Cavitation multiphase flow detection experiment system

Abstract

The invention discloses a cavitation multiphase flow detection experiment system in the field of fluid testing, and the system comprises a liquid circulation pipeline module which comprises an inflow section, a gas-liquid mixing section, a testing section and a backflow section, and is used for forming a liquid flowing loop, and achieving the functions of inflow condition controllability and outflow state recovery of a main flow; the gas inlet and gas-liquid mixing pipeline module is communicated with the gas-liquid mixing section and is used for forming a gas-liquid two-phase fluid medium and realizing the controllability of the gas-phase medium; the cavitation flow experiment module is arranged corresponding to the test section and is used for forming a cavitation flow phenomenon and realizing a cavitation flow visualization function; and the multiphase flow test module is arranged corresponding to the cavitation flow experiment module and is used for detecting the characteristics of the cavitation multiphase flow field and realizing a non-intrusive test function. The gas-liquid two-phase flow state can be controlled, two-phase flow media under different gas-containing conditions can be obtained, cavitation flow states of different degrees can be formed, and cavitation flow characteristics under gas-containing influence can be analyzed conveniently.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid testing, and in particular relates to a cavitation multiphase flow detection experimental system. Background Art

[0002] Cavitation is the process of the appearance, development and disappearance of bubbles in liquids. Cavitation causes blockage of the flow channel, accompanied by vibration and noise, which is not conducive to the efficient operation of fluid machinery and leads to energy waste. It is very difficult to experimentally observe the cavitation phenomenon inside fluid machinery. Existing technologies mostly rely on opening windows in part of the mechanical shell or using endoscopes to obtain very limited cavitation flow information. There are also methods that use vibration and noise sensors to indirectly understand the cavitation situation inside the equipment by analyzing the characteristics of vibration and noise signals. Among them, how to eliminate the interference of mechanical vibration and noise is also a difficult problem.

[0003] With the expansion of energy development and power engineering, the cavitation problem in gas-liquid two-phase flow has attracted attention. Since the measurement and regulation of gas-liquid two-phase flow itself is difficult, cavitation is also a hot spot and difficulty in fluid research. The cavitation flow mechanism under gas-containing conditions is particularly complex, and experimental research technology is very lacking.

[0004] Therefore, technicians in this field are committed to developing a cavitation multiphase flow detection experimental system to solve the problem that the gas-liquid two-phase flow state is difficult to control in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a cavitation multiphase flow detection experimental system, which can control the gas-liquid two-phase flow state, thereby obtaining two-phase flow media under different gas-containing conditions, and can form cavitation flow states of different degrees, which is convenient for analyzing the cavitation flow characteristics under the influence of gas.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a cavitation multiphase flow detection experimental system, comprising: a liquid circulation pipeline module, including an inflow section, a gas-liquid mixing section, a test section and a reflux section, for forming a liquid flow loop, realizing the functions of controllable inflow conditions of the mainstream and recovery of the outflow state; an air intake and gas-liquid mixing pipeline module, connected to the gas-liquid mixing section, for forming a gas-liquid two-phase fluid medium, realizing the controllability of the gas phase medium; a cavitation flow experiment module, corresponding to the test section arrangement, for forming a cavitation flow phenomenon, realizing the function of cavitation flow visualization; a multiphase flow test module, corresponding to the cavitation flow experiment module arrangement, for detecting the characteristics of the cavitation multiphase flow field, realizing a non-invasive test function.

