A Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters

Abstract

The invention discloses a venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters, comprising a water tank, a water tank outlet pipe, a water pump, a water pump outlet pipe, a solenoid valve, a connecting pipe, an elbow, an electromagnetic flowmeter, a pressure gauge, an experimental venturi pipe section, a water tank return pipe, a bubble injection group, a stepper motor, a test table, a computer, a solenoid valve controller, a data acquisition card and a stepper motor controller. The water tank, the water pump, the solenoid valve, the electromagnetic flowmeter, the pressure gauge and the experimental venturi pipe section are connected by connecting pipes and elbows to form a water circuit of the entire experimental system. The computer controls the start and stop of the stepper motor, and the bubble injector connected to the stepper motor completes the fixed flow gas injection operation into the venturi pipe. By adjusting and replacing the bubble injector connected to the stepper motor, the flow characteristic experiment of variable bubble parameters under various working conditions can be realized. The invention can complete the venturi bubble experiment at different gas injection flow rates and gas injection positions.

Description

Technical Field

[0001] The invention relates to the technical field of gas-liquid two-phase flow, in particular to a Venturi gas-water mixing experimental platform with adjustable gas injection flow rate and bubble parameters. Background Art

[0002] Gas-liquid two-phase flow refers to the mixed flow between liquid phase fluid and gas phase fluid. Gas-liquid two-phase flow is a multiphase flow form widely used in nature and in human production and life, and is the most common multiphase flow mode. Gas-liquid two-phase flow has a very broad application space in the fields of power, petrochemical, smelting and refrigeration.

[0003] The Venturi tube has many advantages such as simple structure, stability and durability. It has broad application prospects in various engineering practice fields such as production and life, such as measuring speed and flow. At present, the research of domestic and foreign scientific researchers focuses on parameter measurement and jet devices. Although there are studies on the use of Venturi tubes for mixing, most of them are pre-mixing of gas and air, and there are relatively few studies on the mixing of incompatible gas and liquid. In the exploration of the use of the Venturi mixer formed by the throat opening of the classic Venturi tube for gas-liquid mixing, air compressors are often used as the gas source for experimental research on gas injection pressure. It is impossible to realize experimental research with gas injection flow rate and mixing bubble parameters as variables, which restricts the improvement of gas-liquid mixing effect and comprehensive analysis of flow characteristics mechanism; at the same time, the use of air compressor equipment also greatly increases the manufacturing cost of the test bench. Therefore, a Venturi gas-water mixing test bench with adjustable gas injection flow rate and bubble parameters has become one of the technical keys in this field. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a Venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters, which can stably inject gas into the Venturi tube, adjust the gas injection flow, gas injection position and bubble size in the tube, and realize experimental exploration of the flow characteristics of bubbles in the Venturi tube under multiple variables.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0006] A venturi gas-water mixing experimental table with adjustable gas injection flow and bubble parameters comprises a water tank 1, a water tank outlet pipe 2, a water pump 3, a water pump outlet pipe 4, a solenoid valve 5, a connecting pipe a6, an elbow a7, a connecting pipe b8, an electromagnetic flowmeter 9, a connecting pipe c10, an elbow b11, a pressure gauge 12, an experimental venturi pipe section 13, a connecting pipe d14, an elbow c15, a connecting pipe e16, an elbow d17, a water tank return pipe 18, a bubble injection group 19, a stepping motor 20, an experimental table a21, an experimental table b22, a computer 23, a solenoid valve controller 24, a data acquisition card 25 and a stepping motor controller 26; the water outlet of the water tank 1, the water tank outlet pipe 2 and the water inlet of the water pump 3 are connected in sequence through flanges to form the front half of the water circuit of the experimental system; the water inlet of the water pump 3, the water pump outlet pipe 4, the solenoid valve 5, the connecting pipe a6, the elbow a7, the connecting pipe b8 and the electromagnetic flowmeter The meter 9, connecting pipe c10, elbow b11, pressure gauge 12, experimental venturi tube section 13, connecting pipe d14, elbow c15, connecting pipe e16, elbow d17, water tank return pipe 18, and the return port of water tank 1 are connected in sequence through flanges to form the second half of the experimental system water circuit, and the above two parts together constitute the entire experimental system water circuit; the computer 23, the solenoid valve controller 24 and the solenoid valve 5 are connected through a twisted pair cable, the computer 23 and the data acquisition card 25 are connected through a conversion line, the data acquisition card 25 is connected to the electromagnetic flowmeter 9 and the pressure gauge 12 through twisted pairs, the computer 23, the stepper motor controller 26 and the stepper motor 20 are connected through twisted pairs; the nut 201 at the top of the stepper motor 20 is matched with the bottom of the piston core rod of the bubble injector, and the top of the bubble injector penetrates into the injection hole 131 of the experimental venturi tube section 13, serving as a bubble generating device for the entire experimental table.

