An experimental device for solid-liquid two-phase flow

Abstract

The application discloses a kind of experimental device of solid-liquid two-phase flow, the device includes: support and centrifugal pump installed on support, centrifugal pump is driven by motor, high-speed camera is set opposite with centrifugal pump, centrifugal pump inlet is connected to feed hopper, feed hopper is provided with stirrer, pressure transmitter and flowmeter are connected on the pipeline of centrifugal pump inlet and outlet, the solid-liquid two-phase flow that flows out reenters feed hopper through water outlet pipeline, solid-liquid two-phase flow is stirred uniformly after passing through stirrer and then enters experimental pipeline again, and solid-liquid two-phase flow can be reused all the time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-liquid two-phase flow experiment, in particular to a solid-liquid two-phase flow experiment device. BACKGROUND

[0002] At present, the water conservancy projects such as excavation, dredging and desilting of major rivers and lakes basically apply solid-liquid two-phase flow centrifugal pumps, so the research and development of solid-liquid two-phase flow centrifugal pumps are paid more and more attention. Due to the existence of a large amount of silt in the water flow, in actual application, the flow parts of the solid-liquid two-phase flow centrifugal pump often have serious wear, which will seriously affect the normal operation and safe production of the centrifugal pump. At present, in terms of operating efficiency, the solid-liquid two-phase flow centrifugal pumps in China are generally lower than the similar products abroad. The efficiency of the domestic solid-liquid two-phase flow centrifugal pump is mostly between 40%-60%, although it has improved in recent years, but still needs to be improved. The research on the actual working condition of solid-liquid two-phase flow experiment and the mastery of the motion law of solid particles have a very important influence on improving the service life and safety of the centrifugal pump.

[0003] The traditional centrifugal pump test device has a complex structure, a large volume and a high cost. At present, the centrifugal pump mostly adopts a main shaft directly extending from the pump body part, and then a camera directly photographs the internal flow field of the impeller from the front of the water suction chamber. The shooting area will be blocked by the transmission shaft or the motor of the pump unit, the entire impeller area cannot be shot, and the shooting effect cannot be guaranteed. In addition, when adjusting the inlet valve of the impeller, vortex will be generated after the water flow passes through the valve, which will cause unstable flow at the inlet of the impeller. Usually, a long pipeline is needed to stabilize the water flow. The actual working condition of the solid-liquid two-phase flow experiment is complex, and it is difficult to master the motion law of the solid particles, and the wear measurement is not intuitive enough.

[0004] When the existing solid-liquid two-phase flow experiment device is used, the solid particles and the liquid enter the water storage tank through the water inlet pipe, fall into the impeller chamber through stirring, pass through the water outlet chamber and flow out through the water outlet pipe, and the water flow directly passes through the water outlet chamber and the water outlet pipe. Due to the dynamic and static effects of the water pipe and the impeller, the stability of the fluid flow is affected, and then the accuracy of the experimental data is affected, so the solid-liquid two-phase flow experiment device is needed to solve the above problems. SUMMARY

[0005] In order to solve the above technical defects, the present application provides a solid-liquid two-phase flow experiment device, which studies the motion trajectory of a single large-size particle in the actual working condition, and then analyzes the influence of particle motion on the wear, output power and efficiency of the centrifugal pump through data processing.

[0006] The utility model provides an experimental device of solid-liquid two-phase flow, which comprises a support (10) and a centrifugal pump (101) mounted on the support (10), the centrifugal pump (101) is driven by a motor, a high-speed camera (2111) is arranged opposite to the centrifugal pump (101), the centrifugal pump (101) is connected with a feeding hopper (107) at the inlet, the feeding hopper (107) is provided with a stirrer (106), an outlet pressure transmitter (102), an inlet pressure transmitter (109) and an electromagnetic flowmeter (103) are connected on the pipeline of the inlet and outlet of the centrifugal pump (101), the discharged solid-liquid two-phase flow reenters the feeding hopper (107) through a water outlet pipeline, the solid-liquid two-phase flow is stirred uniformly by the stirrer (106) and then reenters an experimental pipeline, and the solid-liquid two-phase flow can be repeatedly used.

[0007] Optionally, the device comprises a visual centrifugal pump (101) comprising a support (10), an impeller chamber (11), a water outlet chamber (110) and a water outlet pipe (111); the impeller chamber (11) is fixed on the upper surface of the support (10) by bolts, the water outlet chamber (110) is fixed on one end of the upper surface of the impeller chamber (11), and the water outlet pipe (111) is fixed on the upper surface of the water outlet chamber (110); a drainage assembly comprising a third servo motor (20), a bearing (21), a third rotating shaft (22), a drainage plate (23), a through hole (24) and a locking rod (25); the third servo motor (20) is fixed on the side of the water outlet chamber (110), the bearing (21) is embedded on the side wall of the water outlet chamber (110), the third rotating shaft (22) is fixed on the output end of the third servo motor (20), and the third rotating shaft (22) is inserted into the bearing (21), the drainage plate (23) is sleeved on the third rotating shaft (22), the through hole (24) is formed on one end of the drainage plate (23), and the locking rod (25) is screwed into the through hole (24) and is in contact with the third rotating shaft (22); the drainage assembly has two groups, which are distributed on the two sides of the water outlet chamber (110), and the drainage plates (23) are staggered; the centrifugal pump water storage tank (13) is provided with a stirrer (106), a combined hole plate (209) is installed at the outlet of the centrifugal pump water storage tank (13), and an upper hole plate and a lower hole plate are installed at the outlet of the centrifugal pump water storage tank (13), a positioning filter screen and a photoelectric sensor are installed behind the hole plate (209), a impeller is arranged at the center of the end of the inlet flow channel, and two-phase flow passes through the water storage tank (13), the stirrer (106), the hole plate (209), the directional filter screen and the impeller (152) in sequence; the upper hole plate and the lower hole plate have the same structure, and a plurality of water passing holes arranged in a ring shape are formed on the upper hole plate and the lower hole plate; the visual centrifugal pump further comprises a connecting pipe (12), a water storage tank (13), a water inlet pipe (130) and a top cover (14); the connecting pipe (12) is fixed on the upper surface of the middle part of the impeller chamber (11), the water storage tank (13) is fixed on the upper surface of the middle part of the connecting pipe (12), the water inlet pipe (130) is fixed on the upper segment of the side of the water storage tank (13), and the top cover (14) is fixed on the top of the water storage tank (13).

