A cavitation test bench with an increased venturi tube inlet and outlet pressure adjustment range and variable adjustment modes

Abstract

The present invention discloses a cavitation test bench with an increased pressure regulation range of a venturi tube inlet and outlet and a variety of regulation modes, comprising a water storage tank, a water outlet pipe, a water pump, a connecting pipe, a tee, an elbow, a solenoid valve, an electromagnetic flowmeter, a pressure regulating valve, a venturi cavitation section, a digital pressure gauge, a venturi ejector, a variable frequency water pump, a valve, a computer, a data acquisition card, a solenoid valve controller and a variable frequency water pump control box. The water outlet of the water pump is divided into two waterways by the tee in the connecting pipe, and then flows back to the water storage tank after merging through the venturi ejector. The water outlet of the variable frequency water pump is merged into the shunt branch to increase the branch flow. By adjusting the flow of each waterway and the spring compression in the pressure regulating valve, the continuous regulation of the inlet and outlet pressures of the venturi cavitation section within the low pressure range and the single variable regulation are realized, the measurement range is expanded, the range of experimental parameters is expanded, and the safe conduct of the experiment is ensured.

Description

Technical Field

[0001] The invention relates to a hydraulic test bench, in particular to a cavitation test bench with an increased regulating range of the inlet and outlet pressures of a venturi tube and variable regulating modes. Background Art

[0002] When the fluid flows through the throat of the Venturi tube, the Venturi effect is generated, forming a local low-pressure area. When the pressure is as low as the water temperature saturation pressure, cavitation occurs. Venturi cavitation can be applied to hydraulic cavitation technology. Therefore, using experimental methods to explore the influence of flow parameters such as pressure on the cavitation effect of the Venturi tube has good practicality and scientific research value.

[0003] During the cavitation experiment, when the inlet and outlet pressures of the venturi tube drop to a certain pressure value, the water flow in the circulating water pipeline is small, and the effect of continuing to adjust the valve opening to reduce the inlet and outlet pressures is no longer obvious, and the circulating water flow rate will be too low to approach a stagnant state, affecting the experiment. That is, it is impossible to measure continuously under low-pressure conditions. The lower limit of the inlet and outlet water pressure of the venturi tube in the cavitation experiment is limited by the back pressure of the water tank return water. The single-factor variable measurement cannot be controlled, that is, the inlet and outlet water pressures of the venturi tube generally change at the same time, and the control variable method cannot be used to separately detect the influence of the inlet water pressure or the outlet water pressure on the cavitation effect of the venturi tube. Therefore, a test bench that can adjust the inlet and outlet pressures of the venturi tube and adjust the inlet pressure of the venturi tube as a single variable has become a need for technical innovation in this field. Summary of the invention

[0004] In order to realize the continuous regulation of the inlet and outlet pressures of the Venturi tube in a cavitation experiment under low-pressure conditions, to use the inlet pressure of the Venturi tube as a single factor for regulation, and to expand the range of experimental parameters, the present invention provides a cavitation experiment platform with an increased regulation range of the inlet and outlet pressures of the Venturi tube and variable regulation modes.

[0005] In order to achieve the above requirements, the scheme used in the present invention is as follows:

