Gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system and method

Abstract

The present invention provides a gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system and method, the system includes an array channel for collecting gas-liquid two-phase flow cross-sectional velocity information; a fluid circulation device for providing gas-liquid two-phase flow to the array channel; and a data processing control device for processing and controlling the data collected by the array channel; the present invention arranges a data extraction pipe section composed of a plurality of small channel arrays with regular hexagonal cross sections in the array channel, and when the gas-liquid two-phase flow passes through the small channel, there is a loss along the way, and according to the pressure difference and the loss along the way, the flow velocity characteristics of the gas-liquid two-phase flow in the small channel can be obtained. The flow velocity of the gas-liquid two-phase flow in all small channels is extracted and combined into the cross-sectional velocity field of the gas-liquid two-phase flow in the entire pipeline cross section. The pressure sensor of the present invention has the characteristics of small size, large range, high precision, etc., and provides a new method for measuring the cross-sectional velocity field of the gas-liquid two-phase flow.

Description

Technical Field

[0001] The invention relates to the field of gas-liquid two-phase flow velocity field measurement, in particular to a gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system and method. Background Art

[0002] At present, there is no good measurement method for the field measurement of the cross-sectional velocity of gas-liquid two-phase flow. The flow velocity measurement methods mainly include optical, acoustic, electrical, mechanical and other methods.

[0003] Optical methods mainly include PIV and PTV, which use industrial cameras to quickly shoot fluorescent particles and use the tracking ability of particles to characterize the fluid characteristics of the flow field. In recent years, two-phase flow research has gradually tended to PIV full-flow field measurement methods, but traditional PIV technology cannot solve problems such as high image noise and excessive error information due to backward image preprocessing methods, resulting in poor flow field distribution accuracy and increased error vectors. This makes two-phase flow research have great limitations in fluid measurement applications, especially when the dispersed phase content is high. Each particle has different movement speeds, trajectories and other characteristics, which can easily lead to misjudgment in the correlation calculation process. In addition, there is laser technology, which uses image processing methods such as image convolution positioning, Fourier transform frequency analysis and image cross-correlation velocimetry to automatically extract particle position, diameter and velocity information from interference images.

[0004] Acoustics mainly uses ultrasonic technology to measure flow. Ultrasonic measurement of fluid flow has many advantages over other traditional flow measurement methods. The volume flow measured by ultrasound is not affected by the temperature, pressure, viscosity and density of the measured fluid. Due to the propagation characteristics of sound waves in different media, ultrasonic technology can be used to measure the flow of highly corrosive media and non-conductive media. Ultrasonic technology can be well applied to fluid flow measurement in actual engineering.

[0005] Thermal flowmeters based on the principle of thermal balance have become a solution for measuring the flow of gas, liquid, etc. due to their advantages such as sensitivity to low flow, no mechanical structure, little impact on fluid state, and applicability to various pipelines.

[0006] Based on the knowledge of fluid mechanics, pressure change is also a technical method for traditional flow measurement. The differential pressure sensor DPS (Differential Pressure Sensor) is a sensor used to measure the difference between two pressures. It is usually used to measure the pressure difference between the front and rear ends of a device or component. Differential pressure sensors are widely used in many high-precision measurement occasions such as micro-flow measurement, leak testing, clean room monitoring, environmental sealing detection, gas flow measurement, liquid level measurement, etc. In open channels and pipelines with fixed cross-sections, if a differential pressure sensor is used to measure the flow, a flow coefficient can be set in advance, and △h with a certain accuracy can be measured to obtain the flow rate. As the most widely used flowmeter, the differential pressure flowmeter mainly consists of a pressure differential generating device and a pressure differential measuring device. The pressure differential generating device commonly used includes orifice plates, nozzles, and venturi tubes.

[0007] Existing velocity flow meters can only measure the velocity of the entire fluid in the pipeline, but cannot measure the velocity at a specific location because in an actual fluid pipeline, the flow velocity close to the pipe wall is different from the flow velocity at the center of the pipe. Summary of the invention

[0008] One of the purposes of the present invention is to provide a gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system to solve the problem of difficulty in measuring multiphase flow velocity field in the prior art.

