Modularized test device and test method for low-temperature pump with front inducer

Abstract

The invention provides a preposed inducer low-temperature pump modeling test device and test method, which are mainly used for test research and performance prediction of a low-temperature pump, and the device mainly comprises a water inlet system, a power system, a pipeline system, a preposed inducer low-temperature model pump, a data measurement system, a high-speed camera system and an air exhaust system. The water inlet system provides a test medium for the test device. And the power system provides power for the water inlet system, the front inducer low-temperature model pump and the air exhaust system in the test device. The pipeline system adopts a self-circulation pipeline and is simple in structure and convenient to operate. Flow passage components of the device are all made of organic glass. The data measuring system measures inlet and outlet pressure, flow, torque and rotating speed of the front inducer low-temperature pump and is used for analyzing external characteristics of the pump. The high-speed camera system shoots the internal flow and is used for measuring the internal flow of the inducer, the impeller and the volute.

Description

Technical Field

[0001] The invention relates to a front induction cryogenic pump modeling test device and a test method, belonging to the technical field of fluid machinery testing. Background Art

[0002] Cryogenic pumps are special pumps used to transport cryogenic media (such as liquid oxygen, liquid nitrogen, liquid argon, liquid hydrocarbons and liquefied natural gas, etc.) in petroleum, air separation and chemical plants. They also play an important role in aerospace engineering, energy engineering and other fields (such as the filling of rocket cryogenic fuel in space launches, the transportation of liquid air in cryogenic energy storage, etc.). Cryogenic pumps are indispensable wherever cryogenic media need to be transported. They make the cryogenic media flow according to process requirements just like the heart makes the blood flow. It can be seen that in many fields, cryogenic pumps are key equipment related to the fate of the country. Therefore, the development of high-performance cryogenic pumps is of great strategic significance to get rid of the passive situation that most cryogenic pumps in China currently rely on imports.

[0003] Due to the structural characteristics of the small blade outlet width, large impeller outer diameter and small impeller flow channel, as well as the working environment and transport medium, the hydraulic efficiency of cryogenic pumps is generally low and cavitation is very likely to occur at the inlet of the impeller. Nowadays, the more effective way to prevent cavitation in cryogenic pumps is to install an inducer in front of the pump impeller.

[0004] With the continuous development of sensor and control technology, fluid machinery test equipment is also constantly updated, the accuracy and stability of the test equipment have been improved, and the degree of automation of the equipment has also been improved. With the continuous innovation of fluid machinery test technology, the measurement range of the device is also constantly expanding, and it has been widely used not only in traditional energy, chemical and other fields, but also in new energy, environmental protection and other fields.

[0005] However, due to the particularity of the working environment and transport medium of the cryopump, there is no mature test equipment to measure the external characteristics and internal flow of the cryopump. The difficulty and problems of the cryopump test are mainly reflected in the following aspects:

[0006] (1) Cryogenic media are easy to vaporize. The operating environment of cryogenic pumps is generally around -150°C, and the test environment is difficult to control. In addition, the medium transported by cryogenic pumps is low in temperature, easy to vaporize, inconvenient to store, and has high test costs. Therefore, it is necessary to apply the concept of simulation testing to cryogenic pumps, normalize the test environment, and universalize the test media.

[0007] (2) The internal flow of the cryopump cannot be visualized. Most existing test devices can only perform external characteristic tests on cryopumps and cannot measure the internal flow of the pump. Therefore, it is necessary to study and design a pump that meets both the photographic performance and the hydraulic performance of the pump while ensuring strength.

[0008] (3) The existing device is large in size. The existing cryogenic pump test device occupies a large area. At the same time, the initial installation and subsequent maintenance of the test device are difficult and costly. Therefore, it is urgent to solve the problem of the existing device occupying a large area and high test cost.

[0009] The above problems seriously affect the experimental research of cryopumps, and further affect the development of high-performance cryopumps. Therefore, in order to meet the experimental research requirements of cryopumps, improve the efficiency of the test, and reduce the test cost, it is urgent to develop a set of cryopump test equipment. Summary of the invention

[0010] The purpose of the present invention is to solve the problems existing in the prior art and to provide a device capable of performing multiple modeling tests on a cryogenic pump.

