Experimental device for solid-liquid two-phase flow

Abstract

The invention discloses a solid-liquid two-phase flow experiment device which comprises a support and a centrifugal pump installed on the support, the centrifugal pump is driven by a motor, a high-speed camera is arranged right opposite to the centrifugal pump, an inlet of the centrifugal pump is connected with a feeding funnel, the feeding funnel is provided with a stirrer, and the stirrer is connected with a motor. The pressure transmitter and the flow meter are connected to the pipeline of the inlet and the outlet of the centrifugal pump, the flowing-out solid-liquid two-phase flow enters the feeding funnel again through the water outlet pipeline, the solid-liquid two-phase flow enters the experimental pipeline again after being uniformly stirred by the stirrer, and the solid-liquid two-phase flow can be reused all the time.

Description

Technical Field

[0001] The invention relates to the technical field of solid-liquid two-phase flow experiments, in particular to a solid-liquid two-phase flow experimental device. Background Art

[0002] At present, the excavation, silt removal, dredging and other water conservancy projects of major rivers and lakes basically use solid-liquid two-phase flow centrifugal pumps, so the research and development of solid-liquid two-phase flow centrifugal pumps has received more and more attention. Due to the presence of a large amount of sediment in the water flow, in practical applications, the flow components of solid-liquid two-phase flow centrifugal pumps often suffer from severe wear, which will seriously affect the normal operation and safe production of the centrifugal pump. At present, in terms of operating efficiency, my country's solid-liquid two-phase flow centrifugal pumps are generally lower than similar products abroad. The efficiency of domestic solid-liquid two-phase flow centrifugal pumps is mostly between 40% and 60%. Although it has improved in recent years, it still needs to be improved. Studying the actual working conditions of solid-liquid two-phase flow experiments and mastering the movement laws of solid particles have a very important impact on improving the service life and safety of centrifugal pumps.

[0003] The traditional centrifugal pump test device has a complex structure, large size and high cost. At present, most centrifugal pumps use the main shaft to extend directly from the pump body, and then the camera directly takes pictures of the internal flow field of the impeller from the front of the water suction chamber. The shooting area will be blocked by the drive shaft or motor of the pump unit, and the entire impeller area cannot be photographed, and the shooting effect cannot be guaranteed. In addition, when adjusting the impeller inlet valve, the water flow will generate a vortex after passing through the valve, which will cause unstable flow at the impeller inlet, and usually a longer pipeline is required to stabilize the water flow. The actual working conditions of the solid-liquid two-phase flow experiment are relatively complicated, and it is difficult to grasp the movement law of solid particles, and the wear measurement is not intuitive enough.

[0004] 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. The water flows out directly 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 thus affect the accuracy of the experimental data. Therefore, a solid-liquid two-phase flow experimental device is needed to solve the above problems. Summary of the invention

[0005] In order to solve the above technical defects, the present invention proposes an experimental device for solid-liquid two-phase flow to study the motion trajectory of single large-sized particles in actual working conditions, and then analyzes the influence of particle movement on the wear, output power, efficiency and other aspects of the centrifugal pump through data processing.

[0006] The present application provides a solid-liquid two-phase flow experimental device, the device comprising: a bracket (10) and a centrifugal pump (101) installed on the bracket (10), the centrifugal pump (101) being driven by a motor, a high-speed camera system (111) being arranged opposite to the centrifugal pump (101), the inlet of the centrifugal pump (101) being connected to a feeding funnel (107), the feeding funnel (107) being provided with a stirrer (106), an outlet pressure transmitter (102), an inlet pressure transmitter (109) and an electromagnetic flowmeter (103) being connected to the inlet and outlet pipelines of the centrifugal pump (101), the outflowing solid-liquid two-phase flow re-enters the feeding funnel (107) through a water outlet pipeline, the solid-liquid two-phase flow is stirred evenly by the stirrer (106) and then re-enters the experimental pipeline, and the solid-liquid two-phase flow can be reused.

[0007] Optionally, the device comprises: a visualized centrifugal pump (101), the visualized centrifugal pump comprising a bracket (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); a drainage component, the drainage component 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 in 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 guide plate (23) is sleeved on the third rotating shaft (22), the through hole (24) is opened at one end of the guide plate (23), the locking rod (25) is screwed in the through hole (24) and fits with the third rotating shaft (22); there are two groups of the guide components, which are distributed on both sides of the water outlet chamber (110), and the guide plates (23) are staggered.

[0008] Optionally, the device comprises: a centrifugal pump water storage tank (13) is equipped with an agitator (106), an upper orifice plate and a lower orifice plate of a combined orifice plate (209) 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 orifice plate (209), an impeller is arranged at the end center of the inlet flow channel, and the two-phase flow passes through the water storage tank (13), the agitator (106), the orifice plate (209), the directional filter screen and the impeller (152) in sequence, and the upper orifice plate and the lower orifice plate have the same The structure comprises a plurality of water holes arranged in a ring shape on the upper orifice plate and the lower orifice 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 to the middle of the upper surface of the impeller chamber (11), the water storage tank (13) is fixed to the middle of the upper surface of the connecting pipe (12), the water inlet pipe (130) is fixed to the upper side of the water storage tank (13), and the top cover (14) is fixed to the top of the water storage tank (13).

[0009] Optionally, the visualized 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 to the middle of the upper surface of the top cover (14), the first rotating shaft (150) is fixed to 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 to the upper section of the first rotating shaft (150) and is located in the water storage tank (13), and the impeller (152) is fixed to the lower section of the first rotating shaft (150) and is located in the impeller chamber (11).

