CN112763178B - Hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance - Google Patents

Abstract

The invention discloses a hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance. Before the wind tunnel is started, the regulating valve is actuated to a preset opening degree; after the wind tunnel is started, the preset opening degree of the regulating valve is maintained, after the shortest preset time, real-time detection is started, the deviation and the acceleration of a total pressure measurement value and a target value are calculated, and if the total pressure is detected to be close to the target value or the total pressure acceleration is too low in the wind tunnel running time smaller than the longest preset time, the pipeline filling and pressure building between the regulating valve and the nozzle throat are judged to be basically completed, the preset of the opening degree of the regulating valve can be automatically stopped in advance, and the process of real-time feedback regulation is switched. The method can solve the problem that the preset time is too long or too short due to inaccurate estimation, and achieves the purposes of prolonging the effective test time, preventing pressure overshoot and improving the adjustment quality; and the method has larger latitude on estimation before the test, and reduces the dependence on the experience of testers.

Description

Hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance

Technical Field

The method belongs to the technical field of hypersonic wind tunnel tests, and particularly relates to a hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance.

Background

The total pressure is one of the most important control parameters in the hypersonic wind tunnel test, the target value is generally between a few tenths of megapascals and tens of megapascals, and the control precision requirement is better than 1%. When the hypersonic wind tunnel is started, the quick-opening stop valve is quickly opened firstly, and meanwhile, high-pressure air of the air source storage tank flows downstream through the regulating valve and a process pipeline behind the regulating valve, and then passes through the spray pipe, a flow field is established at the outlet of the spray pipe, and a test is carried out. The process pipeline between the regulating valve and the nozzle throat has larger cavity volume under the restriction of field layout and pneumatic design of the hypersonic wind tunnel equipment, and after the hypersonic wind tunnel is started, the nonstationary filling process of the pipeline at the section needs to be completed firstly, and then pressure can be built. Correspondingly, the total pressure of the hypersonic wind tunnel is increased rapidly and then becomes stable gradually, and effective test data can be obtained later.

For the hypersonic wind tunnel, limited air source supply limits the test time to be generally ten seconds to dozens of seconds, and in order to ensure that more data can be obtained in effective test time, after the hypersonic wind tunnel is started, the total pressure can be close to a target value in a short time (generally not more than 3-5 seconds) without obvious overshoot, so that the damage of test equipment caused by airflow impact can be prevented, and then the hypersonic wind tunnel is stably controlled to be close to the target value. After the hypersonic wind tunnel is started, if feedback adjustment is started too early, the total pressure deviation is very large, the control algorithm can greatly increase the opening of the regulating valve, so that the total pressure overshoots, and then the regulation is carried out, so that oscillation is generated, and the time for stabilizing the total pressure is prolonged; if the feedback adjustment is carried out too late, the time for accurately adjusting the total pressure to the target value is correspondingly delayed.

Therefore, for the hypersonic wind tunnel, especially the hypersonic wind tunnel with a large caliber, a reasonable preset method for the opening degree of the regulating valve is adopted in the starting process, the preset process of the regulating valve is stopped in advance by machine selection according to the pressure building condition of the process pipeline, the filling and pressure building process of the process pipeline is effectively shortened, meanwhile, total pressure overshoot and oscillation are prevented or reduced, and the method is very significant for ensuring effective test time and equipment safety.

At present, it is urgently needed to develop a hypersonic wind tunnel regulating valve opening presetting method capable of automatically stopping in advance, so as to make up the problem that the presetting time is too long or too short due to inaccurate estimation, and achieve the purposes of prolonging the effective test time, preventing pressure overshoot and improving the regulating quality.

Disclosure of Invention

The invention aims to solve the technical problem of providing a hypersonic speed wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance.