[0009] One of the purposes of the present invention is achieved as follows: A gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system comprises: an array channel for collecting gas-liquid two-phase flow cross-sectional velocity information; a fluid circulation device for providing gas-liquid two-phase flow to the array channel; and a data processing control device for processing and controlling the data collected by the array channel;

[0010] The array channel includes a data extraction pipe section arranged at one end of the upstream surface, an observation pipe section arranged in the middle and a flow stabilization pipe section arranged at one end of the downstream surface; the data extraction pipe section is composed of a plurality of small channel arrays with regular hexagonal cross-sections; pressure sensors are respectively arranged at both ends of each of the small channels to form two groups of array pressure sensors, and the array pressure sensors are connected to the data processing control device.

[0011] Furthermore, the present invention can be implemented according to the following technical solutions:

[0012] The array pressure sensor is connected to the data processing control device via a data acquisition card, and the data acquisition card is connected to a patrol inspection instrument.

[0013] The flow stabilizing pipe section is formed by an array of multiple small channels with regular hexagonal cross sections; the observation pipe section is a transparent acrylic pipe section; flanges are respectively arranged at both ends of the array channels.

[0014] The fluid circulation device includes a water source unit, an air source unit and a calibration pipeline unit;

[0015] The water source unit includes a water tank, a water pump, and a water tower connected in series;

[0016] The air source unit includes an air pump, a pressure regulating tank and a dryer connected in series;

[0017] The calibration pipeline unit includes three pipelines connected to the mixer, the first pipeline is connected to the water tower and is connected in series with a standard flow meter, a pressure gauge and a temperature gauge; the second pipeline is connected to the dryer and is connected in series with a pressure gauge and a standard flow meter; the third pipeline is connected to the water tank through a pressure gauge;

[0018] The array channel is arranged on the first pipeline of the verification pipeline unit;

[0019] The data processing control device is connected to the fluid circulation device to control the fluid circulation device to perform the circulation work of water source and air source.

[0020] The data processing control device comprises an industrial control computer, a PLC module, a relay and a power supply.

[0021] The second purpose of the present invention is to provide a microchannel array differential pressure detection method for the cross-sectional velocity field of a gas-liquid two-phase flow, so as to solve the problem that the existing method cannot measure the multiphase flow velocity field.

[0022] The second object of the present invention is achieved as follows: A gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection method comprises the following steps:

[0023] A. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection method is applied to a gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system;

[0024] B. The fluid circulation device provides a stable gas-liquid two-phase flow to the array channel. The gas-liquid two-phase flow generates electrical signals at both ends of the pressure sensor in the array channel and outputs them to the data processing control device. The expression of the pressure sensor is:

[0025] E=KΔP (x,y)

[0026] ΔP 水(x,y) =h f水 ρg

[0027] ΔP 气(x,y) =h f气 ρg

[0028] By V 2 =2hf Dg / λL, the velocity expression of the gas-liquid two-phase flow in the array channel is deduced as:

[0029]

[0030] Where P n is the measured pressure value in the pipeline, P 水 is the boundary pressure value of gas-liquid phase, E is the electrical signal, K is the pressure and electrical signal conversion coefficient, f(x,y) is the velocity expression function of the small channel at each position, h f h is the drag loss along the way caused by the force, λ is the drag coefficient along the way, D is the inner diameter of the pipe, L is the length of the laminar flow section of the fluid in the pipe, and g is the local gravity acceleration measured in m / s 2 , ΔP (x,y) Measure the pressure difference of the small channel with coordinates (x, y);

[0031] C. The pressure value in the small channel is detected by the pressure sensor and transmitted to the data processing control device in real time. The pressures generated by the two pressure sensors at different positions in the small channel are subtracted to generate a pressure difference ΔP n ;

[0032] When the pressure difference in the small channel is greater than the minimum pressure difference of the water phase, ΔP n ≥ΔP 水min ≥0, at this time, the pressure difference in the small channel is the pressure difference ΔP generated by the water phase n =ΔP 水相(x,y) , then the fluid velocity in the pipe is

[0033] When the pressure difference in the small channel is less than the minimum pressure difference in the water tank, ΔP 水min ≥ΔP n ≥0, at this time, the pressure difference in the small channel is the pressure difference ΔP generated by the gas phase n =ΔP 气相(x,y) , then the fluid velocity in the pipe is

[0034] D. The data processing and control device integrates the velocity of the gas-liquid two-phase flow in each group of small channels, and finally obtains the cross-sectional velocity field of the gas-liquid two-phase flow.