[0011] In order to achieve the above object, the technical solution proposed in the present invention is: a front induction cryogenic pump modeling test device, including a model pump and a motor for driving the model pump, characterized in that: the model pump is used to simulate the front induction cryogenic pump, and the modeling test device also includes a pipeline system, a water inlet system, an air extraction system and a data measurement system;

[0012] The pipeline system includes a water tank, a pump inlet pipeline, a pump outlet pipeline, an exhaust pipeline and a drainage pipeline; the water tank is a closed structure; the water tank, the pump inlet pipeline, the model pump and the pump outlet pipeline are connected in sequence to form a test circulation loop; the exhaust pipeline and the drainage pipeline are both arranged on the water tank;

[0013] The water inlet system includes a water tank, a water inlet pipeline and a water inlet pump; the drainage pipeline is connected to the water tank; the water inlet pipeline connects the water tank and the water storage tank, and the water inlet pump is arranged on the water inlet pipeline;

[0014] The air extraction system includes a vacuum pump and an air extraction pipeline connecting the vacuum pump and the water storage tank;

[0015] The data measurement system includes a flow meter arranged on the pump outlet pipeline, a torque sensor arranged at the motor output end, a motor controller for controlling the motor, and an inlet and outlet pressure sensor arranged at the inlet and outlet of the model pump.

[0016] The above technical solution is further designed as follows: a pump inlet flow regulating valve and a pump outlet flow regulating valve are respectively provided on the pump inlet pipeline and the pump outlet pipeline; a drain valve is provided on the drain pipeline, an exhaust valve is provided on the exhaust pipeline, a water inlet valve is provided on the water inlet pipeline, and a vacuum valve is provided on the exhaust pipeline.

[0017] The model pump comprises a water suction chamber, a volute, an impeller and an inducer arranged at the front side of the impeller. An optical compensation box is arranged outside the water suction chamber. The volute, the water suction chamber and the optical compensation box are all made of organic glass.

[0018] The water storage tank, the pump inlet pipeline, the pump outlet pipeline and the drainage pipeline are all made of organic glass.

[0019] The modeling test device also includes a high-speed camera system, which includes a high-speed camera, a cold light source and a monitor. The cold light source illuminates the model pump, and the high-speed camera shoots the model pump and transmits the shot images to the monitor.

[0020] The inlet and outlet pressure sensors are connected to the inlet and outlet of the model pump through an inlet pressure sensor pipeline and an outlet pressure sensor pipeline respectively; the motor is connected to the torque sensor through a coupling, and the torque sensor is connected to the model pump through another coupling.

[0021] A water tank flow stabilizer is provided inside the water tank; a water tank flow stabilizer is provided inside the water tank, and the water tank flow stabilizer divides the water tank into a water inlet chamber and a water return chamber, and the water inlet pipeline and the drainage pipeline are connected to the water inlet chamber and the water return chamber respectively.

[0022] A method for testing external characteristics of a front inducer cryogenic pump modeling test device comprises the following steps:

[0023] Step 1: Add the test medium into the water tank;

[0024] Step 2: Open the water inlet valve and the exhaust valve, and pump the test medium in the water tank into the test circulation loop through the water inlet pump;

[0025] Step 3, open the pump inlet flow regulating valve and the pump outlet flow regulating valve, start the motor, adjust the motor speed to the test speed through the motor controller, and adjust the pump outlet flow regulating valve to the test flow;

[0026] Step 4, respectively obtain flow rate, inlet and outlet pressure, torque and speed data through the flow meter, inlet and outlet pressure sensor, torque sensor and motor controller;

[0027] Step 5: Adjust different test flow rates, repeat step 4, and record the corresponding data in sequence;

[0028] Step 6: After the test is completed, draw the external characteristic curve (HQ, PQ, η-Q) according to the acquired data;

[0029] Head H is:

[0030]

[0031] In the formula, pd 、p s Respectively represent the pressure at the outlet and inlet of the model pump; v d 、v s Respectively represent the velocity at the outlet and inlet of the model pump; z d 、z s They represent the distances from the outlet and inlet of the model pump to the measurement reference plane, respectively, and Q is the flow rate;

[0032] Pump effective power P e , shaft power P and efficiency η are:

[0033] P e =ρgQH

[0034] P=P e +P m =2πnM T

[0035]

[0036] Where: P m Indicates mechanical loss power; M T Indicates the torque of the motor.

[0037] An internal flow test method of a front inducer cryogenic pump modeling test device comprises the following steps:

[0038] Step 1: Set the high-speed camera parameters;

[0039] Step 2, adding a test medium into a water tank, and then adding tracer particles into the test medium;

[0040] Step 3: Open the water inlet valve and the exhaust valve, and pump the test medium in the water tank into the test circulation loop through the water inlet pump;

[0041] Step 4: Open the pump inlet flow regulating valve and the pump outlet flow regulating valve, start the motor, adjust the motor speed to the test speed through the motor controller, and adjust the pump outlet flow regulating valve to the test flow;

[0042] Step 5, start the high-speed camera system to collect image data of the model pump;

[0043] Step 6: Adjust different test flow rates, repeat step 5, and record the corresponding data in sequence;

[0044] Step 7: Transfer the collected multiple sets of data to the memory card in the monitor.

