Bypass throttling pressure regulating system for ejector, design method and pressure regulating method

Abstract

The invention discloses a bypass throttling pressure regulating system for an ejector, a design method and a pressure regulating method, and aims to solve the problems that the test duration of an existing ejector is limited, and the cost of an existing test time prolonging scheme is high or the system is complex. The system comprises a main pressure regulating valve of a main control pipeline, a throttling orifice plate of a bypass pipeline and a bypass quick switching valve, wherein the bypass pipeline is connected to the two ends of the main pressure regulating valve in parallel; the working pressure range of the main pressure regulating valve is expanded, the available pressure area of an air source is expanded, and the test duration is prolonged; additional pressure regulating valves or a large number of gas storage tanks are not needed, the number of parts is reduced, and the equipment cost is reduced; in the test process, the main pressure regulating valve and the bypass quick switch valve are controlled to be fully opened only through a PID program, the complexity of the control system is reduced, in addition, due to the existence of the bypass system, the flow flowing through the main pressure regulating valve is reduced, the flow load of the main pressure regulating valve is reduced, the control difficulty of the main pressure regulating valve is further reduced, and the test efficiency is improved. And the service life of the main pressure regulating valve is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of aerospace ground simulation equipment, and more specifically, relates to a bypass throttling and voltage regulation system for ejectors, its design method, and its voltage regulation method. Background Technology

[0002] In recent years, with the rapid development of my country's aerospace industry, the demand for ground simulation equipment such as engine high-altitude test benches and hypersonic wind tunnels to simulate high-altitude flight environments has been increasing. The size of the simulation equipment is getting larger, the simulated flight altitude is getting higher, and the test time is also required to be longer. Therefore, higher requirements are placed on the construction capabilities of ground simulation equipment.

[0003] One of the main functions of ground-based simulation equipment is to provide the atmospheric pressure at flight altitude within the equipment's test chamber. The higher the altitude, the lower the atmospheric pressure; at 20 km, the atmospheric pressure is approximately 5500 Pa, and at 30 km, it is approximately 1100 Pa. One method to achieve the same pressure as high-altitude atmosphere within the test chamber during ground testing is to use an ejector to draw in the air, mixing the low-pressure airflow within the test chamber with the high-pressure airflow from the ejector before releasing it into the atmosphere.

[0004] The high-pressure gas for the ejector comes from a high-pressure gas storage tank. After passing through a pressure regulating valve on the ejector pipeline, it reaches the set pressure and is discharged through the ejector nozzle. The ejector consumes a large amount of gas, especially as the equipment size and simulation height increase. During the test, as the gas source is consumed in large quantities, the gas pressure drops rapidly. The opening of the pressure regulating valve is gradually increased to maintain a constant pressure after the valve. When the pressure regulating valve is fully open, the ejector flow rate begins to decrease, the ejection capacity decreases, and the test can no longer be conducted. Therefore, the test time is limited by the amount of gas in the high-pressure gas storage tank and the operating pressure range of the pressure regulating valve.

[0005] To increase the test duration, there are currently two main methods: (1) Expand the gas source by increasing the gas volume by adding gas storage tanks, etc. This method involves a large amount of engineering work, requires a large site area and a large amount of funding, and cannot improve the gas source utilization rate. (2) Add a bypass pressure regulating valve. This method can improve the gas source utilization rate, but the parallel control of two pressure regulating valves increases the complexity of the system, requires a high level of system measurement and control capabilities, and also increases the cost.

[0006] In view of the shortcomings of the existing technology, there is an urgent need for a pressure regulating system with simple structure, low cost and high gas source utilization rate to solve the problem of limited ejector test time. Summary of the Invention

[0007] The purpose of this invention is to provide a bypass throttling and pressure regulating system, design method, and pressure regulating method for ejectors, solving the problems of high cost of expanding gas source and complexity of dual pressure regulating valve system in existing ejector pressure regulating schemes.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a bypass throttling and voltage regulating system for an ejector, comprising: The main control pipeline has an upstream end for connecting to a high-pressure gas source and a downstream end for connecting to an ejector. A main pressure regulating valve is provided between the upstream and downstream ends, and the main pressure regulating valve is configured to continuously adjust the opening. A bypass pipeline is connected in parallel to both ends of the main pressure regulating valve. A throttling orifice plate and a quick-switching valve are sequentially provided along the airflow direction. The quick-switching valve is configured to be fully open and fully closed.

[0009] Optionally, the upstream end of the main control pipeline is provided with an air inlet, which is used to connect to the high-pressure air source.

[0010] Optionally, the downstream end of the main control pipeline is provided with an ejector interface, which is used to connect the ejector.

[0011] Optionally, the orifice shape of the throttling plate is circular.

