CN115013164A - A method for determining resistance torque when aero-engine starts - Google Patents

Abstract

The application belongs to the technical field of determination of moment of resistance when an aero-engine is started, and particularly relates to a method for determining moment of resistance when an aero-engine is started, which comprises the following steps: cutting off fuel supply of the aircraft engine; starting a starter under the reference altitude and the reference environment temperature, driving the aircraft engine to operate by the starter, recording the rotating speed and time of the aircraft engine to operate, and fitting to obtain the reference resisting moment M when the aircraft engine is started _c.0 (n), wherein n is the rotational speed at which the aircraft engine operates; for reference resisting moment M when starting aero-engine _c.0 Correcting at different altitudes and ambient temperatures to obtain the resisting moment of the aircraft engine during starting

Wherein T is ambient temperature; t is a unit of ₀ Is a reference ambient temperature; p is the pressure at the reference altitude; p ₀ Is the pressure at the reference altitude; kqd is the aerodynamic drag correction factor; kmc is the coefficient of friction resistance.

Description

A method for determining resistance torque when aero-engine starts

technical field

The application belongs to the technical field of determination of resistance torque when an aero-engine is started, and in particular relates to a method for determination of resistance torque when an aero-engine is started.

Background technique

Aero-engine starting is the acceleration process of aero-engine speed from 0 to idle state. The acceleration process of aero-engine speed relies on the output torque of the starter and the torque generated by the aero-engine itself to overcome the resistance torque of the aero-engine to perform work.

Accurately determining the resistance torque when the aero-engine starts is the basis for reliable design of the aero-engine starting. At present, the determination of the resistance torque when the aero-engine starts is mostly obtained through theoretical calculations based on sea level and its normal temperature environment. This method exists. The following defects:

1) Obtained through theoretical calculation, applying a large number of empirical formulas and relying on the technical experience of relevant technical personnel, the results obtained are subjective and arbitrary, and there are situations where there is a large deviation from the actual situation;

2) The change of the aero-engine frictional resistance torque caused by the change of ambient temperature, the influence on the viscosity of the lubricating oil, and the change of the aero-engine aerodynamic resistance torque caused by the change of the altitude and the influence on the atmospheric pressure are not considered. representative.

The present application is made in view of the existence of the above-mentioned technical defects.

It should be noted that the disclosure of the above background technology content is only used to assist the understanding of the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of the present patent application. If the filing date has been disclosed, the above background art should not be used to evaluate the novelty and inventive step of the present application.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide a method for determining the drag torque when an aero-engine is started, so as to overcome or alleviate the known technical defects in at least one aspect.

The technical solution of this application is:

A method for determining resistance torque when an aero-engine is started, comprising:

Cut off the fuel supply of the aircraft engine;

At the reference altitude and the reference ambient temperature, start the starter, drive the aero-engine to run with the starter, record the rotation speed and time of the aero-engine, and obtain the reference resistance torque M _c.0 =f when the aero-engine is started by fitting (n), where n is the rotational speed of the aero-engine;

其中，T为环境温度；T₀为基准环境温度；P为基准海拔高度下的压力；P₀为基准海拔高度下的压力；kqd为气动阻力修正系数；kmc为摩擦阻力系数。The reference resistance torque M _c.0 when the aero-engine is started is corrected at different altitudes and its ambient temperature to obtain the resistance torque when the aero-engine is started

Among them, T is the ambient temperature; T ₀ is the reference ambient temperature; P is the pressure at the reference altitude; P ₀ is the pressure at the reference altitude; kqd is the aerodynamic resistance correction coefficient; kmc is the frictional resistance coefficient.

According to at least one embodiment of the present application, in the above-mentioned method for determining the resistance torque when the aero-engine is started, the reference resistance torque M _c.0 =a·n ² when the aero-engine is started is obtained by fitting, where a is the aero-engine The base resistance torque at start is based on the speed factor.

According to at least one embodiment of the present application, in the above-mentioned method for determining the resistance torque when an aero-engine is started, the reference ambient temperature T ₀ is 288.15K.

According to at least one embodiment of the present application, in the above method for determining the drag torque when an aero-engine is started, the pressure P ₀ at the reference altitude is 101.325 KPa.

