CN113008507A - High-flow high-stability Mach number wind tunnel rapid adjusting system and method based on temporary flushing gas source - Google Patents

Abstract

The invention provides a high-flow high-stability Mach number wind tunnel rapid adjusting system and method based on a temporary flushing gas source. The structure of the device comprises a temporary flushing air source, a main valve, an auxiliary valve, a spray pipe, a pressure sensor, a Mach number sensor and a control unit, wherein the auxiliary valve has faster small flow regulation capacity and is connected with the main valve in parallel. The method comprises the following steps: (1) on the basis of 50% opening of the auxiliary valve, manually adjusting a main valve at a characteristic Mach number point within the wind tunnel capacity range to obtain a curve cluster of the relation between the main valve opening and the air source pressure under the corresponding Mach number; (2) obtaining the opening of a main valve through two-dimensional linear interpolation according to the instruction Mach number and the current air source pressure; (3) and closed-loop PID adjustment of the instruction Mach number is carried out by utilizing the auxiliary valve, and the outlet Mach number is maintained. The invention adopts a composite control strategy of main valve feedforward and auxiliary valve closed loop PID, and solves the problem that the outlet Mach number is not easy to be stable caused by continuous reduction of air source pressure, poor main valve repeatability, strong nonlinearity and slow regulation speed in a wind tunnel test.

Description

High-flow high-stability Mach number wind tunnel rapid adjusting system and method based on temporary flushing gas source

Technical Field

The invention relates to a high-flow high-stability Mach number wind tunnel rapid adjusting system and method based on a temporary flushing gas source, and belongs to the field of aerospace industrial wind tunnel test measurement and control.

Background

The wind tunnel is one of the most commonly used aerodynamic experimental equipments in the aerospace industry, and is a pipe-shaped experimental equipment which is used for generating and controlling airflow in an artificial mode, simulating the flowing condition of the air around an aircraft or a solid body, measuring the effect of the airflow on the solid body and observing physical phenomena. The wind tunnel test is an important means for acquiring aerodynamic data of the aircraft, measuring the appearance design layout of the aircraft and evaluating the flight performance. For a jet-type wind tunnel commonly used in the aerospace industry, wind tunnel test data are obviously influenced by the accuracy of the outlet Mach number, so that the outlet Mach number is one of the pneumatic parameters which need to be controlled accurately most.

The wind tunnel based on the temporary flushing air source is called a temporary flushing wind tunnel, and a high-pressure air storage tank is mostly used as a temporary flushing air source system. Compared with a continuous wind tunnel, the temporary air-charging source can provide larger flow and larger Mach number, the air source pressure in the air storage tank is rapidly reduced due to the rapid consumption of the air source during the operation, and the operation time of the temporary air-charging wind tunnel is usually several seconds to dozens of seconds according to the difference of the initial air source pressure of the temporary air-charging source and the volume of the air storage tank. The rapid reduction of the air source pressure enables the Mach number of the wind tunnel outlet to be reduced, in order to provide stable and accurate Mach number of the outlet in the test process, an adjusting valve is usually arranged between a temporary air source and the outlet of a wind tunnel spray pipe in the current engineering, and the air flow entering the wind tunnel is controlled through the opening of a PID closed-loop adjusting valve, so that the purpose of controlling the Mach number of the outlet is achieved.

The patent with publication number CN110161841A discloses a feedforward-fuzzy PID control method suitable for a transient transonic wind tunnel, which sets PID parameters in real time through fuzzy reasoning, and when an attack angle changes, a feedforward control part sets a feedforward control quantity according to the attack angle feedback, so as to suppress disturbance caused by the change of the attack angle and improve the transient quality of a controller. The patent with publication number CN110702361A discloses a flow field accurate control system and a control method for a direct current temporary impulse type transonic wind tunnel, which solves the control accuracy problem of mach 1.0-1.2 by adopting a control mode of PID control and static feedforward control on grid fingers at two throats of the wind tunnel and optimal control on the flow field. The patent with publication number CN101887267B discloses a wind tunnel mach number controller, which adopts a fuzzy control method with self-adjusting factors at the wind tunnel starting stage, and uses PID control after the mach number is basically stable.