[0010] Optionally, the visualized 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 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 is located in the water storage tank (13); the driving 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); the internal gear (162) is meshed with the driving wheel (167); the visualized centrifugal pump further comprises a quick assembly;

[0011] The quick assembly comprises an electric push rod (30) and an L-shaped connecting rod (31); there are three electric push rods (30), the upper ends of which are fixed to the lower surface of the top cover (14), and the lower ends of which are fixed to the upper surface of the support ring (161), and are symmetrically distributed in a ring shape; the L-shaped connecting rod (31) is fixed between the support ring (161) and the limit plate (165).

[0012] Optionally, the visualized centrifugal pump further includes a connecting column (163), a movable plate (164), a limiting plate (165), and a perforated plate (166); the upper end of the connecting column (163) is fixed to the lower surface of the internal gear (162), the perforated plate (166) is sleeved on the first rotating shaft (150) and fixed to 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 perforated 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 perforated plate (166).

[0013] Optionally, the device includes: an optoelectronic sensor and a directional filter are installed at the inlet of the centrifugal pump (101). In the experiment of observing the motion trajectory of large-size particles, the optoelectronic sensor is connected to a high-speed camera (111). The directional filter only allows particles to enter from one position. When a particle enters the centrifugal pump impeller (152), the reading of the optoelectronic sensor changes, triggering the high-speed camera (111) to take a picture.

[0014] Optionally, when the high-speed camera (111) processes the image of the high-speed flowing water body in the pump, the NL-Means algorithm and the improved wavelet fusion method are used to remove the noise signal. Finally, the canny operator is used to obtain the object contour information, and the wavelet transform method is used to filter out most of the salt-and-pepper noise and stripe noise. The sampling frequency is 1KHZ, and three-layer wavelet decomposition is performed. The decomposition equation is as follows:

[0015]

[0016] Among them, F S is the sampling frequency, and f max is the maximum frequency of the signal. According to the Nyquist sampling theorem, F S = 2f max

[0017] The new wavelet threshold function is used for threshold processing. The threshold function is as follows:

[0018]

[0019] Among them, 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 the approximation degree parameter of the new threshold function;

[0020] After wavelet reconstruction, the NL-means denoising technology is introduced to perform secondary filtering on the Gaussian noise and salt-and-pepper noise that are not completely filtered out in the image. The formula is:

[0021]

[0022] Among them, υ is the noisy image; uNL is the denoised image; the weight ω(x,y) represents the similarity between pixel i and pixel j, which is determined by the neighborhood pixels centered on pixel i and pixel j to ensure the accuracy of its similarity measurement. The calculation formula is:

[0023]

[0024] Among them, Z(x) is the normalization coefficient calculation formula:

[0025]

[0026] Among them, h is the smoothing parameter, the larger its value, the smoother it is;

[0027] Finally, the canny operator is used to detect image edges. The calculation formula is as follows:

[0028]

[0029] θ=atan2(G y ,G x )

[0030] The high threshold is set to 100, the low threshold is set to 50, and the Gaussian radius is 2 to obtain a binary image;

[0031] The threshold condition and connectivity relationship are used to obtain the semantic information of the image, and finally the coordinates of the center of the circle are obtained.

[0032] Optionally, the ExpAssoc equation is used to fit the particle velocity VX in the X-axis direction using the particle coordinates on the impeller flow plane. The expression of the ExpAssoc equation is as follows:

[0033] V x =x0+A1(1-exp(-t / a1))+A2(1-exp(-t / a2))

[0034] The velocity V of the particles on the Y axis is fitted by the Logistic equation y , the expression of the logistic equation V y =A2+(A1-A2) / (1+(t / y0)^p)

[0035] Where A, a are the correlation coefficients obtained by fitting the curve, x0, y0 are the corresponding speeds of the reference points, and t is the time variable;

[0036] The relationship between the particle position and size is obtained by fitting the pixel points occupied by the particle in the acquired image: Z = K1 / (x-b1) + c;

[0037] The fitting equation of the change of the occupied pixels over time is expressed as: x = K2 / (t-b2), and the final Z-axis velocity equation is obtained by derivation of position with respect to time:

[0038] V Z =(K1K2+K1K2b2-K1b1b2) / (K2-b1t+b1b2) 2

[0039] Among them, 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.

[0040] Optionally, a group of laser emitters (32) and laser receiving screens (33) are arranged on both sides of the impeller (152), and the shooting frequency of the high-speed camera system 111 is taken as the sampling frequency of the laser receiving screen (33), which is imported into a computer to obtain the position information of the image on the z-axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a solid-liquid two-phase flow experimental device provided in this application;

[0042] Figure 2 A schematic diagram of visualizing particle addition of a centrifugal pump provided in this application;

[0043] Figure 3 A visual schematic diagram of a centrifugal pump structure provided for this application;

[0044] Figure 4 A visual front view of a centrifugal pump provided for this application;

[0045] Figure 5 A schematic diagram of the location of the drainage components provided for this application;

[0046] Figure 6 A schematic diagram of the drainage component structure provided for this application;

[0047] Figure 7 A schematic diagram of the shortcut component structure provided for this application;

[0048] Figure 8 The rotating coordinate system in the impeller provided in this application is used to calibrate the coordinates of the particles during movement;

[0049] Fig. 9 Schematic diagram of the placement of the laser transmitting and receiving screens on both sides of the impeller provided in this application.