[0045] A cavitation test method for a front inducer cryogenic pump modeling test device comprises the following steps:

[0046] Step 1: Set the high-speed camera parameters;

[0047] Step 2: Add the test medium into the water tank; open the water inlet valve and the exhaust valve, and pump the test medium in the water tank into the test circulation loop through the water inlet pump;

[0048] Step 3, close the exhaust valve;

[0049] Step 4: Start the motor, adjust the motor speed to the test speed, open the pump outlet flow regulating valve, and adjust it to the test flow;

[0050] Step 5: Start the vacuum pump to extract the air in the water storage tank;

[0051] Step 6, collecting flow rate and inlet and outlet pressure data through flow meter and inlet and outlet pressure sensors respectively; and using high-speed camera to collect image data of bubble generation in inducer and impeller parts;

[0052] Step 7, adjust the vacuum pump to control the vacuum degree, adjust the pump inlet flow regulating valve to control the flow, so that the pump will produce different degrees of cavitation;

[0053] Step 8: Collect flow rate, inlet and outlet pressure, torque and speed through flow meter, inlet and outlet pressure sensor, torque sensor and motor controller respectively; and use high-speed camera to collect image data of bubble generation, expansion and collapse in the inducer and impeller.

[0054] The beneficial effects of the present invention are:

[0055] Compared with the prior art, the present invention has the following advantages:

[0056] (1) The present invention constructs a model pump for a cryogenic pump with a front induction wheel, and designs a test circulation loop including a closed water tank, an exhaust system, a water inlet system and other structures, so that the test device can carry out external characteristic tests, internal flow tests, cavitation tests, etc. of the cryogenic pump with a front induction wheel, integrates multiple tests, realizes the integration of device functions, and a set of devices can carry out multiple tests, thereby saving the investment of test device funds.

[0057] (2) The flow-through components such as the front induction cryogenic pump and pipelines of the present invention are all made of organic glass, so that the flow of the entire flow basin can be visualized and the flow phenomenon inside the flow-through components can be photographed.

[0058] (3) In order to improve the operating ability of the cryogenic pump in an environment prone to cavitation, the present invention adds an inducer in front of the impeller, which not only improves the anti-cavitation ability of the cryogenic pump, but also improves the head and efficiency of the cryogenic pump.

[0059] (4) The present invention adopts modeling test technology. On the basis of geometric similarity, motion similarity and dynamic similarity, according to the similarity criterion, the results measured on the test device can be converted into the performance of the actual cryogenic pump, thereby realizing the miniaturization of the device and the normal temperature of the test medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a front view schematic diagram of the present invention;

[0061] Figure 2 It is a top view schematic diagram of the present invention;

[0062] Figure 3 It is a three-dimensional model diagram of the whole device in the present invention;

[0063] Figure 4 This is a structural diagram of the front induction cryogenic pump in the present invention;

[0064] Figure 5 It is a schematic diagram of the arrangement of the high-speed camera system in the present invention.

[0065] In the figure: 1-drain valve; 2-water storage tank; 3-pump outlet flow regulating valve; 4-flow meter; 5-flow meter bracket; 6-inlet pressure sensor pipeline; 7-motor controller; 8-outlet pressure sensor pipeline; 9-left coupling; 10-torque sensor; 11-right coupling; 12-motor; 13-model pump (front induction wheel cryogenic pump); 14-inlet and outlet pressure sensors; 15-pump inlet pipeline; 16-pump inlet flow regulating valve; 17-test bench; 18-water inlet pipeline; 19-water inlet pump; 20-device inlet valve; 21-air extraction pipeline; 22-water tank; 23-water tank bracket; 24-water tank flow stabilizer; 25-vacuum valve; 26-vacuum pump; 27-flow meter outlet flange; 28-flow meter inlet flange; 29-pump outlet pipeline; 30-motor controller bracket; 31-motor bracket; 32-pump outlet flange; 33-pump inlet flange; 34-water tank outlet flange; 35-exhaust pipeline; 36-exhaust valve; 37-drainage pipeline; 38-water tank flow stabilizer; 39-inducer; 40-volute; 41-impeller; 42-monitor; 43-high-speed camera; 44-cold light source. DETAILED DESCRIPTION

[0066] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0067] Embodiment 1

[0068] like Figure 1 , Figure 2 and Figure 3As shown, a front induction cryogenic pump modeling test device of this embodiment includes a power transmission system, a piping system, a model pump 13, a data measurement system, an air extraction system, a water intake system and a high-speed camera system. The model pump 13 is a model pump made based on a similar principle and used to simulate a front induction cryogenic pump.