[0006] A cavitation test bench with an increased inlet and outlet pressure adjustment range and variable adjustment modes of a venturi tube comprises a main water supply section composed of a water storage tank 1, a water outlet pipe a2, a water pump 3, a connecting pipe a4, and a tee a5 connected in sequence; a cavitation test section composed of a connecting pipe b6, an elbow a7, a connecting pipe c8, an elbow b9, a connecting pipe d10, an electromagnetic valve a11, an elbow c12, a connecting pipe e13, an elbow d14, an electromagnetic flowmeter a15, a connecting pipe f16, a pressure regulating valve 17, a venturi cavitation section 18, a digital pressure gauge 19, a connecting pipe g20, an elbow e21, and a connecting pipe h22 connected in sequence; a cavitation test section composed of a connecting pipe i23, an elbow f24, a connecting pipe h25 connected in sequence A three-way diversion section consisting of a connecting pipe j25, an electromagnetic valve b26, an elbow g27, a connecting pipe k28, a tee b29, an electromagnetic flowmeter b30, a connecting pipe l31, and a venturi ejector 32; a return water section consisting of a connecting pipe m33, an elbow h34, and a connecting pipe n35 connected in sequence; an auxiliary water supply section consisting of a water outlet pipe b36, a variable frequency water pump 37, a connecting pipe o38, an elbow i39, a connecting pipe p40, an elbow j41, a connecting pipe q42, an elbow k43, a connecting pipe r44, an elbow l45, a connecting pipe s46, and a valve 47 connected in sequence; and a computer 48, a data acquisition card 49, a solenoid valve controller 50, and a variable frequency water pump control box 51. The upper outlet of the tee a5 at the end of the main water supply section is connected to the inlet of the connecting pipe b6 at the starting end of the cavitation experiment section, and the left outlet of the tee a5 is connected to the inlet of the connecting pipe i23 at the starting end of the tee diversion section; the outlet pipe b36 at the starting end of the auxiliary water supply section is connected to the water storage tank 1 of the main water supply section, and the end connecting pipe s46 is connected to the front inlet of the tee b29 in the tee diversion section; the connecting pipe h22 at the end of the cavitation experiment section is connected to the throat of the Venturi ejector 32 in the tee diversion section; the outlet of the Venturi ejector 32 at the end of the tee diversion section is connected to the connecting pipe m33 at the starting end of the return water section; the connecting pipe n35 at the end of the return water section is connected to the water storage tank 1 of the main water supply section. Connecting lines are set between the computer 48, the data acquisition card 49, the electromagnetic flowmeter a15, the electromagnetic flowmeter b30, and the digital pressure gauge 19; connecting lines are set between the computer 48, the solenoid valve controller 50, the solenoid valve a11, and the solenoid valve b26; and connecting lines are set between the computer 48, the variable frequency water pump control box 51, and the variable frequency water pump 37.

[0007] The pressure regulating valve 17 is a self-operated post-valve pressure regulating valve. The preset pressure value can be changed by rotating the nut to adjust the compression amount of the spring.

[0008] The water storage tank 1 is a cylindrical closed water storage tank, and two circular water outlets and a circular water inlet are arranged on its side; the two water outlets are respectively connected to the water outlet pipe a2 and the water outlet pipe b36, and the water inlet is connected to the connecting pipe n35, and the water inlet is higher than the water outlet.

[0009] The opening of the electromagnetic valve b26 and the frequency of the variable frequency water pump 37 are both controlled by the computer 48. By increasing the opening of the electromagnetic valve b26 and increasing the frequency of the variable frequency water pump 37 through the computer 48, the water flow through the venturi ejector tube 32 can be increased, and a low pressure zone with a gradually decreasing pressure value is formed at the throat of the venturi ejector tube 32, thereby reducing the front and rear pressures of the venturi cavitation section 18 connected thereto. The computer 48 can realize continuous regulation of the inlet and outlet pressures of the venturi cavitation section 18 connected to the throat of the venturi ejector tube 32 within a relatively low or extremely low pressure range by controlling the continuous change of the opening of the electromagnetic valve b26 and the frequency of the variable frequency water pump 37, and the lower limit of the regulation is not limited by the back pressure of the water tank return water, thereby realizing cavitation experiments under relatively low and extremely low pressure conditions.

[0010] The opening of the solenoid valve a11 is controlled by the computer 48 to keep the preset pressure value of the pressure regulating valve 17 as a fixed value. By changing the opening of the solenoid valve a11, the measurement and observation of the cavitation experiment can be achieved when the outlet pressure of the Venturi cavitation section 18 remains unchanged and the inlet pressure changes continuously.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] The opening of the electromagnetic regulating valve is controlled by a computer to change the flow ratio of each section of the waterway, adjust the flow of the diverted water in the three-way diverter section through the Venturi ejector tube, change the throat low pressure, and then realize the continuous adjustment of the inlet and outlet pressures of the Venturi cavitation section connected to the throat of the Venturi ejector tube, complete the continuous adjustable measurement of the experimental Venturi tube ejection effect under low pressure conditions, and ensure that the lower limit of the adjustable inlet and outlet pressure of the Venturi cavitation section is not limited by the back pressure of the water tank return water. The frequency of the variable frequency water pump is adjusted by a computer to increase the flow of the auxiliary water supply section, increase the flow of the diverted water in the three-way diverter section through the Venturi ejector tube, further reduce the throat low pressure, and realize the cavitation experiment of the Venturi cavitation section under extremely low inlet and outlet pressure conditions.