[0007] The stepper motor 20 includes a nut 201, a rotating shaft 202, a motor box 203 and a fixed bracket 204; the nut 201 contains a steel ball, and the side of the rotating shaft 202 is tapped with threads, and the structure is similar to that of a screw. The nut 201 and the rotating shaft 202 together constitute a ball screw structure, which converts the circumferential rotation of the rotating shaft 202 into the axial displacement of the nut 201; the motor box 203 has a rectangular shape, and fixed brackets 204 are set at the four corners of the base to fix the position of the entire stepper motor 20.

[0008] The bubble injection group 19 includes a bubble syringe a191, a bubble syringe b192, a bubble syringe c193 and a bubble syringe d194; the bubble syringe a191 includes a needle a1911, a syringe a1912 and a piston core rod a1913, the bubble syringe b192 includes a needle b1921, a syringe b1922 and a piston core rod b1923, the bubble syringe c193 includes a needle c1931, a syringe c1932 and a piston core rod c1933, and the bubble syringe d194 includes a needle d1941, a syringe d1942 and a piston core rod d1943; the outer diameters of the above needles are all 0.5 cm, wherein the inner diameters of the needles a1911, the needles c1931 and the needles d1941 are all 0.4 cm, and the inner diameter of the needle b1921 is 0.25 cm. The lengths of needles a1911, b1921 and d1941 are all 12 cm, and the length of needle c1931 is 9 cm; the above-mentioned syringes are all cylindrical, wherein an injection head is provided in the center of the top circular surface, and a disc with four through holes is provided at the bottom; the inner diameters of syringes a1912, b1922 and c1932 are all 5 cm, and the outer diameters are all 6 cm; the inner diameter of syringe d1942 is 2.5 cm, and the outer diameter is 3.5 cm; the bottom of each piston core rod is a disc with the same structure, and the middle connection structure of each piston core rod has no contact with the inner wall of the corresponding syringe, wherein the tops of piston core rods a1913, b1923 and c1933 are all discs with the same structure, and the diameters are all 5 cm, and the diameter of the top disc of piston core rod d1943 is 2.5 cm.

[0009] The experimental venturi tube section 13 includes an injection hole 131, a threaded rod a132, a threaded rod b133, a threaded rod c134 and a threaded rod d135; the entire venturi tube section is a venturi cylindrical plexiglass tube with an injection hole 131 at the throat, the injection hole 131 is a cylindrical hole, and the diameter is the same as the outer diameter of the bubble syringe needle; the threaded rod a132, the threaded rod b133, the threaded rod c134 and the threaded rod d135 are four cylindrical threaded rods extending along the cylindrical outer wall of the venturi tube, the distance from the axis of the above-mentioned threaded rod to the axis of the injection hole at the throat of the experimental venturi tube section 13 is equal, the diameter is the same as the diameter of the through hole of the disc on the bottom surface of the bubble syringe syringe, and they are all provided with matching nuts.

[0010] The computer 23 controls the operation of the stepper motor 20 through the stepper motor controller 26. The rotation of the rotating shaft 202 drives the nut 201 to rise axially at a uniform speed, pushing the piston core rod of the bubble syringe connected to it to rise at a uniform speed, pushing the gas in the syringe to be injected into the experimental Venturi tube section 13 through the needle, thereby realizing the constant flow of gas injection by the bubble syringe into the throat of the experimental Venturi tube section 13.

[0011] The bubble injectors in the bubble injection group 19 can be interchangeably connected to the nut 201 of the stepper motor 20. The inner diameter of the needle, the length of the needle and the inner diameter of the syringe of each bubble injector are different. By replacing the bubble injector connected to the rotating shaft 202 of the stepper motor 20, the size, position and number of bubbles generated in the experimental venturi tube section 13 can be changed.