[0008] Optionally, the visual centrifugal pump further comprises a first servo motor (15), a first rotating shaft (150), a stirring rod (151) and an impeller (152); the first servo motor (15) is fixed on the upper surface of the middle part of the top cover (14), the first rotating shaft (150) is fixed on the output end of the first servo motor (15), and the first rotating shaft (150) is inserted into the impeller chamber (11), the connecting pipe (12) and the water storage tank (13), the stirring rod (151) is fixed on the upper segment of the first rotating shaft (150) and located in the water storage tank (13), and the impeller (152) is fixed on the lower segment of the first rotating shaft (150) and located in the impeller chamber (11).

[0009] Optionally, the visual centrifugal pump further comprises a second servo motor (16), a second rotating shaft (160), a support ring (161), an internal gear (162) and a driving wheel (167); the second servo motor (16) is fixed on one end of the upper surface of the top cover (14), the second rotating shaft (160) is fixed on the output end of the second servo motor (16) and located in the water storage tank (13), the driving wheel (167) is fixed on the lower end of the second rotating shaft (160), the support ring (161) is located at the lower end of the top cover (14), the internal gear (162) is embedded in the middle part of the support ring (161) on the outer side, and the internal gear (162) is engaged with the driving wheel (167); the visual centrifugal pump further comprises a quick assembly;

[0010] The quick assembly comprises electric push rods (30) and L-shaped connecting rods (31); the electric push rods (30) are three in total, the upper ends of which are fixed on the lower surface of the top cover (14), the lower ends of which are fixed on the upper surface of the support ring (161) and are arranged in a ring shape in a symmetrical manner, and the L-shaped connecting rods (31) are fixed between the support ring (161) and the limiting plate (165).

[0011] Optionally, the visual centrifugal pump further comprises a connecting column (163), a movable plate (164), a limiting plate (165) and a mesh plate (166); the upper end of the connecting column (163) is fixed on the lower surface of the internal gear (162), the mesh plate (166) is sleeved on the first rotating shaft (150) and fixed on the inner bottom surface of the water storage tank (13), the limiting plate (165) is attached to one end of the upper surface of the mesh plate (166), the movable plate (164) is fixed on the lower end of the connecting column (163), and the movable plate (164) is attached to the other side of the mesh plate (166).

[0012] Optionally, the device comprises a photoelectric sensor and a directional filter screen installed at the inlet of the centrifugal pump (101); in the experiment of observing the motion trajectory of large-size particles, the photoelectric sensor is connected with a high-speed camera (2111), and the directional filter screen allows particles to enter from only one position; when a particle enters the centrifugal pump impeller (152), the reading of the photoelectric sensor changes, triggering the high-speed camera (2111) to shoot.

[0013] Optionally, when processing the image of the high-speed flowing water body in the pump, the high-speed camera (2111) removes noise signals in a manner of NL-Means algorithm and improved wavelet fusion, finally uses a canny operator to obtain object contour information, uses a wavelet conversion manner to filter out most of the salt and pepper noise and stripe noise, the sampling frequency is 1KHZ, three-layer wavelet decomposition is performed, and the decomposition equation is as follows:

[0014]

[0015] wherein, is the sampling frequency, The maximum frequency of the signal is =2 ;

[0016] The new wavelet threshold function is used for threshold processing, and the threshold function is as follows:

[0017]

[0018] Wherein, a, b, m are adjustment factors, a and b (a>0, b>0) are two shape control parameters of the new threshold function, and m (0

[0019] After wavelet reconstruction, NL-means denoising technology is introduced to filter the Gaussian noise and salt and pepper noise in the image, and the formula is:

[0020]

[0021] Wherein, is the image with noise; is the denoised image; the weight The similarity between pixel i and pixel j is represented by the neighborhood pixels centered on pixel i and pixel j, which ensures the accuracy of the similarity measure, and the calculation formula is:

[0022]

[0023] Wherein, Z(x) is the normalization coefficient, and the calculation formula is:

[0024]

[0025] Wherein, h is the smoothing parameter, and the greater the value, the smoother;

[0026] Finally, the canny operator is used for image edge detection, and the calculation formula is as follows:

[0027]

[0028]

[0029]

[0030]

[0031] Wherein, the high threshold is set to 100, the low threshold is set to 50, and the Gaussian radius is 2, and the binary image is obtained;

[0032] The threshold condition and connectivity relationship are used to obtain the semantic information of the image, and finally the center coordinates are calculated.

[0033] Optionally, the ExpAssoc equation is used to fit the particle velocity VX in the X-axis direction with the particle coordinates in the impeller flow channel plane, and the expression of the ExpAssoc equation is as shown in the following formula

[0034]

[0035] The Logistic equation is used to fit the particle velocity VY in the Y-axis direction, and the expression of the Logistic equation is as shown in the following formula y

[0036] wherein A, a are the correlation coefficients obtained by fitting the curve, x0, y0 are the corresponding velocities of the reference point, and t is the time variable;

[0037] According to the pixel points occupied by the particles in the acquired image, a relationship equation between the particle position and size is fitted as shown in the following formula ;

[0038] The pixel points occupied by the particles are fitted with time as shown in the following formula , and the velocity equation of the Z-axis is obtained by derivation of the position with respect to time as shown in the following formula

[0039]

[0040] wherein K, b, c are the correlation coefficients obtained by fitting the curve, x is the pixel point variable, Z is the position variable, and t is the time variable.

[0041] Optionally, a group of laser emitters (32) and laser receiving screens (33) are arranged on both sides of the impeller (152), the sampling frequency of the laser receiving screen (33) is taken as the shooting frequency of the high-speed camera (2111), and the position information of the image in the Z-axis direction is obtained by being introduced into the computer. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 FIG. 1 is a schematic diagram of a solid-liquid two-phase flow experimental device provided by the present application;

[0043] Figure 2 FIG. 2 is a schematic diagram of particle addition of a visual centrifugal pump provided by the present application;

[0044] Figure 3 FIG. 3 is a schematic diagram of the structure of a visual centrifugal pump provided by the present application;

[0045] Figure 4 FIG. 4 is a front view of a visual centrifugal pump provided by the present application;

[0046] Figure 5 FIG. 5 is a schematic diagram of the position of a drainage assembly provided by the present application;

[0047] ​Figure 6 The schematic diagram of the drainage assembly structure provided in the present application is shown in the following figure:

[0048] Figure 7 The schematic diagram of the quick assembly structure provided in the present application is shown in the following figure:

[0049] Figure 8 The rotating coordinate system in the impeller provided in the present application is used to mark the coordinates in the process of particle movement.

[0050] Figure 9 The schematic diagram of the placement position of the laser emitter and receiving screen on both sides of the impeller provided in the present application is shown in the following figure.

