Pump head model test device and test method

Abstract

The present invention belongs to the technical field of research and development testing of water pump model units, and in particular relates to a pump head model test device and test method, comprising a model unit, a head measurement system, and a test pipeline, wherein the two ends of the test pipeline are respectively connected to the high-pressure side and the low-pressure side of the model unit, and the two ends of the head measurement system are respectively connected to the high-pressure side and the low-pressure side of the model unit; a damping system is connected to the test pipeline, and the damping system includes a first control damper and a second control damper connected in parallel. This technical solution can quickly control the test conditions to near the characteristic head by setting two control dampers to cooperate, and further realize the precise adjustment of the head to the characteristic head; relevant head tests are carried out under precise head energy conditions to obtain accurate hydraulic characteristic data, and has a wide range of applications. It has good market application prospects both from the perspective of quickly responding to market demand and saving costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of research and development testing of water pump model units, and in particular relates to a pump head model testing device and a testing method. Background Art

[0002] In the hydraulic R&D tests of pumped storage units or large-flow pumps, the hydraulic performance of the pump involves the research and development of multiple parameters, such as pump flow, hump margin, maximum input, cavitation and pressure pulsation. These parameters are studied under the corresponding head, and their characteristics have very high requirements for head accuracy.

[0003] For example, the flow characteristics of a water pump examine the flow rate of the pump unit at each characteristic head. The average flow rate is often determined by the average of the flow rates at the minimum head and maximum head, or by the weighted flow rate at each characteristic head. The hump margin of a water pump is the margin between the minimum head when a hump appears on the hump angle characteristic curve and the maximum head of the pump station. The maximum input is the maximum input value after efficiency conversion at the minimum head of the pump station, and cavitation is strictly assessed at both the minimum and maximum heads. Pump unit stability, such as the pressure pulsation amplitude, has strict contractually guaranteed values ​​at each characteristic head within the operating head range of the pump station.

[0004] During the development of pump-storage unit pumping conditions and large pump units, particular attention is paid to the study of the hydraulic characteristics of the pump at various characteristic heads of the pump station, and these characteristics are subject to strict assessment indicators. Therefore, during the development and research phase of the pump model unit, high-precision simulation of the pump station head is also required to obtain accurate hydraulic characteristics at the pump characteristic head.

[0005] At this stage, the research and development of pump model units will face the problem of accurate adjustment of the head when the model unit has a large flow rate. Since the slope of the correlation curve between the pump head H and the flow rate Q is negative, that is, its derivative dH / dQ is less than 0, that is, as the flow rate decreases, the pump head shows a monotonically increasing trend. Therefore, when adjusting the head of the model pump unit, the general solution is to add a damper to the test system and adjust the damping of the test system (the system in the pipe) through the damper, so that the system flow rate increases or decreases, and the head decreases or increases. For example, if the pump unit head is to be increased, it is only necessary to increase the system damping coefficient to achieve the effect of reducing the flow rate and increasing the head.

[0006] To accommodate the system's high flow rate and wide head adjustment range, the damper's size and control head range are both relatively large, resulting in a relatively large control resolution. For example, a damper controlling a head range of (0-5) m has a minimum head control resolution of 0.05 m. Achieving a head amplitude of 0.01 m using this damper is difficult. Therefore, when conducting model tests at target heads using this current control method for precise head control, the efficiency is very low and there is a high degree of randomness. Therefore, with tight R&D cycles, how to accurately and quickly control pump head is a critical issue that needs to be addressed. Summary of the Invention

[0007] To overcome the above-mentioned defects and shortcomings of the existing technology, this application provides a pump head model test device and test method. The present invention aims to solve the problem of how to quickly and accurately conduct hydraulic characteristic model tests of the characteristic head of a pump unit; and how to achieve test conditions that simulate the characteristic head of the pump unit and meet the stability requirements of the IEC standard to ensure test stability.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0009] A pump head model test device includes a model unit, a head measurement system and a test pipeline. The two ends of the test pipeline are respectively connected to the high-pressure side and the low-pressure side of the model unit. The two ends of the head measurement system are respectively connected to the high-pressure side and the low-pressure side of the model unit through the test pipeline. A damping system, an electromagnetic flowmeter and a water temperature sensor are connected in the test pipeline. The damping system includes a first control damper and a second control damper connected in parallel. The first control damper and the second control damper are used to adjust the damping of the test pipeline.

[0010] Preferably, in the damping system, the first control damper is a low-precision large-range damping controller with a diameter of 300-700 mm, its lift control range is 0-20 m, and its lift control accuracy is 0.2 m; the second control damper is a high-precision small-range damping controller with a diameter of 50-100 mm, its lift control range is 0-1 m, and its lift control accuracy is 0.01 m.

[0011] Preferably, the lift measurement system includes a first pressure stabilizing box, a second pressure stabilizing box and a pressure differential sensor, and the two ends of the pressure differential sensor are respectively connected to the first pressure stabilizing box and the second pressure stabilizing box; the first pressure stabilizing box is connected to the first air duct, the first pressure duct and the first exhaust pipe leading to the outside of the box, and the first air duct and the first pressure duct are respectively connected to the high-pressure side of the model unit; the first exhaust pipe is connected to valve I, the first air duct is connected to valve II, and the first pressure duct is connected to valve III; the second pressure stabilizing box is connected to the second air duct, the second pressure duct and the second exhaust pipe leading to the outside of the box, and the second air duct and the second pressure duct are respectively connected to the low-pressure side of the model unit; the second exhaust pipe is connected to valve IV, the first air duct is connected to valve V, and the first pressure duct is connected to valve VI.

