System and method for realizing large-flow multi-stage critical state flow control and pressure matching

Abstract

The invention relates to a system and a method for realizing large-flow multistage critical state flow control and pressure matching, belongs to the technical field of pneumatic testing, and aims to solve the problem that an existing large-flow control system cannot realize accurate control and measurement of flow and pressure. The invention discloses a system for realizing high-flow multi-stage critical state flow control and pressure matching. The system comprises gas source equipment, a main path, a first branch, a second branch and a third branch, the main path comprises a main path gas supply pipe, a main path regulating valve group, a first-stage critical system, a second-stage critical system and a third-stage critical system; and linkage emptying regulating valve groups are arranged on the first branch and the third branch. According to the system and the method, accurate control and measurement of flow and pressure can be realized.

Description

Technical Field

[0001] The present invention relates to the field of pneumatic testing technology, and in particular to a system and method for realizing large-flow multi-stage critical state flow control and pressure matching. Background Art

[0002] In the field of aviation technology, it involves the use of large flow control systems to simulate test conditions. Large flow control systems are designed to achieve large flow control and accurate measurement under atmospheric pressure and temperature conditions; existing large flow control systems simulate test conditions, and most of them use variable frequency motors to drive large axial flow fans or centrifugal fans to achieve control over a wide range of flow changes, and are unable to accurately adjust the flow and pressure for continuous and stable changes; and the system is greatly affected by different test pieces, and can only respond to changes in conditions by repeated calibration, verification and reasoning, and other methods. Therefore, there is an urgent need for a system that can achieve flow and pressure control and accurate measurement. Summary of the invention

[0003] In view of the above analysis, an embodiment of the present invention aims to provide a system and method for achieving large-flow multi-stage critical state flow control and pressure matching, so as to solve the problem that existing large-flow control systems cannot achieve accurate control and measurement of flow and pressure.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] The present invention provides a system for realizing large-flow multi-stage critical state flow control and pressure matching, comprising gas source equipment, a main circuit, a first branch circuit, a second branch circuit and a third branch circuit;

[0006] The main circuit includes a main circuit gas supply pipe, a main circuit regulating valve group, a primary critical system, a secondary critical system and a tertiary critical system;

[0007] The first branch and the third branch are provided with a linkage emptying regulating valve group.

[0008] Furthermore, the main regulating valve group includes a switch valve, a main regulating valve, a branch regulating valve and a pressure sensor;

[0009] The pressure sensor, the switch valve, and the main line regulating valve are sequentially arranged on the main line gas supply pipe, and the branch line regulating valve is arranged on the second branch line connected in parallel with the main line;

[0010] The switch valve has a size of DN400 to DN600, the main regulating valve is a main valve with a size of DN400 to DN600, and the branch regulating valve is an auxiliary valve with a size of DN100 to DN200.

[0011] Further, the primary critical system is arranged on the main road, and includes a first constant pressure buffer tank, N1 parallel branch air supply pipes, a connecting section and a pressure sensor;

[0012] A critical venturi nozzle and a switch valve are respectively arranged on each branch air supply pipe;

[0013] One end of the first constant pressure buffer tank is connected to the main air supply pipe, and the other end is connected to N1 branch air supply pipes respectively, and the critical venturi nozzle is arranged on the branch air supply pipe close to one end of the first constant pressure buffer tank;

[0014] The pressure sensor is arranged on the first constant pressure buffer tank.

[0015] Furthermore, the range of N1 is 16 to 26.

[0016] Further, among the critical Venturi nozzles, the critical Venturi nozzles of number N1 / 2 have a size of DN80 to DN100 and a temperature of T1 of 0 to 20°C;

[0017] The critical Venturi nozzle size for N1 / 4 number is DN50~DN60, and the temperature is T1-10;

[0018] The critical Venturi nozzle size for N1 / 4 number is DN25~DN40, and the temperature is T1-20.

[0019] Furthermore, the critical pressure ratio of the primary critical system is in the range of 0.6 to 0.8.

[0020] Furthermore, the three-level critical system is arranged on the main road, after the two-level critical system, and the three-level critical system and the two-level critical system are connected via a main road gas supply pipe;

[0021] The three-level critical system includes two branch air supply pipes connected in parallel, and a regulating valve and a switch valve are respectively arranged on each branch air supply pipe.