[0051] In the drawings, the components represented by each reference numeral are listed as follows:

[0052] Centrifugal pump 101, outlet pressure transmitter 102, electromagnetic flowmeter 103, outlet valve 104, agitator motor 105, agitator 106, feeding hopper 107, inlet valve 108, inlet pressure transmitter 109, trigger device 110, high-speed camera 2111, computer control system 112, torque meter 113, centrifugal pump motor 114;

[0053] Support 10, impeller chamber 11, impeller 152, drainage plate 205, water outlet pipe 111, buckle 207, rotating head 208, combined hole plate 209, agitator 210, water inlet pipe 130, first servo motor 15, motor base 213, bearing cover plate 214, bearing 21, water storage tank 13;

[0054] Water outlet chamber 110, connecting pipe 12, water inlet pipe 130, top cover 14, first rotating shaft 150, stirring rod 151, second servo motor 16, second rotating shaft 160, support ring 161, internal gear 162, connecting column 163, movable plate 164, limiting plate 165, mesh plate 166, driving wheel 167, third servo motor 20, bearing 21, third rotating shaft 22, drainage plate 23, through hole 24, locking rod 25, electric push rod 30, L-shaped connecting rod 31, laser emitter 32, laser receiving screen 33. DETAILED DESCRIPTION

[0055] The solid-liquid two-phase flow experimental device is an experimental device for studying the mixing flow phenomenon of solid particles and liquid. It studies the characteristics, laws and influencing factors of solid-liquid two-phase flow by simulating the flow process of solid-liquid two-phase fluid in a pipeline, a container or a reactor. Before the experiment starts, first start the centrifugal pump and start the countdown for 10 minutes to ensure that the centrifugal pump reaches the rated working state before the particles enter. By calculating the estimated movement time of the solid particles in the pump, the time is compared with the rotation speed of the pump, and the best high-speed camera frame rate is selected. Subsequently, the holes of the combined orifice plate are completely closed by the rotating head, and the solid-liquid two-phase flow in the water storage tank is driven by the stirrer to keep the solid particles mixed uniformly. When the ten-minute countdown is over, the water area of the upper and lower orifice plates is changed by the rotating head, so that the solid-liquid two-phase flow passes through the orifice plate into the impeller chamber, and then passes through the filter hole into the impeller chamber under the guidance of the directional filter screen. A set of photoelectric sensors is placed above the impeller, and the photoelectric sensors are connected with the high-speed camera. After the solid particles fall from the directional filter screen, the photoelectric sensor detects the change of the reading at the moment, so as to trigger the high-speed camera to start shooting, and the high-speed camera works until all the large-size solid particles leave the impeller chamber of the centrifugal pump.

[0056] When the existing solid-liquid two-phase flow experimental device is used, the solid particles and the liquid enter the water storage tank through the water inlet pipe, fall into the impeller chamber through stirring, pass through the water outlet chamber, and then flow out through the water outlet pipe. The water flow directly passes through the water outlet chamber and the water outlet pipe, which will affect the stability of the fluid flow due to the dynamic and static effects of the water pipe and the impeller, and then affect the accuracy of the experimental data.

[0057] As Figure 1 The solid-liquid two-phase flow experimental device provided by the present application is shown in the figure, and the experimental device for solid-liquid two-phase flow disclosed by the present application comprises a support 10 and a centrifugal pump 101 mounted on the support 10. The centrifugal pump 101 is driven by a motor, a high-speed camera 2111 is arranged opposite to the centrifugal pump 101, an inlet of the centrifugal pump 101 is connected with a feeding hopper 107, the feeding hopper 107 is provided with a stirrer 106, an outlet pressure transmitter 102, an inlet pressure transmitter 109 and an electromagnetic flowmeter 103 are connected on the pipeline of the inlet and outlet of the centrifugal pump 101, the outflowing solid-liquid two-phase flow reenters the feeding hopper 107 through the water outlet pipeline, the solid-liquid two-phase flow is stirred uniformly by the stirrer 106 and then reenters the experimental pipeline, and the solid-liquid two-phase flow can be repeatedly used.

[0058] Optionally, the device comprises: a visual centrifugal pump 101, the visual centrifugal pump comprises a support 10, an impeller chamber 11, a water outlet chamber 110 and a water outlet pipe 111; the impeller chamber 11 is fixed on the upper surface of the support 10 by bolts, the water outlet chamber 110 is fixed on the upper surface of the impeller chamber 11 at one end, and the water outlet pipe 111 is fixed on the upper surface of the water outlet chamber 110; a drainage assembly, the drainage assembly comprises a third servo motor 20, a bearing 21, a third rotating shaft 22, a drainage plate 23, a through hole 24 and a locking rod 25; the third servo motor 20 is fixed on the side of the water outlet chamber 110, the bearing 21 is embedded on the side wall of the water outlet chamber 110, the third rotating shaft 22 is fixed on the output end of the third servo motor 20, and the third rotating shaft 22 is inserted into the bearing 21, the drainage plate 23 is sleeved on the third rotating shaft 22, the through hole 24 is formed in one end of the drainage plate 23, and the locking rod 25 is screwed in the through hole 24 and combined with the third rotating shaft 22; the drainage assembly has two groups in total and is distributed on the two side edges of the water outlet chamber 110, and the drainage plates 23 are staggered.

[0059] Optionally, the solid-liquid two-phase flow experimental device disclosed in the application comprises: a visual centrifugal pump, the visual centrifugal pump comprises a support, an impeller chamber, a water outlet chamber and a water outlet pipe; a drainage assembly, the drainage assembly comprises a third servo motor, a bearing, a third rotating shaft, a drainage plate, a through hole and a locking rod; the third servo motor is fixed on the side of the water outlet chamber, the bearing is embedded on the side wall of the water outlet chamber, the third rotating shaft is fixed on the output end of the third servo motor, the drainage plate is sleeved on the third rotating shaft, the through hole is formed in one end of the drainage plate, and the locking rod is screwed in the through hole. To solve the problem that when the existing solid-liquid two-phase flow experimental device is used, solid particles and liquid enter the water storage tank through the water inlet pipe, fall into the impeller chamber through stirring, pass through the water outlet chamber, and flow out through the water outlet pipe, and the water flow directly flows out through the water outlet chamber and the water outlet pipe, which will affect the stability of fluid flow due to the dynamic and static effects of the water pipe and the impeller, and further affect the accuracy of experimental data.