[0012] Based on the above-mentioned pump head model test device, this technical solution proposes a pump head model test device and test method, including equipment assembly, equipment debugging, preliminary preparation for the test and conducting a head test.

[0013] The equipment assembly comprises the following steps:

[0014] Assembling a damping system by connecting a first control damper and a second control damper in parallel to form a damping system;

[0015] Install the test pipeline, connect the water temperature sensor, electromagnetic flowmeter and damping system to the test pipeline in sequence, and connect the two ends of the test pipeline to the high-pressure side and low-pressure side of the model unit respectively to form a closed-loop structure;

[0016] Connect the lift measurement system and connect the two ends of the lift measurement system to the high-pressure side and low-pressure side of the model unit based on the test pipeline.

[0017] The equipment debugging includes the following steps:

[0018] Calibrate the measurement duty factor of the head measurement system;

[0019] Use the lift measurement system to exhaust the air in the test pipeline;

[0020] The measured value of the differential pressure sensor is used to determine whether the lift measurement system is in the zero state; if so, the equipment debugging is completed; if not, the process returns to the step of using the lift measurement system to exhaust the air in the test pipeline.

[0021] The preliminary preparation for the experiment includes the following steps:

[0022] Based on the principle of similarity conversion, the operating parameters of the model unit are set according to the operating parameters of the prototype unit as the simulation test conditions;

[0023] determining a characteristic head according to the operating conditions of the prototype unit, and adjusting a first control damper and a second control damper in the damping system according to the characteristic head;

[0024] The lift measurement system is used to measure the lift of the model unit in real time. Based on the measurement results, it is determined whether the lift stability of the model unit under the current working conditions meets the IEC standard. If so, the current working conditions of the model unit are maintained and the preliminary preparations for the test are completed. If not, the damping system is continuously adjusted until it is satisfied.

[0025] The lift test is carried out by collecting relevant test parameters under the simulated test conditions prepared in the early stage of the test and under the working conditions that meet the IEC standard to carry out the relevant lift test.

[0026] Preferably, the process of assembling the damping system also includes selecting a control damper, that is: selecting a low-precision large-range damping controller with a diameter of 300-700 mm as the first control damper, whose lift control range is 0-20 m and the lift control accuracy is 0.2 m; selecting a high-precision small-range damping controller with a diameter of 50-100 mm as the second control damper, whose lift control range is 0-1 m and the lift control accuracy is 0.01 m.

[0027] Preferably, during the preliminary preparation of the test, adjusting the first control damper and the second control damper in the damping system includes the following steps: first, adjusting the pressure in the test pipeline system to the pressure range corresponding to the test head range through the first control damper; then adjusting the pressure in the test pipeline system to the pressure corresponding to the target head through the second control damper.

[0028] Preferably, during the debugging of the equipment, calibrating the measurement working coefficient of the lift measurement system includes the following steps: inputting different pressures into the differential pressure sensor of the lift measurement system several times, and recording the corresponding measurement parameters of the differential pressure sensor under different pressures; inputting all pressures and measurement parameters into a computer; and determining the measurement working coefficient of the lift measurement system based on the linear relationship between pressure and measurement parameters.

[0029] Preferably, during the debugging of the equipment, using the lift measurement system to discharge the air in the test pipeline includes the following steps: opening valve I, valve II, valve III, valve IV, valve V and valve VI, using the first air bleed pipe, the first pressure bleed pipe and the first exhaust pipe in conjunction with the first pressure stabilizing box to discharge the air on the high-pressure side of the model unit, and using the second air bleed pipe, the second pressure bleed pipe and the second exhaust pipe in conjunction with the second pressure stabilizing box to discharge the air on the low-pressure side of the model unit; after the air is exhausted, closing valves I, valve II, valve IV and valve V, and keeping valves III and valve VI in the open state, to wait for determination of whether the lift measurement system is in the zero state.

[0030] Preferably, during the preliminary preparation for the test, the simulated test conditions include: the lift height of the model unit does not exceed 60m, the rotation speed is 900-1200r / min, the diameter of the impeller lower ring is not less than 250mm, and the test water temperature is between 0-35℃.

[0031] Preferably, during the lift test, the lift test includes any one or more of a weighted efficiency test, a pressure pulsation characteristic test, a cavitation test, a maximum input test, and a hump characteristic test.

[0032] Beneficial effects of the present invention:

[0033] 1) Compared to existing technologies, this technical solution combines a low-precision, large-range control damper with a high-precision, small-range control damper to form a damping system to ensure the accuracy and efficiency of the characteristic head hydraulic characteristics. This damping system is installed in the test pipeline. The low-precision, large-range control damper can be used to quickly control the test conditions to near the characteristic head, and the high-precision, small-range control damper can then be used to precisely adjust the head to the characteristic head. The relevant head tests are carried out under precise head energy conditions to obtain accurate hydraulic characteristic data. This method can be applied to the research of various pumps, including pumped storage pumps, pump units, and cross-flow pumps. It has excellent market application prospects both in terms of rapid response to market demand and cost savings.