[0013] At the same time, by using the nut of the pressure regulating valve to control the compression of the spring inside the valve, single-factor regulation of the Venturi cavitation section with unchanged inlet pressure and changed outlet pressure can be achieved, so as to better observe the influence of a single flow parameter on the cavitation condition of the Venturi tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A three-dimensional front view of a cavitation test bench of the present invention with an increased inlet and outlet pressure adjustment range of a venturi tube and variable adjustment modes;

[0015] Figure 2 It is a three-dimensional front view of a connecting pipe h22 and a Venturi ejector tube 32 in a cavitation test bench with an increased inlet and outlet pressure adjustment range and variable adjustment modes of the present invention;

[0016] Figure 3 It is a three-dimensional front view of a tee a5 in a cavitation test bench with an increased inlet and outlet pressure adjustment range and variable adjustment modes of a venturi tube according to the present invention;

[0017] Figure 4 It is a three-dimensional front view of a tee b29 in a cavitation test bench with an increased inlet and outlet pressure adjustment range and variable adjustment modes of a venturi tube according to the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] The invention discloses a cavitation test bench with an increased inlet and outlet pressure regulating range of a venturi tube and a variety of regulating modes, and mainly comprises a water storage tank 1, a water outlet pipe a2, a water pump 3, a connecting pipe a4, a tee a5, a connecting pipe b6, an elbow a7, a connecting pipe c8, an elbow b9, a connecting pipe d10, an electromagnetic valve a11, an elbow c12, a connecting pipe e13, an elbow d14, an electromagnetic flowmeter a15, a connecting pipe f16, a pressure regulating valve 17, a venturi cavitation section 18, a digital pressure gauge 19, a connecting pipe g20, an elbow e21, a connecting pipe h22, a connecting pipe i23, an elbow f2 4. Connecting pipe j25, solenoid valve b26, elbow g27, connecting pipe k28, tee b29, electromagnetic flowmeter b30, connecting pipe l31, venturi ejector 32, connecting pipe m33, elbow h34, connecting pipe n35, outlet pipe b36, variable frequency water pump 37, connecting pipe o38, elbow i39, connecting pipe p40, elbow j41, connecting pipe q42, elbow k43, connecting pipe r44, elbow l45, connecting pipe s46, valve 47, computer 48, data acquisition card 49, solenoid valve controller 50 and variable frequency water pump control box 51.

[0020] As a preferred embodiment of the present invention, the device structure is as shown in the attached Figure 1As shown. The water storage tank 1, the water outlet pipe a2, and the horizontal port of the water pump 3 are connected in sequence, and the upper port of the water pump 3, the connecting pipe a4, and the lower port of the tee a5 are connected in sequence, and the two parts together constitute the main water supply section. The upper port of the tee a5, the connecting pipe b6, the elbow a7, the connecting pipe c8, the elbow b9, the connecting pipe d10, the solenoid valve a11, the elbow c12, the connecting pipe e13, the elbow d14, the electromagnetic flowmeter a15, the connecting pipe f16, the pressure regulating valve 17, the Venturi cavitation section 18, the digital pressure gauge 19, the connecting pipe g20, the elbow e21, and the connecting pipe h22 are connected in sequence to form the cavitation experiment section. The left port of the tee a5, the connecting pipe i23, the elbow f24, the connecting pipe j25, the electromagnetic valve b26, the elbow g27, the connecting pipe k28, the tee b29, the electromagnetic flowmeter b30, the connecting pipe l31, and the front port of the venturi ejector 32 are connected in sequence to form a tee diversion section. The rear port of the venturi ejector 32, the connecting pipe m33, the elbow h34, the connecting pipe n35, and the return water port of the water storage tank 1 are connected in sequence to form a return water section. The water storage tank 1, the outlet pipe b36, and the horizontal port of the variable frequency water pump 37 are connected in sequence, and the upper port of the variable frequency water pump 37, the connecting pipe o38, the elbow i39, the connecting pipe p40, the elbow j41, the connecting pipe q42, the elbow k43, the connecting pipe r44, the elbow l45, and the connecting pipe s46 (with a valve 47) are connected in sequence, and the two parts together form the auxiliary water supply section. That is, the main water supply section is divided into two branches, the cavitation experiment section and the tee diversion section, from the tee a5, and then merged into the return water section through the Venturi ejector 32. The auxiliary water supply section is a separate section, that is, a branch is drawn from the water storage tank 1 to the tee b29 and merged into the tee diversion section.