[0007] The inflow conditions include the inflow liquid flow rate and the inflow liquid temperature. When the outflow state is restored to the state after one liquid cycle is completed, the conditions for the next inflow are consistent with the previous inflow conditions. Compared with the prior art, the beneficial effects of the present invention are as follows: a liquid circulation pipeline module and an air intake and gas-liquid mixing pipeline module are used to supply liquid and gas to the cavitation flow experiment module respectively. This separate supply method can not only avoid leakage or explosion caused by the interaction between gas and liquid inside the storage tank due to pressure and temperature changes, but also avoid unknown bubbles or air masses in the liquid and unknown droplets in the gas, thereby improving the accuracy and stability of the experiment; the liquid circulation pipeline module can provide a stable liquid flow rate to ensure that the liquid is always at the temperature required by the experiment, thereby improving the reliability of the experimental data; the size of the intake bubbles can be adjusted by the air intake and gas-liquid mixing pipeline module. The module can realize the quantitative setting of various air inlet conditions and facilitate the study of cavitation flow under various gas-containing conditions; the cavitation flow experiment module can realize the visualization of different types of cavitation phenomena, which is convenient for experimenters to intuitively observe the cavitation process and multiphase flow state characteristics, and improve the teaching effect; the multiphase flow test module can be used to conduct non-invasive testing of the cavitation multiphase flow field, avoiding the influence of external interference factors on the experimental results. The test data obtained can also be combined with the phenomena recorded by the cavitation flow experiment module to verify each other and conduct collaborative analysis. The two cooperate with each other to jointly construct a cavitation multiphase flow field test system under gas-containing conditions.

[0008] As a further improvement of the technical solution of the present invention, the cavitation flow experiment module includes a hydrodynamic cavitation generating device arranged on the test section, and a flow recording device is arranged on the outside of the hydrodynamic cavitation generating device, and the flow recording device includes a high-speed camera and an auxiliary light source, and the high-speed camera and the auxiliary light source are symmetrically distributed on both sides of the hydrodynamic cavitation generating device. The use of a high-speed camera can obtain complex flow phenomena in the hydrodynamic cavitation generating device, and then supplemented with an auxiliary light source for light filling, to ensure the clarity of the cavitation flow image and the integrity of the data.

[0009] As a further improvement of the technical solution of the present invention, the multiphase flow test module includes a temperature sensor 1, a pressure sensor 1, a pressure sensor 2 and a temperature sensor 2 which are sequentially arranged on the test section along the inflow direction, the hydraulic cavitation generating device is located between the pressure sensor 1 and the pressure sensor 2, and a vibration test device and a conductivity sensor are arranged corresponding to the hydraulic cavitation generating device, the temperature sensor 1, the pressure sensor 1, the pressure sensor 2, the temperature sensor 2, the vibration test device and the conductivity sensor are all connected to an A / D conversion card, and the A / D conversion card is used to convert the electrical signal measured by the sensor into a digital signal and transmit it to a computer system, and the computer system processes the digital signal and analyzes the multiphase flow characteristics. By setting the temperature sensor and the pressure sensor upstream and downstream of the hydraulic cavitation generating device, the two state parameters of the multiphase flow temperature and pressure can be obtained, the vibration test device can record the vibration of the multiphase flow state in the cavitation generating device, the conductivity sensor can obtain the multiphase flow conductivity distribution data, and the computer system processes and saves these data to achieve a fast, accurate and safe analysis of the cavitation flow characteristics.

[0010] As a further improvement of the technical solution of the present invention, the vibration test device includes a uniaxial acceleration sensor, which is arranged on the hydraulic cavitation generating device through a fixed bracket, and the conductivity sensor is a ring-shaped non-invasive conductivity sensor, and is arranged on the periphery of the hydraulic cavitation generating device. The uniaxial acceleration sensor, with its high sensitivity and high precision, can accurately and comprehensively measure the tiny vibration signal in the inflow direction, providing further data support for the analysis of cavitation flow characteristics.

[0011] As a further improvement of the technical solution of the present invention, the hydrodynamic cavitation generating device is one of a venturi tube, a hydrofoil cavitation generating tube and a wedge cavitation generating tube. By changing the type of the hydrodynamic cavitation generating device, data of various cavitation phenomena can be obtained. Compared with a single cavitation phenomenon, the basic types of cavitation are covered, which can better reflect the complexity and variability in actual operation, so that the experimental results have more external validity.