[0022] Further, the linkage emptying regulating valve group is arranged on the branch, and includes a second branch air supply pipe and a third branch air supply pipe connected in parallel;

[0023] The second branch gas supply pipe is provided with a switch valve and a regulating valve in sequence, the switch valve and the regulating valve are main valves, and the sizes of the switch valve and the regulating valve are both DN400-DN600;

[0024] The third branch gas supply pipe is provided with a switch valve and a regulating valve in sequence, wherein the switch valve and the regulating valve are auxiliary valves, and the sizes of the switch valve and the regulating valve are both DN100-DN200.

[0025] The present invention also provides a method for realizing large flow multi-stage critical state flow control and pressure matching, which is realized by the above system and includes the following steps:

[0026] S1: According to the size of the output airflow of the air source equipment, the openings of the switch valves and the regulating valves on the main road, the first branch, the second branch and the third branch are controlled respectively to determine the size of the output airflow of the main road, the first branch, the second branch and the third branch;

[0027] S2: According to the size of the output airflow on the main road, the first branch, the second branch and the third branch and the regulation principle, adjust the main road regulating valve group, the first critical system, the second critical system, the third critical system and the linked emptying regulating valve group to ensure that the outlet flow fluctuation of the third critical system and the linked emptying regulating valve group is ≤0.1%.

[0028] Furthermore, in step S2, the adjustment principle includes:

[0029] When the maximum flow rate of the test is 80-100 kg / hour (including 80 kg / hour), the front pressure of the primary critical system is 8-10 MPa, the number of nozzles opened in the primary critical system is (4 / 5-1) N1, the front pressure of the secondary critical system is 6-8 MPa, and the number of secondary nozzles opened in the secondary critical system is (4 / 5-1) N2;

[0030] When the maximum flow rate of the test is 50-80 kg / hour (excluding 80 kg / hour), the front pressure of the primary critical system is 6-8 MPa, the number of nozzles opened in the primary critical system is (1 / 2-1) N1, the front pressure of the secondary critical system is 4-6 MPa, and the number of nozzles opened in the primary critical system is (1 / 2-1) N2;

[0031] When the maximum flow rate of the test is less than 50kg / , the front-end pressure of the primary critical system is 4-6MPa, the number of nozzles opened in the primary critical system is (0-1 / 2)N1, the front-end pressure of the secondary critical system is 2-3MPa, and the number of nozzles opened in the secondary critical system is (0-1 / 2)N2.

[0032] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0033] 1. The system of the present invention can achieve a system inlet pressure range of 5MPa to 10MPa, a control flow range of 0kg / s to 100kg / s, a system outlet pressure control range of 0MPa to 0.5MPa, a system outlet flow fluctuation of ≤0.1%, and a flow control accuracy of less than 0.2% through precise control and coordination of the main regulating valve group, the primary critical system, the secondary critical system, the tertiary critical system, and the linkage emptying regulating valve group.

[0034] 2. The system of the present invention controls different air flow ranges through precise regulation and coordination of the main regulating valve group, the first-level critical system, the second-level critical system, the third-level critical system, and the linked emptying regulating valve group, thereby controlling the flow stability of the airflow and achieving accurate control and measurement of flow and pressure.

[0035] 3. In a specific embodiment, the present invention uses a primary critical system, a secondary critical system, and a tertiary critical system connected in series in sequence, and branches with different temperatures are set in parallel in each critical system. Different gas flow rates are formed through the combination of different critical venturi nozzles and switch valves, thereby achieving the purpose of accurately controlling the gas flow rate.

[0036] 4. In a specific embodiment, the present invention controls the pressure of the buffer tank, the inlet pressure of the system, the critical pressure ratio and other parameters to ensure that each level of the critical system reaches the critical state without generating an excessively high-speed post-nozzle airflow. At the same time, the volume of the constant-pressure buffer tank is used to buffer the pressure fluctuation of the air source, and the high-speed airflow output from the previous level critical system through the main air supply pipe is buffered, and the pressure fluctuation is reduced to within 0.1%, so that the flow of the airflow is stable.