[0021] See attached Figure 1A connecting line is set between the computer 48, the data acquisition card 49, the electromagnetic flowmeter a15, the electromagnetic flowmeter b30, and the digital pressure gauge 19, so that the flow and pressure data of the cavitation experiment section and the three-way diversion section can be monitored, and the data is displayed and stored in the computer 48 in real time through the control line and the data acquisition card 49; a connecting line is set between the computer 48, the solenoid valve controller 50, the solenoid valve a11, and the solenoid valve b26, and the computer 48 can control the opening of the solenoid valve a11 and the solenoid valve b26 respectively through the solenoid valve controller 50, Adjust the flow of the cavitation experiment section and the three-way diversion section; set a connecting line between the computer 48, the variable frequency water pump control box 51, and the variable frequency water pump 37. The computer 48 can control the frequency modulation of the variable frequency water pump 37 through the variable frequency water pump control box 51 to change the water flow of the auxiliary water supply section; the opening of the valve 47 can be adjusted by turning the wrench of the valve 47 to change the water flow of the auxiliary water supply section; the compression of the spring in the rotating pressure regulating valve 17 can be changed by rotating the nut of the pressure regulating valve 17 to achieve the adjustment of the pressure in front of the tapered section of the Venturi cavitation section 18. The flange connection structure with a flexible sealing gasket is adopted at the connection of each component and pipeline; each connecting pipeline is a stainless steel water pipe with a circular cross-section, and each elbow is a right-angle stainless steel elbow with a circular cross-section; the pressure regulating valve 17 is a self-acting valve-rear pressure regulating valve. The compression of the spring can be changed by rotating the nut to change the preset pressure value. The Venturi cavitation experiment can be carried out under the preset fixed inlet pressure. The experiment of controlling the inlet pressure to be constant and the outlet pressure as a single variable can be carried out to expand the range of experimental parameters.

[0022] Cavitation occurs when the local pressure of the fluid is as low as the water temperature saturation pressure, and the lower the local pressure, the stronger the cavitation intensity and the more obvious the cavitation phenomenon in the fluid domain. The key to the present invention is to realize the controllable experiment of the entire Venturi cavitation section under low pressure conditions. Figure 1 ,The specific workflow of the entire experimental platform is divided into three stages.

[0023] In the first stage, valve 47 is closed, computer 48 controls electromagnetic valve a11 to be adjusted to any opening between closed and fully opened, and electromagnetic valve b26 is closed. Water in water storage tank 1 is pumped into water pump 3 from outlet pipe a2, and the outlet water of water pump 3 flows to tee a5 through connecting pipe a4, and all flows to cavitation experiment section from tee a5 (the electromagnetic valve b26 of the tee diversion section is closed), flows through electromagnetic valve a11, electromagnetic flowmeter a15, pressure regulating valve 17 in sequence along the flow direction of cavitation experiment section, and then passes through Venturi cavitation section 18. After completing the hydraulic cavitation experiment, it flows through digital pressure gauge 19, and finally flows into the ejection hole at the throat of Venturi ejector 32, and flows into the return water section from the outlet of the gradually expanding section of Venturi ejector 32 (valve 47 and electromagnetic valve b26 are both closed at this time), and finally flows to water storage tank 1 along the flow direction of the return water section, completing the entire water circuit cycle. At this stage, the Venturi cavitation section 18 is connected to the water storage tank 1 through the end pipeline of the cavitation experiment section and the return water section pipeline. The outlet pressure of the Venturi cavitation section 18 is limited by the back pressure of the return water port connected to the connecting pipe n35 and the water storage tank 1. The cavitation experiment of the Venturi cavitation section 18 can only be carried out within a higher inlet and outlet pressure range.