[0034] 2) The maximum lift control range of the damping system of this technical solution is (0-20)m, and the minimum lift control value is 0.01m, which meets the requirements of the IEC standard for lift energy conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the overall structure diagram of the test device for this technical solution

[0036] Figure 2 Schematic diagram of the lift measurement system structure of this technical solution

[0037] Figure 3 This is an efficiency curve diagram completed using the test device in the efficiency test of this technical solution;

[0038] Figure 4 This is a synergy curve diagram completed using the test device in the energy test of this technical solution;

[0039] Figure 5 This is a hump curve diagram completed using the test device in the hump test of this technical solution;

[0040] Figure 6 This is a cavitation curve diagram completed using the test device in the cavitation test of this technical solution;

[0041] Figure 7 This is a pressure pulsation curve diagram completed using the test device in the pressure pulsation test of this technical solution;

[0042] In the picture:

[0043] 1. Model unit; 1.01. High-pressure side; 1.02. Low-pressure side; 2. Head measurement system; 2.01. First pressure-stabilizing tank; 2.02. Second pressure-stabilizing tank; 2.03. Pressure differential sensor; 2.04. First air bleed pipe; 2.05. First pressure-leading pipe; 2.06. First exhaust pipe; 2.07. Second air bleed pipe; 2.08. Second pressure-leading pipe; 2.09. Second exhaust pipe; 2.10. Valve I; 2.11. Valve II; 2.12. Valve III; 2.13. Valve IV; 2.14. Valve V; 2.15. Valve VI; 3. Test pipeline; 4. Damping system; 4.1. First control damper; 4.2. Second control damper; 5. Electromagnetic flowmeter; 6. Water temperature sensor. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0045] Therefore, the following detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment first discloses a pump head model test device and test method. As a basic implementation method of the present invention, the test device includes a model unit, a head measurement system and a test pipeline. The so-called model unit is a test unit designed according to the prototype unit (the pump unit actually installed and used, the volume of the prototype unit is much larger than the volume of the model unit), which can simulate the operating state of the prototype unit based on the similarity conversion principle. The two ends of the test pipeline are respectively connected to the high-pressure side and the low-pressure side of the model unit, and the two ends of the head measurement system are respectively connected to the high-pressure side and the low-pressure side of the model unit through the test pipeline. Specifically, the two ends of the head measurement system are connected to the test pipeline through a pressure measuring hose. A damping system, an electromagnetic flowmeter and a water temperature sensor are connected to the test pipeline, and the damping system includes a first control damper and a second control damper connected in parallel. The first control damper and the second control damper are used to adjust the damping of the test pipeline.

[0048] To further ensure the safety of the experiment, the test pipelines in the experimental device adopt reasonable materials, wall thickness and mechanical seals, so that the pressure bearing capacity reaches 6MPa, which meets the mechanical strength requirements of the test bench.

[0049] Based on the structure of the above test device, the test method includes: equipment assembly, equipment debugging, preliminary preparation for the test and carrying out lift test.

[0050] Equipment assembly includes the following steps:

[0051] S11, assembling a damping system by connecting a first control damper and a second control damper in parallel to form a damping system;

[0052] S12, installing a test pipeline, connecting a water temperature sensor, an electromagnetic flowmeter, and a damping system to the test pipeline in sequence, and connecting both ends of the test pipeline to the high-pressure side and the low-pressure side of the model unit, respectively, to form a closed-loop structure;

[0053] S13, connecting the lift measurement system, and connecting the two ends of the lift measurement system to the high-pressure side and the low-pressure side of the model unit based on the test pipeline.

[0054] Equipment commissioning includes the following steps:

[0055] S21, measurement duty factor for calibration head measurement system;

[0056] S22, exhaust the air in the test pipeline using the head measurement system;

[0057] S23, judging whether the lift measurement system is in a zero state by the measured value of the differential pressure sensor; if so, completing the equipment debugging; if not, returning to the step of exhausting the air in the test pipeline by using the lift measurement system.

[0058] The preliminary preparation for the experiment includes the following steps:

[0059] S31, based on the principle of similarity conversion, according to the operating parameters of the prototype unit, setting the operating parameters of the model unit as simulation test conditions;

[0060] S32, determining a characteristic head according to the operating condition of the prototype unit, and adjusting a first control damper and a second control damper in the damping system according to the characteristic head;

[0061] S33, measuring the head of the model unit in real time through the head measurement system, and determining whether the head stability of the model unit under the current operating condition meets the IEC standard based on the measurement results. If so, maintaining the current operating condition of the model unit and completing the preliminary preparations for the test; if not, continuing to adjust the damping system until it meets the standard;

[0062] Conduct lift test: Under the simulated test conditions prepared in the early stage of the test and under the working conditions that meet the IEC standards, collect relevant test parameters to carry out relevant lift tests.

[0063] Example 2

[0064] This embodiment first discloses a pump head model test device and test method, as a preferred embodiment of the present invention, that is, in the damping system of Example 1, the first control damper is a low-precision large-range damping controller with a diameter of 300-700 mm, and its head control range is 0-20 m, and the head control accuracy is 0.2 m; the second control damper is a high-precision small-range damping controller with a diameter of 50-100 mm, and its head control range is 0-1 m, and the head control accuracy is 0.01 m.