According to at least one embodiment of the present application, in the above-mentioned method for determining the resistance torque when the aero-engine is started, the aerodynamic resistance correction coefficient kqd is 0.5;

The frictional resistance coefficient kmc is taken as 1.

Description of drawings

FIG. 1 is a schematic diagram of a method for determining a resistance torque when an aero-engine is started according to an embodiment of the present application.

In order to better illustrate the present embodiment, some parts of the drawings are omitted, enlarged or reduced, which do not represent the size of the actual product. In addition, the drawings are only used for exemplary illustration and should not be construed as a limitation on this patent.

Detailed ways

In order to make the technical solution of the present application and its advantages more clear, the technical solution of the present application will be further described in detail and completely with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only part of the present application. The examples are only used to explain the present application, but 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 drawings, and other related parts may refer to the general design. If there is no conflict, the embodiments in the present application and the techniques in the embodiments Features can be combined with each other to obtain new embodiments.

Also, unless otherwise defined, technical or scientific terms used in the description of this application shall have the ordinary meaning as understood by those of ordinary skill in the art to which this application belongs. The words "upper", "lower", "left", "right", "center", "vertical", "horizontal", "inner", "outer", etc. used in the description of this application to indicate orientation are only used To indicate the relative direction or positional relationship, rather than implying that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and when the absolute position of the described object changes, its relative positional relationship may also change accordingly. , so it cannot be construed as a limitation on this application. The terms "first", "second", "third" and similar terms used in the description of this application are only used for the purpose of description, to distinguish different components, and cannot be construed as indicating or implying relative importance. Words like "a," "an," or "the" and the like used in the description of this application should not be construed as an absolute limitation on the quantity, but should be construed as the presence of at least one. As used in the description of this application, "comprises" or "comprises" and similar words mean that the elements or things appearing before the word encompass the elements or things listed after the word and their equivalents, but do not exclude other elements or things.

In addition, it should be noted that, unless otherwise expressly specified and limited, the words "installed", "connected", "connected" and the like used in the description of this application should be understood in a broad sense, for example, the connection may be a fixed The connection can also be a detachable connection, or an integral 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, or it can be an internal connection between two components. A skilled person can understand its specific meaning in this application according to specific circumstances.

The present application will be further described in detail below with reference to FIG. 1 .

The acceleration process of aero-engine starting speed relies on the output torque of the starter and the torque generated by the aero-engine itself to overcome the resistance torque of the aero-engine to perform work, as follows:

M _a =M _T +M _CT -M _c ;

in,

M _a is the starting acceleration torque of the aero-engine;

M _T is the torque generated by the aero-engine itself;

M _CT is the starter output torque;

M _c is the aero-engine resistance torque;

According to the above, there are:

M _CT =M _a +M _c -M _T ;

When the aero-engine is in cold operation, the fuel supply of the aero-engine is cut off, and the aero-engine itself does not generate torque, and the aero-engine is driven by the output torque of the starter, which overcomes the resistance torque of the aero-engine to complete the acceleration process and maintains the balance speed. At this time, there are:

in:

η _H is the mechanical efficiency of the aero-engine;

And thus get:

in:

J is the moment of inertia of the aero-engine;

n is the rotational speed at which the aero-engine is running in balance;

t is the time when the aero-engine is running at equilibrium;

The aero-engine drag torque M _c =a·n ² can be obtained by fitting, where a is the coefficient of the reference drag torque based on the rotational speed when the aero-engine is started.

In addition, some experiments have shown that the change of the aero-engine frictional resistance torque caused by the change of the ambient temperature, the influence of the viscosity of the lubricating oil, and the change of the altitude, the influence of the atmospheric pressure, the change of the aero-engine aerodynamic resistance torque can be obtained by The relative ratio of temperature and pressure, and the corresponding coefficient are corrected.

