阅读说明：本技术 一种高超声速进气道激波封口的自适应控制方法 (Self-adaptive control method for shock wave seal of hypersonic air inlet ) 是由 李楠 于 2020-12-12 设计创作，主要内容包括：本发明提供了一种高超声速进气道激波封口的自适应控制方法,结合高超声速飞行器由低马赫加速至高马赫过程中进气道阻力逐渐降低的特点,利用弹性伸缩机构实现进气道压缩面随飞行马赫数自适应移动,以实现宽速裕飞行工况下进气道激波系封口的效果。本发明结构简单、便于安装；同时与主动控制方法相比,不需要外界能量的输入,结构简单便于搭建维护,选择合适弹性系数,可以实现宽速裕飞行工况下激波封口效果。(The invention provides a self-adaptive control method for the shock wave sealing of a hypersonic air inlet, which combines the characteristic that the resistance of the air inlet is gradually reduced in the process that a hypersonic aircraft is accelerated from low Mach to high Mach, and utilizes an elastic telescopic mechanism to realize the self-adaptive movement of a compression surface of the air inlet along with the flying Mach number so as to realize the effect of the shock wave system sealing of the air inlet under the working condition of wide-speed and abundant flight. The invention has simple structure and convenient installation; compared with an active control method, the shock wave sealing device has the advantages that external energy is not needed to be input, the structure is simple, the building and the maintenance are convenient, the proper elastic coefficient is selected, and the shock wave sealing effect under the wide-speed and rich-flight working condition can be realized.)

1. A self-adaptive control method for the shock wave seal of a hypersonic air inlet passage is characterized by comprising the following steps:

the method comprises the following steps: according to the working Mach number and the flight altitude of the hypersonic aircraft, inquiring a standard atmospheric parameter table to obtain the static pressure and the static temperature of the working airflow of the air inlet channel, and performing a ground wind tunnel test on the hypersonic air inlet channel/the isolation section by taking the Mach number, the static pressure and the static temperature of the airflow under n non-design working conditions as incoming flow conditions;

step two: in a wind tunnel test, the incoming flow condition of the first step is given, and after the incoming flow static pressure is constant, the horizontal distance x between the wave system of the air inlet channel and the lip cover of the air inlet channel is obtained through the schlieren measurement technology_iWherein i is 1, 2, 3, … n;

step three: obtaining the resistance F of the compression surface of the air inlet along the air flow direction by a force measuring balance_i；

Step four: calculating the required elastic coefficient k under each working condition_i＝F_i/x_i；

Step five: using the elastic coefficient required under each working condition in the fourth step by a formula (k)₁+k₂+…+k_n) Calculating a mean value, wherein the mean value is used as an elastic coefficient of the elastic device;

step six: selecting an elastic device with the same elastic coefficient as the elastic coefficient obtained in the step five, carrying out ground test verification of the adaptive control of the shock wave seal of the hypersonic air inlet passage, and finishing the design of the adaptive control system of the shock wave seal of the hypersonic air inlet passage if a compression wave system of the air inlet passage hits an upper lip cover, namely the shock wave seal is realized; if the compression wave system of the air inlet channel does not hit the upper lip cover, namely the shock wave sealing is not realized, the elastic coefficient is determined again in the second step until the shock wave sealing is realized.

Technical Field

The invention relates to the technical field of hypersonic inlet channels, in particular to a self-adaptive control method of shock wave sealing.

Background

The air-breathing hypersonic aircraft needs to capture air by itself for organizing the combustion of fuel. The hypersonic air inlet channel is an important part of an air suction type hypersonic propulsion system, and the performance of the hypersonic air inlet channel directly influences the working performance of the propulsion system. The flow coefficient of the air inlet channel has the most direct influence on the thrust of the hypersonic propulsion system, and the reduction of the flow coefficient corresponds to the reduction of the same proportion of the thrust of the propulsion system, so that the key for realizing the maximum performance of the engine is to maintain the maximum air flow capture of the air inlet channel in the flight envelope of the aircraft.

The hypersonic air inlet channel is usually designed at a working point in a cruising state, and in the cruising state, the external compression shock wave of the air inlet channel hits an upper lip cover to realize shock wave sealing, so that the maximum air flow capture is realized. However, in the face of the aircraft's demand for wide-speed-margin flight, at lower flight mach numbers, the shock waves generated by the inlet channel are located outside the lip shroud, causing some flooding. The inlet flow coefficient drops significantly and is accompanied by an overflow resistance. It is therefore important to increase the flow coefficient of the intake duct by control means.

At present, the wave system of the air inlet is controlled to improve the flow coefficient by arranging a special mechanism to adjust the geometric shape of the air inlet or changing the flow state of the air flow by a flow control method to further realize the control of the wave system. However, these methods also pay a high price: the weight is increased seriously, the structure of an actuating mechanism and a control system are complicated, the reliability is reduced, and the like.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a self-adaptive control method for the shock wave sealing of a hypersonic air inlet, which combines the characteristic that the resistance of the air inlet is gradually reduced in the process that a hypersonic aircraft is accelerated from low Mach to high Mach, and utilizes an elastic telescopic mechanism to realize the self-adaptive movement of the compression surface of the air inlet along with the flying Mach number so as to realize the effect of the shock wave sealing of the air inlet under the wide-speed and abundant flying working condition.