[0065] Based on the structure of the above test device, the test method includes: equipment assembly, equipment debugging, preliminary preparation for the test and carrying out lift test.

[0066] Equipment assembly includes the following steps:

[0067] S11, assembling the damping system, selecting a first control damper and a second control damper according to the structural requirements of the damping system, and connecting the first control damper and the second control damper in parallel to form the damping system;

[0068] S12, installing a test pipeline, connecting a water temperature sensor, an electromagnetic flowmeter, and a damping system to the test pipeline in sequence, and connecting both ends of the test pipeline to the high-pressure side and the low-pressure side of the model unit, respectively, to form a closed-loop structure;

[0069] S13, connecting the lift measurement system, and connecting the two ends of the lift measurement system to the high-pressure side and the low-pressure side of the model unit based on the test pipeline.

[0070] Equipment commissioning includes the following steps:

[0071] S21, measurement duty factor for calibration head measurement system;

[0072] S22, exhaust the air in the test pipeline using the head measurement system;

[0073] S23, judging whether the lift measurement system is in a zero state by the measured value of the differential pressure sensor; if so, completing the equipment debugging; if not, returning to the step of exhausting the air in the test pipeline by using the lift measurement system.

[0074] The preliminary preparation for the experiment includes the following steps:

[0075] S31, based on the principle of similarity conversion, according to the operating parameters of the prototype unit, setting the operating parameters of the model unit as simulation test conditions;

[0076] S32, determine the characteristic head according to the working condition of the prototype unit, and adjust the first control damper and the second control damper in the damping system according to the characteristic head. Specifically: first, adjust the pressure in the test pipeline system to the pressure range corresponding to the test head range through the first control damper; then adjust the pressure in the test pipeline system to the pressure corresponding to the target head through the second control damper.

[0077] S33, measuring the head of the model unit in real time through the head measurement system, and determining whether the head stability of the model unit under the current operating condition meets the IEC standard based on the measurement results. If so, maintaining the current operating condition of the model unit and completing the preliminary preparations for the test; if not, continuing to adjust the damping system until it meets the standard;

[0078] Conduct lift test: Under the simulated test conditions prepared in the early stage of the test and under the working conditions that meet the IEC standards, collect relevant test parameters to carry out relevant lift tests.

[0079] Example 3

[0080] This embodiment first discloses a pump head model test device and test method, as a preferred embodiment of the present invention, that is, in Example 1, the head measurement system includes a first pressure stabilizing box, a second pressure stabilizing box and a pressure differential sensor, and the two ends of the pressure differential sensor are respectively connected to the first pressure stabilizing box and the second pressure stabilizing box; the first pressure stabilizing box is connected to a first air bleed pipe, a first pressure bleed pipe and a first exhaust pipe leading to the outside of the box, and the first air bleed pipe and the first pressure bleed pipe are respectively connected to the high-pressure side of the model unit; the first exhaust pipe is connected to a valve I, the first air bleed pipe is connected to a valve II, and the first pressure bleed pipe is connected to a valve III; the second pressure stabilizing box is connected to a second air bleed pipe, a second pressure bleed pipe and a second exhaust pipe leading to the outside of the box, and the second air bleed pipe and the second pressure bleed pipe are respectively connected to the low-pressure side of the model unit; the second exhaust pipe is connected to a valve IV, the first air bleed pipe is connected to a valve V, and the first pressure bleed pipe is connected to a valve VI.

[0081] Based on the structure of the above test device, the test method includes: equipment assembly, equipment debugging, preliminary preparation for the test and carrying out lift test.

[0082] Equipment assembly includes the following steps:

[0083] S11, assembling a damping system by connecting a first control damper and a second control damper in parallel to form a damping system;

[0084] S12, installing a test pipeline, connecting a water temperature sensor, an electromagnetic flowmeter, and a damping system to the test pipeline in sequence, and connecting both ends of the test pipeline to the high-pressure side and the low-pressure side of the model unit, respectively, to form a closed-loop structure;

[0085] S13, connecting the lift measurement system, and connecting the two ends of the lift measurement system to the high-pressure side and the low-pressure side of the model unit based on the test pipeline.

[0086] Equipment commissioning includes the following steps:

[0087] S21, measurement duty factor for calibration head measurement system;

[0088] S22, using the lift measurement system to exhaust the air in the test pipeline, specifically: open valves I, II, III, IV, V, and VI, and use the first bleed pipe, the first pressure-inducing pipe, and the first exhaust pipe in conjunction with the first pressure-sustaining tank to exhaust the air from the high-pressure side of the model unit, and use the second bleed pipe, the second pressure-inducing pipe, and the second exhaust pipe in conjunction with the second pressure-sustaining tank to exhaust the air from the low-pressure side of the model unit; after the air is exhausted, close valves I, II, IV, and V, and keep valves III and VI open to determine whether the lift measurement system is in a zero state;

[0089] S23, judging whether the lift measurement system is in a zero state by the measured value of the differential pressure sensor; if so, completing the equipment debugging; if not, returning to the step of exhausting the air in the test pipeline by using the lift measurement system.