[0060] The application discloses a complete solid-liquid two-phase flow experimental device for real solid-liquid two-phase flow experiment. The experimental device comprises a solid-liquid two-phase flow loop, a water loop and a high-speed photography system. A feeding hopper is arranged on the right side. A valve is arranged at the outlet of a pipeline. The feeding hopper is connected with a stirrer. Two-phase flow working conditions enter a centrifugal pump. A photoelectric sensor and a pressure transmitter are arranged at the inlet. The indication of the photoelectric sensor and the pressure transmitter triggers a trigger device to start a high-speed camera. The high-speed camera is opposite to the centrifugal pump. The centrifugal pump is made of glass. Solid-liquid flow is thrown out of the centrifugal pump. The solid-liquid flow passes through an outlet pressure transmitter and an electromagnetic flowmeter. An outlet pipe is reconnected with the feeding hopper. The solid-liquid two-phase flow is finally recycled into the feeding hopper, so that a circulation experiment is realized. Data are collected and uploaded to a computer control system for processing.

[0061] As Figure 2A visual centrifugal pump particle addition schematic diagram provided by the application is shown, the centrifugal pump runs in the design working condition, the solid particles are put into the system loop at the beginning of the experiment, the motor of the stirrer is started to start the stirrer, the solid particles in the funnel are stirred for a period of time, and then the feed funnel valve and the inlet valve are opened. When the two-phase flow working condition enters the centrifugal pump, the inlet pressure transmitter will produce a reading change to trigger the device to start, so that the high-speed camera starts shooting, the high-speed camera tracks the particle movement in the centrifugal pump, and a computer control system is used to control the high-speed photography system, the image of the particle is controlled, displayed and stored, and the shooting rate of the high-speed camera is 200 frames / s. The flow rate in the whole experimental device pipeline is measured by an electromagnetic flowmeter. The solid-liquid two-phase flow is finally separated by a filter screen, and the solid particles are recycled into the feed funnel, so that the circulating experiment is realized.

[0062] As Figure 3 A centrifugal pump structure schematic diagram provided by the application is shown, the centrifugal pump is driven by a servo motor to rotate the impeller, so that the impeller drives the flow of the whole solid-liquid two-phase flow. In order to make the flow more stable, a flow guide plate is installed in the impeller chamber to eliminate the dynamic and static interference effect of the water pipe and the impeller. In order to control the flow rate at the inlet of the impeller, a combined orifice plate is installed at the outlet of the water storage tank, the water area between the upper and lower orifice plates is changed by rotating the rotating head, so that the purpose of controlling the flow rate is achieved. The solid-liquid two-phase flow enters the water storage tank from the water inlet pipe, is stirred again by the stirrer in the water storage tank to achieve the purpose of uniform mixing of the solid-liquid two-phase flow, and then enters the impeller chamber through the combined orifice plate. After stirring by the impeller, it flows to the water outlet pipe and flows out of the centrifugal pump.

[0063] The support of the centrifugal pump and the impeller chamber on the support, and the water guide chamber of the impeller chamber are all made of transparent organic glass material. The stirrer is installed on the same main shaft, and the same motor can drive the centrifugal pump and the stirrer. The centrifugal pump impeller is coated with low-erosion material, and the average arithmetic average roughness Ra of the surface of the coated impeller is within 0.1 μm.

[0064] Figure 4 A front view of a visual centrifugal pump provided by the application is shown. Figure 5 A flow guide assembly position schematic diagram provided by the application is shown. Figure 6 A flow guide assembly structure schematic diagram provided by the application is shown. As Figures 4-6As shown, the experimental device of the solid-liquid two-phase flow includes: a centrifugal pump water storage tank 13 is provided with a stirrer 106, a combined orifice plate 209 is installed at the outlet of the centrifugal pump water storage tank 13, a positioning filter screen and a photoelectric sensor are installed behind the orifice plate 209, a impeller is arranged at the end of the inlet flow channel, the two-phase flow passes through the water storage tank 13, the stirrer 106, the orifice plate 209, the directional filter screen and the impeller 152 in sequence, the upper orifice plate and the lower orifice plate have the same structure, a plurality of water passing holes arranged in a ring shape are formed on the upper orifice plate and the lower orifice plate; the visual centrifugal pump further includes a connecting pipe 12, a water storage tank 13, a water inlet pipe 130 and a top cover 14; the connecting pipe 12 is fixed on the upper surface of the middle part of the impeller chamber 11, the water storage tank 13 is fixed on the upper surface of the middle part of the connecting pipe 12, the water inlet pipe 130 is fixed on the side edge of the upper section of the water storage tank 13, and the top cover 14 is fixed on the top of the water storage tank 13; the visual centrifugal pump further includes a first servo motor 15, a first rotating shaft 150, a stirring rod 151 and an impeller 152; the first servo motor 15 is fixed on the upper surface of the middle part of the top cover 14, the first rotating shaft 150 is fixed on the output end of the first servo motor 15, and the first rotating shaft 150 is inserted into the impeller chamber 11, the connecting pipe 12 and the water storage tank 13, the stirring rod 151 is fixed on the upper section of the first rotating shaft 150 and located in the water storage tank 13, and the impeller 152 is fixed on the lower section of the first rotating shaft 150 and located in the impeller chamber 11.

[0065] Optionally, the visual centrifugal pump further includes a second servo motor 16, a second rotating shaft 160, a support ring 161, an internal gear 162 and a driving wheel 167; the second servo motor 16 is fixed on one end of the upper surface of the top cover 14, the second rotating shaft 160 is fixed on the output end of the second servo motor 16 and located in the water storage tank 13, the driving wheel 167 is fixed on the lower end of the second rotating shaft 160, the support ring 161 is located at the lower end of the top cover 14, the internal gear 162 is embedded in the middle part of the support ring 161 on the outer side, and the internal gear 162 is engaged with the driving wheel 167; the visual centrifugal pump further includes a quick assembly; the quick assembly includes an electric push rod 30 and an L-shaped connecting rod 31; the electric push rod 30 has three, the upper end is fixed on the lower surface of the top cover 14, the lower end is fixed on the upper surface of the support ring 161, and the three are distributed in a ring shape and symmetrically, and the L-shaped connecting rod 31 is fixed between the support ring 161 and the limiting plate 165.

[0066] Optionally, the visual centrifugal pump further includes a connecting column 163, a movable plate 164, a limiting plate 165 and a mesh plate 166; the connecting column 163 is fixed on the lower surface of the internal gear 162, the mesh plate 166 is sleeved on the first rotating shaft 150 and fixed on the inner bottom surface of the water storage tank 13, the limiting plate 165 is attached to one end of the upper surface of the mesh plate 166, the movable plate 164 is fixed on the lower end of the connecting column 163, and the movable plate 164 is attached to the other side of the mesh plate 166.