The situations of too fast pressure drop and pressure fluctuation of the air source are not considered in the methods, and whether the Mach number can be quickly adjusted stably for a long time is not considered. The method for adjusting the Mach number of the outlet of the large-flow wind tunnel based on the temporary flushing gas source has the following defects: (1) due to the rapid consumption of the air source in the air storage tank, the phenomenon of air source pressure pulsation can be generated, so that the fluctuation of the outlet Mach number is caused, and the stable and high-precision outlet Mach number cannot be provided; (2) the Mach number fluctuation of an outlet is caused by the overshoot brought by the strong adjusting capacity of the adjusting valve; (3) the dead zone, nonlinearity, hysteresis, poor repeatability, slow regulation speed and other characteristics of the regulating valve can reduce the real-time performance and reliability of the control system. In addition, the method increases the complexity of the control algorithm, and the situation that the characteristics of the regulating valve are not ideal in practical engineering application is not considered, so that the method has certain limitation.

Disclosure of Invention

The invention provides a high-flow high-stability Mach number wind tunnel rapid regulation system and a method based on a temporary flushing gas source, and aims to design a low-cost and easily-realized temporary flushing wind tunnel system, realize rapid regulation of outlet Mach number through low-complexity control logic, stably keep for a long time, and overcome the problems of slow and unstable outlet Mach number regulation caused by continuous pressure reduction of the temporary flushing gas source and poor repeatability, strong nonlinearity and slow regulation speed of a main valve in the temporary flushing wind tunnel system.

The technical solution of the invention is as follows:

a high-flow high-stability Mach number wind tunnel rapid regulation system and a method based on a temporary flushing gas source structurally comprise the temporary flushing gas source, a main valve, an auxiliary valve, a spray pipe, a pressure sensor, a Mach number sensor and a control unit, and are shown in figure 1. The temporary flushing gas source comprises an air compressor set and a high-pressure spherical tank, and the gas source outputs large-flow airflow which is adjusted by a main valve and an auxiliary valve and then is ejected through a spray pipe; the main valve is a large-flow regulating valve, the auxiliary valve is a small-flow regulating valve, and the auxiliary valve has higher regulating speed and higher regulating precision; the spray pipe is a contraction spray pipe with a certain outlet area.

Further, the air compressor unit inputs compressed high-pressure gas into a high-pressure spherical tank for storage, so as to form a temporary flushing gas source capable of outputting large flow;

furthermore, the main valve is a wind tunnel large-flow regulating valve, the large-flow regulating capacity is strong, and the characteristics of dead zones, hysteresis, poor repeatability and the like which are not beneficial to precise regulation exist in the low regulating speed;

furthermore, the auxiliary valve is a mechanism additionally arranged in the invention, is a small-flow high-precision quick adjusting valve, has strong small-flow adjusting capacity, is connected with the main valve in parallel, and improves the rapidity and stability of the Mach number adjustment of the wind tunnel outlet;

further, the pressure sensor is positioned at the outlet of the spherical tank and used for measuring the pressure of the temporary charging air source;

furthermore, the Mach number sensor is positioned at the outlet of the spray pipe, and the Mach number of the outlet is calculated according to the total static pressure difference of the outlet of the spray pipe;

further, the control unit calculates a control command to control the opening of the main valve and the auxiliary valve according to the Mach number command, the actual Mach number measured by the Mach number sensor and the current temporary charging source pressure measured by the pressure sensor;

a high-flow high-stability Mach number wind tunnel rapid regulation system and method based on temporary flushing gas source, the regulation method thereof integrates the characteristics of main and auxiliary valves, and forms a composite control strategy adopting main valve feedforward and auxiliary valve closed loop PID, as shown in figure 2, the method comprises the following concrete steps:

(1) through experiments, the regulation rules of the main valve under different Mach numbers and air source pressures are mastered, and an air source pressure curve cluster of the opening of the main valve under different Mach numbers is obtained;

(2) according to instruction Mach number M_rAnd the current source pressure P_asObtaining the current main valve opening through two-dimensional linear interpolation, and using the current main valve opening as open-loop feedforward regulation of a large-flow wind tunnel stable Mach number regulation strategy based on a temporary flushing gas source;

(3) and performing equal Mach number closed-loop regulation by using the auxiliary valve, and regulating the opening of the auxiliary valve by adopting a PID algorithm commonly used in engineering to accurately correct the Mach number of the wind tunnel outlet.