[0090] The preliminary preparation for the experiment includes the following steps:

[0091] S31, based on the principle of similarity conversion, according to the operating parameters of the prototype unit, setting the operating parameters of the model unit as simulation test conditions;

[0092] S32, determining a characteristic head according to the operating condition of the prototype unit, and adjusting a first control damper and a second control damper in the damping system according to the characteristic head;

[0093] S33, measuring the head of the model unit in real time through the head measurement system, and determining whether the head stability of the model unit under the current operating condition meets the IEC standard based on the measurement results. If so, maintaining the current operating condition of the model unit and completing the preliminary preparations for the test; if not, continuing to adjust the damping system until it meets the standard;

[0094] Conduct lift test: Under the simulated test conditions prepared in the early stage of the test and under the working conditions that meet the IEC standards, collect relevant test parameters to carry out relevant lift tests.

[0095] Example 4

[0096] This embodiment first discloses a pump head model test method, which is a preferred embodiment of the present invention and includes equipment assembly, equipment debugging, preliminary test preparation and carrying out a head test.

[0097] Equipment assembly includes the following steps:

[0098] S11, assemble the damping system, select a low-precision, large-range damping controller with a diameter of 300-700 mm as the first control damper, with a lift control range of 0-20 m and a lift control accuracy of 0.2 m; select a high-precision, small-range damping controller with a diameter of 50-100 mm as the second control damper, with a lift control range of 0-1 m and a lift control accuracy of 0.01 m; connect the first control damper and the second control damper in parallel to form a damping system;

[0099] S12, installing a test pipeline, connecting a water temperature sensor, an electromagnetic flowmeter, and a damping system to the test pipeline in sequence, and connecting both ends of the test pipeline to the high-pressure side and the low-pressure side of the model unit, respectively, to form a closed-loop structure;

[0100] S13, connecting the lift measurement system, and connecting the two ends of the lift measurement system to the high-pressure side and the low-pressure side of the model unit based on the test pipeline.

[0101] Equipment commissioning includes the following steps:

[0102] S21, calibrate the measurement working coefficient of the head measurement system. Specifically, different pressures are input into the differential pressure sensor of the head measurement system several times. This requires the use of external equipment (any equipment or method that can pressurize the differential pressure sensor as required), and record the corresponding measurement parameters of the differential pressure sensor under different pressures; input all pressures and measurement parameters into a computer; determine the measurement working coefficient of the head measurement system based on the linear relationship between pressure and measurement parameters. Specifically: the measurement parameter of the differential pressure sensor is an electrical signal, and there is a linear relationship between the electrical signal value and pressure. The slope of the linear relationship is the measurement working coefficient of the head measurement system. In the actual test process, the electrical signal value measured by the differential pressure sensor is multiplied by the measurement working coefficient, and combined with the relationship between head and pressure, the head parameter can be obtained, that is, the head measurement is achieved;

[0103] S22, using the lift measurement system to exhaust the air in the test pipeline, specifically: open valves I, II, III, IV, V, and VI, and use the first air bleed pipe, the first pressure bleed pipe, and the first exhaust pipe in conjunction with the first pressure stabilizing tank to exhaust the air on the high-pressure side of the model unit, and use the second air bleed pipe, the second pressure bleed pipe, and the second exhaust pipe in conjunction with the second pressure stabilizing tank to exhaust the air on the low-pressure side of the model unit; after the air is exhausted, close valves I, II, IV, and V, and keep valves III and VI open to determine whether the lift measurement system is in a zero state. During this period, under the connection of the first pressure bleed pipe and the second pressure bleed pipe, the energy of the first pressure stabilizing tank is equivalent to that of the high-pressure side of the model unit, and the energy of the second pressure stabilizing tank is equivalent to that of the low-pressure side of the model unit;

[0104] S23, judge whether the head measurement system is in the zero point state through the measurement value of the pressure difference sensor. Specifically, the differential pressure sensor measures the differential pressure between the first pressure stabilizing tank and the second pressure stabilizing tank to measure the static head of the model unit. The so-called zero point state, that is, the head of the model unit in the non-working state should be zero; if it is in the zero point state, the equipment debugging is completed. If it is not in the zero point state, it may be that the air in the test pipeline has not been completely discharged, and it is necessary to return to the step of using the head measurement system to discharge the air in the test pipeline, that is, return to step S22.

[0105] The preliminary preparation for the experiment includes the following steps:

[0106] S31, based on the principle of similarity conversion, set the operating parameters of the model unit according to the operating parameters of the prototype unit as the simulation test conditions. Specifically, the head height of the model unit does not exceed 60m, the speed is 900-1200r / min, the diameter of the runner lower ring is not less than 250mm, and the test water temperature is between 0-35℃, so as to meet the IEC standard of the test Reynolds number of not less than 4×10 6 requirements;

[0107] S32, determining a characteristic head according to the operating condition of the prototype unit, and adjusting a first control damper and a second control damper in the damping system according to the characteristic head. Specifically, first, adjusting the pressure in the test piping system to a pressure range corresponding to the test head range by using the first control damper; then, adjusting the pressure in the test piping system to a pressure corresponding to the target head by using the second control damper;

[0108] S33, measuring the head of the model unit in real time through the head measurement system, and determining whether the head stability of the model unit under the current operating condition meets the IEC standard based on the measurement results. If so, maintaining the current operating condition of the model unit and completing the preliminary preparations for the test; if not, continuing to adjust the damping system until it meets the standard;

[0109] Conduct lift test: Under the simulated test conditions prepared in the early stage of the test and under the working conditions that meet the IEC standards, collect relevant test parameters to carry out relevant lift tests.