[0067] Optionally, the device comprises a photoelectric sensor and a directional filter screen installed at the inlet of the centrifugal pump 101, the photoelectric sensor is connected with the high-speed camera 2111 in the experiment of observing the trajectory of large-size particle movement, the directional filter screen only allows particles to enter from one position, when particles enter the centrifugal pump impeller 152, the reading of the photoelectric sensor changes, triggering the high-speed camera 2111 to shoot.

[0068] The experimental device of the solid-liquid two-phase flow comprises a visualized centrifugal pump, the visualized centrifugal pump comprising a support 10, an impeller chamber 11, a water outlet chamber 110 and a water outlet pipe 111; the impeller chamber 11 is fixed on the upper surface of the support 10 by bolts, the water outlet chamber 110 is fixed on the upper surface of one end of the impeller chamber 11, and the water outlet pipe 111 is fixed on the upper surface of the water outlet chamber 110; the support 10 serves as a support, the impeller chamber 11 serves as a protection and storage, and the water outlet chamber 110 and the water outlet pipe 111 provide a fluid outflow channel; a drainage assembly comprising a third servo motor 20, a bearing 21, a third rotating shaft 22, a drainage plate 23, a through hole 24 and a locking rod 25; the third servo motor 20 is fixed on the side of the water outlet chamber 110, the bearing 21 is embedded on the side wall of the water outlet chamber 110, the third rotating shaft 22 is fixed on the output end of the third servo motor 20 and is inserted into the bearing 21, the drainage plate 23 is sleeved on the third rotating shaft 22, the through hole 24 is opened at one end of the drainage plate 23, and the locking rod 25 is screwed in the through hole 24 and is attached to the third rotating shaft 22; the third servo motor 20 provides a power source, the bearing 21 is sealed to facilitate rotation of the third rotating shaft 22, the third rotating shaft 22 transmits power, the drainage plate 23 is used for guiding water flow, the through hole 24 serves as a connection, and the locking rod 25 serves as a fixing.

[0069] The visual centrifugal pump further comprises a connecting pipe 12, a water storage tank 13, a water inlet pipe 130 and a top cover 14; the connecting pipe 12 is fixed on the middle part of the upper surface of the impeller chamber 11, the water storage tank 13 is fixed on the middle part of the upper surface of the connecting pipe 12, the water inlet pipe 130 is fixed on the upper section of the side of the water storage tank 13, and the top cover 14 is fixed on the top of the water storage tank 13; the connecting pipe 12 plays a connecting role, the water storage tank 13 plays a storage role and is used for mixing fluid, the water inlet pipe 130 introduces liquid and solid particles into the water storage tank 13, and the top cover 14 plays a sealing role; the visual centrifugal pump further comprises a first servo motor 15, a first rotating shaft 150, a stirring rod 151 and an impeller 152; the first servo motor 15 is fixed on the middle part of the upper surface of the top cover 14, the first rotating shaft 150 is fixed on the output end of the first servo motor 15, and the first rotating shaft 150 is inserted into the impeller chamber 11, the connecting pipe 12 and the water storage tank 13, the stirring rod 151 is fixed on the upper section of the first rotating shaft 150 and is located in the water storage tank 13, and the impeller 152 is fixed on the lower section of the first rotating shaft 150 and is located in the impeller chamber 11; the first servo motor 15 provides a power source, the first rotating shaft 150 transmits power, the stirring rod 151 uniformly mixes liquid and solid particles, and the impeller 152 is used for mixing fluid; the visual centrifugal pump further comprises a second servo motor 16, a second rotating shaft 160, a support ring 161, an internal gear 162 and a driving wheel 167; the second servo motor 16 is fixed on one end of the upper surface of the top cover 14, the second rotating shaft 160 is fixed on the output end of the second servo motor 16 and is located in the water storage tank 13, the driving wheel 167 is fixed on the lower end of the second rotating shaft 160, the support ring 161 is located at the lower end of the top cover 14, the internal gear 162 is inlaid in the middle part of the support ring 161 on the outer side, and the internal gear 162 is engaged with the driving wheel 167; the second servo motor 16 provides a power source, the second rotating shaft 160 converts power, the support ring 161 plays a supporting role, and the driving wheel 167 and the internal gear 162 transmit power; the visual centrifugal pump further comprises a connecting column 163, a movable plate 164, a limiting plate 165 and a mesh plate 166; the upper end of the connecting column 163 is fixed on the lower surface of the internal gear 162, the mesh plate 166 is sleeved on the first rotating shaft 150 and is fixed on the inner bottom surface of the water storage tank 13, the limiting plate 165 is attached to one end of the upper surface of the mesh plate 166, the movable plate 164 is fixed on the lower end of the connecting column 163, and the movable plate 164 is attached to the other side of the mesh plate 166; the connecting column 163 plays a connecting role, the movable plate 164 plays a sealing role, the limiting plate 165 plays a limiting role, and the mesh plate 166 provides a fluid flow channel.

[0070] The working principle is as follows: the third rotating shaft 22 is inserted into the bearing 21 of the side wall of the water outlet chamber 110, and the drainage plate 23 is inserted, and the locking rod 25 is tightened on the through hole 24, and the two drainage plates 23 are perpendicular to the side wall of the water outlet chamber 110 during the experiment, and are staggered; the liquid and solid particles enter the water storage tank 13 through the water inlet pipe 130, the first servo motor 15 is started, the first rotating shaft 150 is driven to rotate, the stirring rod 151 is driven to rotate, the liquid and the solid particles are uniformly mixed; then the second servo motor 16 is started, the second rotating shaft 160 is driven to rotate, the driving wheel 167 is driven to rotate, the inner gear 162 is driven to rotate in the support ring 161, the connecting column 163 is driven to rotate, the movable plate 164 below the connecting column 163 is driven to rotate, the movable plate 164 is driven to rotate into the limiting plate 165, the mesh plate 166 is exposed, the fluid flows into the connecting pipe 12 from the mesh of the mesh plate 166, enters the impeller chamber 11, is stirred by the impeller 152, and then flows out through the water outlet chamber 110 and the water outlet pipe 111; when the fluid passes through the water outlet chamber 110, due to the staggered drainage plates 23, the flow path is S-shaped, which can effectively reduce the dynamic and static effects of the water outlet pipe 111 and the impeller 152; when the experiment is finished, the third servo motor 20 can be started, the third servo motor 20 drives the third rotating shaft 22 to rotate in the bearing 21, drives the drainage plate 23 to rotate, and is attached to the inner side wall of the water outlet chamber 110, so that the fluid can flow out faster. This step can avoid the influence of the dynamic and static effects of the water outlet pipe 111 and the impeller 152 on the accuracy.