[0024] In the second stage, valve 47 is completely closed, computer 48 controls electromagnetic valve a11 to be fully opened, and electromagnetic valve b26 is adjusted to any opening between closed and fully opened. After water pump 3 is started, water in water storage tank 1 is pumped into water pump 3 from outlet pipe a2, and water from water pump 3 flows to tee a5 through connecting pipe a4, and is divided into cavitation test section and tee diversion section from tee a5. Main stream water flows through electromagnetic valve a11, electromagnetic flowmeter a15, pressure regulating valve 17 in sequence along the flow direction of cavitation test section, and then passes through Venturi cavitation section 18. After completing hydraulic cavitation experiment, it flows through digital pressure gauge 19, and finally flows into the ejection hole at the throat of Venturi ejector 32, and is ejected by diversion water of tee diversion section at the throat of Venturi ejector. The diverted water flows along the diverting section of the three-way flow through the electromagnetic valve b26, flows into the right end inlet of the three-way b29, and then all flows out from its rear end outlet (the valve 47 is completely closed at this time), continues to flow through the electromagnetic flowmeter b30, and finally flows to the throat of the Venturi ejector 32, forming a low-pressure area and ejecting the mainstream water to complete the cavitation experiment. After the confluence of the main and diverted water, it flows into the return water section from the outlet of the gradually expanding section of the Venturi ejector 32. After the confluence, the return water flows along the return water section and finally flows into the water storage tank 1. In this stage, the Venturi cavitation section 18 is connected to the throat of the Venturi ejector tube 32 through the end pipeline of the cavitation test section, and the outlet pressure of the Venturi cavitation section 18 is limited by the pressure of the low-pressure area of ​​the throat of the Venturi ejector tube 32 (the larger the opening of the electromagnetic valve b26, the lower the throat pressure, and this pressure must be lower than the back pressure of the return water port connected to the connecting pipe n35 and the water storage tank 1), so the Venturi cavitation section 18 can perform cavitation experiments within a relatively low inlet and outlet pressure range. However, when the opening of the electromagnetic valve b26 is adjusted to the maximum, the diverted water flow rate reaches the maximum, the throat pressure of the Venturi ejector tube 32 reaches the minimum, and the inlet and outlet pressures of the Venturi cavitation section 18 reach the lower limit that can be adjusted in the second stage.

[0025] In the third stage, if you want to conduct a cavitation experiment under a lower pressure and observe a better cavitation property image, you should open the valve 47, and the computer 48 controls the solenoid valve a11 and the solenoid valve b26 to be fully opened. After the water pump 3 is started, the water in the water storage tank 1 is pumped into the water pump 3 from the outlet pipe a2, and the water output of the water pump 3 flows to the tee a5 through the connecting pipe a4, and is divided into the cavitation experiment section and the tee diversion section from the tee a5; then the variable frequency water pump 37 is started, and the water in the water storage tank 1 is pumped into the variable frequency water pump 37 from the outlet pipe b36, and the water output of the variable frequency water pump 37 flows along the auxiliary water supply section, flows through the valve 47, and then flows into the tee diversion section through the front port of the tee b29. The main stream of water flows along the cavitation test section in sequence through the solenoid valve a11, the electromagnetic flowmeter a15, the pressure regulating valve 17, and then through the Venturi cavitation section 18. After completing the hydraulic cavitation experiment, it flows through the digital pressure gauge 19, and finally flows into the ejection hole at the throat of the Venturi ejector 32, and is ejected by the diverted water of the three-way diverter section at the throat of the Venturi ejector. The diverted water flows along the three-way diverter section, through the solenoid valve b26, flows into the right end inlet of the three-way b29, and then merges with the water of the auxiliary water supply section and flows out from its rear end outlet, continues to flow through the electromagnetic flowmeter b30, and finally flows to the throat of the Venturi ejector 32, forming a low-pressure area and ejecting the main stream of water that completes the cavitation experiment. After the main and diverted water merge, it flows into the return water section from the outlet of the gradually expanding section of the Venturi ejector 32. After the merger, the return water flows along the return water section and finally flows into the water storage tank 1. In this stage, the venturi cavitation section 18 is connected to the throat of the venturi ejector tube 32 through the end pipeline of the cavitation test section. The outlet pressure of the venturi cavitation section 18 is limited by the pressure of the low-pressure area of ​​the throat of the venturi ejector tube 32. At this time, the opening of the solenoid valve b26 is adjusted to the maximum. The frequency conversion pump control box 51 is controlled by the computer 48 to adjust the frequency of the frequency conversion pump 37 so that the flow of the auxiliary water supply section continues to increase. After the diverted water and the water supply of the auxiliary water supply section merge, the flow is further increased on the basis of the upper limit of the second stage, and the throat pressure of the venturi ejector tube 32 continues to decrease. When the flow of the auxiliary water supply section increases to the maximum, the inlet and outlet pressures of the venturi cavitation section 18 reach the lower limit that can be adjusted in the third stage. Therefore, the cavitation experiment of the venturi cavitation section 18 can be carried out within the extremely low inlet and outlet pressure range.