[0050] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0051] Centrifugal pump 101, outlet pressure transmitter 102, electromagnetic flowmeter 103, outlet valve 104, stirrer motor 105, stirrer 106, feeding hopper 107, inlet valve 108, inlet pressure transmitter 109, trigger device 110, high-speed camera system 111, computer control system 112, torque meter 113, centrifugal pump motor 114;

[0052] Bracket 10, impeller chamber 11, impeller 152, guide plate 205, water outlet pipe 111, buckle 207, rotating head 208, combination orifice plate 209, stirrer 210, water inlet pipe 130, first servo motor 15, motor base 213, bearing cover plate 214, bearing 21, water storage tank 13;

[0053] 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, supporting 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, guide 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

[0054] The solid-liquid two-phase flow experimental device is an experimental device used to study the mixed flow phenomenon of solid particles and liquids. It studies the characteristics, laws and influencing factors of solid-liquid two-phase flow by simulating the flow process of solid-liquid two-phase fluids in pipes, containers or reactors. Before the experiment begins, the centrifugal pump is started and a 10-minute countdown is started to ensure that the centrifugal pump reaches the rated working state before the particles enter. The estimated movement time of the solid particles in the pump is calculated, and the time is compared with the rotation speed of the pump to select the best high-speed camera shooting frame rate. Subsequently, the holes of the combined orifice plate are completely closed with a rotating head, and the solid-liquid two-phase flow entering the water storage tank is driven by the agitator to keep the solid particles mixed evenly. When the ten-minute countdown is over, the water flow 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 enters the impeller chamber through the filter hole under the guidance of the directional filter. A set of photoelectric sensors is placed directly above the impeller, and the photoelectric sensors are connected to the high-speed camera. When the solid particles fall from the directional filter and are detected by the photoelectric sensor, the reading of the photoelectric sensor changes, triggering the high-speed camera to start shooting. The high-speed camera continues to work until all large-sized solid particles leave the impeller chamber of the centrifugal pump.

[0055] 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. The water flows out directly 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, thereby affecting the accuracy of the experimental data.

[0056] like Figure 1 The figure shows a schematic diagram of a solid-liquid two-phase flow experimental device provided by the present application. The solid-liquid two-phase flow experimental device disclosed in the present application includes: a bracket 10 and a centrifugal pump 101 installed on the bracket 10, the centrifugal pump 101 is driven by a motor, a high-speed camera system 111 is arranged opposite to the centrifugal pump 101, the inlet of the centrifugal pump 101 is connected to a feeding funnel 107, the feeding funnel 107 is provided with a stirrer 106, the inlet and outlet pipelines of the centrifugal pump 101 are connected to an outlet pressure transmitter 102, an inlet pressure transmitter 109 and an electromagnetic flowmeter 103, the outflowing solid-liquid two-phase flow re-enters the feeding funnel 107 through the water outlet pipeline, the solid-liquid two-phase flow is stirred evenly by the stirrer 106 and then enters the experimental pipeline again, and the solid-liquid two-phase flow can be reused.

[0057] Optionally, the device includes: a visualized centrifugal pump 101, the visualized centrifugal pump includes a bracket 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; a drainage component, the drainage component 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 water outlet chamber 110, the bearing 21 is embedded in 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 guide plate 23 is sleeved on the third rotating shaft 22, the through hole 24 is opened at one end of the guide plate 23, the locking rod 25 is screwed in the through hole 24, and fits with the third rotating shaft 22; there are two groups of the drainage components, which are distributed on both sides of the water outlet chamber 110, and the guide plates 23 are staggered.

[0058] Optionally, the solid-liquid two-phase flow experimental device disclosed in the present application includes: a visual centrifugal pump, which includes a bracket, an impeller chamber, a water outlet chamber and a water outlet pipe; a drainage component, which includes 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 to the side of the water outlet chamber, the bearing is embedded in the side wall of the water outlet chamber, the third rotating shaft is fixed to the output end of the third servo motor, the drainage plate is sleeved on the third rotating shaft, the through hole is opened at one end of the drainage plate, and the locking rod is screwed into the through hole. In order 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, and flow out through the water outlet chamber through the water outlet pipe, while the water flow flows out directly 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, thereby affecting the accuracy of the experimental data.

[0059] The present invention discloses a complete solid-liquid two-phase flow experimental device to conduct a real solid-liquid two-phase flow experiment. The experimental device includes a solid-liquid two-phase flow circuit, a water circuit and a high-speed photography system. The right side is a feeding funnel, a valve is installed at the pipeline outlet, the feeding funnel is connected to a stirrer, and the two-phase flow condition enters a centrifugal pump. A photoelectric sensor and a pressure transmitter are arranged at the inlet, and the indication triggers a trigger device to start a high-speed camera. The high-speed camera is facing the centrifugal pump. The centrifugal pump is made of visual glass. The solid-liquid flow is thrown out through the centrifugal pump, passes through the outlet pressure transmitter and the electromagnetic flowmeter, and the outlet pipe is reconnected to the feeding funnel. The solid-liquid two-phase flow will eventually be recycled into the feeding funnel, thereby realizing a cyclic experiment. The collected data is uploaded to a computer control system for processing.

[0060] like Figure 2 Shown is a schematic diagram of a visualized centrifugal pump particle addition provided by the present application. The centrifugal pump operates in the design working condition. The solid particles enter the feeding funnel at the beginning of the experiment and are placed in the system loop. The motor of the agitator is started to start the agitator. After stirring for a while until the solid particles in the funnel are roughly stirred, the feeding funnel valve and the inlet valve are opened. When the two-phase flow condition enters the centrifugal pump, the inlet pressure transmitter will produce a reading change, thereby triggering the trigger device to start, so that the high-speed camera starts shooting. The high-speed camera tracks the movement of particles in the centrifugal pump, and uses a computer control system to control the high-speed photography system to control, display and store the image of the particles. The shooting rate of the high-speed camera is 200 frames per second. The flow rate in the entire experimental device pipeline is measured by an electromagnetic flowmeter. The solid-liquid two-phase flow will eventually be separated by a filter, and the solid particles will be recovered into the feeding funnel, thereby realizing a cycle experiment.