[0012] As a further improvement of the technical solution of the present invention, the liquid circulation pipeline module also includes a temperature-controlled water tank, a valve 1, a centrifugal pump, an electromagnetic flowmeter 1, and a valve 2 arranged on the reflux section in sequence along the inflow direction. Flow research under different temperatures and different flow rates can be achieved at a lower test cost.

[0013] As a further improvement of the technical solution of the present invention, the temperature-controlled water tank includes a water tank, a temperature controller, an electric heating rod, several temperature sensors three, a cold water switching channel, an electromagnetic flowmeter two, an electromagnetic flowmeter three, a valve three and a valve four. Several of the temperature sensors three are arranged in layers along the height direction of the water tank and are connected to the temperature controller. The electric heating rod is arranged at the center position near the bottom of the water tank. The cold water switching channel is connected to the side of the bottom of the water tank. The electromagnetic flowmeter two and the valve three are arranged at the water outlet end of the cold water switching channel. The electromagnetic flowmeter three and the valve four are arranged at the water inlet end of the cold water switching channel. The electromagnetic flowmeter two and the electromagnetic flowmeter three are both equipped with a built-in microprocessor. The microprocessor is used to calculate and display the total flow rate, and control the cold water flow rate by adjusting the opening and closing degree of valve three and valve four. When any temperature sensor three reaches the set temperature, the temperature controller turns off the power supply of the electric heating rod and / or closes valve three and valve four. The layered temperature sensors form a continuous sensor network in the water tank, which can comprehensively and completely detect the temperature environment in the water tank. By adjusting the valve opening and closing degree, the liquid level in the temperature-controlled water tank is ensured to be always within the appropriate range, providing a stable experimental basis for the analysis of cavitation flow characteristics.

[0014] As a further improvement of the technical solution of the present invention, the air intake and gas-liquid mixing pipeline module includes an air intake device and a gas-liquid mixing device, and the gas-liquid mixing device includes a check valve, a multi-way interface, a gas delivery pipe and a bubble generator that are sequentially connected to the air outlet end of the air intake device. The multi-way interface is connected to multiple gas delivery pipes to ensure that the gas can be evenly delivered to the liquid. The size of the air intake bubble can be adjusted in combination with the bubble generator, and the influence of different bubble size setting schemes on the cavitation flow characteristics can be studied.

[0015] As a further improvement of the technical solution of the present invention, the multi-channel interface includes a gas-discharge diverter, one side of the gas-discharge diverter is provided with an inlet joint, and the other side is provided with 2N equally spaced outlet joints, the outlet joint is connected to the bubble generator through a gas delivery pipe, the bubble generator includes 2N metal joints, a circular porous plate is detachably provided inside the metal joint, the gas-liquid mixing section is provided with inlet holes that are adapted to the size and number of the metal joints, the inlet holes are distributed in front and behind each other along the inflow direction, and the angle between two adjacent inlet holes on the same side is 360° / N. The stability and consistency between the various gas delivery pipes can be guaranteed, so as to ensure that each bubble generator can obtain sufficient air pressure and gas volume, and avoid experimental stagnation caused by insufficient airflow. The angle between two adjacent inlet holes is 360° / N, so that the bubbles are fully mixed with each part of the liquid, and the porous plate is a circular cross-section plate with replaceable opening size and opening number to form bubble groups of different sizes and scales.

[0016] As a further improvement of the technical solution of the present invention, the air intake device includes an air compressor, a filter, a gas storage tank, a pressure reducing valve, a gas solenoid valve and a gas flow meter connected in sequence, the air compressor input end is provided with a filter screen, the gas storage tank is provided with a pressure gauge and a safety valve, the gas flow meter is used to monitor the gas flow at the output end of the air intake device in real time, the pressure gauge is used to display the gas pressure value in the gas storage tank in real time, and the gas solenoid valve is used to quickly cut off or connect the gas passage. The gas pressure is changed by adjusting the pressure reducing valve, and then the gas flow is adjusted. The compressor with a filter screen and a filter can control the quality of the air to ensure the purity of the gas. The gas enters the gas storage tank after pressurization and stabilizes the system pressure, ensuring the stability of the output gas flow and air pressure, and ensuring the gas characteristics entering the experimental system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the system structure of a preferred embodiment of the present invention.