[0035] Furthermore, the present invention can be implemented according to the following technical solutions:

[0036] In step B, the power is turned on, the rotary valve of the calibration pipeline unit is opened, the water source unit and the air source unit are opened, the water pump draws the water in the water tank and flows to the top of the water tower, forming a water pressure difference and flowing out from the bottom, the water flows through the standard flow meter, pressure gauge, array channel and temperature gauge in sequence, the water in the water tank and the gas in the air source unit are passed into the mixer together, and finally reach the water tank to form a closed loop.

[0037] In the step B, the gas-liquid two-phase fluid is in a stable state within a certain period of time. When the fluid passes through the array channel, the inspection meter and the data acquisition card start to operate, supply power and collect signals to the sensors in each small channel. The signal is transmitted from the FPC circuit board to the inspection meter and then to the data acquisition card. Each time the pressure information in a small channel of a layer of the array channel is inspected, the collected signal enters the data processing control device.

[0038] The present invention arranges a data extraction pipe section composed of a plurality of small channel arrays with regular hexagonal cross sections in an array channel, and arranges pressure sensors at both ends of each small channel. The pressures of the two pressure sensors at different positions in the small channel are subtracted to generate a pressure difference. The pressure difference in the same pipeline is different, which represents the different flow rate of the fluid in the pipeline. Since the pressure difference between the gas and liquid phases is large, it can also be used as a standard to distinguish the gas and liquid in the small channel. The pressure at different positions will have different manifestations. In different small channels, the same position and the same distance are arranged with the same row of pressure sensors. When the gas-liquid two-phase flow passes through the small channel, due to the loss along the way, the flow rate characteristics of the gas-liquid two-phase flow in the small channel can be obtained according to the pressure difference and the loss along the way. The flow velocity of the gas-liquid two-phase flow in all small channels is extracted and combined into the cross-sectional velocity field of the gas-liquid two-phase flow in the entire pipeline cross section. The pressure sensor of the present invention has the characteristics of small size, large range, high precision, etc., and provides a new method for measuring the cross-sectional velocity field of the gas-liquid two-phase flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the present invention.

[0040] Figure 2 It is a schematic diagram of the structure of the array channel of the present invention.

[0041] Figure 3 It is a schematic diagram of the structure of the small channel of the present invention.

[0042] Figure 4 It is a cross-sectional view of a data extraction pipe section in the array channel of the present invention.

[0043] In the figure: 1. dryer, 2. rotary valve, 3. standard flow meter, 4. water pump, 5. array channel, 6. temperature gauge, 7. pressure gauge, 8. data extraction pipe section, 9. flange, 10. flow stabilizing pipe section, 11. observation pipe section, 12. front pressure sensor data cable, 13. rear pressure sensor power cable, 14. front pressure sensor power cable, 15. rear pressure sensor data cable, 16. small channel, 17. pressure sensor, 18. FPC circuit board. DETAILED DESCRIPTION

[0044] Example 1

[0045] like Figure 1 As shown, the gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system of the present invention includes an array channel 5 for collecting gas-liquid two-phase flow cross-sectional velocity information; a fluid circulation device that provides gas-liquid two-phase flow to the array channel 5; and a data processing control device that processes and controls the data collected by the array channel 5.