[0110] Example 5

[0111] This embodiment first discloses a pump head model test method as a preferred embodiment of the present invention, that is, in Example 4, the head test includes a weighted efficiency test, that is, an efficiency test under the characteristic head of the water pump (here refers to the model unit) operating condition (that is, after adjusting the damping system in step S32, the characteristic head meets the IEC standard in step S33), mainly to obtain the weighted efficiency.

[0112] Before the weighted efficiency test, in step S32, after adjusting the first control damper, the corresponding pressure range is as follows: Figure 3 Among the three parallel vertical lines, the range between the vertical lines on both sides, after adjusting the second control damper, the pressure corresponding to the target head is as follows Figure 3 The middle vertical line position shown in the figure can achieve the purpose of accurately adjusting the target lift through the cooperation of the first control damper and the second control damper.

[0113] After the working conditions are stable (i.e. the fluctuation of the electromagnetic sensor measurement parameters is within the allowable range), the flow rate Q is recorded by the electromagnetic flowmeter, the head height H is obtained by the measurement parameters of the differential pressure sensor, the speed n and output torque M are recorded by the dynamometer inside the model unit, and the water temperature w is recorded by the water temperature sensor installed in the test pipeline. t During the whole test, the speed of the model unit is kept constant. When the guide vane opening is equal to different constants, the above steps are repeated to record the flow rate Q, head height H, model unit speed n, output torque M and water temperature w at different working conditions (different guide vane openings). t (w t Used to calculate the density of water ρ), according to the calculation formula of the efficiency of the pump working condition test point Obtain the original test data η of the efficiency of the pump under characteristic head conditions i , and record the original test data η of the pump operating characteristic head under all different operating conditions (different guide vane openings) i . Where g represents the gravity coefficient and ρ represents the water density.

[0114] The obtained test efficiency (i.e. the original test data of the efficiency of the pump under characteristic head condition) is calculated by the IEC (International Electrotechnical Commission) two-step method to obtain the efficiency η under the reference Reynolds number. m*i (m is the number of operating points, η m*i Represents the original test data η of efficiency under m operating points i ) and the efficiency η of the prototype unit under Reynolds number pi Conversion.

[0115] The weighted efficiency η pave is the efficiency η at each operating point pi The weighted sum is: Among them, w i is the efficiency weighting factor under each characteristic head, η pi is the prototype efficiency of the characteristic head (%).

[0116] Example 6

[0117] This embodiment first discloses a pump head model test method as a preferred embodiment of the present invention, that is, in Example 4, the head test includes a pressure pulsation characteristic test, that is, a pressure pulsation test under the characteristic head of the water pump (here refers to the model unit) operating condition (that is, after adjusting the damping system in step S32, the characteristic head meets the IEC standard in step S33), mainly to obtain the pressure pulsation characteristics.

[0118] Before the pressure pulsation characteristic test is carried out, in step S32, after adjusting the first control damper, the corresponding pressure range is as follows: Figure 7 Among the three parallel vertical lines, the range between the vertical lines on both sides, after adjusting the second control damper, the pressure corresponding to the target head is as follows Figure 7 The middle vertical line position shown in the figure can achieve the purpose of accurately adjusting the target lift through the cooperation of the first control damper and the second control damper.

[0119] After the working conditions are stable (i.e. the fluctuation of the measurement parameters of the electromagnetic sensor is within the allowable range), the pressure pulsation characteristics are measured by the pressure pulsation test system. Specifically, the pressure pulsation test system is a system outside the test device, which is mainly connected to the model unit through multiple sensors. Each sensor corresponds to a signal channel. The pressure pulsation test system completes the synchronous sampling of the signals of each channel, records the analog signal waveform in the time domain, and uses the FFT (Fast Fourier Transform) analysis method to perform spectrum analysis on the signal to determine the maximum frequency domain amplitude and its corresponding frequency; the sampling frequency of the pressure pulsation test system is 2000Hz, and the sampling time is 12 seconds; the pressure pulsation time domain amplitude adopts the maximum peak-to-peak value of the pressure pulsation within the time domain range, and the pressure pulsation time domain waveform recorded by the pressure pulsation test system is subjected to 97% confidence level mixed double peak calculation and FFT analysis. The calculation results are provided in the form of relative parameters, as shown below:

[0120]

[0121]

[0122]

[0123] Where ΔH represents the double amplitude of pressure pulsation (m), determined by 97% confidence level; H represents the height of the head (m); ff n represents the frequency ratio; f l represents the main frequency of pressure pulsation obtained by FFT analysis (Hz); f n represents the rotation frequency (Hz); (ΔH) f represents the pressure pulsation frequency domain amplitude (m); A represents the pressure pulsation time domain relative value (%); A f Represents the relative value of pressure pulsation frequency domain (%).

[0124] Example 7

[0125] This embodiment first discloses a pump head model test method as a preferred embodiment of the present invention. That is, in Example 4, the head test includes a cavitation test, mainly to obtain cavitation characteristics.