Further, the step (1) of manually debugging to master the regulation rules of the main valve under different Mach numbers and air source pressures to obtain the main valve opening-air source pressure curve cluster under different Mach numbers specifically comprises the following steps:

step 1-1, opening the auxiliary valve to 50% of opening degree, so that bidirectional adjustment can be conveniently carried out during closed-loop control;

step 1-2, adjusting the main valve to make the Mach number M of the outlet close to the Mach number M of the set value_r. Record the air supply pressure P at this time_asAnd main valve opening A_m；

And 1-3, due to the characteristic of temporary flushing of the gas source, the pressure of the gas source can be continuously reduced along with the rapid consumption of the gas in the high-pressure tank, so that the Mach number of the outlet can be continuously reduced after being stabilized for a short time. When the Mach number M of the outlet cannot be stabilized in a short time, repeating the step 1-2;

step 1-4, repeating step 1-3 until the set Mach number M can not be maintained_rUntil it is transiently stable. So far, a set of corresponding relations of the main valve opening and the air source pressure are obtained, wherein the set Mach number is maintained within the deviation allowable range;

step 1-5, modifying the set Mach number M_rRepeating the steps 1-4 until all the key Mach number points are covered;

and step 1-6, obtaining a main valve opening-air source pressure relation curve cluster based on the steps 1-2 to 1-5.

Further, the open-loop feedforward regulation in step (2) means that the main valve is opened to a reference opening and kept before the closed-loop PID regulation is performed on the auxiliary valve. Specifically, the current set mach number and the temporary charging source pressure are obtained, and then the main valve opening required under the current set mach number and the gas source pressure is obtained through two-dimensional linear interpolation according to the main valve opening and gas source pressure curve cluster obtained in the step (2).

And (3) after the main valve is opened to a certain reference opening according to the main valve opening-air source pressure curve cluster, performing closed-loop PID (proportion integration differentiation) adjustment through the fast-reading high-precision auxiliary valve, performing small-range accurate correction on the actual Mach number, and keeping the stability for a certain time.

Further, the step (3) isThe PID control algorithm is based on the deviation between the command value and the actual value, and the deviation is based on the deviation, and the deviation is based on_PE(k)+K_I∑E(k)+K_DE_C(k) Control and adjust parameter K according to actual working condition_P、K_IAnd K_D. Wherein E (k) is a deviation between the control quantity command value and the actual feedback value, E_C(k) Is the variation rate of the deviation, which is the variation rate of the deviation of the controlled variable per unit time, K_PIs a proportional gain factor, K_IIs an integral gain coefficient, K_DIs a differential gain factor.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a high-flow high-stability Mach number wind tunnel rapid regulation system and a method based on a temporary flushing gas source.

According to the invention, the large-range flow and Mach number are regulated through the open-loop feedforward regulation of the main valve, the small-range flow and Mach number are accurately corrected through the closed-loop PID regulation of the auxiliary valve, the accuracy of the wind tunnel outlet Mach number is higher and the regulation speed is higher due to the combination of coarse regulation and fine regulation, and the instability of the outlet Mach number caused by the rapid reduction of the air source pressure due to the excessively slow regulation speed is avoided.

The invention adjusts the main valve in an open-loop feedforward adjustment mode, each adjustment of the main valve is one-way one-time adjustment, and bidirectional multiple adjustment and correction are not needed, thereby effectively avoiding the problems possibly caused by dead zone, hysteresis, nonlinearity and poor repeatability of the main valve in the existing system and improving the reliability and repeatability of the system.

The invention only needs to be simply transformed on the basis of the common system in the prior art, namely an auxiliary valve is additionally arranged.

Drawings

FIG. 1 is a gas path structure and control signal diagram of a large-flow high-stability Mach number wind tunnel rapid regulation system based on a temporary flushing gas source;

FIG. 2 is a control logic diagram of a high-flow high-stability Mach number wind tunnel rapid adjustment method based on a temporary flushing gas source;

FIG. 3 is a flow chart of the operation of a high flow and high stable Mach number wind tunnel rapid regulation system and method based on a temporary flushing gas source;

FIG. 4 is a main valve opening-air source pressure curve cluster under different Mach numbers;

FIG. 5 is a graph of Mach 0.8 experiment;

Detailed Description

The technical solution of the present invention is further explained with reference to the drawings and the specific embodiments.