[0037] 5. In a specific embodiment, each nozzle in the primary critical system and the secondary critical system of the present invention is calibrated with an accurate and traceable outflow coefficient, and can measure the accurate gas flow while controlling the flow.

[0038] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0040] Figure 1 It is a schematic diagram of the system composition of the multi-stage critical state flow control and pressure matching of the present invention.

[0041] Reference numerals:

[0042] 1-main road; 2-first branch road; 3-second branch road; 4-third branch road. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0044] The present invention provides a system for realizing large-flow multi-stage critical state flow control and pressure matching, comprising gas source equipment, a main circuit, a first branch circuit, a second branch circuit and a third branch circuit;

[0045] The main circuit includes a main circuit gas supply pipe, a main circuit regulating valve group, a primary critical system, a secondary critical system and a tertiary critical system;

[0046] The first branch and the third branch are provided with a linkage emptying regulating valve group;

[0047] The main regulating valve group includes a switch valve, a main regulating valve, a branch regulating valve and a pressure sensor; the pressure sensor, the switch valve and the main regulating valve are sequentially arranged on the main gas supply pipe, and the branch regulating valve is arranged on a second branch connected in parallel with the main gas supply pipe;

[0048] The size of the switch valve is DN400~DN600, the main regulating valve is the main valve with a size of DN400~DN600, and the branch regulating valve is the auxiliary valve with a size of DN100~DN200; the sizes of the main regulating valve and the branch regulating valve are different, respectively covering different flow control ranges, so as to achieve the function of initially stabilizing the pressure of the gas entering the primary critical system when the pressure of the incoming gas source from the gas source equipment (i.e., the front end of the system) fluctuates; the pressure sensor collects and records the pressure at the outlet of the gas source equipment; different opening combinations of the openings of the switch valve, the main regulating valve and the branch regulating valve produce different airflow pressure losses, thereby achieving the function of initially stabilizing the pressure of the gas entering the primary critical system.

[0049] The first-level critical system is arranged on the main road, including the first constant pressure buffer tank, N1 parallel branch air supply pipes, a connecting section and a pressure sensor; each branch air supply pipe is respectively arranged with a critical venturi nozzle and a switch valve in sequence; one end of the first constant pressure buffer tank is connected to the main air supply pipe, and the other end is respectively connected to N1 branch air supply pipes, and the critical venturi nozzle is arranged on the branch air supply pipe near one end of the first constant pressure buffer tank; the pressure sensor is arranged on the first constant pressure buffer tank; the first constant pressure buffer tank has a certain volume, which can buffer the pressure fluctuation of the incoming gas source and reduce the pressure fluctuation to less than 0.1%; the N1 critical venturi nozzles and the switch valve can be independently controlled, and different gas flow flows are formed by the combination of different critical venturi nozzles and switch valves, so as to achieve the purpose of accurately controlling the gas flow; the pressure sensor records the inlet pressure of the first-level critical system. Among them, the value range of N1 is 16 to 26.

[0050] It should be noted that the connecting section is a collecting pipe, which is used to collect the gas in the gas supply pipes of N1 parallel branches of the primary critical system, so that the outlet pressures of different parallel branches are mixed evenly, which is conducive to the stability of the inlet pressure of the secondary critical system; at the same time, due to the different sizes and temperatures of the critical Venturi nozzles set on different branches, different axial displacements will be generated, and axial compensation measures can be configured on the connecting section. For example, a length adjuster and an expansion joint are set on the connecting section to absorb axial displacement of 3-5mm, compensate for different axial telescopic displacements, and meet the structural deformation requirements. Among them, the size of the critical Venturi nozzles of N1 / 2 is DN80~DN100, and the temperature is T1 (T1 is 0-20℃); the size of the critical Venturi nozzles of N1 / 4 is DN50~DN60, and the temperature is T1-10; the size of the critical Venturi nozzles of N1 / 4 is DN25~DN40, and the temperature is T1-20.