[0046] like Figure 2 As shown, the array channel 5 includes a data extraction pipe section 8 arranged at one end of the upstream surface, an observation pipe section 11 arranged in the middle, and a flow stabilization pipe section 10 arranged at one end of the downstream surface. The observation pipe section 11 is a transparent acrylic pipe section, which can be used for optical, acoustic, and other non-invasive speed measuring instruments. It can be connected to other measuring instruments as needed to detect the velocity information of particles in the fluid-solid field and verify the accuracy of other flow velocity measuring devices. The observation pipe section 11 is for fluid simulation verification. Under the stratified flow state, the fluid flow rate in the array channel 5 can replace the flow rate in the observation pipe section 11. The fluid flows through the data extraction pipe section 8 through the main pipeline, then flows through the observation pipe section 11, and then flows through the flow stabilization pipe section 10. The purpose of the latter flow stabilization pipe section 10 is to rectify and form a stable flow shape. After the fluid passes through the array channel 5, it is recombined in the observation pipe section 11 to form a gas-liquid two-phase flow in the pipeline. Due to the flow stabilization pipe section 10 of the same array-type small channel 16 at the rear, the flow shape is fixed within a certain range. Within a certain flow velocity range, the flow velocity in the observation pipe section 11 can be replaced by the flow velocity in the data extraction pipe section 8 .

[0047] The data extraction pipe section 8 and the flow stabilization pipe section 10 are both composed of a plurality of small channels 16 arrayed with regular hexagonal cross sections, which play a role in stabilizing the manifold. These small channels 16 arrayed together are composed of photosensitive resin materials printed by 3D. Pressure sensors 17 are respectively arranged at both ends of the small channels 16 of the data extraction pipe section 8, forming two groups of array pressure sensors 17 sensors, which are used for detecting the flow velocity of the gas-liquid two-phase flow in the channel.

[0048] The cross-section of the small channel 16 is in the shape of a regular hexagon. With the same amount of material, the hexagonal structure is the most stable under stress. The gaps produced when the hexagons are bent into a curved surface are the smallest, and the space utilization rate is the highest. When the fluid flows in the pipeline, pressure loss will occur. Since the cross-sectional area of ​​all small channels 16 is the same, when the fluid material is the same, the pressure difference in different pipelines is different, which means that the flow rate of the fluid in the pipeline is different. Two-phase flow is two materials, namely gas phase and water phase. Since the two phases have different ranges, the pressure in the small channel 16 will be very different to distinguish the gas and liquid phases.

[0049] According to the relationship between the loss of fluid along the pipeline and the flow rate, the placement of the pressure sensor 17 in the small pipeline is designed. The pressure sensor 17 is a micro sensor made of MEMS technology. The sensor is embedded on the PFC circuit board. Two small holes with the same distance are distributed on each small channel 16, and the size of the small hole can just pass through the pressure sensor 17. The pressure sensor 17 has a large range and high precision. It can ensure that it can measure the pressure of the gas phase while measuring the water phase pressure. Since the pressure change is small, the sensor is required to have a certain degree of accuracy. The wiring is connected to the pipeline wall, and the connection line is powered by the power supply and the data acquisition card. In order to avoid too many data acquisition cards and power supplies, and to avoid interference from other factors, a patrol meter is set between the power supply and the data acquisition card to patrol each layer and collect data.

[0050] The pressure generated by the two pressure sensors 17 at different positions in the small channel 16 is subtracted to generate a pressure difference. The signal is transmitted from the FPC circuit board to the inspection instrument and then to the data acquisition card. Each time, the information in a small channel 16 is inspected. Similarly, the power supply system is also inspected by the inspection instrument, thereby realizing the collection and transmission of the signal of each layer of pressure sensor 17. Then, the velocity field of the gas-liquid two-phase interface is formed by the collection of all signals. The array pressure sensor 17 sensor is connected to the data processing control device through the data acquisition card, and the data acquisition card is connected to the inspection instrument.

[0051] The data extraction pipe section 8 is composed of a 3D printed small channel 16, an FPC circuit board, and a MEMS pressure sensor 17. The cross-section of the array is a regular hexagonal small channel 16 made by 3D printing as the basic skeleton of the stable flow field. The FPC circuit board is used as the connected circuit board and the signal sensing line for the signal connection, and the MEMS pressure sensor 17 is used as the sensing unit. The FPC circuit board 18 is printed using printed circuit board technology. When the pressure sensor 17 on the FPC circuit board 18 coincides with the position of the through hole, the FPC circuit board 18 and the small channel 16 are glued together, and each row of small channels 16 are glued together to form an array pressure sensor 17 sensor. When the fluid passes through, the array pressure sensor 17 sensor is used to detect the characteristics of the gas-liquid two-phase flow, and two groups of array pressure sensors 17 sensors are formed within a distance before and after. The pressure sensor 17 is waterproof and does not affect the gas-liquid two-phase flow in the flow field.