[0026] See attached Figure 2 In the horizontal direction, the port opposite to the small arrow in the wireframe is the front port of the Venturi ejector 32, through which the diverted water of the three-way diverter section flows in, and forms a low-pressure area at the throat to eject the mainstream water of the cavitation experiment section; in the vertical direction, the pipe opposite to the arrow in the wireframe is the connecting pipe h22, through which the mainstream water of the cavitation experiment section flows into the throat of the Venturi ejector 32; the diverted water of the three-way diverter section and the mainstream water of the cavitation experiment section merge at the Venturi ejector 32 and then flow out in the direction indicated by the large arrow in the wireframe, and the port on the side indicated by the large arrow is the rear port of the Venturi ejector 32.

[0027] See attached Figure 3In the vertical direction, the port opposite to the large arrow in the wireframe is the lower port of the tee a5, and the total flow water of the main water supply section flows in through this port; in the vertical direction, the port on one side of the arrow is the port of the tee a5, and a part of the total flow water of the main water supply section flows into the cavitation experimental section along this port as the mainstream water; in the horizontal direction, the port on one side of the small arrow is the left port of the tee a5, and another part of the total flow water of the main water supply section flows into the tee diversion section along this port as the diversion water.

[0028] See attached Figure 4 , perpendicular to the horizontal direction, the small arrow indicates that the opposite port is the right port of the tee b29, and the diverted water of the tee diversion section flows in through this port; in the horizontal direction, the middle arrow indicates that the opposite port is the front port of the tee b29, and the outlet water of the variable frequency water pump of the auxiliary water supply section flows in through this port and merges into the diverted water; in the horizontal direction, the large arrow indicates that the side port is the rear port of the tee a5, and the outlet water of the variable frequency water pump merges into the diverted water and then flows out along this port.

[0029] In summary, compared with the conventional hydraulic cavitation test bench, the present invention uses a computer to control the opening of the electromagnetic regulating valve and the frequency of the variable frequency water pump to adjust the flow rate flowing through the venturi ejector tube, and realizes continuous regulation of the inlet and outlet pressures of the venturi cavitation section connected to the throat of the venturi ejector tube within a relatively low or extremely low pressure range, so that the lower limit of the regulation of the inlet and outlet pressures of the venturi cavitation section is not limited by the back pressure of the water tank return water, thereby increasing the range of pressure regulation; by using the nut of the pressure regulating valve to control the compression amount of the spring in the valve, single-factor regulation of the venturi cavitation section in which the inlet pressure remains unchanged and the outlet pressure changes can be achieved, thereby expanding the experimental range of the cavitation experiment.