[0012] The beneficial effects of the present invention are:

[0013] The present invention discloses a venturi gas-water mixing test bench with adjustable gas injection flow rate and bubble parameters. Compared with a conventional venturi bubble test bench using an air compressor, a stepper motor and a bubble injector are used to replace the air compressor as a bubble generator under various working conditions, thereby realizing experiments under rated gas injection flow rate and reducing the purchase and operation costs of the experiments. Moreover, by replacing the bubble injector connected to the stepper motor, various parameters of bubbles generated in the venturi tube are changed, thereby completing the flow characteristic experiment with variable bubble parameters under various working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A front view three-dimensional diagram of a Venturi gas-water mixing experimental platform with adjustable gas injection flow rate and bubble parameters according to the present invention;

[0015] Figure 2 A rear three-dimensional diagram of a venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters according to the present invention;

[0016] Figure 3 A three-dimensional view of a venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters after the stepping motor, bubble injector and experimental venturi tube section are connected;

[0017] Figure 4 This is a first front view (Venturi tube section) of a Venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters after the stepping motor, bubble injector and experimental Venturi tube section are connected;

[0018] Figure 5 It is a second front view (Venturi tube section) of a Venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters after the stepping motor, bubble injector and experimental Venturi tube section are connected;

[0019] Figure 6 The third front view (Venturi tube section) of the stepping motor, bubble injector and experimental Venturi tube section of the Venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters of the present invention after being connected;

[0020] Figure 7 A three-dimensional view of a stepper motor of a Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters according to the present invention;

[0021] Figure 8 A three-dimensional view of a bubble injector group of a venturi gas-water mixing experimental platform with adjustable gas injection flow rate and bubble parameters according to the present invention;

[0022] Fig. 9 The present invention is a three-dimensional view of an experimental venturi tube section of a venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0024] The present invention is a venturi gas-water mixing experimental platform with adjustable gas injection flow and bubble parameters, comprising a water tank 1, a water tank outlet pipe 2, a water pump 3, a water pump outlet pipe 4, a solenoid valve 5, a connecting pipe a6, an elbow a7, a connecting pipe b8, an electromagnetic flowmeter 9, a connecting pipe c10, an elbow b11, a pressure gauge 12, an experimental venturi pipe section 13, a connecting pipe d14, an elbow c15, a connecting pipe e16, an elbow d17, a water tank return pipe 18, a bubble injection group 19, a stepper motor 20, an experimental table a21, an experimental table b22, a computer 23, a solenoid valve controller 24, a data acquisition card 25 and a stepper motor controller 26. The stepper motor 20 comprises a nut 201, a rotating shaft 202, a motor box 203 and a fixing bracket 204. The bubble injection group 19 includes a bubble injector a191, a bubble injector b192, a bubble injector c193 and a bubble injector d194; the bubble injector a191 includes a needle a1911, a syringe a1912 and a piston core rod a1913, the bubble injector b192 includes a needle b1921, a syringe b1922 and a piston core rod b1923, the bubble injector c193 includes a needle c1931, a syringe c1932 and a piston core rod c1933, and the bubble injector d194 includes a needle d1941, a syringe d1942 and a piston core rod d1943. The experimental venturi tube section 13 includes an injection hole 131, a threaded rod a132, a threaded rod b133, a threaded rod c134 and a threaded rod d135.

[0025] Reference Figure 1 and Figure 2The water outlet of water tank 1, water tank outlet pipe 2, and water inlet of water pump 3 are connected in sequence through flanges to constitute the front half of the water circuit of the experimental system. The water outlet of water pump 3, water pump outlet pipe 4, solenoid valve 5, connecting pipe a6, elbow a7, connecting pipe b8, electromagnetic flowmeter 9, connecting pipe c10, elbow b11, pressure gauge 12, experimental venturi tube section 13, connecting pipe d14, elbow c15, connecting pipe e16, elbow d17, water tank return pipe 18, and water return port of water tank 1 are connected in sequence through flanges to constitute the back half of the water circuit of the experimental system. The above two parts together constitute the water circuit of the entire experimental system, and each elbow in the water circuit is a stainless steel right-angle elbow, and each component is connected by a disc-shaped flange with a flexible sealing gasket. The computer 23, the solenoid valve controller 24 and the solenoid valve 5 are connected via twisted pair cables, the computer 23 and the data acquisition card 25 are connected via a conversion line, the data acquisition card 25 is connected to the electromagnetic flow meter 9 and the pressure gauge 12 via twisted pair cables, and the computer 23, the stepper motor controller 26 and the stepper motor 20 are connected via twisted pair cables. Figure 3 , which is the bubble generating and observing mechanism of the whole experimental platform. The nut 201 at the top of the stepping motor 20 is matched with the bottom of the piston core rod of the bubble injector. The needle at the top of the bubble injector penetrates into the injection hole 131 of the experimental venturi tube section 13, serving as the bubble generating device of the whole experimental platform.