[0052] like Figure 3 and Figure 4As shown, the cross section of the small channel 16 is a regular hexagonal hole with a side length of 1mm, and a through hole is opened on the channel wall for the pressure sensor 17 to contact the water. 1124 small channel 16 structural through holes are arranged in the overall pipeline cross section. The center distance between the through holes is 1.1mm, and the distance between the center of the outer circle of small holes and the tube wall is 0.5mm. Flanges 9 are respectively provided at both ends of the array channel 5. A front pressure sensor data line 12 and a front pressure sensor power line 14 are provided at the front pressure sensor 17 of the data extraction pipe section 8, and a rear pressure sensor data line 15 and a rear pressure sensor power line 13 are provided at the rear pressure sensor 17. The data extraction pipe section 8 and the flow stabilizing pipe section 10 are placed in the acrylic pipe, the leads are connected, and connected to the flange 9 to prevent fluid outflow.

[0053] The external leads of the FPC circuit board 18 are connected to the data processing control device through the data acquisition card. Powered by a stable power supply, the power supply is connected to the inspection meter, and the data acquisition card is also connected to the inspection meter. The signal is transmitted from the FPC circuit board to the inspection meter and then to the data acquisition card, and the information in one layer of array channel 5 is inspected each time. Similarly, the power supply is also inspected by the inspection meter, thereby realizing the collection and transmission of the signal of each pressure sensor 17. In order to ensure simultaneity, a simultaneous switch is set at the front end of the power inspection meter and the data acquisition card inspection meter, so that the two groups of inspection meters can be inspected at the same time, and the pressure sensor 17 in each channel can be quickly connected and responded quickly. The inspection meter and the array pressure sensor 17 are used in conjunction with the sensor to perform patrol detection, alarm control, transmission output, data acquisition and communication on multi-channel temperature, pressure, liquid level, flow, weight and other process parameters.

[0054] like Figure 1 As shown, the fluid circulation device includes a water source unit, an air source unit and a test pipeline unit. The water source unit includes a series-connected water tank (volume of 11.5m 3 )、Water pump 4 (25LG3-10X5, 3m 3 / h, 2.2kW), water tower (2×2×2.5m). The water tank is used to provide the water source required for the experiment. The water tower uses the height difference to form a large water pressure, and the water pump 4 provides the power required for water circulation. The three work together to provide a water source with sufficient pressure for the fluid circulation device.

[0055] The air source unit includes a series-connected silent air pump (flow rate 2.6Nm3 / min, pressure 1.1MPa, 11.5kw), a pressure-surge tank (single volume 2.5m 3 , pressure 1.0MPa), dryer 1 (normal temperature 220V, 3.5m 3). The silent air pump provides sufficient pressure and volume of clean gas for the fluid circulation device, and minimizes the noise. The pressure regulating tank can provide sufficient gas storage space and pressure regulation function, so that the output gas pressure is stable and easy to adjust.

[0056] The calibration pipeline unit includes three pipelines (DN25 / 20 / 15 / 10, DN50 / 40 / 32, DN100 / 80 / 65) connected to the mixer. Each pipeline is equipped with front and rear straight pipe sections, a screw valve 2, a pneumatic clamp, a short section, and a ±0.075% absolute pressure transmitter and a 0.2% temperature transmitter. The straight pipe section is used to stabilize the flow. The small channel 16 device is installed according to the principle of ten before and five after (a straight pipe section with a distance of ten times the inner diameter of the pipeline needs to be installed before the inlet, and a straight pipe section with a distance of five times the inner diameter of the pipeline needs to be installed after the outlet). The screw valve 2 is used to open and close the valve 2 of the fluid circulation device. The pneumatic clamp is used to fix the array channel 5 to be calibrated. The pipeline and the short section can slide back and forth on the linear guide rail. The straight pipe section and the short section adopt a quick-install structure to facilitate the installation and connection of the variable diameter pipeline. The absolute pressure transmitter is used to monitor the pressure inside the pipeline at any time. The temperature transmitter converts the signal of the temperature sensor into a current signal, connects it to the secondary instrument, and then displays the corresponding temperature.