[0069] In this embodiment, the power transmission system includes a motor 12, a left coupling 9, a torque sensor 10, a right coupling 11, a motor bracket 31, a motor controller bracket 30 and a motor controller 7. The motor 12 and the motor controller 7 are respectively mounted on the test bench 17 through the motor bracket 31 and the motor controller bracket 30, and the test bench 17 and the motor bracket 31 and the motor controller bracket 30 are connected by bolts. The motor 12 is connected to the torque sensor 10 through the right coupling 11, and the torque sensor 10 is connected to the front induction wheel cryogenic pump 13 through the left coupling 9 to achieve power transmission and torque measurement.

[0070] The control cabinet 7 controls the switch of the motor and the size of the speed to carry out research on the performance of the front induction cryogenic pump at different speeds.

[0071] The pipeline system includes an inlet flow regulating valve 16, an outlet flow regulating valve 3, a water storage tank 2, a pump inlet pipeline 15, a pump outlet pipeline 29, a drainage pipeline 33, a device water inlet pipeline 18 and a water storage tank exhaust pipeline 35. The water storage tank 2 is a closed water tank, and a water storage tank flow stabilizer 24 is provided inside, which is respectively connected to the drainage pipeline 37, the device water inlet pipeline 18, the pump inlet pipeline 15, the pump outlet pipeline 29 and the water storage tank exhaust pipeline 35.

[0072] The water tank 2, the pump inlet pipeline 15, the front inducer cryogenic pump 13 and the pump outlet pipeline 29 are connected in sequence to form a test circulation loop for conducting an external characteristic test and an internal flow test of the front inducer cryogenic pump 13. This part of the pipeline is supported on the test bench 17 by the water tank bracket 23 and the flow meter bracket 5.

[0073] The water storage tank 2, the pump inlet pipeline 15, the front induction cryogenic pump 13 and the pump outlet pipeline 29 are connected in sequence to form a circulation loop.

[0074] The water tank 2 is provided with an exhaust system, which includes an exhaust pipeline 21 and a vacuum pump 26. The exhaust pipeline 21 connects the vacuum pump 26 and the water tank 2 for conducting a cavitation test of the front induction wheel cryogenic pump; the exhaust pipeline 21 is also provided with a vacuum valve 25.

[0075] The water inlet system includes a water tank 22 , a water inlet pipeline 18 and a water inlet pump 19 ; the drainage pipeline 33 is connected to the water tank 22 ; the water inlet pipeline 18 connects the water tank 22 and the water storage tank 2 , and the water inlet pump 18 is arranged on the water inlet pipeline 18 .

[0076] A water tank flow stabilizer 38 is provided in the water tank 22, and the water tank flow stabilizer 38 divides the water tank 22 into a water inlet chamber and a water return chamber. The water tank 22 is connected to the water storage tank 2 through a drainage pipeline 37 and a water inlet pipeline 18 respectively. A water inlet pump 19 is provided on the water inlet pipe 18 of the device, which is used to pump the medium in the water tank 22 into the water storage tank 2; the drainage pipeline 37 is connected to the water return chamber, the water inlet pipeline 18 is connected to the water inlet chamber, and the water inlet valve 20, the water inlet pump 19 and the water inlet pipeline 18 are connected in sequence.

[0077] In this embodiment, the water tank 2 is used to contain the test medium. The bottom pipe of the water tank 2 is connected to the pump inlet pipeline 15, and the top pipe of the water tank 2 is connected to the pump outlet pipeline 29.

[0078] The pump inlet pipeline 15 is composed of an inlet flow regulating valve 16, a pump inlet straight pipe section, a pump inlet flange 33 and a water tank outlet flange 34; the pump outlet pipeline 29 is composed of a pump outlet elbow, a pump outlet straight pipe section, a flow meter 4, a pump outlet flow regulating valve 3, etc.; the flow meter 4 is installed on the pump outlet pipeline 29 through the flow meter inlet and outlet flanges 27 and 28, the inner diameter of the pipeline connected to the inlet of the front inducer cryogenic pump 13 is 36 mm, and the inner diameter of the pump outlet pipeline is 30 mm; the length of the inlet pipeline of the front inducer cryogenic pump 13 is approximately 10 times the inner diameter of the inlet of the inducer cryogenic pump.