[0026] As a preferred embodiment of the present invention, Figure 1 and Figure 2 As shown, the water in the water tank 1 enters the outlet pipe 2 through the outlet, is sucked into the water inlet of the water pump 3, and then flows out from the outlet of the water pump 3, and then flows through the water pump outlet pipe 4, the solenoid valve 5, the connecting pipe a6, the elbow a7, the connecting pipe b8, the electromagnetic flowmeter 9, the connecting pipe c10, the elbow b11 and the pressure gauge 12, and then enters the experimental Venturi tube section 13 to complete the Venturi bubble experiment, and then flows back to the water tank through the connecting pipe d14, the elbow c15, the connecting pipe e16, the elbow d17, the water tank return pipe 18, and the return port of the water tank 1. This is the working process of the entire experimental water circuit. The computer 23 controls the electromagnetic valve 5 by adjusting the electromagnetic valve controller 24, thereby adjusting the experimental water flow rate; the electromagnetic flowmeter 9 and the pressure gauge 12 transmit the real-time measured flow value and pressure value to the data acquisition card 25 through the twisted pair, and the data acquisition card 25 transmits the measured value to the computer through the conversion line; the computer 23 acts on the stepper motor controller 26, controls the start and stop of the stepper motor 20 through the stepper motor controller 26, and changes the rotation angle of each step of the stepper motor 20 with the help of the frequency division effect of the stepper motor controller 26, thereby changing the advancement speed of the nut 201 connected to it. Figure 4After the stepper motor 20 is started by the stepper motor controller 26, the shaft 202 starts to rotate at a constant speed, the shaft 202 and the nut 201 form a ball screw structure, and the nut 201 starts to rise at a constant speed along the direction indicated by the wireframe arrow in the figure driven by the shaft 202; Figure 5 As the nut 201 rises, the piston core rod a1913 of the bubble syringe a191 connected thereto is driven to rise at a uniform speed. As the piston core rod a1913 is pushed forward, the gas in the syringe a1912 is discharged into the throat of the experimental venturi tube section 13 through the needle a1911 at a constant flow rate, forming bubbles close to the flow center of the throat as shown in the figure. The experimental water flow rate can be adjusted to observe the flow characteristics of large bubbles in the turbulent area of ​​the venturi tube throat when the gas injection volume is large under various working conditions; Figure 6 If the bubble injector a191 is replaced by the bubble injector c193 and connected to the nut 201 at the top of the stepper motor 20, due to the short length of the needle c1932, bubbles close to the throat boundary as shown in the figure are formed during the experiment, and the experimental water flow rate can be adjusted to observe the flow characteristics of large bubbles in the laminar zone of the boundary layer in the throat of the venturi tube when the gas injection volume is large under various working conditions; similarly, if the bubble injector a191 is replaced by the bubble injector b192, the flow characteristics of small bubbles in the turbulent zone of the throat of the venturi tube when the gas injection volume is large can be observed; if the bubble injector a191 is replaced by the bubble injector d194, the flow characteristics of large bubbles in the turbulent zone of the throat of the venturi tube when the gas injection volume is small can be observed, thereby realizing the flow characteristics experiment of variable bubble parameters under various working conditions.

[0027] like Figure 7 The stepper motor 20 includes a nut 201, a rotating shaft 202, a motor box 203 and a fixed bracket 204; the nut 201 contains a steel ball, and the side of the rotating shaft 202 is tapped with threads, and the structure is similar to that of a screw. The nut 201 and the rotating shaft 202 together constitute a ball screw structure, which converts the circumferential rotation of the rotating shaft 202 into the axial displacement of the nut 201; the motor box 203 has a rectangular shape, and fixed brackets 204 are arranged at the four corners of the base to fix the position of the entire stepper motor 20.