[0051] The pressure in front of the critical Venturi nozzle is automatically achieved through pneumatic matching. It should be noted that the pressure in front of the critical Venturi nozzle is controlled by adjusting the pressure of the first constant pressure buffer tank and the number of critical Venturi nozzles opened. The critical Venturi nozzle flow is calculated by measuring the pressure of the first constant pressure buffer tank, and the critical Venturi nozzle flow and the pressure in front of the nozzle meet the following conditions:

[0052] The critical Venturi nozzle flow rate of the primary critical system = the primary critical system discharge coefficient × the pressure before the nozzle × the nozzle throat area.

[0053] Therefore, in the primary critical system, as long as the number of critical Venturi nozzles that are controlled to be opened is determined, the total nozzle throat area of ​​the critical Venturi nozzles can be determined. It is known that the outflow coefficient is a dimensionless constant. The critical Venturi nozzle flow is calculated by measuring the pressure of the first constant pressure buffer tank. Substituting it into the above formula, the pressure before the nozzle can be obtained. Among them, the outflow coefficient is an important parameter to characterize the flow characteristics of the nozzle. It is used to correct the deviation between the theoretical flow rate and the actual flow rate. The outflow coefficient is defined as the ratio of the actual mass flow rate to the theoretical mass flow rate, that is, the outflow coefficient (C) = actual mass flow rate / theoretical mass flow rate. There are usually two methods to determine the outflow coefficient: theoretical calculation and real flow calibration. The present invention adopts the real flow calibration method to determine the outflow coefficient.

[0054] The pressure range of the first buffer tank is 5-10 MPa, that is, the inlet pressure of the primary critical system is 5-10 MPa, and its critical pressure ratio ranges from 0.6 to 0.8, which can ensure that the primary critical system reaches the critical state without generating an excessively high-speed post-nozzle airflow.

[0055] The secondary critical system is arranged on the main road, behind the primary critical system, and the secondary critical system and the primary critical system are connected through the main air supply pipe; the secondary critical system includes a second constant pressure buffer tank, N2 parallel branch air supply pipes (the value range of N2 is 26 to 36), a connecting section and a pressure sensor; a critical venturi nozzle and a switch valve are arranged on each branch air supply pipe in sequence; one end of the second constant pressure buffer tank is connected to the main air supply pipe, and the other end is connected to N2 branch air supply pipes respectively, and the critical venturi nozzle is arranged on the branch air supply pipe near the second constant pressure buffer one end of the tank; the pressure sensor is arranged on the second constant pressure buffer tank; the second constant pressure buffer tank has a certain volume, which can buffer the pressure fluctuation of the incoming gas source, buffer the high-speed airflow output by the primary critical system through the main air supply pipe, and reduce the pressure fluctuation to less than 0.1%; the N2 critical Venturi nozzles and the switch valve can be independently controlled, and different gas flow rates are formed by the combination of different critical Venturi nozzles and switch valves, so as to achieve the purpose of accurately controlling the gas flow; the stable reading value of the pressure sensor determines the flow of the secondary critical system.

[0056] In the secondary critical system, the critical Venturi nozzle size of N2 / 2 is DN80~DN100, and the temperature is T2 (T2 is 0-20℃); the critical Venturi nozzle size of N2 / 4 is DN50~DN60, and the temperature is T2-10; the critical Venturi nozzle size of N2 / 4 is DN25~DN40, and the temperature is T2-20.

[0057] The pressure range of the second buffer tank is 3-8MPa, that is, the inlet pressure of the secondary critical system is 3-8MPa, and the critical pressure ratio range is 0.6-0.8, which can ensure that the secondary critical system reaches the critical state without generating too high a speed of nozzle backflow. The critical Venturi nozzle front pressure of the secondary critical system is also automatically completed through pneumatic matching, and its formula is similar to that of the primary critical system, that is, the critical Venturi nozzle flow of the secondary critical system = the secondary critical system outflow coefficient × the nozzle front pressure × the nozzle throat area. When the critical Venturi nozzle flow, the secondary critical system outflow coefficient and the nozzle throat area are known (the number of critical Venturi nozzles opened can be controlled to determine the total nozzle throat area of ​​the critical Venturi nozzles), the pneumatic nozzle front pressure can be used.