[0012] Optionally, the orifice plate is made of stainless steel.

[0013] In a second aspect, the present invention provides a design method for a bypass throttling and voltage regulating system for an ejector as described in the first aspect, comprising the following steps: S1, based on the existing ejector's total working pressure P 02 Working flow rate Q, main pressure regulating valve (2) working pressure range P 01min ≤P 01≤ P 01max The new minimum operating pressure of the main pressure regulating valve will be determined based on the desired increase in test duration. ; S2, based on the gas specific heat ratio γ, gas constant R, and total gas source temperature T0, calculate the design constant α and opening area A of the throttling orifice plate (4); S3, based on the orifice area A and P of the throttling orifice plate 01max Select high-pressure resistant materials and design the external dimensions of the throttling orifice plate; S4. Calculate and select the bypass pipe inner diameter based on the opening area A and the design flow velocity; S5, select a quick-on / off valve with a matching bore diameter based on the inner diameter of the bypass pipeline.

[0014] Optionally, in S2, the formula for calculating the design constant α is: .

[0015] Optionally, in S2, the formula for calculating the opening area A is: ,in γ is the specific heat ratio of the gas, R is the gas constant, and T0 is the total temperature of the gas source.

[0016] Thirdly, the present invention provides a bypass throttling and voltage regulation method for an ejector, based on the system described in the first aspect, comprising the following steps: Step 1: Simultaneously open the main pressure regulating valve and the quick-opening valve, setting the quick-opening valve to fully open; Step 2: Real-time acquisition of the pressure after the main control pipeline and bypass pipeline merge, and adjustment of the main pressure regulating valve opening through PID program to maintain the system pressure at the set value after adjustment.

[0017] Optionally, in step two, the pressure control accuracy of the PID program is ±0.01MPa.

[0018] The beneficial effects of this invention are as follows: the pressure regulating system only adds a bypass pipeline, a throttling orifice plate, and a bypass quick-switching valve to the original main pipeline, which expands the working pressure range of the main pressure regulating valve, broadens the available pressure range of the gas source, and extends the test duration; and it eliminates the need for additional pressure regulating valves or a large number of gas storage tanks, reducing the number of components and lowering equipment costs; during the test, only the main pressure regulating valve needs to be controlled by a PID program, while the bypass quick-switching valve remains fully open, reducing the complexity of the pressure regulating control system. At the same time, due to the existence of the bypass system, the flow rate through the main pressure regulating valve is reduced, lowering the flow load on the main pressure regulating valve, thereby further reducing the control difficulty of the main pressure regulating valve and extending its service life.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0021] Figure 1 A schematic structural diagram of the ejector bypass throttling and voltage regulation system of Embodiment 1 of the present invention is shown.

[0022] Figure 2 A flowchart of the design method of the ejector bypass throttling and voltage regulation system of Embodiment 2 of the present invention is shown.

[0023] Figure 3 A flowchart of the bypass throttling and voltage regulation method for ejectors according to Embodiment 3 of the present invention is shown.

[0024] Explanation of reference numerals in the attached figures: 1. Main control pipeline; 2. Main pressure regulating valve; 3. Bypass pipeline; 4. Orifice plate; 5. Quick-opening valve; 6. Inlet port; 7. Ejector port. Detailed Implementation

[0025] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0026] like Figure 1 As shown, this embodiment provides a bypass throttling and voltage regulating system for an ejector, comprising: The main control pipeline 1 has an upstream end for connecting to a high-pressure gas source and a downstream end for connecting to an ejector. A main pressure regulating valve 2 is provided between the upstream and downstream ends. The main pressure regulating valve 2 is configured to continuously adjust the opening. The bypass pipeline 3 is connected in parallel to both ends of the main pressure regulating valve 2. A throttling orifice plate 4 and a quick-switching valve 5 are sequentially provided along the airflow direction. The quick-switching valve 5 is configured to be fully open and fully closed.

[0027] The working principle of this voltage regulation system is as follows: The upstream of the main control pipeline 1 is connected to a high-pressure gas source. The total pressure of the gas flow in the pipeline before the split is equal to the high-pressure gas source pressure P. 01 (Without bypass test, P) 01 From P 01max To P 01min After the pressure is reduced, the airflow splits into two streams. One stream flows from the main control line 1 through the main pressure regulating valve 2, and the other stream flows from the bypass line 3 through the orifice plate 4 and the quick-switching valve 5. The total pressure after the two streams merge is P. 02 (i.e., the total working pressure of the ejector), after merging, the airflow finally flows into the ejector. At the start of pressure regulation, the quick-opening valve 5 and the main pressure regulating valve 2 open simultaneously. The quick-opening valve 5 is fully open; only the opening of the main pressure regulating valve 2 needs to be adjusted via PID control to maintain P. 02 constant.