[0018] Figure 2 It is a schematic structural diagram of a temperature-controlled water tank according to a preferred embodiment of the present invention.

[0019] Figure 3 It is a schematic structural diagram of a multiphase flow test module according to a preferred embodiment of the present invention.

[0020] Figure 4 It is a schematic structural diagram of a hydraulic cavitation generating device according to a preferred embodiment of the present invention.

[0021] Figure 5 It is a schematic structural diagram of a circular porous plate according to a preferred embodiment of the present invention.

[0022] Figure 6 It is a schematic diagram of the structure of a multi-channel interface according to a preferred embodiment of the present invention.

[0023] Figure 7 Schematic diagram of the distribution of air inlet holes in a preferred embodiment of the present invention.

[0024] Figure 8 Schematic diagram of the distribution of cavitation phenomenon under the hydraulic cavitation generating device.

[0025] Among them, 1 temperature-controlled water tank, 2 valve 1, 3 centrifugal pump, 4 electromagnetic flowmeter 1, 5 gas-liquid mixing device, 6 gas-liquid mixing section, 7 metal joint, 8 porous plate, 9 gas delivery pipe, 10 multi-way interface, 11 check valve, 12 temperature sensor 1, 13 pressure sensor 1, 14 hydraulic cavitation generator, 15 pressure sensor 2, 16 temperature sensor 2, 17 valve 2, 18 air intake device, 19 gas flowmeter, 20 gas storage tank, 21 pressure gauge, 22 safety valve, 23 pressure reducing valve, 24 gas solenoid valve, 25 filter, 26 air compressor, 27 vibration test device, 28 uniaxial acceleration sensor, 29 flow recording device, 30 high-speed camera, 31 A / D conversion card, 32 computer system, 33 temperature controller, 34 electric heating rod, 35 valve three, 36 electromagnetic flowmeter two, 37 valve four, 38 electromagnetic flowmeter three, 39 temperature sensor three, 40 conductivity sensor, 41 liquid flow circuit, 42 gas exhaust diverter, 43 gas outlet connector. DETAILED DESCRIPTION

[0026] like Figure 1-3 As shown, a cavitation multiphase flow detection experimental system includes: a liquid circulation pipeline module, including an inflow section, a gas-liquid mixing section 6, a test section and a reflux section, and a temperature-controlled water tank 1, a valve 2, a centrifugal pump 3, an electromagnetic flowmeter 4, and a valve 2 17 arranged on the reflux section in sequence along the inflow direction, which are used to form a liquid flow loop 41 to achieve the functions of controllable inflow conditions of the mainstream and recovery of the outflow state; an air intake and gas-liquid mixing pipeline module, which is connected to the gas-liquid mixing section 6, and is used to form a gas-liquid two-phase fluid medium to achieve the controllability of the gas phase medium; a cavitation flow experiment module, which is set corresponding to the test section, is used to form a cavitation flow phenomenon and realize the function of cavitation flow visualization; a multiphase flow test module, which is set corresponding to the cavitation flow experiment module, is used to detect the characteristics of the cavitation multiphase flow field and realize the non-invasive test function; specifically, the inflow condition includes the inflow liquid flow rate and the inflow liquid temperature, and the outflow state is restored to the condition that the inflow condition is consistent with the previous inflow condition after one liquid cycle is completed.