[0079] All flow-through components in the piping system (water tank 2, pump inlet pipeline 15, pump outlet pipeline 29, drainage pipeline 33, device water inlet pipeline 18 and water tank exhaust pipeline 35, etc.) are made of plexiglass, which can directly observe the operation of the impeller inside the cryogenic pump and the flow of the fluid, with good visualization effect; the designed pipeline direction leaves enough space for internal flow measurement to facilitate the experiment; the valves in the piping system are ball valves, and all valves are connected to the pipelines with flanges; the liquid level in the water tank 2 is higher than the installation position of the model pump, and there is no need to prime the pump when starting the pump.

[0080] like Figure 4As shown, the front induction cryopump 13 in this embodiment is composed of a water suction chamber, an induction wheel 39, a semi-open impeller 41, a pump front cover plate, bolts, a volute 40, pump inlet and outlet flanges 32 and 33, a sealing gasket, an optical compensation box, etc. The volute 40, the water suction chamber, the pump front cover plate and the optical compensation box are made of organic glass with good light transmittance, and a high-speed camera can be directly used to shoot the internal flow. They are bonded with organic glass glue, the volute 40 is processed by mold opening technology, and the impeller 41 and the induction wheel 39 are both made of aluminum alloy 3D printing. The structure of the front induction cryopump 13 is reduced according to the real cryopump, and an induction wheel is added to the front end of the impeller to improve the pump's anti-cavitation ability. On the basis of considering the performance of the test medium, according to the modeling theory, the specific structural dimensions of the model pump are determined so that the internal flow conditions of the real pump can be converted from the internal flow test results of the model pump. The shaft seal of the cryopump adopts a mechanical seal with good sealing performance. The inducer 39 and the impeller 41 are easy to replace to meet the needs of the internal flow of the cryopump under different inducer and impeller structures. An optical compensation box made of organic glass is provided outside the cryopump water absorption chamber to offset the refraction of light through the wall of the water absorption chamber and reduce the measurement error caused by light refraction.

[0081] The data measurement system of this example includes a flow meter 4, a torque sensor 10, an inlet and outlet pressure sensor 14 and a motor controller 7. The flow meter 4 is installed on the pump outlet pipeline to measure the flow rate; the inlet and outlet pressure sensor 14 detection points are provided at the pump inlet and outlet, and the inlet and outlet pressure sensor pipelines 6 and 8 are connected to the inlet and outlet pressure sensor 14; the torque sensor 10 is located between the motor 12 and the front induction wheel cryogenic pump 13, and is used to measure the torque when the device is running; the motor controller 7 is used to control and measure the speed of the pump when it is running.

[0082] The high-speed camera system includes a high-speed camera 43, a cold light source 44 and a monitor 42. The cold light source 44 illuminates the front induction cryopump 13. The high-speed camera 43 photographs the front induction cryopump 13 and transmits the photographed images to the monitor 42 for presentation.

[0083] Embodiment 2

[0084] This embodiment uses the test device of the first embodiment to carry out the external characteristic test of the front inducer cryogenic pump. The main steps are:

[0085] 1) Add a certain amount of test medium into the water tank 22.

[0086] 2) Check whether all instruments and equipment are normal.

[0087] 3) Open the water inlet valve 20, turn on the power of the test device, open the exhaust valve 36, and use the water inlet pump 19 to pump the test medium in the water tank 22 into the test circulation loop.

[0088] 4) Open the pump inlet flow regulating valve 16 and the pump outlet flow regulating valve 3, start the motor 12, adjust the speed through the motor controller 7, adjust the flow to the maximum flow, and remove the air in the pipeline.

[0089] 5) Adjust the speed to the test speed and adjust the pump outlet flow control valve 3 to the test flow.

[0090] 6) After the operation is stable, the flow rate, inlet and outlet pressure, torque and speed are recorded by the flow meter 4, the inlet and outlet pressure sensor 14, the torque sensor 10 and the motor controller 7 respectively.

[0091] 7) Adjust the flow rate, repeat step 6, and record the data of external characteristic measurements in sequence.

[0092] 8) After all tests are completed, adjust the speed to zero and press the stop button of the motor 12. Perform data processing and draw the external characteristic curve (HQ, PQ, η-Q).

[0093] 9) Turn off the power supply and drain the test medium in the pipeline and the water storage tank 2 through the drainage pipeline 37. Clean up the test site.