[0126] Before the cavitation test, in step S32, after adjusting the first control damper, the corresponding pressure range is as follows: Figure 6 Among the three parallel vertical lines, the range between the vertical lines on both sides, after adjusting the second control damper, the pressure corresponding to the target head is as follows Figure 6 The middle vertical line position shown in the figure can achieve the purpose of accurately adjusting the target lift through the cooperation of the first control damper and the second control damper.

[0127] The cavitation characteristics are based on the normal frequency variation range when the pump station has the highest and lowest heads. The test speed of the cavitation test is constant, and the cavitation reference surface is the center line of the guide vane. The critical cavitation coefficient and the primary cavitation coefficient of the water pump are tested by selecting characteristic operating points on the synergistic curve of the water pump (here refers to the model unit). The critical cavitation coefficient is σ 0.5 ,σ 0.5 It refers to the cavitation coefficient when the efficiency is reduced by 0.5% compared with the efficiency without cavitation. The critical cavitation test is determined by the energy method. The primary cavitation coefficient is σ i ,σ i The incipient cavitation coefficient is defined as the cavitation coefficient corresponding to the appearance of visible bubbles on the surfaces of the two impeller blades as the suction head decreases, that is, the vacuum degree in the draft tube increases. In the operating region greater than the optimal flow rate, the incipient cavitation coefficient is determined by combining visual observation with the noise method.

[0128] Example 8

[0129] This embodiment first discloses a pump head model test method as a preferred embodiment of the present invention, that is, in Example 4, the head test includes a maximum input test, that is, the energy test of the minimum characteristic head of the water pump (here refers to the model unit) corresponding to the grid frequency of 50.5Hz mainly obtains the maximum input.

[0130] Before the maximum input test, in step S32, after adjusting the first control damper, the corresponding pressure range is as follows Figure 4 Near the intersection of , after adjusting the second control damper, the pressure corresponding to the target head is as follows Figure 4 The intersection position is shown, and the purpose of accurately adjusting the target lift is achieved through the cooperation of the first control damper and the second control damper.

[0131] During the entire test, the speed of the model unit is kept constant, and the flow rate Q, head height H, model unit speed n, output torque M and water temperature w at the operating point are measured. t , record the original test data P of the pump's characteristic head under working conditions i The power obtained is converted into the maximum input power P after considering the efficiency within the maximum normal frequency variation range of the power station. max Calculation.

[0132] Furthermore, the head test also includes a unit flow characteristic test, which is obtained by converting the energy of the maximum and minimum characteristic heads of the water pump when the pump is connected to the corresponding grid at 50Hz. The test process is similar to the maximum input test, and the average flow obtained is the arithmetic mean of the flow at the maximum and minimum characteristic heads.

[0133] Example 9

[0134] This embodiment first discloses a pump head model test method, as a preferred embodiment of the present invention, that is, in Example 4, the head test includes a hump characteristic test, that is, an energy test at a hump angle, mainly to obtain hump performance, hump characteristics (see Appendix Figure 5 ) The coupling angle corresponding to the minimum flow rate (the flow rate corresponding to the maximum head) is used as the hump angle. While keeping the angle unchanged, starting from a lower head (corresponding to a larger flow rate, generally greater than the minimum flow rate), the test system damping is gradually increased until the hump characteristic fully appears. During this process, the flow characteristic is a process of gradually decreasing.

[0135] The hump angle is the coupling angle corresponding to the maximum gross head of the pump station (here refers to the unit model) at a grid frequency of 50Hz. This angle is determined by the pump coupling value method. The test process is to gradually increase the pipeline damping through the damping composite system, and the key points are precisely adjusted by a high-precision small-range damping controller. Specifically: in the area between the larger flow and the minimum flow, a low-precision large-range control damper is used to adjust the test pipeline damping to reduce the flow in a larger range. When approaching the minimum flow, a high-precision small-range control damper is used to continue to increase the system damping in a small range and slightly reduce the flow. After each adjustment, the flow Q, head height H, model unit speed n, output torque M and water temperature w of the measurement operating point are recorded after the system pressure stabilizes. t , until the hump characteristic fully appears, and finally calculate the hump margin ΔA%. Among them, the head data and flow data collected by the hump test are expressed by the pressure coefficient and flow coefficient respectively. Specifically, the pressure coefficient is expressed as: The flow coefficient is expressed as: Where, ψ represents the pressure coefficient; u represents the linear flow velocity, i.e., u = πnD / 60; It represents the flow coefficient and D represents the nominal diameter (m).

Claims

1. A pump head model test device, characterized by: The system comprises a model unit, a lift measurement system and a test pipeline, wherein the two ends of the test pipeline are respectively connected to the high-pressure side and the low-pressure side of the model unit, and the two ends of the lift measurement system are respectively connected to the high-pressure side and the low-pressure side of the model unit through the test pipeline; a damping system, an electromagnetic flowmeter and a water temperature sensor are connected in the test pipeline, and the damping system comprises a first control damper and a second control damper connected in parallel, and the first control damper and the second control damper are used to adjust the damping of the test pipeline; In the damping system, the first control damper is a low-precision, large-range damping controller with a diameter of 300-700 mm, whose lift control range is 0-20 m and lift control accuracy is 0.2 m; the second control damper is a high-precision, small-range damping controller with a diameter of 50-100 mm, whose lift control range is 0-1 m and lift control accuracy is 0.01 m; The lift measurement system includes a first pressure stabilizing box, a second pressure stabilizing box and a pressure differential sensor, and the two ends of the pressure differential sensor are respectively connected to the first pressure stabilizing box and the second pressure stabilizing box; the first pressure stabilizing box is connected to the first air bleed pipe, the first pressure bleed pipe and the first exhaust pipe leading to the outside of the box, and the first air bleed pipe and the first pressure bleed pipe are respectively connected to the high-pressure side of the model unit; the first exhaust pipe is connected to valve I, the first air bleed pipe is connected to valve II, and the first pressure bleed pipe is connected to valve III; the second pressure stabilizing box is connected to the second air bleed pipe, the second pressure bleed pipe and the second exhaust pipe leading to the outside of the box, and the second air bleed pipe and the second pressure bleed pipe are respectively connected to the low-pressure side of the model unit; the second exhaust pipe is connected to valve IV, the first air bleed pipe is connected to valve V, and the first pressure bleed pipe is connected to valve VI.