[0027] In this embodiment, the temperature-controlled water tank 1 includes a water tank, a temperature controller 33, an electric heating rod 34, six temperature sensors 39, a cold water switching channel, an electromagnetic flowmeter 2 36, an electromagnetic flowmeter 38, a valve 35 and a valve 4 37. The six temperature sensors 39 are symmetrically distributed in pairs and arranged in layers along the height direction of the water tank and are all connected to the temperature controller 33. The electric heating rod 34 is set at the center position near the bottom of the water tank. The cold water switching channel is connected to the side of the bottom of the water tank. The electromagnetic flowmeter 2 36 and the valve 4 Gate three 35 is arranged at the water outlet end of the cold water switching channel, electromagnetic flowmeter three 38 and valve four 37 are arranged at the water inlet end of the cold water switching channel, electromagnetic flowmeter two 36 and electromagnetic flowmeter three 38 are both equipped with a built-in microprocessor, the microprocessor is used to calculate and display the total flow rate, and control the cold water flow rate by adjusting the opening and closing degree of valve three 35 and valve four 37. When any temperature sensor three 39 reaches the set temperature, the temperature controller 33 turns off the power supply of the electric heating rod 34 and / or closes valve three 35 and valve four 37.

[0028] The cavitation flow experiment module includes a hydraulic cavitation generating device 14 arranged on the test section, and a flow recording device 29 connected to a computer system 32 is arranged on the outer side of the hydraulic cavitation generating device 14. The flow recording device 29 includes a high-speed camera 30 and an auxiliary light source symmetrically distributed on both sides of the hydraulic cavitation generating device 14. When the flow of the hydraulic cavitation generating device 14 is visible, the high-speed camera 30 is connected through the computer system 32 to synchronously display the flow conditions of the medium in the cavitation generating device and the cavitation occurrence conditions.

[0029] Since cavitation is accompanied by changes in heat absorption or heat release, the degree of internal cavitation can be reflected by measuring the temperature of the fluid around the hydraulic cavitation generating device 14; since cavitation is accompanied by pressure fluctuations, the degree of cavitation and the impact of cavitation can be reflected by measuring the pressure pulsation of the inlet and outlet fluids of the hydraulic cavitation generating device 14. The multiphase flow test module includes a temperature sensor 12, a pressure sensor 13, a pressure sensor 15 and a temperature sensor 16 which are sequentially arranged on the test section along the inflow direction. The hydraulic cavitation generator 14 is located between the pressure sensor 13 and the pressure sensor 15. The upstream and downstream temperature changes and pressure pulsation conditions are used to assist in judging the degree of cavitation. A vibration test device 27 and a conductivity sensor 40 are arranged corresponding to the hydraulic cavitation generator 14. The temperature sensor 12, the pressure sensor 13, the pressure sensor 15, the temperature sensor 16, the vibration test device 27 and the conductivity sensor 40 are all connected to an A / D conversion card 31. The A / D conversion card 31 is used to convert the electrical signal measured by the sensor into a digital signal and transmit it to a computer system 32. The computer system 32 processes the digital signal and analyzes the multiphase flow characteristics.

[0030] Below through Figure 4 The hydraulic cavitation generating device 14 is described in detail. The hydraulic cavitation generating device 14 is one of a venturi tube, a hydrofoil cavitation generating tube and a wedge-shaped cavitation generating tube. The hydrofoil cavitation generating tube includes a mounting flange, a test pipe and a hydrofoil fixed at the center of the test pipe cross section. The wedge-shaped cavitation generating tube includes a mounting flange, a test pipe and a wedge-shaped block fixed at the bottom of the test pipe. The corresponding model is selected according to the experimental requirements and connected to the liquid circulation pipeline system through the mounting flange. The venturi tube and the test pipe are both made of transparent plexiglass, which can realize visual observation of the flow field. Pressure sensors and temperature sensors are installed upstream and downstream of the hydraulic cavitation generating device 14 to monitor the pressure and temperature status of the medium passing through the hydraulic cavitation generating device 14.

[0031] The vibration testing device 27 includes a uniaxial acceleration sensor 28, which is mounted on the hydraulic cavitation generating device 14 through a fixed bracket. The conductivity sensor 40 is a circular non-invasive conductivity sensor 40. Taking the Venturi tube as an example, the conductivity sensor 40 is mounted on the outer periphery of the throat of the Venturi tube, which can measure the conductivity of different liquid media without affecting the flow of the liquid itself.