[0058] The three-level critical system is arranged on the main road, behind the two-level critical system, and the three-level critical system and the two-level critical system are connected by a main air supply pipe; the three-level critical system includes two branch air supply pipes in parallel, and each branch air supply pipe is respectively provided with a regulating valve and a switch valve in turn, and the flow range is adjusted by adjusting the opening of the switch valve and the regulating valve to form different opening combinations, and the pressure of the incoming gas source is adjusted, so as to ensure that the pressure ratio of the incoming gas source before and after passing through the critical Venturi nozzle of the two-level critical system is reasonable, so as to control the stable flow of the flow; the inlet pressure of the two-level critical system is 3-8MPa, and its critical pressure ratio range is 0.6-0.8, which can ensure that the two-level critical system reaches the critical state without generating an excessively high-speed post-nozzle airflow, so the inlet pressure range of the three-level system is 1.8MPa-6.4MPa.

[0059] The linked emptying regulating valve group is arranged on the branch, including a second branch air supply pipe and a third branch air supply pipe connected in parallel, a switch valve and a regulating valve are arranged on the second branch air supply pipe in sequence (the switch valve and the regulating valve are main valves, and the sizes of the switch valve and the regulating valve are both DN400-DN600), and a switch valve and a regulating valve are arranged on the third branch air supply pipe in sequence (the switch valve and the regulating valve are auxiliary valves, and the sizes of the switch valve and the regulating valve are both DN100-DN200), the switch valve and the regulating valve are different in size, and respectively cover different flow control ranges; the gas source equipment outputs the incoming gas source through the branch, and the incoming gas source regulates the pressure of the incoming gas source through the linked emptying regulating valve group, and then is discharged into the atmosphere through the second branch air supply pipe; a pressure sensor is arranged before the switch valve of the second branch air supply pipe, and the value of the sensor is the inlet pressure feedback value of the linked emptying regulating valve group, and different flow capacities are generated by different opening combinations of the switch valve and the regulating valve, and the inlet pressure of the linked emptying regulating valve group is matched to realize the flow and pressure regulation function of the source airflow.

[0060] The system also includes a safety valve, which is arranged on the main gas supply pipe and is located before the switch valve of the main regulating valve group. If an abnormal situation occurs in the system (that is, the outlet pressure of the system exceeds the operating pressure by about 10%), the safety valve will trip to ensure that the system does not have an accident due to excessive pressure.

[0061] It should be noted that each nozzle in the primary critical system and the secondary critical system has been calibrated with an accurate and traceable outflow coefficient, so the accurate gas flow rate can be measured while controlling the flow rate. After the primary critical system is the second constant pressure buffer tank of the secondary critical system. The second constant pressure buffer tank is mainly used for buffering and decelerating the high-speed airflow after the nozzle of the primary critical system, creating a small fluctuation and accurate pressure stability point. The critical flow area combined by the secondary critical system is larger than that of the primary critical system. The system can automatically match the buffer tank pressure of the secondary critical system by adopting the principle of aerodynamic matching, that is, when the conservation of the flow before and after is equal, the critical flow area is inversely proportional to the constant pressure of the constant pressure buffer tank. By comparing the flow of the primary critical system with the flow of the secondary critical system, the system flow measurement function can be decompressed to check whether it is normal. The flow deviation of the first critical system and the second critical system should be within 0.1%, which is reasonable. After the secondary critical system, the airflow flows into the tertiary critical system. By combining the different openings of the switch valve and the regulating valve in the tertiary critical system, different flow ranges can be controlled, and the pressure ratio before and after the nozzle of the secondary critical system can be reasonable, thereby controlling the flow stability of the airflow.

[0062] The present invention also provides a method for realizing large flow multi-stage critical state flow control and pressure matching, which is realized by the above system and includes the following steps:

[0063] S1: According to the size of the output airflow of the air source equipment, the openings of the switch valves and the regulating valves on the main road, the first branch, the second branch and the third branch are controlled respectively to determine the size of the output airflow of the main road, the first branch, the second branch and the third branch;

[0064] Specifically, by controlling the openings of the switch valves and regulating valves on the main line, the first branch, the second branch and the third branch respectively, different openings correspond to different pipeline pressure losses, which determines the different flow rates in each pipeline.