The invention discloses a hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance, which is characterized in that the method is applied to a hypersonic wind tunnel provided with a regulating valve and a quick-opening stop valve, and the method comprises the following steps:

a. estimating the pressure behind the regulating valve according to the current test state and historical data;

b. calculating the corresponding opening degree of the regulating valve by using the gas source pressure and the pressure behind the valve according to an empirical formula given by a manufacturer of the regulating valve, and taking the opening degree as an initial preset opening degree;

c. the operator sets the shortest preset time, the longest preset time, the preset section total pressure upper limit, the preset section total pressure increasing lower limit and relevant control parameters of the regulating valve;

d. an operator manually operates the regulating valve to an initial preset opening degree, and presets the regulating valve;

e. performing a hypersonic wind tunnel test, controlling a program to open a quick-opening stop valve, starting the hypersonic wind tunnel to run, and starting timing;

f. the control program detects, calculates and judges whether the regulating valve stops presetting in advance according to the set condition or not in a periodic mode;

g. and the control program performs a feedback regulation link according to the set control parameters and the measured total pressure until the hypersonic wind tunnel test is finished.

Further, the total pressure threshold value of the "preset section total pressure upper limit" of the regulating valve is 0.9 times of the target value.

Further, the lower limit of the total pressure increase rate of the preset section of the regulating valve is 0.1 time of the target value per second.

Further, the setting conditions of step f are as follows:

f1. if the running time of the hypersonic wind tunnel is less than the shortest preset time, the regulating valve keeps the initial preset opening unchanged;

f2. if the running time of the hypersonic wind tunnel is less than the longest preset time, and meanwhile, the total pressure is less than the total pressure upper limit of the preset section or the total pressure increasing rate is greater than the total pressure increasing rate lower limit of the preset section, the adjusting valve keeps the initial preset opening degree unchanged;

f3. except for the two conditions of f1 and f2, the filling process of the pressure regulating pipeline of the hypersonic wind tunnel is judged to be finished, the opening presetting process of the regulating valve is stopped, and the feedback regulating process is switched to.

The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance comprises the steps of presetting a regulating valve to an initial preset opening degree before a hypersonic wind tunnel is started; after the hypersonic wind tunnel is started, firstly keeping the regulating valve at an initial preset opening degree, after the shortest preset time, starting to detect in real time and calculate the deviation and the acceleration of a total pressure measurement value and a target value, and if the total pressure is detected to be close to the target value or the total pressure acceleration is too low within the running time of the hypersonic wind tunnel to be less than the longest preset time, judging that the filling and pressure building of a pipeline between the regulating valve and the throat of the spray pipe are basically finished, automatically stopping the opening degree presetting of the regulating valve in advance, and switching to a real-time feedback regulating process.

The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance considers the problems that an empirical formula is not accurate enough, air source pressure fluctuates due to the influence of other peripheral hypersonic wind tunnel tests, and mechanical errors of the regulating valve cannot be overcome, and the problems that the initial preset opening degree of the regulating valve and the pipeline filling time cannot be accurately calculated due to the factors can be solved.

The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance does not detect and judge total pressure within the shortest preset time after the hypersonic wind tunnel is started, and can avoid misjudgment caused by equipment action lag.

The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance determines whether a control program stops the opening degree presetting of the regulating valve in advance or not by judging whether the total pressure exceeds a preset section total pressure upper limit or whether the total pressure acceleration rate is smaller than a preset section total pressure acceleration rate lower limit or not after the hypersonic wind tunnel is started, starts to perform feedback regulation, and can prevent the total pressure overshoot or the inefficient filling from wasting test time due to overshoot.

The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance can solve the problem that due to inaccurate estimation, the preset time of the regulating valve is too long or too short, achieves the purposes of prolonging the effective test time, preventing pressure overshoot and improving the regulating quality, has larger latitude on the regulation of the regulating valve opening degree before the test, and reduces the dependence on the experience of testers.

Drawings

Fig. 1 is a schematic layout diagram of a hypersonic wind tunnel using a hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance according to the present invention in embodiment 1;

fig. 2 is a schematic diagram of an implementation process in embodiment 1, which is obtained by using the hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance according to the present invention;

FIG. 3 is a curve corresponding to the total pressure and the valve opening of the regulating valve obtained by the hypersonic wind tunnel regulating valve opening presetting method capable of automatically stopping in advance.

In the figure 1, an airsource storage tank 2, a quick-openingstop valve 3, apressure transmitter 4 before a regulating valve, a regulatingvalve 5, apressure transmitter 6 after the regulating valve, aprocess pipeline 7, a stabilizingsection 8, atotal pressure transmitter 9, aspray pipe throat 10 and a spray pipe.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples.