[0094] The external characteristics of the micro pump can be obtained by calculation based on the above measurement data. The specific calculation method is as follows:

[0095] The head H represents the energy increment of the unit weight of liquid pumped by the pump from the pump inlet to the pump outlet, and its unit is m. Its calculation method is shown in formula (1):

[0096]

[0097] In the formula, p d 、p s Respectively represent the pressure at the outlet and inlet of the front induction cryogenic pump; v d 、v s They represent the velocities at the outlet and inlet of the front induction cryogenic pump, respectively, and are given by v = 4Q / πD 2 Calculated; z d 、z s They respectively represent the distance from the outlet and inlet of the front induction wheel cryogenic pump to an optional measurement reference plane. In this embodiment, the desktop is used as the reference plane, and the distance is the height from the pump inlet and outlet to the desktop; Q is the flow rate.

[0098] Pump effective power P e Also known as output power, it indicates the effective energy obtained by the medium transported from the front induction cryogenic pump in the pump per unit time. Its calculation method is shown in formula (2). Shaft power P, also known as input power, indicates the power transmitted from the prime mover to the pump shaft. Its calculation method is shown in formula (3). Efficiency η is the effective power Pe The ratio of the load to the shaft power P is shown in formula (4).

[0099] P e =ρgQH (2)

[0100] P=P e +P m =2πnM T (3)

[0101]

[0102] Where: P m Indicates mechanical loss power, kW; M T Indicates the torque of the motor, N·m.

[0103] Embodiment 3

[0104] This embodiment uses the test device of the first embodiment to carry out the internal flow test of the front inducer cryogenic pump. The main steps are:

[0105] 1) Arrangement of high-speed camera. The internal flow test of the front induction cryogenic pump 13 mainly includes shooting of the impeller, volute and inducer 39. When shooting the flow inside the impeller and volute, the arrangement of the high-speed camera system is as follows: Figure 5 As shown in (a), when photographing the flow in the induction wheel 39, the high-speed camera system is arranged as follows: Figure 5 (b) is shown. The LED cold light source 44 is adjusted to a suitable brightness to illuminate the impeller 41 and the volute 40 area. The shooting angle of the high-speed camera 43 and the irradiation angle of the LED cold light source are placed at a suitable position to ensure the quality of the shooting. The high-speed camera 43 is connected to the monitor 42.

[0106] 2) Set the parameters of the high-speed camera, mainly including: shooting frequency, exposure time, external calibration and selection of reference points. The shooting frequency of the high-speed camera 43 is selected to be 2000frame / s. When the light permits, the exposure time is as short as possible to reduce the blur of the image. The external calibration is mainly set near the object to be photographed and used as a dimensional reference for measurement and analysis. The selection of the reference point is mainly based on the type of the object to be photographed and the motion analysis, and the coordinate origin is set according to the motion state of the object to be photographed.

[0107] 3) Adding the test medium: According to the size of the pump, pitaya seeds are selected as tracer particles and placed in the water tank 22 together with the test medium.

[0108] 4) Start the front inducer cryogenic pump test device according to the relevant steps of the external characteristics test, and conduct the test under different flow conditions.

[0109] 5) Filming of internal flow: After the device is running stably, start the high-speed camera system to film the measured area.

[0110] 6) Data storage: Multiple sets of data are captured and transferred to the memory card in the monitor 42.

[0111] 7) End the test. Turn off the power and clean up the test site.

[0112] Embodiment 4

[0113] This embodiment uses the test device of the first embodiment to carry out the cavitation test of the front induction cryogenic pump. The steps are as follows:

[0114] 1) Arrange and set up the high-speed camera according to the internal flow test.

[0115] 2) Pump the test medium into the test circulation loop with reference to the external characteristic test, and close the exhaust valve 36.

[0116] 3) Start the motor 12, adjust the speed to the test speed, open the pump outlet flow regulating valve 3, and adjust it to the test flow.

[0117] 4) Start the vacuum pump 26 to extract the air in the water storage tank 2 to reduce the pressure in the tank.

[0118] 5) After the front induction cryogenic pump 13 runs stably, the flow rate and inlet and outlet pressures are recorded by the flow meter 4 and the inlet and outlet pressure sensors 14. A high-speed camera is used to shoot the bubble generation situation at the induction wheel and impeller.

[0119] 6) Adjust the vacuum pump 26 to control the vacuum degree, and adjust the pump inlet flow regulating valve 16 to control the flow, so that the pump undergoes cavitation to varying degrees.

[0120] 7) After the operation is stable, the flow rate, inlet and outlet pressure, torque and speed are recorded by the flow meter 4, the inlet and outlet pressure sensor 14, the torque sensor 10 and the motor controller 7 respectively.

[0121] 8) Use a high-speed camera to capture images of flow changes such as bubble generation, expansion and collapse.

[0122] 9) Save and process the test data.