[0071] As Figure 7 The schematic diagram of the quick assembly structure provided by the application is shown, and the embodiment is based on the above-mentioned embodiment, further comprising: a quick assembly, the quick assembly comprising an electric push rod 30 and an L-shaped connecting rod 31; the electric push rod 30 has three, the upper end is fixed on the lower surface of the top cover 14, the lower end is fixed on the upper surface of the support ring 161, and they are arranged in a ring shape and symmetrically distributed, and the L-shaped connecting rod 31 is fixed between the support ring 161 and the limiting plate 165; the electric push rod 30 can realize position change, and the L-shaped connecting rod 31 plays a connecting role.

[0072] The working principle is as follows: during the experiment, the electric push rod 30 is in a fully stretched state, the inner gear 162 is engaged with the driving wheel 167, the movable plate 164 is on the upper surface of the mesh plate 166, and the limiting plate 165 is wrapped above the mesh plate 166; after the experiment is finished, the electric push rod 30 is started, the electric push rod 30 is retracted, the support ring 161 and the inner gear 162 are moved upwards, and then the connecting column 163 and the L-shaped connecting rod 31 are moved upwards, so that the movable plate 164 and the limiting plate 165 are moved upwards, and the mesh plate 166 is completely exposed. This step can further improve the water flow speed and accelerate the outflow of the fluid in the device.

[0073] Before the experiment, the centrifugal pump is started and the countdown of 10 minutes is started to ensure that the centrifugal pump reaches the rated working state before the particles enter. By calculating the estimated movement time of the solid particles in the pump, the time is compared with the rotation speed of the pump to select the best high-speed camera frame rate. Then, the holes of the combined orifice plate are completely closed by the rotating head, and the solid-liquid two-phase flow in the water storage tank is driven by the stirrer to keep the solid particles mixed uniformly. When the ten-minute countdown is over, the water area of the upper and lower orifice plates is changed by the rotating head, so that the solid-liquid two-phase flow passes through the orifice plate into the impeller chamber, and is guided by the directional filter screen to pass through the filter hole into the impeller chamber. A set of photoelectric sensors is placed in the position directly above the impeller, and the photoelectric sensors are connected with the high-speed camera. When the solid particles fall from the directional filter screen and are detected by the photoelectric sensor, the reading of the photoelectric sensor changes, thereby triggering the high-speed camera to start shooting, and the high-speed camera works until all the large-size solid particles leave the impeller chamber of the centrifugal pump.

[0074] Optionally, the high-speed camera (2111) uses the NL-Means algorithm and the improved wavelet fusion method to remove noise signals when processing the image of the high-speed flowing water body in the pump, and finally uses the canny operator to obtain object contour information, uses the wavelet conversion method to filter out most of the salt and pepper noise and stripe noise, the sampling frequency is 1KHZ, three-layer wavelet decomposition is performed, and the decomposition equation is as follows:

[0075]

[0076] wherein, is the sampling frequency, is the maximum frequency of the signal. According to the Nyquist sampling theorem, =2

[0077] A new wavelet threshold function is used for threshold processing, and the threshold function is as follows:

[0078]

[0079] wherein, a, b, and m are adjustment factors, a and b (a>0, b>0) are two shape control parameters of the new threshold function, and m (0<m<1) is an approximation degree parameter of the new threshold function;

[0080] After wavelet reconstruction, the NL-means denoising technology is introduced to perform secondary filtering on the Gaussian noise and salt and pepper noise not completely filtered in the image, and the formula is:

[0081]

[0082] wherein, is the image with noise; The image after denoising; weight The similarity between pixel i and pixel j is determined by the neighborhood pixels centered on pixel i and pixel j, which ensures the accuracy of the similarity measure, and the calculation formula is:

[0083]

[0084] Wherein, Z(x) is a normalization coefficient, and the calculation formula is:

[0085]

[0086] Wherein, h is a smoothing parameter, and the greater the value, the smoother;

[0087] Finally, the image edge detection is carried out by using canny operator, and the calculation formula is as follows:

[0088]

[0089]

[0090]

[0091]

[0092] Wherein, the high threshold is set to 100, the low threshold is set to 50, and the Gaussian radius is 2, and a binary image is obtained;

[0093] The threshold condition and the connectivity relationship are used to obtain the image semantic information, and finally the center coordinates are obtained.

[0094] Optionally, the particle coordinates of the impeller flow passage plane are used to fit the movement speed VX of the particles in the X axis direction by ExpAssoc equation, and the expression of ExpAssoc equation is as follows:

[0095]

[0096] The movement speed VY of the particles in the Y axis direction is fitted by Logistic equation, and the expression of Logistic equation is as follows: y

[0097] Wherein, A and a are the correlation coefficients obtained by fitting the curve, x0 and y0 are the corresponding speeds of the reference point, and t is a time variable;

[0098] According to the pixel points occupied by the particles in the obtained image, the relationship equation between the particle position and size is fitted: ;

[0099] The fitting equation of the pixel points occupied by the particles with time is expressed as: ​The velocity equation of the final Z axis is obtained by derivation of position versus time:

[0100]

[0101] wherein K, b, c are the correlation coefficients obtained by fitting the curve, x is the pixel variable, Z is the position variable, and t is the time variable.

[0102] Optionally, a set of laser emitters (32) and laser receiving screens (33) are arranged on both sides of the impeller (152), the sampling frequency of the laser receiving screen (33) is the frequency of the high-speed camera 2111, and the image position information on the z axis is obtained by being introduced into a computer.

[0103] Figure 8 A rotating coordinate system in the impeller is provided for calibrating the coordinates of the particle movement process. In order to obtain the trajectory of the particle, image preprocessing is first performed, including image selection and PS image batch processing, to ensure that all particles have the same inlet conditions. In the image captured by the camera, the light scattering and diffraction caused by the transparent pump body, water body and non-transparent particles, and the water flow fluctuation caused by the rotation of the impeller in the pump have a great influence on the image. There are many salt and pepper noise and stripe noise in the image. To filter out the noise, when processing the image of the high-speed flowing water body in the pump, the image is first converted into a gray image. Most of the salt and pepper noise and stripe noise are filtered out by using wavelet conversion. The sampling frequency is 1KHZ, and three-layer wavelet decomposition is performed. Then, a new wavelet threshold function is used for threshold processing. After the processing is completed, wavelet reconstruction is performed. After the reconstruction is completed, the NL-means denoising technology is introduced to perform secondary filtering on the Gaussian noise and salt and pepper noise in the image that have not been completely filtered out, so as to ensure the integrity of the semantic information while filtering out the noise signal as much as possible. Finally, the canny operator is used for image edge detection, and the threshold condition and connectivity relationship are used to obtain the semantic information of the image, and the center coordinates are finally obtained. Then, the processed image is superimposed to obtain the trajectory of the particle. The result is analyzed, and the accuracy of image recognition is improved to a certain extent. First, all the images are superimposed to obtain the trajectory of the solid particle. Assuming that a camera frequency of 200 frames per second is used, the time for a large-size particle to enter the impeller chamber to leave the impeller chamber is 0.1s, and a total of 20 photos are taken during this process. The photos are superimposed. Due to the high difficulty of nonlinear fitting of complex trajectories, existing nonlinear equations cannot realize the fitting of such complex trajectories, so a relatively regular trajectory in the figure is selected to fit the data, so as to derive the trajectory equation of the particle.