According to the above, an embodiment of the present application provides a method for determining a resistance torque when an aero-engine is started, including:

Cut off the fuel supply of the aircraft engine;

At the reference altitude and the reference ambient temperature, start the starter, drive the aero-engine to run with the starter, record the rotation speed and time of the aero-engine, and obtain the reference resistance torque M _c.0 =f when the aero-engine is started by fitting (n), where n is the rotational speed of the aero-engine;

其中，T为环境温度；T₀为基准环境温度；P为基准海拔高度下的压力；P₀为基准海拔高度下的压力；kqd为气动阻力修正系数；kmc为摩擦阻力系数。The reference resistance torque M _c.0 when the aero-engine is started is corrected at different altitudes and its ambient temperature to obtain the resistance torque when the aero-engine is started

Among them, T is the ambient temperature; T ₀ is the reference ambient temperature; P is the pressure at the reference altitude; P ₀ is the pressure at the reference altitude; kqd is the aerodynamic resistance correction coefficient; kmc is the frictional resistance coefficient.

As for the method for determining the resistance torque when the aero-engine is started disclosed in the above-mentioned embodiments, those skilled in the art can understand that the design is based on the cold-state operation of the aero-engine driven by the starter at the reference altitude and its reference ambient temperature. The reference resistance torque M _c.0 when the aero-engine is started is obtained, and then corrected at different altitudes and its ambient temperature to obtain the resistance torque M _c when the aero-engine is started. Considering the environmental temperature change, the influence on the viscosity of the lubricating oil , resulting in the change of the aero-engine frictional resistance torque, and the change in the aero-engine aerodynamic resistance torque caused by the change in the aero-engine without considering the altitude change, the influence on the atmospheric pressure, has high accuracy, and can cover different altitudes and their ambient temperature.

In some optional embodiments, in the above method for determining the resistance torque when the aero-engine is started, the fitting obtains the reference resistance torque M _c.0 =a·n ² when the aero-engine is started, where a is the aero-engine The base resistance torque at start is based on the speed factor.

In some optional embodiments, in the above method for determining the drag torque when the aero-engine is started, the reference ambient temperature T ₀ is 288.15K.

In some optional embodiments, in the above method for determining the drag torque when an aero-engine is started, the pressure P ₀ at the reference altitude is 101.325 KPa.

In some optional embodiments, in the above-mentioned method for determining the resistance torque when an aero-engine is started, the aerodynamic resistance correction coefficient kqd may be initially set to 0.5, and the frictional resistance coefficient kmc may be initially set to 1. The specific values can be driven by the starter to perform cold operation. Make corrections.

The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other.

So far, the technical solutions of the present application have been described with reference to the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments, without departing from the principles of the present application. Under the premise that those skilled in the art can make equivalent changes or replacements to the relevant technical features, the technical solutions after these changes or replacements will fall within the protection scope of the present application.

Claims (5)

1. a method for determining resistance torque when an aero-engine is started, is characterized in that, comprises: Cut off the fuel supply of the aircraft engine; At the reference altitude and the reference ambient temperature, start the starter, drive the aero-engine to run with the starter, record the rotation speed and time of the aero-engine, and obtain the reference resistance torque M _c.0 =f when the aero-engine is started by fitting (n), where n is the rotational speed of the aero-engine; The reference resistance torque M _c.0 when the aero-engine is started is corrected at different altitudes and its ambient temperature to obtain the resistance torque when the aero-engine is started

Among them, T is the ambient temperature; T ₀ is the reference ambient temperature; P is the pressure at the reference altitude; P ₀ is the pressure at the reference altitude; kqd is the aerodynamic resistance correction coefficient; kmc is the frictional resistance coefficient. 2. The method for determining resistance torque when an aero-engine is started according to claim 1, characterized in that, The fitting obtains the reference resistance torque M _c.0 =a·n ² when the aero-engine is started, where a is a coefficient of the reference resistance torque at the start of the aero-engine based on the rotational speed. 3. The method for determining resistance torque when an aero-engine is started according to claim 1, characterized in that, The reference ambient temperature T ₀ is taken as 288.15K. 4. The method for determining resistance torque when an aero-engine is started according to claim 1, characterized in that, The pressure P ₀ at the reference altitude is 101.325KPa. 5. The method for determining resistance torque when an aero-engine is started according to claim 1, characterized in that, The aerodynamic resistance correction coefficient kqd is taken as 0.5; The frictional resistance coefficient kmc is taken as 1.

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