzle throat area at each operating point on the right boundary of the engine flight envelope, adjust the outer envelope area to the minimum value and calculate the maximum outer-to-inner pressure ratio.

[0039] Specifically, the maximum external-to-internal pressure ratio can be calculated using the engine overall performance calculation model.

[0040] The increase in the engine's bypass area will reduce the fan pressure ratio, which in turn will lead to a decrease in the engine's thrust, and increase the bypass ratio, resulting in a decrease in core engine flow and an increase in exhaust temperature, which will have an adverse effect on the engine. When determining the maximum bypass pressure ratio, it is necessary to comprehensively consider aspects such as the afterburner and the mixing loss of the nozzle.

[0041] Step 5. Based on the height and Mach number corresponding to the enlarged nozzle throat area at each operating point on the right boundary of the engine flight envelope, calculate the thrust under different external-internal pressure ratios between the minimum external-internal pressure ratio and the maximum external-internal pressure ratio, and take the external-internal pressure ratio corresponding to the maximum thrust that meets the exhaust temperature requirements as the optimal external-internal pressure ratio.

[0042] Specifically, the overall engine performance calculation model can be used to calculate the thrust under different external and internal pressure ratios. The difference between adjacent different external and internal pressure ratios is 1%.

[0043] Step 6: When the engine flight envelope enters the right boundary, based on the optimal outer-to-inner pressure ratio of the corresponding operating point, the outer-to-inner pressure ratio is closed-loop controlled by adjusting the outer-to-inner pressure ratio.

[0044] The optimal external and internal pressure ratios of each operating point at the right boundary of the engine flight envelope can be saved in the engine controller. When the engine flight envelope enters the right boundary, the external and internal pressure ratios are closed-loop controlled through the external area based on the optimal external and internal pressure ratios of the corresponding operating point, such as Figure 2 As shown, the specific process is as follows:

[0045] S1. Calculate the deviation between the external and internal pressure ratio of the engine and the optimal external and internal pressure ratio ,in, is the optimal external-to-internal pressure ratio of the engine; is the external-to-internal pressure ratio of the engine, , is the external pressure, For the internal pressure.

[0046] S2. Calculate the control current of the electro-hydraulic servo valve of the outer area adjustment mechanism actuator using the PI control algorithm ,in, is the proportional control parameter, which is a constant; The balance current of the electro-hydraulic servo valve of the outer area adjustment mechanism actuator is a constant; is the integral control parameter, which is a constant; Indicates the integration phase.

[0047] S3, the outer area adjustment mechanism actuator electro-hydraulic servo valve control current , which is transmitted to the electro-hydraulic servo valve of the outer circumference area adjustment mechanism actuator to drive the outer circumference area adjustment mechanism actuator, and the outer circumference area adjustment mechanism adjusts the outer circumference area to make the deviation of the outer circumference pressure ratio of the engine from the optimal outer circumference pressure ratio Tends to zero.

[0048] The method for controlling the outer inner pressure ratio at the right boundary of the flight envelope of an aviation turbofan engine disclosed in the above-mentioned embodiment is designed to perform closed-loop control of the outer inner pressure ratio by adjusting the outer area based on the optimal outer inner pressure ratio of the corresponding operating point when the flight envelope of the engine enters the right boundary, so as to maintain the outer inner pressure ratio at the optimal outer inner pressure ratio. This can reduce the mixing loss in the afterburner and the nozzle while meeting the exhaust temperature requirements, thereby improving the thrust, optimizing the engine performance, reducing the aerodynamic load of the heat shield in the afterburner and the nozzle, and improving the reliability of the structure.

[0049] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine, characterized in that: include: Step 1: According to the engine flight envelope and control plan, the altitude and Mach number corresponding to the nozzle throat area at each operating point on the right boundary of the flight envelope are obtained after the area is enlarged; Step 2: Calculate the engine performance parameters based on the height and Mach number corresponding to the nozzle throat area at each operating point on the right boundary of the engine flight envelope after the nozzle throat area is enlarged to obtain the inherent pressure; Step 3: Based on the enlarged internal pressure of the nozzle throat area at each operating point on the right boundary of the engine flight envelope, calculate the minimum external pressure that can meet the cooling of the afterburner and nozzle, and obtain the minimum external-to-internal pressure ratio; Step 4: Based on the height and Mach number corresponding to the nozzle throat area enlarged at each operating point on the right boundary of the engine flight envelope, the outer envelope area is adjusted to the minimum value, and the maximum outer-to-inner pressure ratio is calculated; Step 5: Based on the height and Mach number corresponding to the enlarged nozzle throat area at each operating point on the right boundary of the engine flight envelope, the thrust under different external and internal pressure ratios is calculated between the minimum external and internal pressure ratio and the maximum external and internal pressure ratio, and the external and internal pressure ratio corresponding to the maximum thrust that meets the exhaust temperature requirement is taken as the optimal external and internal pressure ratio; Step 6: When the engine flight envelope enters the right boundary, based on the optimal outer and inner pressure ratio of the corresponding operating point, the outer and inner pressure ratio is closed-loop controlled by adjusting the outer area, including: S1. Calculate the deviation between the engine's external and internal pressure ratio and the optimal external and internal pressure ratio Δ=p Dem -p, where p Dem is the optimal external and internal pressure ratio of the engine; p is the external and internal pressure ratio of the engine, p=p 16 / p6,p 16 is the extrinsic pressure, p6 is the intrinsic pressure; S2. Calculate the control current of the electro-hydraulic servo valve of the outer area adjustment mechanism actuator using the PI control algorithm Among them, K p is the proportional control parameter, which is a constant; I 平衡 K is the balance current of the electro-hydraulic servo valve of the outer area adjustment mechanism actuator, which is a constant; i is the integral control parameter, which is a constant; Indicates the integral link; S3. The control current I of the electro-hydraulic servo valve of the outer envelope area adjustment mechanism actuator is transmitted to the electro-hydraulic servo valve of the outer envelope area adjustment mechanism actuator to drive the outer envelope area adjustment mechanism actuator, and the outer envelope area adjustment mechanism adjusts the outer envelope area so that the deviation Δ between the outer envelope pressure ratio and the optimal outer envelope pressure ratio of the engine approaches zero.

2. The method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine according to claim 1, characterized in that: In step 2, the engine performance parameters are calculated based on the overall engine performance calculation model to obtain the intrinsic pressure.

3. The method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine according to claim 2, characterized in that: In step three, the minimum external pressure that can meet the cooling of the afterburner and nozzle is calculated by simulation to obtain the minimum external pressure ratio.

4. The method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine according to claim 3, characterized in that: In step 4, the maximum external-to-internal pressure ratio is calculated using the overall engine performance calculation model.

5. The method for controlling the internal pressure ratio outside the right boundary of the flight envelope of an aviation turbofan engine according to claim 4, characterized in that: In step five, the thrust under different external-to-internal pressure ratios is calculated using the engine overall performance calculation model, and the difference between adjacent different external-to-internal pressure ratios is 1%.

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