[0065] S2: According to the size of the output airflow on the main road, the first branch, the second branch and the third branch and the regulation principle, adjust the main road regulating valve group, the first critical system, the second critical system, the third critical system and the linked emptying regulating valve group to ensure that the outlet flow fluctuation of the third critical system and the linked emptying regulating valve group is ≤0.1%.

[0066] The regulatory principles include:

[0067] When the maximum flow rate of the test is 80-100 kg / hour (including 80 kg / hour), the front pressure of the primary critical system is 8-10 MPa, the number of nozzles opened in the primary critical system is (4 / 5-1) N1, the front pressure of the secondary critical system is 6-8 MPa, and the number of secondary nozzles opened in the secondary critical system is (4 / 5-1) N2;

[0068] When the maximum flow rate of the test is 50-80 kg / hour (excluding 80 kg / hour), the front pressure of the primary critical system is 6-8 MPa, the number of nozzles opened in the primary critical system is (1 / 2-1) N1, the front pressure of the secondary critical system is 4-6 MPa, and the number of nozzles opened in the primary critical system is (1 / 2-1) N2;

[0069] When the maximum flow rate of the test is less than 50kg / , the front pressure of the primary critical system is 4-6MPa, the number of nozzles opened in the primary critical system is (0-1 / 2)N1, the front pressure of the secondary critical system is 2-3MPa, and the number of nozzles opened in the secondary critical system is (0-1 / 2)N2;

[0070] The main regulating valve group is automatically adjusted according to the inlet pressure of the first-level critical system; the linked exhaust regulating valve group is automatically adjusted according to the outlet pressure of the gas source equipment; the third-level critical system level is automatically adjusted according to the 0.6-0.8 value of the inlet pressure of the second-level critical system.

[0071] There are two parallel branches in the main regulating valve group and the linkage emptying regulating valve group. The regulating valve (auxiliary valve) in the branch is responsible for precise control. The opening range of its precise regulation is between 20% and 70%. Whenever the opening of the auxiliary valve is less than 20%, the main valve of the regulating valve (main valve) automatically reduces the opening. Whenever the opening of the auxiliary valve is greater than 70%, the main valve automatically increases the opening, so that the opening of the auxiliary valve is maintained between 20% and 70%, with good regulation characteristics. At the same time, the auxiliary valve adopts a control method that determines the travel speed by deviation, ensuring that it has the characteristics of rapid regulation of large deviations and precise regulation and control of small deviations.

[0072] The system and method of the present invention can achieve a system inlet pressure range of 5MPa to 10MPa, a control flow range of 0kg / s to 100kg / s, a system outlet pressure control range of 0MPa to 0.5MPa, a system outlet flow fluctuation of ≤0.1%, and a flow control accuracy within 0.2%.

[0073] Example 1

[0074] This embodiment provides a system for realizing large-flow multi-stage critical state flow control and pressure matching, including a gas source device, a main path, a first branch path, a second branch path, and a third branch path;

[0075] The main circuit includes a main circuit gas supply pipe, a main circuit regulating valve group, a primary critical system, a secondary critical system and a tertiary critical system;

[0076] The first branch and the third branch are provided with a linkage emptying regulating valve group;

[0077] The main regulating valve group includes a switch valve, a main regulating valve, a branch regulating valve and a pressure sensor; the pressure sensor, the switch valve and the main regulating valve are sequentially arranged on the main gas supply pipe, and the branch regulating valve is arranged on a second branch connected in parallel with the main gas supply pipe;

[0078] The switch valve has a size of DN400, the main regulating valve is a main valve with a size of DN400, and the branch regulating valve is an auxiliary valve with a size of DN150;

[0079] The first-level critical system is arranged on the main road, and includes a first constant pressure buffer tank, 25 (N1) parallel branch air supply pipes, a connecting section and a pressure sensor; a critical venturi nozzle and a switch valve are arranged on each branch air supply pipe in sequence; one end of the first constant pressure buffer tank is connected to the main air supply pipe, and the other end is connected to 25 branch air supply pipes respectively, and the critical venturi nozzle is arranged on the branch air supply pipe near one end of the first constant pressure buffer tank; the pressure sensor is arranged on the first constant pressure buffer tank;

[0080] The connecting section is a collecting pipe, which is used to collect the gas in the 25 parallel branch gas supply pipes of the primary critical system; among them, the size of 13 critical Venturi nozzles is DN80, and the temperature is T1=20℃; the size of 6 critical Venturi nozzles is DN50, and the temperature is 10℃; the size of 6 critical Venturi nozzles is DN25, and the temperature is 0℃.