[0028] The flow rate Q2 flowing through the bypass always satisfies the formula The bypass flow rate decreases synchronously with the gas source pressure, among which, Where A is the total temperature of the air source, and A is the orifice area of ​​the throttling orifice plate 4. The maximum pressure of the high-pressure gas source is given by Q, where Q is the ejector flow rate and Q is the gas flow characteristic coefficient. , Here, R is the specific heat ratio of the gas, and R is the gas constant. For design constants, Without a bypass structure, the minimum air source pressure corresponding to the main pressure regulating valve 2 opening to its maximum value is: At this time, its throttling area is at its maximum. Therefore, after adding the bypass, the flow rate when the main pressure regulating valve 2 is at its maximum opening is... The ejector flow rate Q is constant and satisfies Substituting into formulas Q2 and Q1, we can obtain: the minimum working pressure before the main pressure regulating valve 2, corresponding to P when there is no bypass. 01min Reduced to the point where there is a bypass < That is, the working pressure range of the main pressure regulating valve 2 in the pressure regulating system (i.e., the available pressure range of the air source) from... Expand to This expands the working pressure range of the main pressure regulating valve 2 and improves the utilization rate of the air source. At the same time, the bypass structure is simple, and the quick-opening valve 5 only needs to be fully open or closed. Only the opening degree of the main pressure regulating valve 2 needs to be controlled, and the control system is also simple. In addition, due to the existence of the bypass system, the flow rate through the main pressure regulating valve is reduced, and the flow load of the main pressure regulating valve is reduced, thereby further reducing the control difficulty of the main pressure regulating valve and extending the service life of the main pressure regulating valve.

[0029] Specifically, this system only requires continuous adjustment of the opening degree of the main pressure regulating valve 2, while the bypass switching valve remains fully open throughout the entire process. Compared with dual-valve coordinated control, this reduces the complexity of the control system. The bypass diverts part of the airflow through the orifice plate 4, ensuring that the minimum working pressure upstream of the main pressure regulating valve 2 is reduced from... Down to The available pressure range of the gas source is expanded, which directly improves the gas source utilization rate and extends the test duration.

[0030] Optionally, the upstream end of the main control pipeline 1 is provided with an air inlet 6, which is used to connect to the upstream high-pressure gas source pipeline system.

[0031] Optionally, the downstream end of the main control pipeline 1 is provided with an ejector interface 7, which is used to connect to the downstream ejector pipeline system.

[0032] Optionally, the orifice shape of the throttling orifice plate 4 is circular.

[0033] Specifically, the circular opening has a uniform flow channel cross-section, and the airflow flows along the hole wall without dead corners. Compared with the square opening, it reduces the airflow resistance coefficient and reduces the pressure loss of the gas source. The flow coefficient of the circular opening is constant, and there is no flow fluctuation caused by local eddies. The bypass flow rate has a linear relationship with the change of the high-pressure gas source, avoiding the total flow rate from deviating from the ejector requirements due to flow fluctuations, thus improving the stability of the test.

[0034] Optionally, the orifice plate 4 is made of stainless steel.

[0035] Example 2

[0036] like Figure 2 As shown, this embodiment provides a design method for a bypass throttling and voltage regulating system for an ejector as described in Embodiment 1, including the following steps: S1 is based on the existing ejector's total working pressure P. 02 Working flow rate Q, main pressure regulating valve (2) working pressure range P 01min ≤P 01≤ P 01max The new minimum operating pressure of the main pressure regulating valve will be determined based on the desired increase in test duration. ; S2 calculates the design constant α and the opening area A of the throttling orifice plate 4 based on the gas specific heat ratio γ, gas constant R, and total gas source temperature T0. In this step, the formula for calculating α is: The formula for calculating the opening area A is: ,in γ is the specific heat ratio of the gas, R is the gas constant, and T0 is the total temperature of the gas source.

[0037] S3, based on the opening area A and P of the throttling orifice plate 4 01max Select high-pressure resistant materials and design the external dimensions of the throttling orifice plate 4; S4. Calculate and select the inner diameter of the bypass pipe 3 based on the opening area A and the design flow velocity; S5, select a quick-start valve 5 with a matching bore diameter based on the inner diameter of the bypass pipeline 3.

[0038] This embodiment's design method solves the problem of component mismatch and system instability caused by experience-based selection through a complete process design, including design constant α calculation, orifice plate 4 calculation, orifice plate size design, bypass pipeline 3 selection, and on / off valve matching. Specifically, each step is based on the ejector operating parameters (P... 02 Q) and gas source parameters (P) 01max , Quantitative design avoids matching problems such as insufficient flow of the main pressure regulating valve 2 and excessively thin bypass pipeline 3, thus improving the success rate of system commissioning; those skilled in the art only need to substitute parameters to complete the design, shortening the design cycle.