[0104] The collected pictures are processed by image processing technology, the image is first converted into a gray image, most of the salt and pepper noise and stripe noise are filtered by wavelet conversion, the sampling frequency is 1KHZ, three-layer wavelet decomposition is performed, and the relative rotating coordinate system rotating with the impeller is adopted , the particles in the flow passage are mainly subjected to gravity, resistance, pressure gradient force, virtual mass force and the like, the motion equation of the particles is as follows: A

[0105]

[0106]

[0107] wherein p is pressure, is the velocity component in the coordinate axis direction, g is gravitational acceleration, is the density of water, , is the density of particles, the rotation angle of the coordinate system , the resistance coefficient , is the Reynolds number of the particles.

[0108] The coordinates of the next moment are calculated through the given coordinates :

[0109]

[0110]

[0111] The coordinates of each point can be obtained by integrating the above formula, the calculated coordinates are corrected with the image coordinates to obtain the point coordinates on the xy plane. The real flow time is corrected, and the corrected flow time at the initial position as the 0 moment is obtained. Combined with the corrected flow time and the velocity of the particles in the X, Y and Z axes, the motion equations in three directions can be fitted. X, Y axis direction: the high-speed camera is directly opposite the direction of the impeller, and the image after superposition can clearly show the motion trajectory of the solid particles in the X-Y plane. All the images are imported and superposed to obtain the approximate motion trajectory, and the motion trajectory equation of the solid particles in the X-Y plane can be derived through the data change of the centroid coordinates. The expression of the ExpAssoc equation is as follows

[0112]

[0113] The motion velocity Vy of the particles in the Y axis is fitted by the Logistic equation, and the expression of the Logistic equation is as follows

[0114] ​​

[0115] where A, a are the correlation coefficient of the fitting curve, x0, y0 are the corresponding velocity of the reference point, t is the time variable.

[0116] Finally, the z-axis information of the particle is obtained by the laser emitting and receiving device, which is combined with the xy-axis equation and imported into the computer to obtain the final equation of the particle movement model in the pump.

[0117] Figure 9 The schematic diagram of the placement position of the laser emitting and receiving screen on both sides of the impeller is provided for the present application. When the particles move in the centrifugal pump, the reading of the photoelectric sensor in the receiving screen changes, thereby recording the z-axis position information of the point.

[0118] A new wavelet threshold function is used for threshold processing. Compared with the traditional wavelet threshold function, the function has good adaptability in actual use, and has less influence on the approximation degree of the reconstructed signal and the original signal. The threshold function is as follows:

[0119]

[0120] where a, b, m are the adjustment factors, a and b (a > 0, b > 0) are two shape control parameters of the new threshold function, and m (0 < m < 1) is the approximation degree parameter of the new threshold function.

[0121] The movement time of the solid particle in the pump is roughly estimated by estimating the internal fluid motion. It is assumed that the fluid is uniformly accelerated motion inside until the velocity is equal to the fluid velocity. The outlet velocity of the liquid is the final velocity of the particle, and the formula is used. The time used is roughly estimated.

[0122] The actual number of frames per second should be shot by combining the impeller speed, the movement time of the solid particle and the frame rate of the camera given by the formula. The directional filter screen has only one hole. When the particle enters the centrifugal pump impeller, the photoelectric sensor triggers the high-speed camera to shoot at a given speed.

[0123] The third rotating shaft is inserted into the bearing of the side wall of the water outlet chamber, and the drainage plate is inserted at the same time, the locking rod is screwed on the through hole, and the two drainage plates are perpendicular to the side wall of the water outlet chamber during the experiment, and are staggered, the fluid flow path is S-shaped, the dynamic and static effects of the water outlet pipe and the impeller can be effectively reduced, when the experiment is finished, the third servo motor is started, the third servo motor drives the third rotating shaft to rotate in the bearing, drives the drainage plate to rotate, and is attached to the inner side wall of the water outlet chamber, so that the fluid can flow out quickly, and the setting can avoid the influence of the dynamic and static effects of the water outlet pipe and the impeller on the accuracy.

[0124] The upper and lower hole plates are installed at the inlet of the centrifugal pump, the area of the water passing hole is changed by rotating the upper hole plate, so that the size of the flow is controlled, and the effect of flow regulation is also achieved, the impeller chamber is made of visual material, and the movement of particles in the flow field is clearly captured. The directional filter screen and the photoelectric sensor are installed at the water inlet, so that the initial conditions and positions of the particles entering the centrifugal pump are the same, and the reading of the photoelectric sensor is changed to trigger the shooting of the high-speed camera at the moment when the particles enter the centrifugal pump, and experiments on particles at different positions can be carried out.

[0125] In the wear measurement of the centrifugal pump, the traditional brush paint method is changed into using low-etching material to cover the centrifugal pump impeller, the wear degree is quantified through the mass loss before and after the experiment, and the wear degree of different positions is observed by changing the thickness of the low-etching material. In the final image processing process, a new wavelet threshold function is combined with NL-means denoising technology to carry out image denoising processing, which greatly improves the accuracy and accuracy of image recognition, and has good adaptability to complex environment. The laser generating and receiving device is used for z-axis positioning of solid particles, and the resistance information change of the receiving screen is used to obtain the z-axis position of the particles at this moment, which solves the problem of difficult z-axis information acquisition to a certain extent.

[0126] The application discloses a complete solid-liquid two-phase flow experimental device for real solid-liquid two-phase flow experiment, which comprises a solid-liquid two-phase flow loop, a water loop and a high-speed photography system, a feeding hopper is arranged on the right side, a valve is arranged on the pipeline outlet, the feeding hopper is connected with a stirrer, two-phase flow working conditions enter a centrifugal pump, a photoelectric sensor and a pressure transmitter are arranged at the inlet, the indication of the pressure transmitter triggers a trigger device to start a high-speed camera, the high-speed camera is opposite to the centrifugal pump, the centrifugal pump is made of visual glass, solid-liquid flow is thrown out of the centrifugal pump, passes through an outlet pressure transmitter and an electromagnetic flowmeter, the outlet pipe is reconnected with the feeding hopper, and the solid-liquid two-phase flow is finally recycled into the feeding hopper, so that a circulating experiment is realized, data is collected and uploaded to a computer control system for processing.