[0057] The first pipeline of the calibration pipeline unit is connected to the water tower and is connected in series with a standard flow meter 3, a pressure gauge 7 and a temperature gauge 6; the second pipeline is connected to the dryer 1 and is connected in series with a pressure gauge 7 and a standard flow meter 3; the third pipeline is connected to the water tank through a pressure gauge 7.

[0058] The array channel 5 is arranged on the first pipeline of the verification pipeline unit. The data processing control device is connected with the fluid circulation device to control the fluid circulation device to perform the circulation work of the water source and the air source.

[0059] The data processing control device includes an industrial control computer, a PLC module, a relay and a power supply.

[0060] The hardware of the data processing and control device adopts an industrial control computer, the control module adopts a Siemens PLC module, the relay can adopt a Panasonic product, and the field valve 2 and instrument power supply adopt a Siemens power supply module to ensure the reliability of the measurement and control of the entire device. PLC realizes various controls of the measurement part, collects various signals in real time to complete the control of the calibration process, can reliably realize remote operation, and also has data frontier processing and management functions, mainly realizing all flow meters and various transmitters to automatically collect and output multi-channel control signals to automatically control the flow to meet the calibration requirements. The industrial control computer controls the switches of each valve 2 in the system, and is connected to each absolute pressure transmitter, temperature transmitter, standard flow meter 3, pressure gauge 7 and temperature gauge 6 in the system.

[0061] Example 2

[0062] The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection method of the present invention comprises the following steps:

[0063] A. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection method is applied to the gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system described in Example 1. The inspection instrument is debugged to synchronize the circuit input and pressure output signals in the inspection instrument.

[0064] B. Turn on the power, open the rotary valve 2 of the calibration pipeline unit, open the water source unit and the air source unit, and the water pump 4 pumps the water in the water tank and flows it to the top of the water tower, forming a water pressure difference and flowing out from the bottom. The water flows through the standard flow meter 3, pressure gauge 7, array channel 5 and thermometer 6 in sequence. The water in the water tank and the gas in the air source unit are introduced into the mixer together. In the mixer, the gas and liquid are distributed according to the volume fraction and introduced into the water tank together to form a closed loop.

[0065] The gas-liquid two-phase fluid flows from the pipeline into the matrix channel. When the fluid encounters the pressure sensor 17, the pressure sensor 17 generates an electrical signal. After the fluid passes through the data extraction pipe section 8, it is recombined in the observation pipe section 11 to form a gas-liquid two-phase flow in the pipeline. Since the flow stabilizing pipe section 10 with the same array of small channels 16 structure as the data extraction pipe section 8 is arranged at the rear, the flow shape can be fixed within a certain range. Therefore, within a certain flow rate range, the flow rate of the observation pipe section 11 can be replaced by the flow rate in the small channel 16.

[0066] The gas-liquid two-phase fluid presents a stable state within a certain period of time. When the fluid passes through the array channel 5, the inspection instrument and the data acquisition card start to operate, supply power and collect signals to the sensors in each small channel 16. The signal is transmitted from the FPC circuit board to the inspection instrument and then to the data acquisition card. Each time the pressure information in a small channel 16 of a layer of array channel 5 is inspected, the collected signal enters the data processing control device.

[0067] The fluid circulation device provides a stable gas-liquid two-phase flow to the array channel 5. The gas-liquid two-phase flow generates an electrical signal at both ends of the pressure sensor 17 in the array channel 5 and outputs it to the data processing control device. The expression of the pressure sensor 17 is:

[0068] E=KΔP (x,y)

[0069] ΔP 水(x,y) =h f水 ρg

[0070] ΔP 气(x,y) =h f气 ρg

[0071] By V 2=2h f Dg / λL, the gas-liquid two-phase flow velocity in the array channel 5 is expressed as:

[0072]

[0073] This expression shows that the velocity is only related to the gas or liquid phase along the resistance loss h f related.