Claims

1. A cavitation test bench with an increased pressure adjustment range for the inlet and outlet of a venturi tube and multiple adjustment modes, characterized in that: The invention comprises a main water supply section which is connected in sequence to a water storage tank (1), a water outlet pipe a (2), a water pump (3), a connecting pipe a (4), and a tee a (5); a cavitation experiment section which is connected in sequence to a connecting pipe b (6), an elbow a (7), a connecting pipe c (8), an elbow b (9), a connecting pipe d (10), an electromagnetic valve a (11), an elbow c (12), a connecting pipe e (13), an elbow d (14), an electromagnetic flowmeter a (15), a connecting pipe f (16), a pressure regulating valve (17), a Venturi cavitation section (18), a digital pressure gauge (19), a connecting pipe g (20), an elbow e (21), and a connecting pipe h (22); and a connecting pipe i (23), an elbow f (24), a connecting pipe j (25), an electromagnetic valve b (26), an elbow g (27), a connecting pipe k (28), a tee b (29), an electromagnetic flowmeter b (30), a connecting pipe A three-way flow divider section consisting of a pipe l (31) and a venturi ejector (32); a return water section including a connecting pipe m (33), an elbow h (34), and a connecting pipe n (35) connected in sequence; an auxiliary water supply section including a water outlet pipe b (36), a variable frequency water pump (37), a connecting pipe o (38), an elbow i (39), a connecting pipe p (40), an elbow j (41), a connecting pipe q (42), an elbow k (43), a connecting pipe r (44), an elbow l (45), a connecting pipe s (46), and a valve (47) connected in sequence; and a computer (48), a data acquisition card (49), an electromagnetic valve controller (50), and a variable frequency water pump control box (51); an upper outlet of a three-way a (5) at the end of the main water supply section is connected to an inlet of a connecting pipe b (6) at the starting end of the cavitation experiment section, and a left outlet of the three-way a (5) is connected to an inlet of a connecting pipe i (23) at the starting end of the three-way flow divider section; The outlet pipe b (36) at the starting end of the auxiliary water supply section is connected to the water storage tank (1) of the main water supply section, and the terminal connecting pipe s (46) is connected to the front inlet of the tee b (29) in the tee diversion section; the terminal connecting pipe h (22) of the cavitation experiment section is connected to the throat of the venturi ejector (32) in the tee diversion section; the outlet of the venturi ejector (32) at the terminal of the tee diversion section is connected to the connecting pipe m (33) at the starting end of the return water section; the terminal connecting pipe n (35) of the return water section is connected to the water storage tank (1) of the main water supply section; a computer (48), a data acquisition card (49), an electromagnetic flowmeter a (15), an electromagnetic flowmeter b (30), and a digital pressure gauge (19) are arranged between A connecting line is provided between the computer (48), the solenoid valve controller (50), the solenoid valve a (11), and the solenoid valve b (26); and a connecting line is provided between the computer (48), the variable frequency water pump control box (51), and the variable frequency water pump (37); the pressure regulating valve (17) is a self-operated post-valve pressure regulating valve, and the preset pressure value can be changed by rotating the nut to adjust the compression amount of the spring; the water storage tank (1) is a cylindrical closed water storage tank, and two circular water outlets and a circular water inlet are provided on its side; the two water outlets are respectively connected to the water outlet pipe a (2) and the water outlet pipe b (36), and the water inlet is connected to the connecting pipe n (35), and the water inlet is at a higher level than the water outlet.

2. A cavitation test bench with an increased inlet and outlet pressure adjustment range and variable adjustment modes according to claim 1, characterized in that: The opening of the electromagnetic valve b (26) and the frequency of the variable frequency water pump (37) are both controlled by the computer (48). By increasing the opening of the electromagnetic valve b (26) and increasing the frequency of the variable frequency water pump (37) through the computer (48), the water flow rate flowing through the Venturi ejector tube (32) can be increased, and a low-pressure zone with a gradually decreasing pressure value is formed at the throat of the Venturi ejector tube (32), thereby reducing the front and rear pressures of the Venturi cavitation section (18) connected thereto. The computer (48) can realize continuous regulation of the inlet and outlet pressures of the Venturi cavitation section (18) connected to the throat of the Venturi ejector tube (32) within a relatively low or extremely low pressure range by controlling the continuous change of the opening of the electromagnetic valve b (26) and the frequency of the variable frequency water pump (37), and the regulation lower limit is not limited by the back pressure of the water tank return water, thereby realizing cavitation experiments under relatively low and extremely low pressure conditions.

3. According to claim 1, a cavitation test bench with an increased inlet and outlet pressure adjustment range and variable adjustment modes of a venturi tube, characterized in that: The opening of the electromagnetic valve a (11) is controlled by a computer (48) to keep the preset pressure value of the pressure regulating valve (17) at a fixed value. By changing the opening of the electromagnetic valve a (11), the measurement and observation of the cavitation experiment can be achieved when the outlet pressure of the Venturi cavitation section (18) remains unchanged and the inlet pressure changes continuously.

Images