[0061] like Figure 3The figure shows a visual schematic diagram of the structure of a centrifugal pump provided by the present application. The centrifugal pump is driven by a servo motor to rotate the impeller, so that the impeller drives the flow of the entire solid-liquid two-phase flow. In order to make the flow more stable, a guide plate is installed in the impeller chamber to eliminate the dynamic and static interference effect between the water pipe and the impeller. In order to control the flow at the impeller inlet, a combined orifice plate is installed at the outlet of the water storage tank. By rotating the rotating head, the water flow area between the upper and lower orifice plates is changed, thereby achieving the purpose of controlling the flow rate. The solid-liquid two-phase flow enters the water storage tank from the water inlet pipe, and is stirred again by the agitator inside 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, and after being stirred by the impeller, it flows to the outlet pipe and out of the centrifugal pump.

[0062] The bracket of the centrifugal pump, the impeller chamber on the bracket, and the water diversion chamber of the impeller chamber are all made of transparent organic glass material. The agitator is installed on the same main shaft, and the same motor can drive the centrifugal pump and the agitator. The impeller of the centrifugal pump is covered with a low-corrosive material, and the average arithmetic mean roughness Ra of the impeller surface after coating is within 0.1μm.

[0063] Figure 4 A visual front view of a centrifugal pump provided for this application; Figure 5 A schematic diagram of the location of the drainage components provided for this application; Figure 6 This is a schematic diagram of the drainage component structure provided in this application. Figure 4-6 As shown, the experimental device for solid-liquid two-phase flow includes: a centrifugal pump water storage tank 13 is equipped with an agitator 106, and a combined orifice plate 209 upper orifice plate and a lower orifice plate are installed at the outlet of the centrifugal pump water storage tank 13, a positioning filter and a photoelectric sensor are installed behind the orifice plate 209, and an impeller is arranged at the end center of the inlet flow channel. The two-phase flow passes through the water storage tank 13, the agitator 106, the orifice plate 209, the directional filter and the impeller 152 in sequence. The upper orifice plate has the same structure as the lower orifice plate, and a plurality of ring-shaped water holes are opened on the upper orifice plate and the lower orifice plate; the visual centrifugal pump also 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 to the impeller chamber 1 1, the water tank 13 is fixed to the middle of the upper surface of the connecting pipe 12, the water inlet pipe 130 is fixed to the upper section of the side of the water tank 13, and the top cover 14 is fixed to the top of the water tank 13; the visualized 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 to the middle of the upper surface of the top cover 14, the first rotating shaft 150 is fixed to 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 tank 13, the stirring rod 151 is fixed to the upper section of the first rotating shaft 150 and is located in the water tank 13, and the impeller 152 is fixed to the lower section of the first rotating shaft 150 and is located in the impeller chamber 11.

[0064] Optionally, the visual centrifugal pump also 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 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 is located in the water storage tank 13, the driving 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 is meshed with the driving wheel 167; the visual centrifugal pump also includes a quick assembly; the quick assembly includes an electric push rod 30 and an L-shaped connecting rod 31; there are three electric push rods 30, the upper end is fixed to the lower surface of the top cover 14, the lower end is fixed to the upper surface of the support ring 161, and they are symmetrically distributed in a ring shape, and the L-shaped connecting rod 31 is fixed between the support ring 161 and the limit plate 165.

[0065] Optionally, the visualized 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 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 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.

[0066] Optionally, the device includes: a photoelectric sensor and a directional filter are installed at the inlet of the centrifugal pump 101. In the experiment of observing the movement trajectory of large-sized particles, the photoelectric sensor is connected to the high-speed camera 111, and the directional filter 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 111 to shoot.

[0067] The experimental device for solid-liquid two-phase flow includes: a visualized centrifugal pump, which includes a bracket 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 bracket 10 plays a supporting role, the impeller chamber 11 plays a protective and storage role, and the water outlet chamber 110 and the water outlet pipe 111 provide a fluid outflow channel; a drainage component, which 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 to the water outlet chamber 110 On the side, the bearing 21 is embedded in 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 in the bearing 21, the guide plate 23 is sleeved on the third rotating shaft 22, and the through hole 24 is opened at one end of the guide plate 23. The locking rod 25 is screwed in the through hole 24 and fits with the third rotating shaft 22; the third servo motor 20 provides a power source, the bearing 21 is sealed, which is convenient for the third rotating shaft 22 to rotate, and the third rotating shaft 22 transmits power. The guide plate 23 is used to guide the water flow, the through hole 24 plays a connecting role, and the locking rod 25 plays a fixing role; there are two groups of drainage components, which are distributed on both sides of the water outlet chamber 110, and the guide plates 23 are staggered.

[0068] The visualized 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 to the middle of the upper surface of the impeller chamber 11, the water storage tank 13 is fixed to the middle of the upper surface of the connecting pipe 12, the water inlet pipe 130 is fixed to the upper side of the water storage tank 13, and the top cover 14 is fixed to the top of the water storage tank 13; the connecting pipe 12 has a connecting function, the water storage tank 13 has a storage function for mixing fluids, the water inlet pipe 130 passes liquid and solid particles into the water storage tank 13, and the top cover 14 has a sealing function; the visualized centrifugal pump further includes a first servo motor 15, a first rotating shaft 150, a stirring rod 151 and an impeller 15 2; the first servo motor 15 is fixed to the middle of the upper surface of the top cover 14, the first rotating shaft 150 is fixed to 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 to the upper section of the first rotating shaft 150 and is located in the water storage tank 13, and the impeller 152 is fixed to 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 mixes the liquid and solid particles evenly, and the impeller 152 is used to mix the fluid; the visual centrifugal pump also 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 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 is located in the water storage tank 13, the driving 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 is meshed 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, the driving wheel 167 and the internal gear 162 transmits power; the visualized 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 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 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; the connecting column 163 has a connecting effect, the movable plate 164 has a sealing effect, the limiting plate 165 has a limiting effect, and the mesh plate 166 provides a fluid flow channel.