[0123] 10) Turn off the power and clean up the test site.

[0124] Embodiment 5

[0125] The main steps of the present embodiment in carrying out a model test on the test device of the first embodiment are as follows:

[0126] 1) Determine the simulation target. The simulation test method in the front induction cryogenic pump 13 test device mainly includes two types: size simulation and medium simulation between the prototype pump and the cryogenic pump.

[0127] 2) Establish the size modeling of the prototype pump and the cryogenic pump. According to the Buckingham method (π theorem), the similarity criteria between pumps with similar sizes are established, which is mainly manifested in the equality of the specific head, specific flow rate and Reynolds number between the model pump and the prototype pump.

[0128]

[0129] Where: n represents the speed, r / min; ρ represents the density, kg / m 3 ; D is the size of the pump; ψ is the specific head of the pump; φ is the specific flow rate of the pump; ν is the kinematic viscosity of the conveying medium, N·s / m 2 ;Re c Reynolds number of the pump.

[0130] Through the above dimensionless variable operation, the specific power Ne and specific speed n of the pump can also be obtained. s .

[0131]

[0132] 3) Establish medium modeling of prototype pump and cryogenic pump. Based on the size modeling, the specific head ψ, specific flow φ and Reynolds number Re of the two pumps are c Similarly, clean water is used as the medium instead of the low-temperature medium for testing. The density and viscosity of the two are different. In order to make the model pump for conveying clean water similar to the low-temperature pump, the medium modeling needs to be carried out according to the similarity criterion.

[0133] Assume that the characteristic dimension of the prototype pump is D p , the density of the medium is ρ p , the viscosity of the medium is μ p , the characteristic dimension of the model pump is D m , the density of the medium is ρ m , the viscosity of the medium is μ m .

[0134] The characteristic dimensions of the model pump need to meet the following requirements:

[0135]

[0136] The speed of the model pump needs to meet the following requirements:

[0137]

[0138] The flow rate of the model pump needs to meet the following requirements:

[0139]

[0140] Finally, ensure that the specific head of the two pumps is equal. The head of the model pump needs to meet the following requirements:

[0141]

[0142] Where: x is the modeling coefficient. According to different values, modeling test schemes under different working conditions can be obtained.

[0143] Through the entire simulation test program, as long as the geometric dimensions of the two pumps satisfy equation (10), the size simulation can be achieved, and when the rotation speed and flow rate of the two pumps satisfy equations (11) and (12), the medium simulation can be achieved. On the basis of the simulation of the two, the performance of the cryogenic pump can be directly derived according to the performance of the model pump.

[0144] The technical solutions of the present invention are not limited to the above-mentioned embodiments, and any technical solutions obtained by equivalent replacement methods fall within the scope of protection required by the present invention.

Claims

1. A front induction cryogenic pump model test device, comprising a model pump and a motor for driving the model pump, characterized in that: The model pump is used to simulate the front induction cryogenic pump, and the model test device also includes a pipeline system, a water inlet system, an air extraction system and a data measurement system; The pipeline system includes a water tank, a pump inlet pipeline, a pump outlet pipeline, an exhaust pipeline and a drainage pipeline; the water tank is a closed structure; the water tank, the pump inlet pipeline, the model pump and the pump outlet pipeline are connected in sequence to form a test circulation loop; the exhaust pipeline and the drainage pipeline are both arranged on the water tank; The water inlet system includes a water tank, a water inlet pipeline and a water inlet pump; the drainage pipeline is connected to the water tank; the water inlet pipeline connects the water tank and the water storage tank, and the water inlet pump is arranged on the water inlet pipeline; The air extraction system includes a vacuum pump and an air extraction pipeline connecting the vacuum pump and the water storage tank; The data measurement system includes a flow meter arranged on the pump outlet pipeline, a torque sensor arranged at the motor output end, a motor controller for controlling the motor, and an inlet and outlet pressure sensor arranged at the inlet and outlet of the model pump.

2. The front induction cryogenic pump modeling test device according to claim 1, characterized in that: The pump inlet pipeline and the pump outlet pipeline are respectively provided with a pump inlet flow regulating valve and a pump outlet flow regulating valve; the drain pipeline is provided with a drain valve, the exhaust pipeline is provided with an exhaust valve, the water inlet pipeline is provided with a water inlet valve, and the exhaust pipeline is provided with a vacuum valve.

3. The front induction cryogenic pump modeling test device according to claim 2, characterized in that: The model pump comprises a water suction chamber, a volute, an impeller and an inducer arranged at the front side of the impeller. An optical compensation box is arranged outside the water suction chamber. The volute, the water suction chamber and the optical compensation box are all made of organic glass.