[0039] Example 3

[0040] like Figure 3 As shown, this embodiment provides a bypass throttling and voltage regulation method for an ejector, based on the system of Embodiment 1, including the following steps: Step 1: Simultaneously open the main pressure regulating valve 2 and the quick-opening valve 5, and set the quick-opening valve 5 to fully open; Step two: Real-time pressure is collected at the junction of main control line 1 and bypass line 3. The opening of the main pressure regulating valve 2 is adjusted using a PID program to maintain the system pressure at the set value. In this step, the pressure control accuracy of the PID program is ±0.01MPa.

[0041] Specifically, in this adjustment method, the main pressure regulating valve 2 and the bypass switch valve open synchronously to reduce the combined pressure P. 02 Overshoot protection for the ejector and pressure sensor; acquisition of the pressure after the main control line 1 and bypass line 3 merge (i.e., the ejector inlet pressure P). 02 This directly addresses the ejector's operational requirements, reducing control deviation compared to acquiring main line pressure; it only adjusts the opening of the main pressure regulating valve 2, avoiding coupling interference from dual-valve regulation and shortening pressure stabilization time; and it stabilizes P... 02 Even if the gas source pressure changes from P 01max Reduced to P 01newmin The ejector can still maintain the rated flow rate Q, thus extending the test duration.

[0042] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A bypass throttling and voltage regulating system for an ejector, characterized in that, include: The main control pipeline (1) has an upstream end for connecting to a high-pressure gas source and a downstream end for connecting to an ejector. A main pressure regulating valve (2) is provided between the upstream and downstream ends. The main pressure regulating valve (2) is configured to continuously adjust the opening. The bypass pipeline (3) is connected in parallel to both ends of the main pressure regulating valve (2), and a throttling orifice plate (4) and a quick-switching valve (5) are sequentially provided along the airflow direction. The quick-switching valve (5) is configured to be fully open and fully closed.

2. The bypass throttling and voltage regulating system for an ejector according to claim 1, characterized in that, The upstream end of the main control pipeline (1) is provided with an air inlet (6), which is used to connect to the high-pressure gas source.

3. The bypass throttling and voltage regulating system for an ejector according to claim 1, characterized in that, The downstream end of the main control pipeline (1) is provided with an ejector interface (7), which is used to connect the ejector.

4. The bypass throttling and voltage regulating system for an ejector according to claim 1, characterized in that, The orifice of the throttling plate (4) has a circular opening.

5. The bypass throttling and voltage regulating system for an ejector according to claim 1, characterized in that, The orifice plate (4) is made of stainless steel.

6. A design method for a bypass throttling and voltage regulating system for an ejector as described in claim 1, characterized in that, Includes the following steps: S1, based on the existing ejector's total working pressure P 02 Working flow rate Q, main pressure regulating valve (2) working pressure range P 01min ≤P 01≤ P 01max The new minimum operating pressure of the main pressure regulating valve will be determined based on the desired increase in test duration. ; S2, based on the gas specific heat ratio γ, gas constant R, and total gas source temperature T0, calculate the design constant α and opening area A of the throttling orifice plate (4); S3, based on the opening area A and P of the throttling orifice plate (4) 01max Select high-pressure resistant material and design the external dimensions of the throttling orifice plate (4); S4, calculate the inner diameter of the bypass pipe (3) and select the type based on the opening area A and the design flow velocity; S5, select a quick-start valve (5) with matching bore diameter according to the inner diameter of the bypass pipeline (3).

7. The design method of the bypass throttling and voltage regulation system for the ejector according to claim 6, characterized in that, In S2, the formula for calculating the design constant α is as follows: .

8. The design method of the bypass throttling and voltage regulation system for the ejector according to claim 7, characterized in that, In S2, the formula for calculating the opening area A is: ,in γ is the specific heat ratio of the gas, R is the gas constant, and T0 is the total temperature of the gas source.

9. A bypass throttling and voltage regulation method for an ejector. Based on the system of claim 1, characterized in that, Includes the following steps: Step 1: Simultaneously open the main pressure regulating valve (2) and the quick-opening valve (5), and set the quick-opening valve (5) to be fully open; Step 2: Real-time acquisition of the pressure after the main control pipeline (1) and the bypass pipeline (3) merge, and adjustment of the opening of the main pressure regulating valve (2) by the PID program to maintain the system pressure at the set value.

10. The bypass throttling and voltage regulation method for an ejector according to claim 9, characterized in that, In step two, the pressure control accuracy of the PID program is ±0.01MPa.

Images