2. A pump head model test device and test method, characterized in that: A pump head model test device according to claim 1 is used, including: equipment assembly, equipment debugging, preliminary test preparation and carrying out head test; The equipment assembly comprises the following steps: Assembling a damping system by connecting a first control damper and a second control damper in parallel to form a damping system; Install the test pipeline, connect the water temperature sensor, electromagnetic flowmeter and damping system to the test pipeline in sequence, and connect the two ends of the test pipeline to the high-pressure side and low-pressure side of the model unit respectively to form a closed-loop structure; Connect the lift measurement system and connect the two ends of the lift measurement system to the high-pressure side and low-pressure side of the model unit based on the test pipeline; The equipment debugging includes the following steps: Calibrate the measurement duty factor of the head measurement system; Use the lift measurement system to exhaust the air in the test pipeline; The measured value of the differential pressure sensor is used to determine whether the lift measurement system is in the zero state. If so, the equipment commissioning is completed. If not, the process returns to the step of using the lift measurement system to exhaust the air in the test pipeline. The preliminary preparation for the experiment includes the following steps: Based on the principle of similarity conversion, the operating parameters of the model unit are set according to the operating parameters of the prototype unit as the simulation test conditions; determining a characteristic head according to the operating conditions of the prototype unit, and adjusting a first control damper and a second control damper in the damping system according to the characteristic head; The lift measurement system measures the lift of the model unit in real time. Based on the measurement results, it is determined whether the lift stability of the model unit under the current operating conditions meets the IEC standard. If so, the current operating conditions of the model unit are maintained and the preliminary preparations for the test are completed. If not, the damping system is continuously adjusted until the conditions are met. The lift test is carried out by collecting relevant test parameters under the simulated test conditions prepared in the early stage of the test and under the working conditions that meet the IEC standard to carry out the relevant lift test.

3. A pump head model test device and test method as claimed in claim 2, characterized in that: The process of assembling the damping system also includes selecting a control damper, namely: A low-precision, wide-range damping controller with a diameter of 300 to 700 mm is selected as the first control damper, with a head control range of 0 to 20 m and a head control accuracy of 0.2 m. A high-precision small-range damping controller with a diameter of 50 to 100 mm is selected as the second control damper. Its lift control range is 0 to 1 m and the lift control accuracy is 0.01 m.

4. A pump head model test device and test method as claimed in claim 3, characterized in that: During the preliminary preparation for the test, adjusting the first control damper and the second control damper in the damping system includes the following steps: First, the pressure in the test piping system is adjusted to a pressure range corresponding to the test head range through the first control damper; Then, the pressure in the test pipeline system is adjusted to the pressure corresponding to the target head through the second damper.

5. A pump head model test device and test method as claimed in claim 2, characterized in that: During the equipment commissioning process, calibrating the measurement working coefficient of the head measurement system includes the following steps: Input different pressures into the differential pressure sensor of the lift measurement system several times, and record the corresponding measurement parameters of the differential pressure sensor under different pressures; Input all pressure and measurement parameters into the computer; determine the measurement working coefficient of the head measurement system based on the linear relationship between pressure and measurement parameters.

6. A pump head model test device and test method as claimed in claim 2, characterized in that: During the equipment commissioning process, exhausting the air in the test pipeline using the lift measurement system includes the following steps: Open valves I, II, III, IV, V, and VI, and use the first air bleed pipe, the first pressure bleed pipe, and the first exhaust pipe in conjunction with the first pressure stabilizing tank to exhaust the air on the high-pressure side of the model unit. Use the second air bleed pipe, the second pressure bleed pipe, and the second exhaust pipe in conjunction with the second pressure stabilizing tank to exhaust the air on the low-pressure side of the model unit. After the air is exhausted, close valves I, II, IV, and V, and keep valves III and VI open to determine whether the head measurement system is in the zero state.

7. A pump head model test device and test method as claimed in claim 2, characterized in that: During the preliminary preparation for the test, the simulated test conditions include: the lift height of the model unit does not exceed 60m, the rotation speed is 900~1200r / min, the diameter of the impeller lower ring is not less than 250mm, and the test water temperature is between 0-35℃.

8. A pump head model test device and test method as claimed in claim 2, characterized in that: During the lift test, the lift test includes any one or more of a weighted efficiency test, a pressure pulsation characteristic test, a cavitation test, a maximum input test, and a hump characteristic test.

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