4. The front induction cryogenic pump modeling test device according to claim 3, characterized in that: The water storage tank, the pump inlet pipeline, the pump outlet pipeline and the drainage pipeline are all made of organic glass.

5. The front induction cryogenic pump modeling test device according to claim 4, characterized in that: It also includes a high-speed camera system, which includes a high-speed camera, a cold light source and a monitor. The cold light source illuminates the model pump, and the high-speed camera shoots the model pump and transmits the shot images to the monitor.

6. The front inducer cryogenic pump modeling test device according to any one of claims 1 to 5, characterized in that: The inlet and outlet pressure sensors are connected to the inlet and outlet of the model pump through an inlet pressure sensor pipeline and an outlet pressure sensor pipeline respectively; the motor is connected to the torque sensor through a coupling, and the torque sensor is connected to the model pump through another coupling.

7. The front induction cryogenic pump modeling test device according to claim 6, characterized in that: A water tank flow stabilizer is provided inside the water tank; a water tank flow stabilizer is provided inside the water tank, the water tank flow stabilizer divides the water tank into a water inlet chamber and a water return chamber, and the water inlet pipeline and the drainage pipeline are connected to the water inlet chamber and the water return chamber respectively.

8. An external characteristic test method of the front inducer cryogenic pump model test device according to claim 5, characterized in that: The steps include: Step 1: Add the test medium into the water tank; Step 2: Open the water inlet valve and the exhaust valve, and pump the test medium in the water tank into the test circulation loop through the water inlet pump; Step 3, open the pump inlet flow regulating valve and the pump outlet flow regulating valve, start the motor, adjust the motor speed to the test speed through the motor controller, and adjust the pump outlet flow regulating valve to the test flow; Step 4, respectively obtain flow rate, inlet and outlet pressure, torque and speed data through the flow meter, inlet and outlet pressure sensor, torque sensor and motor controller; Step 5: Adjust different test flow rates, repeat step 4, and record the corresponding data in sequence; Step 6: After the test is completed, draw the external characteristic curve (HQ, PQ, η-Q) according to the acquired data; Head H is: In the formula, p d 、p s Respectively represent the pressure at the outlet and inlet of the model pump; v d 、v s Respectively represent the velocity at the outlet and inlet of the model pump; z d 、z s They represent the distance from the outlet and inlet of the model pump to the measurement reference plane respectively; Q is the flow rate; Pump effective power P e , shaft power P and efficiency η are: P e =ρgQH P=P e +P m =2πnM T Where: P m Indicates mechanical loss power; M T Indicates the torque of the motor.

9. An internal flow test method for the front inducer cryogenic pump modeling test device according to claim 5, characterized in that: The steps include: Step 1: Set the high-speed camera parameters; Step 2, adding the test medium into the water tank, and then adding the tracer particles into the test medium; Step 3: Open the water inlet valve and the exhaust valve, and pump the test medium in the water tank into the test circulation loop through the water inlet pump; Step 4: Open the pump inlet flow regulating valve and the pump outlet flow regulating valve, start the motor, adjust the motor speed to the test speed through the motor controller, and adjust the pump outlet flow regulating valve to the test flow; Step 5, start the high-speed camera system to collect image data of the model pump; Step 6: Adjust different test flow rates, repeat step 5, and record the corresponding data in sequence; Step 7: Transfer the collected multiple sets of data to the memory card in the monitor.

10. A cavitation test method for the front inducer cryogenic pump model test device according to claim 5, characterized in that: The steps include: Step 1: Set the high-speed camera parameters; Step 2: Add the test medium into the water tank; open the water inlet valve and the exhaust valve, and pump the test medium in the water tank into the test circulation loop through the water inlet pump; Step 3, close the exhaust valve; Step 4: Start the motor, adjust the motor speed to the test speed, open the pump outlet flow regulating valve, and adjust it to the test flow; Step 5: Start the vacuum pump to extract the air in the water storage tank; Step 6, respectively collecting flow rate and inlet and outlet pressure data through the flow meter and inlet and outlet pressure sensors; and using a high-speed camera to collect image data of bubble generation at the inducer and impeller parts; Step 7, adjust the vacuum pump to control the vacuum degree, adjust the pump inlet flow regulating valve to control the flow, so that the pump will produce different degrees of cavitation; Step 8: Collect flow rate, inlet and outlet pressure, torque and speed through flow meter, inlet and outlet pressure sensor, torque sensor and motor controller respectively; and use high-speed camera to collect image data of bubble generation, expansion and collapse in the inducer and impeller.

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