[0069] 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 guide plate 23 is inserted at the same time, and the locking rod 25 is tightened on the through hole 24. During the experiment, the two guide plates 23 are perpendicular to the side wall of the water outlet chamber 110 and are staggered; the liquid and solid particles enter the water storage tank 13 through the water inlet pipe 130, and the first servo motor 15 is started to drive the first rotating shaft 150 to rotate, and drive the stirring rod 151 to rotate to mix the liquid and solid particles evenly; then the second servo motor 16 is started to drive the second rotating shaft 160 to rotate, drive the driving wheel 167 to rotate, and then drive the internal gear 162 to rotate in the support ring 161, drive the connecting column 163 to rotate, so that the connecting column 1 The movable plate 164 below the 63 rotates, and the movable plate 164 rotates into the limit plate 165, the mesh plate 166 is exposed, and the fluid flows into the connecting pipe 12 from the mesh holes exposed by the mesh plate 166, enters the impeller chamber 11, is stirred by the impeller 152, and 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 guide 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 over, the third servo motor 20 can be started, and the third servo motor 20 drives the third shaft 22 to rotate in the bearing 21, drives the guide plate 23 to rotate, and fits on the inner wall of the water outlet chamber 110, which can speed up the outflow of the fluid. This step can avoid the dynamic and static effects of the water outlet pipe 111 and the impeller 152, which affect the accuracy of the realization.

[0070] like Figure 7 The figure shows a schematic diagram of the structure of the quick assembly provided by the present application. This embodiment is based on the above embodiment and also includes: a quick assembly, the quick assembly includes an electric push rod 30 and an L-shaped connecting rod 31; there are three electric push rods 30, the upper end of which is fixed to the lower surface of the top cover 14, and the lower end is fixed to the upper surface of the support ring 161, and they are symmetrically distributed in a ring shape, and the L-shaped connecting rod 31 is fixed between the support ring 161 and the limit plate 165; the electric push rod 30 can realize position change, and the L-shaped connecting rod 31 plays a connecting role.

[0071] Working principle: During the experiment, the electric push rod 30 is in a fully extended state, the inner gear 162 is meshed with the driving wheel 167, the movable plate 164 is on the upper surface of the mesh plate 166, and the limit plate 165 is wrapped above the mesh plate 166; when the experiment is over, the electric push rod 30 is started, the electric push rod 30 shrinks, and drives the support ring 161 and the inner gear 162 to move upward, and then drives the connecting column 163 and the L-shaped connecting rod 31 to move upward, so that the movable plate 164 and the limit plate 165 move upward, and the mesh plate 166 is completely exposed. This step can further increase the water flow speed and speed up the outflow of the fluid in the device.

[0072] Before the experiment starts, start the centrifugal pump first and start a 10-minute countdown to ensure that the centrifugal pump reaches its rated working state before the particles enter. Calculate the estimated movement time of the solid particles in the pump, compare this time with the rotational speed of the pump, and select the best frame rate for the high-speed camera to shoot. Subsequently, use the rotating head to completely close all the holes of the combined orifice plate. The solid-liquid two-phase flow entering the water storage tank is driven by the stirrer to keep the solid particles evenly mixed. When the ten-minute countdown ends, change the water passing area of the upper and lower orifice plates through the rotating head, so that the solid-liquid two-phase flow passes through the orifice plate and enters the impeller chamber, and enters the impeller chamber through the filter holes under the guidance of the directional filter screen. A set of photoelectric sensors is placed at the position directly above the impeller. The photoelectric sensors are connected to the high-speed camera. When the solid particles fall from the directional filter screen and are detected by the photoelectric sensors, the readings of the photoelectric sensors change, triggering the high-speed camera to start shooting. The high-speed camera keeps working until all the large-sized solid particles leave the impeller chamber of the centrifugal pump.

[0073] Optionally, when processing the high-speed flowing water body image in the pump, the high-speed camera (111) uses the NL-Means algorithm and the improved wavelet fusion method to remove the noise signal. Finally, the canny operator is used to obtain the object contour information, and the wavelet transform method is used to filter out most of the salt-and-pepper noise and stripe noise. The sampling frequency is 1KHZ, and three-layer wavelet decomposition is performed. The decomposition equation is as follows:

[0074]

[0075] Among them, F S is the sampling frequency, and f max is the maximum frequency of the signal. According to the Nyquist sampling theorem, F S = 2f max

[0076] The new wavelet threshold function is used for threshold processing. The threshold function is as follows:

[0077]

[0078] Among them, a, b, and m are adjustment factors. a and b (a>0, b>0) are the two shape control parameters of the new threshold function, and m (0<m<1) is the approximation degree parameter of the new threshold function;

[0079] After wavelet reconstruction, the NL-means denoising technology is introduced to perform secondary filtering on the Gaussian noise and salt-and-pepper noise that are not completely filtered out in the image. The formula is:

[0080]

[0081] Among them, υ is the noisy image; u NLis the denoised image; the weight ω(x,y) represents the similarity between pixel i and pixel j, which is determined by the neighborhood pixels centered on pixel i and pixel j to ensure the accuracy of its similarity measurement. The calculation formula is:

[0082]

[0083] Among them, Z(x) is the normalization coefficient calculation formula:

[0084]

[0085] Among them, h is the smoothing parameter, the larger its value, the smoother it is;

[0086] Finally, the canny operator is used to detect image edges. The calculation formula is as follows:

[0087]

[0088] θ=atan2(G y ,G x )

[0089] The high threshold is set to 100, the low threshold is set to 50, and the Gaussian radius is 2 to obtain a binary image;

[0090] The threshold condition and connectivity relationship are used to obtain the semantic information of the image, and finally the coordinates of the center of the circle are obtained.