[0032] The air intake and gas-liquid mixing pipeline module includes an air intake device 18 and a gas-liquid mixing device 5. The air intake device 18 includes an air compressor 26, a filter 25, a gas storage tank 20, a pressure reducing valve 23, a gas solenoid valve 24 and a gas flow meter 19 connected in sequence. A filter screen is provided at the input end of the air compressor 26. A pressure gauge 21 and a safety valve 22 are provided on the gas storage tank 20. The gas flow meter 19 is used to monitor the gas flow at the output end of the air intake device 18 in real time. The pressure gauge 21 is used to display the gas pressure value in the gas storage tank 20 in real time. The gas solenoid valve 24 is controlled by a computer system 32 and is used to quickly cut off or connect the gas passage.

[0033] The gas-liquid mixing device 5 includes a check valve 11, a multi-way interface 10, a gas delivery pipe 9 and a bubble generator which are sequentially connected to the gas solenoid valve 24. The multi-way interface 10 includes a gas-discharge diverter 42, one side of which is provided with an inlet connector, and the other side of which is provided with six equidistantly distributed outlet connectors 43, such as Figure 5 As shown, the gas outlet connector 43 is connected to the bubble generator through the gas delivery pipe 9. The bubble generator includes six metal connectors 7. A circular porous plate 8 is detachably provided inside the metal connector 7. Figure 6 As shown, taking N=3 as an example, the gas-liquid mixing section 6 is provided with air inlet holes that are adapted to the size and number of the metal joint 7. The air inlet holes are distributed three in front and three in the inlet direction, and the angle between two adjacent air inlet holes on the same side is 120°. Figure 7 As shown, in actual application, the number of air inlet holes can be increased or decreased according to the size of the circulation pipeline.

[0034] After being roughly filtered through the filter, the air enters the air compressor 26, and after being compressed, it enters the filter 25 for secondary fine filtration. After filtering out tiny particles, moisture and other impurities in the air, it is stored in the gas storage tank 20. After the pressure of the gas in the gas storage tank 20 is stabilized, the gas passes through the gas solenoid valve 24 and then passes through the gas flow meter 19, flows through the check valve 11 and enters the gas exhaust diverter 42, and finally the bubble size and scale are controlled by the bubble generator, thereby controlling the gas-liquid two-phase flow components. The principle of adjusting the bubble size is: in the gas-liquid mixing device 5, the gas reaches the porous plate 8 through the gas delivery pipe 9. The porous plates 8 with different opening sizes and numbers have a dispersing and refining effect on the gas. The porous plates 8 with small opening sizes and large numbers will cause the gas to be divided into smaller bubbles when passing through; on the contrary, the porous plates 8 with large opening sizes and small numbers will produce larger bubbles. The principle of regulating the intake bubble flow is as follows: the regulation of the bubble flow is mainly achieved by controlling the gas flow; in the intake device 18, the gas flow meter 19 monitors the gas flow in real time, the pressure sensor monitors the gas pressure, and the gas pressure is changed by adjusting the pressure reducing valve 23, thereby adjusting the gas flow. When the opening of the pressure reducing valve 23 increases, the gas pressure decreases, the flow rate increases, and the flow rate increases; conversely, the opening of the pressure reducing valve 23 decreases, the gas pressure increases, the flow rate decreases, and the flow rate decreases accordingly; the gas solenoid valve 24 works in conjunction with the pressure reducing valve 23. When the gas flow needs to be precisely controlled, the gas solenoid valve 24 can quickly cut off or connect the gas passage.

[0035] The experimental steps using the system of the present invention are as follows: S1: First, the temperature of the temperature-controlled water tank 1 is set on the temperature controller 33, and the valve 3 35 is opened, a proper amount of water is added to the water tank, and the electric heating rod 34 is turned on. After the set temperature is reached, the temperature controller 33 cuts off the power supply and stops heating.

[0036] S2: Turn on the air compressor 26 until the pressure in the air storage tank 20 reaches the set value required for the experiment, and connect the metal joints 7 to the air inlet holes of the gas-liquid mixing section 6 respectively.