A flow chart of a high-flow high-stability mach number wind tunnel rapid regulation system and method based on a temporary flushing gas source is shown in fig. 3. The original temporary-impulse type wind tunnel system is provided with a main valve which is a large-flow butterfly valve and has strong large-flow adjusting capacity, the adjusting precision of the main valve is 0.1%, the Mach number changes by 0.02-0.05 due to the fact that the opening degree is adjusted by 0.1%, 30s is needed when the main valve is fully closed to be fully opened, dead zones exist between 0-10% of the opening degree, the problems of hysteresis and poor up-down repetition degree exist, and the precise adjustment of the Mach number at the outlet of the wind tunnel cannot be well realized. Meanwhile, the adjustment speed is low, so that the Mach number of the wind tunnel outlet cannot be stabilized for the required time due to the fact that the air source pressure is rapidly reduced. Therefore, a small-flow high-precision quick auxiliary valve is additionally arranged on the basis, the valve adjusting precision is 0.01%, the opening degree is adjusted by 0.01% so that the Mach number is changed by 0.01-0.02, 10s is needed from full opening to full closing, no dead zone or hysteresis exists, the repeatability is good, and the flow can be accurately adjusted in a small range.

The air-cooled screw type air compressor unit is adopted to pump air to the high-pressure spherical tank, so that the pressure of an air source in the spherical tank reaches 750kPa, and the volume of the spherical tank is 500m³The area of the outlet of the spray pipe is 450mm multiplied by 400mm, and the quick adjustment method for stabilizing the Mach number is as follows:

(1) based on the system, the main valve is manually debugged, the regulation rule of the main valve under the Mach number of 0.4-0.8 is mastered, and the opening-air source pressure curve cluster of the main valve under different Mach numbers is obtained, and the method specifically comprises the following steps:

step 1-1, opening the auxiliary valve to 50% of opening degree, and performing regular exploration on the main valve on the basis, so that the auxiliary valve can be adjusted in two directions when closed-loop control is added;

step 1-2, manually adjusting the main valve to make the outlet Mach number close to 0.4. Specifically, the auxiliary valve is kept unchanged at 50% opening, and the main valve is manually adjusted so that the outlet Mach number is equal to or greater than 0.35 and equal to or less than 0.45. Record the air supply pressure at this time

And main valve opening

And 1-3, due to the characteristic of temporary flushing of the gas source, the pressure of the gas source can be continuously reduced along with the rapid consumption of the gas in the high-pressure tank, so that the Mach number of the outlet can be continuously reduced after being stabilized for a short time. When the Mach number of the outlet is reduced to be less than 0.35, repeating the step 1-2 to ensure that the Mach number of the outlet meets the condition that M is more than or equal to 0.35 and less than or equal to 0.45 again, and recording the air source pressure at the moment

And main valve opening

And 1-4, repeating the steps 1-3 until the transient stability of the outlet Mach number of which M is more than or equal to 0.35 and less than or equal to 0.45 cannot be maintained. So far, a set of corresponding relations of the main valve opening and the air source pressure for maintaining the set Mach number within the deviation +/-0.05 is obtained

Step 1-5, changing the set Mach number to 0.5, repeating the step 1-4, and obtaining the corresponding relation between the main valve opening and the air source pressure when the outlet Mach number is 0.5

Repeating the steps in this manner1-5, until covering 0.4-0.8 Mach number.

And 1-6, obtaining a main valve opening-air source pressure relation curve cluster based on the steps 1-2 to 1-5, as shown in FIG. 4.