[0091] Optionally, the ExpAssoc equation is used to fit the particle velocity VX in the X-axis direction using the particle coordinates on the impeller flow plane. The expression of the ExpAssoc equation is as follows:

[0092] V x =x0+A1(1-exp(-t / a1))+A2(1-exp(-t / a2))

[0093] The velocity V of the particles on the Y axis is fitted by the Logistic equation y , the expression of the logistic equation V y =A2+(A1-A2) / (1+(t / y0)^p)

[0094] Where A, a are the correlation coefficients obtained by fitting the curve, x0, y0 are the corresponding speeds of the reference points, and t is the time variable;

[0095] The relationship between the particle position and size is obtained by fitting the pixel points occupied by the particle in the acquired image: Z = K1 / (x-b1) + c;

[0096] The fitting equation of the change of the occupied pixels over time is expressed as: x = K2 / (t-b2), and the final Z-axis velocity equation is obtained by derivation of position with respect to time:

[0097] V Z =(K1K2+K1K2b2-K1b1b2) / (K2-b1t+b1b2) 2

[0098] Among them, 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.

[0099] Optionally, a group of laser emitters (32) and laser receiving screens (33) are arranged on both sides of the impeller (152), and the shooting frequency of the high-speed camera system 111 is taken as the sampling frequency of the laser receiving screen (33), which is imported into a computer to obtain the position information of the image on the z-axis.

[0100] Figure 8 The rotating coordinate system in the impeller provided in this application is used to calibrate the coordinates of the particles during the movement process. In order to obtain the movement trajectory of the particles, image preprocessing is first performed, including image selection and PS image batch processing, to ensure that all particles have the same entrance conditions. In the image captured by the camera, due to the light refraction and scattering caused by the transparent pump body, water body and non-transparent particles blocking and the water flow fluctuations caused by the rotation of the impeller in the pump, there are more 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 grayscale image, and most of the salt and pepper noise and stripe noise are filtered out by 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, NL-means denoising technology is introduced to perform secondary filtering on the Gaussian noise and salt and pepper noise that are not completely filtered out in the image, thereby ensuring 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 image semantic information, and finally the coordinates of the center of the circle are obtained. Then, by superimposing the processed images, the motion trajectory of the particles is obtained, and the results are analyzed, which improves the accuracy of image recognition to a certain extent. First, all images are superimposed to obtain the motion trajectory of solid particles. Assuming a camera frequency of 200 frames per second, the time for large-sized particles to enter the impeller chamber and leave the impeller chamber is 0.1s. A total of 20 photos are taken in this process, and these photos are superimposed. Since the nonlinear fitting of complex trajectories is very difficult, the existing nonlinear equations cannot achieve the fitting of such complex trajectories. Therefore, a more regular trajectory in the figure is selected to fit the data to derive the trajectory equation of the particles.

[0101] The collected images were processed by image processing technology. First, the images were converted into grayscale images. Wavelet transformation was used to filter out most of the salt and pepper noise and stripe noise. The sampling frequency was 1KHZ. Three-layer wavelet decomposition was performed. A relative rotating coordinate system (θ, R) rotating with the impeller was used. The particles were mainly affected by gravity, resistance, pressure gradient force, false mass force, etc. in the flow channel. The additional mass force coefficient C of the particles was A =0.5, the equation of motion of the particle is as follows:

[0102]

[0103] Where p is the pressure, (W θ ,W r ) is the velocity component in the direction of the coordinate axis, g is the gravitational acceleration, ρ is the density of water, ρ s is the particle density, the coordinate system rotation angle Drag coefficient C d =24(1+0.125R e 0.72 ) / R e ,R e is the particle Reynolds number.

[0104] By given coordinates (θ i ,R i ), calculate the next time t i+1 =t i +Δt coordinates (θ i+1 ,R i+1 ):

[0105]

[0106] Integrating the above formula can get the coordinates of each point, and then correcting the calculated coordinates and image coordinates to get the coordinates of the point on the xy plane. Correct the real flow time to get the corrected flow time with the initial position as 0. Combining the corrected flow time and the speed of the particles on the X, Y, and Z axes, the motion equations in three directions can be fitted. X, Y axis direction: The high-speed camera is facing the direction of the impeller, and the captured images can be superimposed to clearly show the motion trajectory of the solid particles on the XY plane. All images are imported and superimposed to obtain a rough motion trajectory. The motion trajectory equation of the solid particles on the XY plane can be derived through the data changes of the centroid coordinates. The expression of the ExpAssoc equation is as follows:

[0107] V x =x0+A1(1-exp(-t / a1))+A2(1-exp(-t / a2))

[0108] The motion velocity Vy of the particle in the Y-axis is fitted by the Logistic equation, and the expression of the Logistic equation

[0109] V y = A2 + (A1 - A2) / (1 + (t / y0)^p)

[0110] where A and a are the correlation coefficients obtained from the fitted curve, x0 and y0 are the corresponding velocities of the reference points, and t is the time variable.

[0111] Finally, the z-axis information of the particle is obtained through the laser generation and reception device. This information is combined with the xy-axis equation and imported into the computer, and finally the motion model equation of the particle in the pump is obtained.