[0037] S3: Turn on the centrifugal pump 3, slowly open valve 12 and valve 2 17, so that the water in the water tank flows through the electromagnetic flowmeter 14, temperature sensor 12, pressure sensor 13, hydraulic cavitation generator 14, pressure sensor 2 15, temperature sensor 2 16 in sequence, and finally returns to the temperature-controlled water tank 1 through valve 2 17.

[0038] S4: The control computer system 32 opens the gas solenoid valve 24 and adjusts the pressure reducing valve 23, so that the gas in the gas storage tank 20 flows through the pressure reducing valve 23, the solenoid valve, the check valve 11, the multi-way interface 10 and the gas delivery pipe 9 in sequence and forms dispersed small bubbles under the action of the porous plate 8, and is fully mixed with the liquid in the gas-liquid mixing section 6 to form a two-phase flow.

[0039] S5: The high-speed camera 30 is connected to the computer system 32, and the images captured by the camera are displayed in the computer system 32. At the same time, the vibration of the cavitation generating device, the distribution of electrical conductivity, the temperature change of the upstream and downstream, and the pressure pulsation of each sensor first transmit the data to the A / D conversion card 31, and the A / D conversion card 31 then converts the relevant signals into digital signals and displays them synchronously in the computer system 32, and saves them together with the captured images.

[0040] S6: After the experiment is over, first turn off the compressor, then close the gas solenoid valve 24, slowly close valve 1 2 and valve 2 17, and finally cut off the power supply of the centrifugal pump 3.

[0041] S7: Change the temperature of the water in the water tank according to the experimental requirements and repeat the above steps.

[0042] like Figure 8 The figure shows the distribution of cavitation phenomena of different degrees and types. Figure (a) shows the examples of the bubble-like floating cavitation phenomenon and the sheet-like fixed cavitation phenomenon in the venturi tube, Figure (b) shows the examples of the floating bubble-like cavitation phenomenon, the attached sheet-like cavitation phenomenon and the end-falling cloud-like cavitation phenomenon in the hydrofoil cavitation generating tube, and Figure (c) shows the examples of the attached sheet-like cavitation phenomenon and the end-falling cloud-like cavitation phenomenon in the wedge-shaped cavitation generating tube. Various cavitation phenomenon experiments can reveal the influence of different gas-containing conditions on different cavitation types and provide new information for studying the cavitation flow characteristics.

[0043] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A cavitation multiphase flow detection experimental system, characterized in that: include: The liquid circulation pipeline module includes an inflow section, a gas-liquid mixing section, a test section and a reflux section, which are used to form a liquid flow loop to achieve the functions of controlling the inflow condition of the mainstream and restoring the outflow state; An air intake and gas-liquid mixing pipeline module is connected to the gas-liquid mixing section and is used to form a gas-liquid two-phase fluid medium to achieve controllability of the gas phase medium; A cavitation flow experiment module, corresponding to the test section setting, is used to form a cavitation flow phenomenon and realize the function of cavitation flow visualization; The multiphase flow test module is arranged corresponding to the cavitation flow experiment module, and is used to detect the characteristics of the cavitation multiphase flow field and realize a non-invasive test function.

2. The cavitation multiphase flow detection experimental system according to claim 1, characterized in that: The cavitation flow experiment module includes a hydraulic cavitation generating device arranged on a test section, and a flow recording device is arranged outside the hydraulic cavitation generating device. The flow recording device includes a high-speed camera and an auxiliary light source, and the high-speed camera and the auxiliary light source are symmetrically distributed on both sides of the hydraulic cavitation generating device.