[0028] like Figure 8The bubble injection group 19 includes a bubble syringe a191, a bubble syringe b192, a bubble syringe c193 and a bubble syringe d194; the bubble syringe a191 includes a needle a1911, a syringe a1912 and a piston core rod a1913, the bubble syringe b192 includes a needle b1921, a syringe b1922 and a piston core rod b1923, the bubble syringe c193 includes a needle c1931, a syringe c1932 and a piston core rod c1933, and the bubble syringe d194 includes a needle d1941, a syringe d1942 and a piston core rod d1943. Among them, the needle a1911 of the bubble syringe a191 has an outer diameter of 0.5 cm, an inner diameter of 0.4 cm, and a length of 12 cm, the syringe a1912 has an outer diameter of 6 cm, an inner diameter of 5 cm, the piston core rod a1913 has a top disk diameter of 5 cm, a middle cross connection part width of 4.5 cm, and a bottom disk diameter of 7.5 cm; the needle b1921 of the bubble syringe b192 has an outer diameter of 0.5 cm, an inner diameter of 0.25 cm, and a length of 12 cm, the syringe b1922 has an outer diameter of 6 cm, an inner diameter of 5 cm, the piston core rod b1923 has a top disk diameter of 5 cm, a middle cross connection part width of 4.5 cm, and a bottom disk diameter of 7.5 cm; the needle c1931 of the bubble syringe c193 has an outer diameter of 0.5 cm, an inner diameter of 0.4 cm, and a length of 9 cm, The outer diameter of syringe c1932 is 6 cm, the inner diameter is 5 cm, the top disk diameter of piston core rod c1933 is 5 cm, the width of the middle cross connecting part is 4.5 cm, and the bottom disk diameter is 7.5 cm; the outer diameter of needle d1941 of bubble syringe d194 is 0.5 cm, the inner diameter is 0.4 cm, and the length is 12 cm, the outer diameter of syringe d1942 is 3 cm, the inner diameter is 2.5 cm, the top disk diameter of piston core rod d1943 is 2.5 cm, the width of the middle cross connecting part is 2.2 cm, and the bottom disk diameter is 7.5 cm, that is, bubble syringe b192, bubble syringe c193 and bubble syringe d194 are respectively the needle inner diameter single variable comparison experimental pieces, needle length single variable comparison experimental pieces and syringe inner diameter single variable comparison experimental pieces of bubble syringe a191.

[0029] like Fig. 9The experimental venturi tube section 13 includes an injection hole 131, a threaded rod a132, a threaded rod b133, a threaded rod c134 and a threaded rod d135; the entire venturi tube section is a venturi cylindrical plexiglass tube with an injection hole 131 at the throat, the injection hole 131 is a cylindrical hole with a diameter of 0.5 cm, which is the same as the outer diameter of the bubble syringe needle; the threaded rod a132, the threaded rod b133, the threaded rod c134 and the threaded rod d135 are four cylindrical threaded rods extending along the cylindrical outer wall of the venturi tube, the distance from the axis of the above-mentioned threaded rod to the axis of the injection hole at the throat of the experimental venturi tube section 13 is equal, the diameter is the same as the diameter of the through hole of the disc on the bottom surface of the bubble syringe syringe, and they are all provided with matching nuts.

[0030] To summarize, the present invention uses a stepper motor and a bubble injector to replace an air compressor as a bubble generator under various working conditions, which not only achieves a stable gas injection flow rate but also reduces the overall experimental cost; by replacing the bubble injector connected to the stepper motor, the various parameters of bubble generation in the Venturi tube can be changed, and the flow characteristics experiment with variable bubble parameters under various working conditions can be completed.

Claims

1. A Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters, characterized in that: The invention comprises a water tank (1), a water tank outlet pipe (2), a water pump (3), a water pump outlet pipe (4), an electromagnetic valve (5), a connecting pipe a (6), an elbow a (7), a connecting pipe b (8), an electromagnetic flow meter (9), a connecting pipe c (10), an elbow b (11), a pressure gauge (12), an experimental venturi tube section (13), a connecting pipe d (14), an elbow c (15), a connecting pipe e (16), an elbow d (17), a water tank return pipe (18), a bubble injection group (19), and a stepping motor. (20), experimental table a (21), experimental table b (22), computer (23), electromagnetic valve controller (24), data acquisition card (25) and stepper motor controller (26); the water outlet of the water tank (1), the water outlet pipe of the water tank (2) and the water inlet of the water pump (3) are connected in sequence through flanges to form the front half of the water circuit of the experimental system; the water inlet of the water pump (3), the water outlet pipe of the water pump (4), the electromagnetic valve (5), the connecting pipe a (6), the elbow a (7), the connecting pipe b (8), the electromagnetic flowmeter ( 9), connecting pipe c (10), elbow b (11), pressure gauge (12), experimental venturi tube section (13), connecting pipe d (14), elbow c (15), connecting pipe e (16), elbow d (17), water tank return pipe (18), and the return port of the water tank (1) are connected in sequence through flanges to form the second half of the experimental system water circuit. The above two parts together constitute the entire experimental system water circuit; the computer (23), the solenoid valve controller (24) and the solenoid valve (5) are connected through twisted pair cables, and the computer (23) and the solenoid valve controller (24) are connected to the solenoid valve (5) through twisted pair cables. The computer (23) and the data acquisition card (25) are connected via a conversion line, the data acquisition card (25) is respectively connected to the electromagnetic flow meter (9) and the pressure gauge (12) via twisted pair cables, the computer (23), the stepping motor controller (26) and the stepping motor (20) are connected via twisted pair cables; the nut (201) at the top of the stepping motor (20) is matched with the bottom of the piston core rod of the bubble injector, and the top of the bubble injector is inserted into the injection hole (131) of the experimental venturi tube section (13), serving as a bubble generating device for the entire experimental platform.