[0112] Fig. 9 This is a schematic diagram of the placement positions of the laser emission and reception screens on both sides of the impeller provided by this application. When there are particles moving in the centrifugal pump, the readings of the photoelectric sensors in the reception screen change, thereby recording the z-axis position information of this point.

[0113] The new wavelet threshold function is used for threshold processing. Compared with the traditional wavelet threshold function, this function has better self-adaptability in practical applications and has less influence on the approximation degree between the reconstructed signal and the original signal. The threshold function is as follows:

[0114]

[0115] where a, b, and m are adjustment factors, a and b (a > 0, b > 0) are the two shape control parameters of the new threshold function, and m (0 < m < 1) is the approximation degree parameter of the new threshold function.

[0116] The motion time of the solid particle in the pump is roughly estimated by predicting the internal fluid motion situation. It is assumed that the fluid is in uniformly accelerated motion inside until the velocity is equal to the fluid velocity. Let the liquid outlet velocity be the final velocity of the particle, and the time used is roughly estimated using the formula X = ∫∫a(t)dt.

[0117] The rotational speed of the impeller, the motion time of the solid particle, and the frame rate of the camera shooting are combined through the given formula to obtain the actual number of frames to be shot per second. The directional filter screen has only one hole. When a particle enters the centrifugal pump impeller, the photoelectric sensor triggers the high-speed camera to shoot at a given speed.

[0118] The present invention inserts the third rotating shaft into the bearing of the side wall of the water outlet chamber through the drainage component set, and inserts the drainage plate at the same time, and tightens the locking rod on the through hole. During the experiment, the two drainage plates are perpendicular to the side wall of the water outlet chamber and are staggered. The fluid flow path is S-shaped, which can effectively reduce the dynamic and static effects of the water outlet pipe and the impeller. When the experiment is over, the third servo motor can be started, and the third servo motor drives the third rotating shaft to rotate in the bearing, drives the drainage plate to rotate, and fits on the inner wall of the water outlet chamber, which can accelerate the outflow of fluid. This setting can avoid the influence of the dynamic and static effects of the water outlet pipe and the impeller on the accuracy of realization. The present invention sets a quick component. When the experiment is over, the electric push rod is started, the electric push rod shrinks, drives the support ring and the inner gear to move upward, and then drives the connecting column and the L-shaped connecting rod to move upward, so that the movable plate and the limit plate move upward, and the mesh plate is completely exposed. This setting can further increase the water flow speed and accelerate the outflow of fluid in the device.

[0119] Upper and lower orifice plates are installed at the inlet of the centrifugal pump. By rotating the upper orifice plate, the area of ​​the water hole is changed to control the flow rate and achieve a rectification effect. The impeller chamber is made of visual materials to clearly capture the movement of particles in the flow field. A directional filter and photoelectric sensor are installed at the water inlet to ensure that the initial conditions and positions of particles entering the centrifugal pump are the same. At the moment when the particles enter the centrifugal pump, the reading of the photoelectric sensor is changed to trigger the shooting of the high-speed camera, so that experiments can be conducted on particles in different positions.

[0120] In the wear measurement of centrifugal pumps, the traditional method of painting was changed to using low-corrosion materials to cover the centrifugal pump impeller. The degree of wear was quantified by the mass loss before and after the experiment, and the wear degree of different parts was observed by the change in the thickness of the low-corrosion material. In the final image processing process, the new wavelet threshold function was combined with the NL-means denoising technology to perform image denoising, which greatly improved the precision and accuracy of image recognition and had good adaptability to complex environments. The solid particles were positioned on the z-axis using a laser generator and receiver, and the z-axis position of the particles at this moment was obtained using the change in the resistance information of the receiving screen, which to a certain extent solved the problem of the difficulty in obtaining z-axis information.

[0121] The present invention discloses a complete solid-liquid two-phase flow experimental device for conducting a real solid-liquid two-phase flow experiment. The experimental device includes a solid-liquid two-phase flow circuit, a water circuit and a high-speed photography system. A feeding funnel is on the right side, a valve is installed at the pipeline outlet, the feeding funnel is connected to a stirrer, and the two-phase flow condition enters a centrifugal pump. A photoelectric sensor and a pressure transmitter are arranged at the inlet, and a trigger device thereof is triggered to start a high-speed camera. The high-speed camera is directly facing the centrifugal pump. The centrifugal pump is made of visual glass. The solid-liquid flow is thrown out through the centrifugal pump, passes through the outlet pressure transmitter and the electromagnetic flowmeter, and the outlet pipe is reconnected to the feeding funnel. The solid-liquid two-phase flow will eventually be recovered into the feeding funnel, thereby realizing a cyclic experiment, and the collected data is uploaded to a computer control system for processing.

Claims

1. An experimental device for solid-liquid two-phase flow, characterized in that: The device 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 system (111) is arranged opposite to the centrifugal pump (101); the inlet of the centrifugal pump (101) is connected to a feeding funnel (107); the feeding funnel (107) is provided with a stirrer (106); the inlet and outlet pipelines of the centrifugal pump (101) are connected to an outlet pressure transmitter (102), an inlet pressure transmitter (109) and an electromagnetic flowmeter (103); the outflowing solid-liquid two-phase flow re-enters the feeding funnel (107) through a water outlet pipeline; the solid-liquid two-phase flow is stirred evenly by the stirrer (106) and then re-enters the experimental pipeline; the solid-liquid two-phase flow can be reused.