3. A cavitation multiphase flow detection experimental system according to claim 2, characterized in that: The multiphase flow test module includes a temperature sensor 1, a pressure sensor 1, a pressure sensor 2 and a temperature sensor 2 which are sequentially arranged on the test section along the inflow direction; the hydraulic cavitation generating device is located between the pressure sensor 1 and the pressure sensor 2; a vibration testing device and a conductivity sensor are arranged corresponding to the hydraulic cavitation generating device; the temperature sensor 1, the pressure sensor 1, the pressure sensor 2, the temperature sensor 2, the vibration testing device and the conductivity sensor are all connected to an A / D conversion card; the A / D conversion card is used to convert the electrical signal measured by the sensor into a digital signal and transmit it to a computer system; the computer system processes the digital signal and analyzes the multiphase flow characteristics.

4. The cavitation multiphase flow detection experimental system according to claim 3, characterized in that: The vibration testing device comprises a uniaxial acceleration sensor, which is arranged on the hydraulic cavitation generating device through a fixed bracket. The conductivity sensor is a circular non-invasive conductivity sensor, which is arranged on the periphery of the hydraulic cavitation generating device.

5. The cavitation multiphase flow detection experimental system according to claim 2, characterized in that: The hydraulic cavitation generating device is one of a venturi tube, a hydrofoil cavitation generating tube and a wedge-shaped cavitation generating tube.

6. The cavitation multiphase flow detection experimental system according to claim 1, characterized in that: The liquid circulation pipeline module also includes a temperature-controlled water tank, a valve 1, a centrifugal pump, an electromagnetic flowmeter 1, which are sequentially arranged on the inflow section along the inflow direction, and a valve 2 arranged on the reflux section.

7. The cavitation multiphase flow detection experimental system according to claim 6, characterized in that: The temperature-controlled water tank includes a water tank, a temperature controller, an electric heating rod, several temperature sensors three, a cold water switching channel, an electromagnetic flowmeter two, an electromagnetic flowmeter three, a valve three and a valve four. Several of the temperature sensors three are arranged in layers along the height direction of the water tank and are connected to the temperature controller. The electric heating rod is arranged at the center position near the bottom of the water tank. The cold water switching channel is connected to the side of the bottom of the water tank. The electromagnetic flowmeter two and the valve three are arranged at the water outlet end of the cold water switching channel. The electromagnetic flowmeter three and the valve four are arranged at the water inlet end of the cold water switching channel. The electromagnetic flowmeter two and the electromagnetic flowmeter three are both equipped with a built-in microprocessor. The microprocessor is used to calculate and display the total flow rate, and control the cold water flow rate by adjusting the opening and closing degree of valve three and valve four. When any temperature sensor three reaches the set temperature, the temperature controller turns off the power supply of the electric heating rod and / or closes valve three and valve four.

8. The cavitation multiphase flow detection experimental system according to claim 1, characterized in that: The air intake and gas-liquid mixing pipeline module includes an air intake device and a gas-liquid mixing device, and the gas-liquid mixing device includes a check valve, a multi-way interface, a gas delivery pipe and a bubble generator which are sequentially connected to the air outlet end of the air intake device.

9. The cavitation multiphase flow detection experimental system according to claim 8, characterized in that: The multi-channel interface includes a gas-exhaust diverter, one side of the gas-exhaust diverter is provided with an air inlet connector, and the other side is provided with 2N equidistantly distributed air outlet connectors, the air outlet connector is connected to the bubble generator through a gas delivery pipe, the bubble generator includes 2N metal connectors, a circular porous plate is detachably provided inside the metal connector, the gas-liquid mixing section is provided with air inlet holes that are adapted to the size and number of the metal connectors, the air inlet holes are distributed in front and behind along the inlet direction, and the angle between two adjacent air inlet holes on the same side is 360° / N.

10. The cavitation multiphase flow detection experimental system according to claim 9, characterized in that: The air intake device includes an air compressor, a filter, a gas storage tank, a pressure reducing valve, a gas solenoid valve and a gas flow meter connected in sequence. The air compressor input end is provided with a filter screen, the gas storage tank is provided with a pressure gauge and a safety valve, the gas flow meter is used to monitor the gas flow at the output end of the air intake device in real time, the pressure gauge is used to display the gas pressure value in the gas storage tank in real time, and the gas solenoid valve is used to quickly cut off or connect the gas passage.

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