The technical scheme adopted for solving the technical problems comprises the following specific steps:

the method comprises the following steps: according to the working Mach number and the flight altitude of the hypersonic aircraft, inquiring a standard atmospheric parameter table to obtain the static pressure and the static temperature of the working airflow of the air inlet channel, and performing a ground wind tunnel test on the hypersonic air inlet channel/the isolation section by taking the Mach number, the static pressure and the static temperature of the airflow under n non-design working conditions as incoming flow conditions;

step two: in a wind tunnel test, the incoming flow condition of the first step is given, and after the incoming flow static pressure is constant, the horizontal distance x between the wave system of the air inlet channel and the lip cover of the air inlet channel is obtained through the schlieren measurement technology_iWherein i is 1, 2, 3, … n;

step three: obtaining the resistance F of the compression surface of the air inlet along the air flow direction by a force measuring balance_i；

Step four: computingRequired elastic coefficient k under various working conditions_i＝F_i/x_i；

Step five: using the elastic coefficient required under each working condition in the fourth step by a formula (k)₁+k₂+…+k_n) Calculating a mean value, wherein the mean value is used as an elastic coefficient of the elastic device;

step six: selecting an elastic device with the same elastic coefficient as the elastic coefficient obtained in the step five, carrying out ground test verification of the adaptive control of the shock wave seal of the hypersonic air inlet passage, and finishing the design of the adaptive control system of the shock wave seal of the hypersonic air inlet passage if a compression wave system of the air inlet passage hits an upper lip cover, namely the shock wave seal is realized; if the compression wave system of the air inlet channel does not hit the upper lip cover, namely the shock wave sealing is not realized, the elastic coefficient is determined again in the second step until the shock wave sealing is realized.

The invention has the advantages of providing a set of complete design method, obtaining data, designing the elastic coefficient and finally verifying. The method utilizes the characteristic that the resistance of the hypersonic aircraft is reduced in the process of accelerating from low Mach to high Mach, utilizes different resistances and combines an elastic device to move the compression surface to a specific position so as to realize shock wave sealing, and has simple structure and convenient installation; compared with an active control method, the shock wave sealing device has the advantages that external energy is not needed to be input, the structure is simple, the building and the maintenance are convenient, the proper elastic coefficient is selected, and the shock wave sealing effect under the wide-speed and rich-flight working condition can be realized.

Drawings

FIG. 1 is a design flow chart of an adaptive control method for a shock seal of a hypersonic air inlet.

FIG. 2 is a schematic view of the installation of the air inlet and the elastic device of the present invention.

Fig. 3 is an inlet flow field without adaptive control.

Fig. 4 shows the inlet flow field when adaptive control is performed.

Wherein, 2.1 is an air inlet compression surface, and 2.2 is an air inlet lip cover; 2.3 is the engine body; 2.4 is an elastic device.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The examples are as follows:

the design flow chart of the self-adaptive control method of the shock wave seal of the hypersonic air inlet channel is shown in figure 1. The elastic coefficient required by the elastic device in the figure 2 is obtained through a wind tunnel test, when the flight Mach number and the flight height of the aircraft are low, the angles of the resistance and the compression wave system are large, the compression surface 2.1 of the air inlet channel moves to the right side in the figure, and then the compression wave system is made to hit the lip cover 2.2 of the air inlet channel; when the flight mach number and the height are higher, the resistance and the compression wave system angle are reduced, the compression surface 2.1 of the air inlet channel moves to the left side in the figure under the action of the elastic device 2.4, and the compression wave system is made to hit the lip cover 2.2 of the air inlet channel. Fig. 3 shows a flow field of the intake duct when adaptive control is not performed, and in fig. 4, adaptive control is used to achieve an effect of sealing a wave system of the intake duct, thereby improving a flow coefficient of the intake duct.

The method of the embodiment comprises the following steps:

the method comprises the following steps: according to the working Mach number and the flight altitude of the hypersonic aircraft, inquiring a standard atmospheric parameter table to obtain the static pressure and the static temperature of the working airflow of the air inlet channel, and performing a ground wind tunnel test on the hypersonic air inlet channel/the isolation section by taking the Mach number, the static pressure and the static temperature of the airflow under n non-design working conditions as incoming flow conditions;

step two: in a wind tunnel test, the incoming flow condition of the first step is given, and after the incoming flow static pressure is constant, the horizontal distance x between the wave system of the air inlet channel and the lip cover of the air inlet channel is obtained through the schlieren measurement technology_iWherein i is 1, 2, 3, … n;

step three: obtaining the resistance F of the compression surface of the air inlet along the air flow direction by a force measuring balance_i；

Step four: calculating the required elastic coefficient k under each working condition_i＝F_i/x_i；

Step five: using the elastic coefficient required under each working condition in the fourth step by a formula (k)₁+k₂+…+k_n) Calculating a mean value, wherein the mean value is used as an elastic coefficient of the elastic device;

step six: selecting an elastic device with the same elastic coefficient as the elastic coefficient obtained in the step five, carrying out ground test verification of the adaptive control of the shock wave seal of the hypersonic air inlet passage, and finishing the design of the adaptive control system of the shock wave seal of the hypersonic air inlet passage if a compression wave system of the air inlet passage hits an upper lip cover, namely the shock wave seal is realized; if the compression wave system of the air inlet channel does not hit the upper lip cover, namely the shock wave sealing is not realized, the elastic coefficient is determined again in the second step until the shock wave sealing is realized.