Claims

1. An experimental apparatus for solid-liquid two-phase flow, characterized in that, The device includes: a bracket (10) and a centrifugal pump (101) mounted on the bracket (10). The centrifugal pump (101) is driven by a motor. A high-speed camera (2111) is positioned opposite the centrifugal pump (101). The inlet of the centrifugal pump (101) is connected to a feeding funnel (107). The feeding funnel (107) is equipped with a stirrer (106). The outlet pressure transmitter (102), the inlet pressure transmitter (109), and the electromagnetic flowmeter (103) are connected to the inlet and outlet pipes of the centrifugal pump (101). The solid-liquid two-phase flow flows out and re-enters the feeding funnel (107) through the outlet pipe. After being stirred evenly by the stirrer (106), the solid-liquid two-phase flow re-enters the experimental pipeline. The solid-liquid two-phase flow can be reused continuously. Centrifugal pump (101), the centrifugal pump includes a support (10), an impeller chamber (11), a water outlet chamber (110) and a water outlet pipe (111). The impeller chamber (11) is fixed to the upper surface of the bracket (10) by bolts, the water outlet chamber (110) is fixed to one end of the upper surface of the impeller chamber (11), and the water outlet pipe (111) is fixed to the upper surface of the water outlet chamber (110); The drainage assembly includes a third servo motor (20), a bearing (21), a third rotating shaft (22), a drainage plate (23), a through hole (24), and a locking rod (25). The third servo motor (20) is fixed on the side of the outlet chamber (110), the bearing (21) is embedded in the side wall of the outlet chamber (110), the third rotating shaft (22) is fixed on the output end of the third servo motor (20), and the third rotating shaft (22) is inserted into the bearing (21). The diversion plate (23) is sleeved on the third rotating shaft (22), the through hole (24) is opened at one end of the diversion plate (23), and the locking rod (25) is screwed into the through hole (24) and fits against the third rotating shaft (22). There are two sets of diversion components, which are distributed on both sides of the outlet chamber (110), and the diversion plates (23) are staggered. The centrifugal pump water storage tank (13) is equipped with a stirrer (106). The outlet of the centrifugal pump water storage tank (13) is equipped with an upper orifice plate and a lower orifice plate of a combined orifice plate (209). A positioning filter and a photoelectric sensor are installed behind the orifice plate (209). An impeller is set at the center of the end of the inlet flow channel. The two-phase flow passes through the water storage tank (13), stirrer (106), orifice plate (209), directional filter and impeller (152) in sequence. The upper orifice plate and the lower orifice plate have the same structure. Several rings of water passage holes are opened on the upper orifice plate and the lower orifice plate. The centrifugal pump also includes a connecting pipe (12), a water storage tank (13), an inlet pipe (130), and a top cover (14). The connecting pipe (12) is fixed in the middle of the upper surface of the impeller chamber (11), the water storage tank (13) is fixed in the middle of the upper surface of the connecting pipe (12), the water inlet pipe (130) is fixed in the upper side of the water storage tank (13), and the top cover (14) is fixed in the top of the water storage tank (13).

2. The experimental apparatus for solid-liquid two-phase flow as described in claim 1, characterized in that, The centrifugal pump also includes a first servo motor (15), a first rotating shaft (150), a stirring rod (151), and an impeller (152). The first servo motor (15) is fixed in the middle of the upper surface of the top cover (14). The first rotating shaft (150) is fixed at the output end of the first servo motor (15). The first rotating shaft (150) is inserted into the impeller chamber (11), the connecting pipe (12) and the water storage tank (13). The stirring rod (151) is fixed in the upper section of the first rotating shaft (150) and is located in the water storage tank (13). The impeller (152) is fixed in the lower section of the first rotating shaft (150) and is located in the impeller chamber (11).

3. The experimental apparatus for solid-liquid two-phase flow as described in claim 1, characterized in that, The centrifugal pump also includes a second servo motor (16), a second rotating shaft (160), a support ring (161), an internal gear (162), and a drive wheel (167). The second servo motor (16) is fixed to one end of the upper surface of the top cover (14), the second rotating shaft (160) is fixed to the output end of the second servo motor (16) and located in the water storage tank (13), the drive wheel (167) is fixed to the lower end of the second rotating shaft (160), the support ring (161) is located at the lower end of the top cover (14), the outer side of the internal gear (162) is embedded in the middle of the support ring (161), and the internal gear (162) meshes with the drive wheel (167); The centrifugal pump also includes a quick-connect component; The quick-access component includes an electric push rod (30) and an L-shaped connecting rod (31). There are three electric push rods (30), with the upper end fixed to the lower surface of the top cover (14) and the lower end fixed to the upper surface of the support ring (161), and they are distributed in a ring symmetrical manner. The L-shaped connecting rod (31) is fixed between the support ring (161) and the limiting plate (165).

4. The experimental apparatus for solid-liquid two-phase flow as described in claim 1, characterized in that, The centrifugal pump also includes a connecting column (163), a movable plate (164), a limiting plate (165), and a mesh plate (166). The upper end of the connecting column (163) is fixed to the lower surface of the internal gear (162), the mesh plate (166) is sleeved on the first rotating shaft (150) and fixed to the bottom surface of the water storage tank (13), the limiting plate (165) is attached to one end of the upper surface of the mesh plate (166), the movable plate (164) is fixed to the lower end of the connecting column (163) and the movable plate (164) is attached to the other side of the mesh plate (166).

5. The experimental apparatus for solid-liquid two-phase flow as described in claim 1, characterized in that, The device includes: a photoelectric sensor and a directional filter installed at the inlet of the centrifugal pump (101). In the experiment of observing the motion trajectory of large particles, the photoelectric sensor is connected to a high-speed camera (2111). The directional filter only allows particles to enter from one position. When a particle enters the centrifugal pump impeller (152), the reading of the photoelectric sensor changes, triggering the high-speed camera (2111) to take a picture.

6. The experimental apparatus for solid-liquid two-phase flow as described in claim 1, characterized in that, A set of laser emitters (32) and laser receivers (33) are set on both sides of the impeller (152). The shooting frequency of the high-speed camera (2111) is taken as the sampling frequency of the laser receiver (33), and imported into the computer to obtain the position information of the image on the z-axis.

Images