[0081] The secondary critical system is arranged on the main road, behind the primary critical system, and the secondary critical system and the primary critical system are connected through the main air supply pipe; the secondary critical system includes a second constant pressure buffer tank, 36 (N2) parallel branch air supply pipes, a connecting section and a pressure sensor; a critical venturi nozzle and a switch valve are arranged on each branch air supply pipe in sequence; one end of the second constant pressure buffer tank is connected to the main air supply pipe, and the other end is connected to 36 branch air supply pipes respectively, and the critical venturi nozzle is arranged on one end of the branch air supply pipe close to the second constant pressure buffer tank; the pressure sensor is arranged on the second constant pressure buffer tank; the 36 critical venturi nozzles and the switch valve can be independently controlled.

[0082] In the secondary critical system, the size of 18 critical Venturi nozzles is DN100 and the temperature is T2 (20℃); the size of 9 critical Venturi nozzles is DN60 and the temperature is 10℃; the size of 9 critical Venturi nozzles is DN40 and the temperature is 0℃.

[0083] The linked emptying regulating valve group is arranged on the branch, including a second branch air supply pipe and a third branch air supply pipe in parallel, and a switch valve and a regulating valve are arranged in sequence on the second branch air supply pipe (the switch valve and the regulating valve are main valves, and the sizes of the switch valve and the regulating valve are both DN400), and a switch valve and a regulating valve are arranged in sequence on the third branch air supply pipe (the switch valve and the regulating valve are auxiliary valves, and the sizes of the switch valve and the regulating valve are both DN150).

[0084] The system also includes a safety valve, which is arranged on the main gas supply pipe and is located before the switch valve of the main regulating valve group.

[0085] Example 2

[0086] This embodiment provides a method for achieving large flow rate multi-stage critical state flow control and pressure matching, which is implemented by the system of embodiment 1 and includes the following steps:

[0087] S1: According to the size of the output airflow of the air source equipment (the maximum flow rate is 80kg), the opening of the switch valve and the regulating valve on the main road, the first branch, the second branch and the third branch is controlled respectively to determine the size of the output airflow of the main road, the first branch, the second branch and the third branch;

[0088] S2: According to the size of the output airflow on the main road, the first branch, the second branch and the third branch and the regulation principle, adjust the main road regulating valve group, the first critical system, the second critical system, the third critical system and the linked emptying regulating valve group to ensure that the outlet flow fluctuation of the third critical system and the linked emptying regulating valve group is ≤0.1%.

[0089] The regulation principle is:

[0090] The front pressure of the primary critical system is 8-10 MPa, and the number of nozzles opened in the primary critical system is 20. The front pressure of the secondary critical system is 6-8 MPa, and the number of secondary nozzles opened in the secondary critical system is 29.

[0091] The main regulating valve group is automatically adjusted according to the inlet pressure of the first-level critical system; the linked exhaust regulating valve group is automatically adjusted according to the outlet pressure of the gas source equipment; the third-level critical system level is automatically adjusted according to the 0.6-0.8 value of the inlet pressure of the second-level critical system.

[0092] This embodiment can control the system outlet flow fluctuation to be ≤0.1%, and the flow control accuracy is within 0.2%.

[0093] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A system for realizing large flow multi-stage critical state flow control and pressure matching, characterized in that: Including gas source equipment, main line, first branch line, second branch line and third branch line; The main circuit includes a main circuit gas supply pipe, a main circuit regulating valve group, a primary critical system, a secondary critical system and a tertiary critical system; The first branch and the third branch are provided with a linkage emptying regulating valve group.