(2) On the curve cluster obtained in the step (1), according to the instruction Mach number M_rAnd the current source pressure P_asObtaining the current main valve opening A by two-dimensional linear interpolation_mAs an open-loop feedforward regulation of a high-flow wind tunnel stable Mach number regulation strategy based on a temporary flushing gas source, when a system is started, a main valve is directly opened to the current opening A according to an interpolation result_mThe problems of hysteresis, poor repeatability and the like caused by the reciprocating adjustment of the main valve are avoided;

(3) keeping the main valve still, the auxiliary valve according to U (K) ═ K_PE(k)+K_I∑E(k)+K_DE_C(k) Performing equal Mach number closed-loop PID regulation, and selecting proper PID parameter K_P、K_IAnd K_DAnd accurately correcting the Mach number of the wind tunnel outlet.

Taking Mach number of 0.8 as an example, the initial air source pressure is 750kPa, and the volume of the spherical tank is 500m³The area of the outlet of the spray pipe is 450mm multiplied by 400mm, the adjustment result shown in figure 5 is obtained through main valve open-loop feedforward adjustment and auxiliary valve closed-loop PID correction, and the invention can realize the stable Mach number rapid adjustment within a long-time temporary air source capacity range within 40s, the Mach number error is within +/-0.001, and the Mach number error can be maintained about 60 s.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (5)