The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance is applied to a hypersonic wind tunnel provided with a regulating valve and a quick-opening stop valve, and comprises the following steps:

a. estimating the pressure behind the regulating valve according to the current test state and historical data;

b. calculating the corresponding opening degree of the regulating valve by using the gas source pressure and the pressure behind the valve according to an empirical formula given by a manufacturer of the regulating valve, and taking the opening degree as an initial preset opening degree;

c. the operator sets the shortest preset time, the longest preset time, the preset section total pressure upper limit, the preset section total pressure increasing lower limit and relevant control parameters of the regulating valve;

d. an operator manually operates the regulating valve to an initial preset opening degree, and presets the regulating valve;

e. performing a hypersonic wind tunnel test, controlling a program to open a quick-opening stop valve, starting the hypersonic wind tunnel to run, and starting timing;

f. the control program detects, calculates and judges whether the regulating valve stops presetting in advance according to the set condition or not in a periodic mode;

g. and the control program performs a feedback regulation link according to the set control parameters and the measured total pressure until the hypersonic wind tunnel test is finished.

Further, the total pressure threshold value of the "preset section total pressure upper limit" of the regulating valve is 0.9 times of the target value.

Further, the lower limit of the total pressure increase rate of the preset section of the regulating valve is 0.1 time of the target value per second.

Further, the setting conditions of step f are as follows:

f1. if the running time of the hypersonic wind tunnel is less than the shortest preset time, the regulating valve keeps the initial preset opening unchanged;

f2. if the running time of the hypersonic wind tunnel is less than the longest preset time, and meanwhile, the total pressure is less than the total pressure upper limit of the preset section or the total pressure increasing rate is greater than the total pressure increasing rate lower limit of the preset section, the adjusting valve keeps the initial preset opening degree unchanged;

f3. except for the two conditions of f1 and f2, the filling process of the pressure regulating pipeline of the hypersonic wind tunnel is judged to be finished, the opening presetting process of the regulating valve is stopped, and the feedback regulating process is switched to.

Example 1

The total pressure target value of the hypersonic wind tunnel test working condition of the embodiment is 10MPa, and the current air source pressure is 20 MPa. The hypersonic wind tunnel test requires that the unsteady filling and pressure building process of theprocess pipeline 6 can be completed quickly and stably within 5 seconds, and no obvious overshoot and oscillation exist in the process.

As shown in fig. 1, the pressure regulating pipeline of the hypersonic wind tunnel according to this embodiment is sequentially provided with an air source storage tank 1, a quick-opening stop valve 2, apressure transmitter 3 before a regulating valve, a regulatingvalve 4, apressure transmitter 5 after the regulating valve, aprocess pipeline 6, a stabilizingsection 7, atotal pressure transmitter 8, anozzle throat 9 and anozzle 10 from front to back along an airflow direction. Theprocess pipeline 6 between the regulatingvalve 4 and thenozzle throat 9 has a large cavity volume, and the hypersonic wind tunnel is inevitably subjected to an unsteady filling and pressure building process of theprocess pipeline 6 firstly when being started.

As shown in fig. 2, the method of the present embodiment includes the following steps:

a. according to historical data, the pressure drop between the regulatingvalve 4 and the stabilizingsection 7 is about 0.35MPa in the current test state, and correspondingly, the pressure behind the regulatingvalve 4 is 10.35 MPa;

b. according to an empirical formula given by a regulating valve manufacturer, the pressure before the regulatingvalve 4 is determined to be 20MPa according to an air source pressure gauge, the pressure after the regulatingvalve 4 is 10.35MPa, and the corresponding opening degree of the regulatingvalve 4 is calculated to be about 40 percent;

c. an operator sets the shortest preset time to be 1s, the longest preset time to be 5s, the preset section total pressure upper limit to be 9MPa and the preset section total pressure acceleration lower limit to be 1MPa/s according to experience on an upper computer;

d. the operator manually operates the regulatingvalve 4 to 40% of opening;

e. performing a hypersonic wind tunnel test, controlling a program to open the quick-opening stop valve 2, starting the hypersonic wind tunnel to run, and starting timing;