2. The system according to claim 1, characterized in that The main regulating valve group includes a switch valve, a main regulating valve, a branch regulating valve and a pressure sensor; The pressure sensor, the switch valve, and the main line regulating valve are sequentially arranged on the main line gas supply pipe, and the branch line regulating valve is arranged on the second branch line connected in parallel with the main line; The switch valve has a size of DN400 to DN600, the main regulating valve is a main valve with a size of DN400 to DN600, and the branch regulating valve is an auxiliary valve with a size of DN100 to DN200.

3. The system according to claim 2, characterized in that The primary critical system is arranged on the main road, and includes a first constant pressure buffer tank, N1 parallel branch gas supply pipes, a connecting section and a pressure sensor; A critical venturi nozzle and a switch valve are respectively arranged on each branch air supply pipe; One end of the first constant pressure buffer tank is connected to the main air supply pipe, and the other end is connected to N1 branch air supply pipes respectively, and the critical venturi nozzle is arranged on the branch air supply pipe close to one end of the first constant pressure buffer tank; The pressure sensor is arranged on the first constant pressure buffer tank.

4. The system according to claim 3, characterized in that The range of N1 is 16 to 26.

5. The system according to claim 4, characterized in that Among the critical Venturi nozzles, the critical Venturi nozzles of number N1 / 2 have a size of DN80 to DN100 and a temperature of T1 of 0 to 20°C; The critical Venturi nozzle size for N1 / 4 number is DN50~DN60, and the temperature is T1-10; The critical Venturi nozzle size for N1 / 4 number is DN25~DN40, and the temperature is T1-20.

6. The system according to claim 5, characterized in that The critical pressure ratio of the primary critical system is in the range of 0.6 to 0.

8.

7. The system according to claim 6, characterized in that The three-level critical system is arranged on the main road, after the two-level critical system, and the three-level critical system and the two-level critical system are connected via a main road gas supply pipe; The three-level critical system includes two branch air supply pipes connected in parallel, and a regulating valve and a switch valve are respectively arranged on each branch air supply pipe.

8. The system according to claim 7, characterized in that The linkage emptying regulating valve group is arranged on the branch road, and includes a second branch road air supply pipe and a third branch road air supply pipe connected in parallel; The second branch gas supply pipe is provided with a switch valve and a regulating valve in sequence, the switch valve and the regulating valve are main valves, and the sizes of the switch valve and the regulating valve are both DN400-DN600; The third branch gas supply pipe is provided with a switch valve and a regulating valve in sequence, wherein the switch valve and the regulating valve are auxiliary valves, and the sizes of the switch valve and the regulating valve are both DN100-DN200.

9. A method for realizing high-flow multi-stage critical state flow control and pressure matching, implemented by the system according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: According to the size of the output airflow of the air source equipment, the openings of the switch valves and the regulating valves on the main road, the first branch, the second branch and the third branch are controlled respectively to determine the size of the output airflow of the main road, the first branch, the second branch and the third branch; S2: According to the size of the output airflow on the main road, the first branch, the second branch and the third branch and the regulation principle, adjust the main road regulating valve group, the first critical system, the second critical system, the third critical system and the linked emptying regulating valve group to ensure that the outlet flow fluctuation of the third critical system and the linked emptying regulating valve group is ≤0.1%.

10. The method according to claim 9, characterized in that In step S2, the adjustment principle includes: When the maximum flow rate of the test is 80-100 kg / hour (including 80 kg / hour), the front pressure of the primary critical system is 8-10 MPa, the number of nozzles opened in the primary critical system is (4 / 5-1) N1, the front pressure of the secondary critical system is 6-8 MPa, and the number of secondary nozzles opened in the secondary critical system is (4 / 5-1) N2; When the maximum flow rate of the test is 50-80 kg / hour (excluding 80 kg / hour), the front pressure of the primary critical system is 6-8 MPa, the number of nozzles opened in the primary critical system is (1 / 2-1) N1, the front pressure of the secondary critical system is 4-6 MPa, and the number of nozzles opened in the primary critical system is (1 / 2-1) N2; When the maximum flow rate of the test is less than 50kg / , the front-end pressure of the primary critical system is 4-6MPa, the number of nozzles opened in the primary critical system is (0-1 / 2)N1, the front-end pressure of the secondary critical system is 2-3MPa, and the number of nozzles opened in the secondary critical system is (0-1 / 2)N2.

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