Translated fromChinese

1.一种基于暂冲气源的大流量高稳定马赫数风洞快速调节系统及方法，其特征是结构包括暂冲气源、主阀、辅阀、喷管、压力传感器、马赫数传感器及控制单元；所述暂冲气源包括空气压缩机组和高压球罐，气源输出大流量气流，经过主阀和辅阀调节后，通过喷管射出；所述主阀为大流量调节阀，辅阀为小流量调节阀，辅阀具有更快的调节速度和更高的调节精度；所述喷管为出口面积一定的收缩喷管；所述控制单元根据马赫数指令、马赫数传感器测得的实际马赫数及压力传感器测得的当前暂冲气源压力，计算出控制指令对主阀、辅阀进行开度控制。1. a high-flow high-stability Mach number wind tunnel fast adjustment system and method based on a transient gas source, is characterized in that the structure comprises a transient gas source, a main valve, an auxiliary valve, a nozzle, a pressure sensor, a Mach number sensor and control unit; the temporary air source includes an air compressor unit and a high-pressure spherical tank, and the air source outputs a large flow of air, which is adjusted by the main valve and the auxiliary valve, and then ejected through the nozzle; the main valve is a large flow control valve, and the auxiliary The valve is a small flow control valve, and the auxiliary valve has faster adjustment speed and higher adjustment accuracy; the nozzle is a shrinking nozzle with a certain outlet area; the control unit is based on the Mach number command and the Mach number sensor. The actual Mach number and the current pressure of the slug gas source measured by the pressure sensor are used to calculate the control command to control the opening of the main valve and the auxiliary valve.2.根据权利要求1所述的一种基于暂冲气源的大流量高稳定马赫数风洞快速调节系统及方法，其特征在于所述主阀为大流量调节阀，大流量调节能力强，调节速度慢，通常存在死区、滞环、重复度差等不利于精确调节的特性；辅阀为本发明增设的机构，采用小流量高精度快速调节阀，小流量调节能力强，调节速度快，与主阀并联连接，提高风洞出口马赫数快速调节能力。2. The system and method for fast adjustment of a large-flow high-stability Mach number wind tunnel based on a transient gas source according to claim 1, wherein the main valve is a large-flow control valve, and the large-flow adjustment capability is strong, The adjustment speed is slow, and there are usually dead zones, hysteresis, poor repetition and other characteristics that are not conducive to accurate adjustment; the auxiliary valve is an additional mechanism of the present invention, and adopts a small flow high-precision rapid adjustment valve, which has strong small flow adjustment ability and fast adjustment speed. , which is connected in parallel with the main valve to improve the rapid adjustment capability of the Mach number at the outlet of the wind tunnel.3.根据权利要求1所述的一种基于暂冲气源的大流量高稳定马赫数风洞快速调节系统及方法，其特征在于其调节方法包括以下步骤：3. a kind of fast adjustment system and method for a large flow high stable Mach number wind tunnel based on a transient gas source according to claim 1, is characterized in that its adjustment method comprises the following steps:(1)在辅阀50％开度的基础上，对风洞能力范围内的几个特征马赫数点进行主阀手动调节，获得相应马赫数下主阀开度和暂冲气源压力关系曲线簇；(1) On the basis of the 50% opening of the auxiliary valve, manually adjust the main valve at several characteristic Mach number points within the capacity of the wind tunnel, and obtain the relationship curve between the opening degree of the main valve and the pressure of the temporary gas source under the corresponding Mach number cluster;(2)根据指令马赫数M_r及当前气源压力，通过二维线性插值获得当前主阀开度，作为基于暂冲气源的大流量风洞稳定马赫数调节策略的开环前馈调节；(2) According to the command Mach number_Mr and the current air source pressure, the current main valve opening is obtained through two-dimensional linear interpolation, which is used as an open-loop feedforward adjustment for the stable Mach number adjustment strategy of the large-flow wind tunnel based on the transient air source;(3)利用辅阀进行指令马赫数的闭环PID调节，维持风洞出口马赫数。(3) Use the auxiliary valve to perform the closed-loop PID adjustment of the command Mach number to maintain the Mach number at the outlet of the wind tunnel.4.根据权利要求3所述的一种基于暂冲气源的大流量高稳定马赫数风洞快速调节系统及方法，其特征是所述步骤(1)通过手动调试，掌握不同马赫数和气源压力下主阀的调节规律，获得不同马赫数下主阀开度-气源压力曲线簇，具体包括以下步骤：4. a kind of high-flow high-stability Mach number wind tunnel fast adjustment system and method based on the transient gas source according to claim 3, it is characterized in that described step (1) through manual debugging, master different Mach number and gas The regulation rule of the main valve under the source pressure is obtained, and the main valve opening-air source pressure curve cluster under different Mach numbers is obtained, which includes the following steps:(1)将辅阀开到50％开度，便于闭环控制时可以双向调节；(1) Open the auxiliary valve to 50% opening, which is convenient for two-way adjustment during closed-loop control;(2)调节主阀，使得出口马赫数M接近设定值马赫数M_r。记录此时气源压力P_as和主阀开度A_m；(2) Adjust the main valve so that the outlet Mach number M is close to the set value Mach number M_r . Record the air source pressure P_as and the main valve opening_Am at this time;(3)由于暂冲气源的特性，随着高压罐中气体的快速消耗，气源压力会不断下降，从而出口马赫数稳定较短时间后会不断减小。当出口马赫数M无法短时间内稳定时，重复步骤(2)；(3) Due to the characteristics of the transient gas source, with the rapid consumption of the gas in the high-pressure tank, the gas source pressure will continue to drop, so the outlet Mach number will continue to decrease after a short period of stability. When the exit Mach number M cannot be stabilized in a short time, repeat step (2);(4)重复步骤(3)，直至无法维持设定马赫数M_r的短暂稳定为止。至此获得维持该设定马赫数在偏差允许范围内的主阀开度和气源压力的一组对应关系；(4) Step (3) is repeated until the temporary stability of the set_Mach number Mr cannot be maintained. So far, a set of corresponding relationships between the main valve opening and the air source pressure to maintain the set Mach number within the allowable deviation range are obtained;(5)修改设定马赫数M_r，重复步骤(4)，直至覆盖所有的关键马赫数点；(5) Modify the set Mach number M_r and repeat step (4) until all the key Mach number points are covered;(6)基于上述步骤(2)至步骤(5)，获得主阀开度-气源压力关系曲线簇。(6) Based on the above steps (2) to (5), obtain the main valve opening-air source pressure relationship curve cluster.5.根据权利要求4所述的一种基于暂冲气源的大流量高稳定马赫数风洞快速调节系统及方法，其特征是采取主阀前馈和辅阀闭环PID的复合控制策略，解决了风洞试验中由于暂冲气源压力不断下降及主阀重复度差、非线性强、调节速度慢带来的出口马赫数不容易稳定的问题。5. a kind of high-flow high-stability Mach number wind tunnel fast adjustment system and method based on the transient gas source according to claim 4, it is characterized in that adopting the composite control strategy of main valve feedforward and auxiliary valve closed-loop PID to solve the problem. In the wind tunnel test, the problem that the outlet Mach number is not easy to stabilize due to the continuous drop of the pressure of the temporary gas source, the poor repeatability of the main valve, the strong nonlinearity and the slow adjustment speed is solved.

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