f. detecting, calculating and judging whether the opening degree is kept at 40% according to the set condition by the control program according to the period of 0.1 s; in the process that the running time of the hypersonic wind tunnel is less than 1s, the opening degree of the regulatingvalve 4 is maintained at 40%; in the process that the running time of the hypersonic wind tunnel is less than 3.1s, the total pressure is less than 9MPa, the total pressure acceleration rate is greater than 1MPa/s, and the opening degree of the regulatingvalve 4 is still maintained at 40%; when the running time of the hypersonic wind tunnel is 3.1s, detecting that the total pressure is 9.02MPa and is greater than the upper limit of the total pressure of the preset section, namely 9MPa, judging to finish the filling process in the pipeline in advance, and stopping the preset process of maintaining the 40% opening degree of the regulatingvalve 4;

g. and the control program detects the total pressure in real time, implements PID (proportion integration differentiation) regulation, and controls the opening of the regulatingvalve 4 until the hypersonic wind tunnel test is finished.

As shown in fig. 3, as can be seen from the curve of the total pressure and the valve opening degree of the regulating valve in the present embodiment, in 0.3s after the hypersonic wind tunnel is started, the total pressure remains zero due to the operation delay of the quick-opening stop valve 2, and then the rapid climbing is started to fill the inside of the pipeline. At 3.1s, the total pressure reaches 9MPa, the control program automatically stops presetting the regulatingvalve 4 in advance, feedback control is started, and then the opening degree of the regulatingvalve 4 is slightly increased. At 3.6s, the total pressure approaches 9.5MPa, and the control algorithm starts to decrease the opening of the regulatingvalve 4, so that the total pressure slowly increases to approach the target value. After 4.2s, the pressure control precision reaches 1%, the test requirement is met, and the time is advanced by 0.8s compared with the initial estimation preset time. In the running process of the hypersonic wind tunnel, the total pressure is stable without overshoot, the pressure in front of the regulatingvalve 4 is continuously reduced due to the limited air source volume, the opening degree of the regulatingvalve 4 is increased on the whole, and the total pressure is dynamically maintained to be stable.

Although the embodiments of the present invention have been disclosed above, it is not limited to the applications listed in the description and the embodiments, but it can be applied to various fields suitable for the present invention. Additional modifications and refinements of the present invention will readily occur to those skilled in the art without departing from the principles of the present invention, and therefore the present invention is not limited to the specific details and illustrations shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (3)

1. The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance is characterized in that the method is applied to a hypersonic wind tunnel provided with a regulating valve and a quick-opening stop valve, and the method comprises the following steps:

a. estimating the pressure behind the regulating valve according to the current test state and historical data;

b. calculating the corresponding opening degree of the regulating valve by using the gas source pressure and the pressure behind the valve according to an empirical formula given by a manufacturer of the regulating valve, and taking the opening degree as an initial preset opening degree;

c. the operator sets the 'shortest preset time', 'longest preset time', 'preset section total pressure upper limit', 'preset section total pressure acceleration lower limit' of the regulating valve;

d. an operator manually operates the regulating valve to an initial preset opening degree, and presets the regulating valve;

e. performing a hypersonic wind tunnel test, controlling a program to open a quick-opening stop valve, starting the hypersonic wind tunnel to run, and starting timing;

f. the control program detects, calculates and judges whether the regulating valve stops presetting in advance according to the set condition or not in a periodic mode;

f1. if the running time of the hypersonic wind tunnel is less than the shortest preset time, the regulating valve keeps the initial preset opening unchanged;

f2. if the running time of the hypersonic wind tunnel is less than the longest preset time, and meanwhile, the total pressure is less than the total pressure upper limit of the preset section or the total pressure increasing rate is greater than the total pressure increasing rate lower limit of the preset section, the adjusting valve keeps the initial preset opening degree unchanged;

f3. except for the two conditions of f1 and f2, judging that the filling process of a pressure regulating pipeline of the hypersonic wind tunnel is finished, stopping the opening presetting process of a regulating valve, and switching to a feedback regulating process;

g. and the control program performs a feedback regulation link according to the set control parameters and the measured total pressure until the hypersonic wind tunnel test is finished.

2. The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance as claimed in claim 1, characterized in that the total pressure threshold value of the preset section total pressure upper limit of the regulating valve is 0.9 times of the target value.

3. The hypersonic wind tunnel regulating valve opening degree presetting method capable of automatically stopping in advance as claimed in claim 1, characterized in that a preset section total pressure acceleration lower limit of the regulating valve is 0.1 times of a target value per second.

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