2. The solid-liquid two-phase flow experimental device according to claim 1, characterized in that: The device comprises: A visualized centrifugal pump (101), comprising a bracket (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); A drainage assembly, the 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 in 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 guide plate (23) is sleeved on the third rotating shaft (22), the through hole (24) is opened at one end of the guide plate (23), the locking rod (25) is screwed in the through hole (24) and fits with the third rotating shaft (22); there are two groups of the guide components, which are distributed on both sides of the water outlet chamber (110), and the guide plates (23) are staggered.

3. The solid-liquid two-phase flow experimental device according to claim 1, characterized in that: The device comprises: a centrifugal pump water storage tank (13) is equipped with an agitator (106); an upper orifice plate and a lower orifice plate of a combined orifice plate (209) 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 orifice plate (209); an impeller is arranged at the end center of the inlet flow channel; two-phase flow passes through the water storage tank (13), the agitator (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; and a plurality of water holes arranged in a ring shape are opened on the upper orifice plate and the lower orifice plate; The visualized 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 to the middle of the upper surface of the impeller chamber (11), the water storage tank (13) is fixed to the middle of the upper surface of the connecting pipe (12), the water inlet pipe (130) is fixed to the upper side of the water storage tank (13), and the top cover (14) is fixed to the top of the water storage tank (13).

4. The solid-liquid two-phase flow experimental device according to claim 1, characterized in that: The visualized 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 to the middle of the upper surface of the top cover (14); the first rotating shaft (150) is fixed to 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 to the upper section of the first rotating shaft (150) and is located in the water storage tank (13); and the impeller (152) is fixed to the lower section of the first rotating shaft (150) and is located in the impeller chamber (11).

5. The solid-liquid two-phase flow experimental device according to claim 3, characterized in that: The visualized 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 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 is located in the water storage tank (13); the driving 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) is meshed with the driving wheel (167); The visual centrifugal pump also includes a quick-release component; The quick assembly comprises an electric push rod (30) and an L-shaped connecting rod (31); There are three electric push rods (30), the upper ends of which are fixed to the lower surface of the top cover (14), and the lower ends of which are fixed to the upper surface of the support ring (161), and they are symmetrically distributed in a ring shape. The L-shaped connecting rod (31) is fixed between the support ring (161) and the limit plate (165).

6. The solid-liquid two-phase flow experimental device according to claim 3, characterized in that: The visualized 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 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 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 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).

7. The solid-liquid two-phase flow experimental device according to claim 1, characterized in that: The device comprises: a photoelectric sensor and a directional filter are installed at the inlet of the centrifugal pump (101); in an experiment of observing the movement trajectory of large-sized particles, the photoelectric sensor is connected to a high-speed camera (111); the directional filter 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 (111) to shoot.

8. The solid-liquid two-phase flow experimental device according to claim 1, characterized in that: When the high-speed camera (111) processes the image of the high-speed flowing water in the pump, the NL-Means algorithm and the improved wavelet fusion method are used to remove the noise signal, and finally the canny operator is used to obtain the object contour information, and the wavelet conversion method is used to filter out most of the salt and pepper noise and stripe noise. The sampling frequency is 1KHZ, and three-layer wavelet decomposition is performed. The decomposition equation is as follows: Among them, F S is the sampling frequency, f max is the maximum frequency of the signal. According to the Nyquist sampling theorem, we can get F S =2f max Threshold processing is performed using a new wavelet threshold function, and the threshold function is as follows: Among them, 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 the approximation degree parameter of the new threshold function; After wavelet reconstruction, the NL-means denoising technique is introduced to perform secondary filtering on the Gaussian noise and salt-and-pepper noise that have not been completely filtered out in the image. The formula is: Among them, υ is the noisy image; u NL is the denoised image; the weight ω(x,y) represents the similarity between pixel i and pixel j, which is determined by the neighborhood pixels centered on pixel i and pixel j to ensure the accuracy of its similarity measurement. The calculation formula is: Among them, the formula for calculating the normalization coefficient Z(x) is: Among them, h is the smoothing parameter, and the larger its value, the smoother; Finally, the canny operator is used for image edge detection, and the calculation formula is as follows: θ=atan2(G y ,G x ) Among them, the high threshold is set to 100, the low threshold is set to 50, and the Gaussian radius is 2 to obtain a binary image; The semantic information of the image is obtained using the threshold condition and the connectivity relationship, and finally the center coordinates are obtained.

9. The solid-liquid two-phase flow experimental device according to claim 7, characterized in that: Taking the particle coordinates in the impeller passage plane, the ExpAssoc equation is used to fit the particle movement speed VX in the X-axis direction. The expression of the ExpAssoc equation is as shown in the formula V x =x0+A1(1-exp(-t / a1))+A2(1-exp(-t / a2)) The velocity V of the particles on the Y axis is fitted by the Logistic equation y , the expression of the logistic equation V y =A2+(A1-A2) / (1+(t / y0)^p) Among them, A and a are the correlation coefficients obtained by fitting the curve, x0 and y0 are the corresponding speeds of the reference points, and t is the time variable; According to the pixels occupied by the particles in the acquired image, the relationship equation between the particle position and size is fitted: Z = K1 / (x - b1) + c; The fitting equation for the number of pixels occupied changing with time is expressed as: x = K2 / (t - b2), and the final velocity equation of the Z-axis is obtained by differentiating the position with respect to time: In Z =(K1K2+K1K2b2-K1b1b2) / (K2-b1t+b1b2) 2 Among them, K, b, and 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.

10. The experimental device for solid-liquid two-phase flow according to claim 7, wherein a set of laser emitters (32) and a laser receiving screen (33) are arranged on both sides of the impeller (152). The shooting frequency of the above high-speed imaging system 111 is taken as the sampling frequency of the laser receiving screen (33) and imported into the computer, so as to obtain the position information of the image on the z-axis.

Images