2. A Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters according to claim 1, characterized in that: The bubble injection group (19) comprises a bubble injector a (191), a bubble injector b (192), a bubble injector c (193) and a bubble injector d (194); the bubble injector a (191) comprises a needle a (1911), a syringe a (1912) and a piston core rod a (1913); the bubble injector b (192) comprises a needle b (1921), a syringe b (1922) and a piston core rod b (1923); The bubble syringe c (193) includes a needle c (1931), a syringe c (1932) and a piston core rod c (1933), and the bubble syringe d (194) includes a needle d (1941), a syringe d (1942) and a piston core rod d (1943); the outer diameters of the above needles are all 0.5 cm, among which the inner diameters of the needles a (1911), c (1931) and d (1941) are all 0.4 cm, and the inner diameters of the needles b (19 21) has an inner diameter of 0.25 cm, and the lengths of needles a (1911), b (1921) and d (1941) are all 12 cm, and the length of needle c (1931) is 9 cm; the above syringes are all cylindrical, wherein the center of the top circular surface has an injection head, and the bottom has a disk with four through holes, and the inner diameters of syringes a (1912), b (1922) and c (1932) are all 5 cm, and the outer diameters are all 6 cm, and the needles The inner diameter of cylinder d (1942) is 2.5 cm, and the outer diameter is 3.5 cm; the bottom of each piston core rod is a disc with the same structure, and the middle connection structure of each piston core rod has no contact with the inner wall of the corresponding syringe. Among them, the tops of piston core rod a (1913), piston core rod b (1923), and piston core rod c (1933) are all discs with the same structure, with a diameter of 5 cm. The diameter of the top disc of piston core rod d (1943) is 2.5 cm.

3. The Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters according to claim 1, characterized in that: The experimental venturi tube section (13) comprises an injection hole (131), a threaded rod a (132), a threaded rod b (133), a threaded rod c (134) and a threaded rod d (135); the entire venturi tube section is a venturi cylindrical organic glass tube with an injection hole (131) at the throat, the injection hole (131) is a cylindrical hole, and the diameter is the same as the outer diameter of the bubble syringe needle; the threaded rod a (132), the threaded rod b (133), the threaded rod c (134) and the threaded rod d (135) are four cylindrical threaded rods extending along the outer wall of the cylindrical venturi tube, the distance between the axis of the threaded rod and the axis of the injection hole at the throat of the experimental venturi tube section (13) is equal, the diameter is the same as the diameter of the through hole of the disc at the bottom of the bubble syringe syringe, and each of the threaded rods is provided with a matching nut.

4. The Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters according to claim 1, characterized in that: The computer (23) controls the operation of the stepper motor (20) through the stepper motor controller (26), and the rotation of the rotating shaft (202) drives the nut (201) to rise axially at a uniform speed, thereby pushing the piston core rod of the bubble injector connected thereto to rise at a uniform speed, pushing the gas in the syringe to be injected into the experimental venturi tube section (13) through the needle, thereby achieving a constant flow of gas injection from the bubble injector into the throat of the experimental venturi tube section (13).

5. The Venturi gas-water mixing test bench with adjustable gas injection flow and bubble parameters according to claim 1, characterized in that: The bubble injectors in the bubble injection group (19) can be interchangeably connected to the nut (201) of the stepper motor (20); the inner diameter of the needle, the length of the needle and the inner diameter of the syringe of each bubble injector are different; by replacing the bubble injector connected to the rotating shaft (202) of the stepper motor (20), the size, position and number of bubbles generated in the experimental venturi tube section (13) can be changed.

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