[0074] Where P n is the measured pressure value in the pipeline, P 水 is the boundary pressure value of gas-liquid phase, E is the electrical signal, K is the conversion coefficient between pressure and electrical signal, f(x,y) is the velocity expression function of small channel 16 at each position, h f h is the drag loss along the way caused by the force, λ is the drag coefficient along the way, D is the inner diameter of the pipe, L is the length of the laminar flow section of the fluid in the pipe, and g is the local gravity acceleration measured in m / s 2 , ΔP (x,y) Measure the pressure difference of the small channel 16 at the coordinate (x, y);

[0075] C. The pressure value (pressure difference) in the small channel 16 is detected by the (MEMS) pressure sensor 17 and transmitted to the data processing control device in real time. The pressures generated by the two pressure sensors 17 at different positions in the small channel 16 are subtracted to generate a pressure difference ΔP n ;

[0076] In the process of data processing, the conclusions obtained from previous experimental results should be followed to judge the properties of the phase in the small channel 16, that is, the pressure variation range of pure water and pure gas is different. Under the same flow rate, the pressure range of pure water phase is 100kp-200kp, and the pressure range of gas phase is 1kp-2kp. The pressure of pure water phase is much greater than that of pure gas phase. 水min Here, 100 kp is used. Due to the tension of water, only a gas phase and a liquid phase are generated in the small channel 16, so the pressure value in the small channel 16 can be easily determined, and the velocity in the small channel 16 can be calculated by using the relationship expression of the gas-liquid two-phase flow velocity in the array channel 5.

[0077] When the pressure difference in the small channel 16 is greater than the minimum pressure difference of the water phase, ΔP n ≥ΔP 水min ≥0, at this time, the pressure difference in the small channel 16 is the pressure difference ΔP generated by the water phase n =ΔP 水相(x,y) , then the fluid velocity in the pipe is

[0078] When the pressure difference in the small channel 16 is less than the minimum pressure difference of the water tank, ΔP 水min ≥ΔP n≥0, at this time, the pressure difference in the small channel 16 is the pressure difference ΔP generated by the gas phase n =ΔP 气相(x,y) , then the fluid velocity in the pipe is

[0079] D. The data processing control device integrates the velocity of the gas-liquid two-phase flow in each group of small channels 16, and finally obtains the cross-sectional velocity field of the gas-liquid two-phase flow. The flow velocity of the gas-liquid two-phase flow in all small channels 16 is extracted and combined into the cross-sectional velocity field of the gas-liquid two-phase flow in the entire pipeline cross section. When the gas-liquid two-phase flow flows through the array channel 5, after simulation calculation, the gas-liquid two-phase flow in the channel under the action of the data extraction pipe section 8 and the steady flow pipe section 10 can characterize the distribution of the gas-liquid two-phase flow velocity field in the detection section.

Claims

1. A gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system, characterized in that: It includes: an array channel for collecting velocity information of gas-liquid two-phase flow cross section; A fluid circulation device for providing gas-liquid two-phase flow to the array channel; and a data processing control device for processing and controlling the data collected by the array channel; The array channel includes a data extraction pipe section arranged at one end of the upstream surface, an observation pipe section arranged in the middle, and a flow stabilization pipe section arranged at one end of the downstream surface; the data extraction pipe section is formed by a plurality of small channel arrays with regular hexagonal cross sections; pressure sensors are respectively arranged at both ends of each of the small channels to form two groups of array pressure sensors, and the array pressure sensors are connected to the data processing control device; The data processing and control device integrates the velocity of the gas-liquid two-phase flow in each group of small channels, and finally obtains the cross-sectional velocity field of the gas-liquid two-phase flow.

2. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system according to claim 1 is characterized in that: The array pressure sensor is connected to the data processing control device via a data acquisition card, and the data acquisition card is connected to a patrol inspection instrument.

3. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system according to claim 1, characterized in that: The flow stabilizing pipe section is formed by an array of multiple small channels with regular hexagonal cross sections; the observation pipe section is a transparent acrylic pipe section; flanges are respectively arranged at both ends of the array channels.

4. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system according to claim 1, characterized in that: The fluid circulation device includes a water source unit, an air source unit and a calibration pipeline unit; The water source unit includes a water tank, a water pump, and a water tower connected in series; The air source unit includes an air pump, a pressure regulating tank and a dryer connected in series; The calibration pipeline unit includes three pipelines connected to the mixer, the first pipeline is connected to the water tower and is connected in series with a standard flow meter, a pressure gauge and a temperature gauge; the second pipeline is connected to the dryer and is connected in series with a pressure gauge and a standard flow meter; the third pipeline is connected to the water tank through a pressure gauge; The array channel is arranged on the first pipeline of the verification pipeline unit; The data processing control device is connected to the fluid circulation device to control the fluid circulation device to perform the circulation work of water source and air source.

5. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system according to claim 1, characterized in that: The data processing control device comprises an industrial control computer, a PLC module, a relay and a power supply.

6. A gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection method, characterized in that: The steps include: A. The gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection method is applied to the gas-liquid two-phase flow cross-sectional velocity field microchannel array differential pressure detection system according to claim 1; B. The fluid circulation device provides a stable gas-liquid two-phase flow to the array channel. The gas-liquid two-phase flow generates electrical signals at both ends of the pressure sensor in the array channel and outputs them to the data processing control device. The expression of the pressure sensor is: E=KΔP (x,y) ΔP 水(x,y) =h f水 ρg ΔP 气(x,y) =h f气 ρg By V 2 =2h f Dg / λL, the velocity expression of the gas-liquid two-phase flow in the array channel is deduced as: Where P n is the measured pressure value in the pipeline, P 水 is the boundary pressure value of gas-liquid phase, E is the electrical signal, K is the pressure and electrical signal conversion coefficient, f(x,y) is the velocity expression function of the small channel at each position, h f h is the drag loss along the way caused by the force, λ is the drag coefficient along the way, D is the inner diameter of the pipe, L is the length of the laminar flow section of the fluid in the pipe, and g is the local gravity acceleration measured in m / s 2 , ΔP (x,y) Measure the pressure difference of the small channel with coordinates (x, y); C. The pressure value in the small channel is detected by the pressure sensor and transmitted to the data processing control device in real time. The pressures generated by the two pressure sensors at different positions in the small channel are subtracted to generate a pressure difference ΔP n ; When the pressure difference in the small channel is greater than the minimum pressure difference of the water phase, ΔP n ≥ΔP 水min ≥0, at this time, the pressure difference in the small channel is the pressure difference ΔP generated by the water phase n =ΔP 水相(x,y) , then the fluid velocity in the pipe is When the pressure difference in the small channel is less than the minimum pressure difference in the water tank, ΔP 水min ≥ΔP n ≥0, at this time, the pressure difference in the small channel is the pressure difference ΔP generated by the gas phase n =ΔP 气相(X,y) , then the fluid velocity in the pipe is D. The data processing and control device integrates the velocity of the gas-liquid two-phase flow in each group of small channels, and finally obtains the cross-sectional velocity field of the gas-liquid two-phase flow.

7. The microchannel array differential pressure detection method for gas-liquid two-phase flow cross-sectional velocity field according to claim 6 is characterized in that In step B, the power is turned on, the rotary valve of the calibration pipeline unit is opened, the water source unit and the air source unit are opened, the water pump draws the water in the water tank and flows to the top of the water tower, forming a water pressure difference and flowing out from the bottom, the water flows through the standard flow meter, pressure gauge, array channel and temperature gauge in sequence, the water in the water tank and the gas in the air source unit are passed into the mixer together, and finally reach the water tank to form a closed loop.

8. The microchannel array differential pressure detection method for gas-liquid two-phase flow cross-sectional velocity field according to claim 6, characterized in that In the step B, the gas-liquid two-phase fluid is in a stable state within a certain period of time. When the fluid passes through the array channel, the inspection meter and the data acquisition card start to operate, supply power and collect signals to the sensors in each small channel. The signal is transmitted from the FPC circuit board to the inspection meter and then to the data acquisition card. Each time the pressure information in a small channel of a layer of the array channel is inspected, the collected signal enters the data processing control device.

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