Liquid cargo pump test system and test method

Abstract

The invention provides a liquid cargo pump test system and test method, and belongs to the technical field of ship equipment. The liquid cargo pump test system comprises a pump test tank, a test pump, a suction pipeline, a discharge pipeline, a storage tank, a first temperature sensor, a second temperature sensor, a first pressure sensor, a second pressure sensor, a first flow meter and a second flow meter. The first end of the suction pipeline is connected to the bottom of the storage tank, the second end of the suction pipeline is connected to the side wall of the pump test tank, the first end of the discharge pipeline is connected with an output port of the test pump, the second end of the discharge pipeline is connected to the side wall of the storage tank, and the bottom of the storage tank is higher than the top of the pump test tank in the vertical direction; the first temperature sensor, the first pressure sensor and the first flow meter are connected to the suction pipeline, and the second temperature sensor, the second pressure sensor and the second flow meter are connected to the discharge pipeline. The working environment of the liquid cargo pump can be simulated, and the performance of the test pump can be detected.

Description

Technical Field

[0001] The present disclosure relates to the technical field of ship equipment, and in particular to a liquid cargo pump test system and test method. Background Art

[0002] Under the background of global green, low-carbon and energy transformation, the supply and demand of LNG (Liquefied Natural Gas), which is clean, stable and safe, has grown rapidly, and has won the favor of most countries and energy giants. Therefore, the equipment for transmitting LNG has attracted attention, especially the submersible liquid cargo pumps for transporting and transferring LNG.

[0003] In the related art, when a liquid cargo pump is transporting LNG, the liquid cargo pump needs to be immersed in the bottom of the liquid cargo tank to complete the transfer from the liquid cargo tank to the LNG receiving station.

[0004] Since the temperature of LNG is usually minus 165℃, the working temperature requirement for liquid cargo pumps is extremely high. Therefore, designing a test system that fits the actual working environment has extremely high practical engineering significance and can provide guarantee for the safe and efficient operation of the liquid cargo pumps under actual conditions. Summary of the invention

[0005] The disclosed embodiment provides a liquid cargo pump test system and test method, which can simulate the working environment of the liquid cargo pump and detect the performance of the test pump to ensure the safety of the liquid cargo pump during actual use. The technical solution is as follows:

[0006] An embodiment of the present disclosure provides a liquid cargo pump test system, which includes: a pump test tank, a test pump, a suction pipe, a discharge pipe, a storage tank, a first temperature sensor, a second temperature sensor, a first pressure sensor, a second pressure sensor, a first flow meter and a second flow meter; the first end of the suction pipe is connected to the bottom of the storage tank, the second end of the suction pipe is connected to the side wall of the pump test tank, the test pump is located in the pump test tank, the first end of the discharge pipe is connected to the output port of the test pump, the second end of the discharge pipe is connected to the side wall of the storage tank, and in the vertical direction, the bottom of the storage tank is higher than the top of the pump test tank; the first temperature sensor, the first pressure sensor and the first flow meter are connected to the suction pipe, and the second temperature sensor, the second pressure sensor and the second flow meter are connected to the discharge pipe.

[0007] In an implementation of the embodiment of the present disclosure, the suction pipe and the discharge pipe both include an outer tube and an inner tube that are concentrically distributed, and a heat insulation material layer is provided between the outer tube and the inner tube.

[0008] In another implementation of the embodiment of the present disclosure, the space between the inner wall and the outer wall of the storage tank is filled with insulation material.

[0009] In another implementation of the embodiment of the present disclosure, the length L1 of the suction pipe is 2n×(8~10)×D1, wherein n is the number of valves on the suction pipe, and D1 is the diameter of the suction pipe; the length L2 of the discharge pipe is 2N×(8~10)×D2, wherein N is the number of valves on the discharge pipe, and D2 is the diameter of the discharge pipe.

[0010] In another implementation of the embodiment of the present disclosure, the liquid cargo pump test system also includes: a liquefaction converter and a one-way valve, the air inlet of the liquefaction converter is connected to the top of the storage tank through a pipe, the discharge port of the liquefaction converter is connected to the top of the storage tank through a pipe, and the one-way valve is connected to the pipeline between the discharge port of the liquefaction converter and the top of the storage tank.

[0011] In another implementation of the embodiment of the present disclosure, the liquid cargo pump test system further includes a differential pressure sensor, and the differential pressure sensor is connected to the discharge pipe.

[0012] An embodiment of the present disclosure provides a test method for a liquid cargo pump, which is implemented using the liquid cargo pump test system as described above, including: controlling the test pump to operate at a set speed; controlling the valve opening of the suction pipe to adjust the flow of the suction pipe to different test values; determining the performance parameters of the test pump under different test values, the performance parameters including at least one of head, shaft power and efficiency; fitting a performance curve based on the test values ​​and the performance parameters, the performance curve being a curve about flow and performance parameters.

[0013] In another implementation of the embodiment of the present disclosure, the lift of the test pump is determined using the following formula:

[0014]

[0015] In formula (1), H is the head of the test pump, P d The outlet pressure of the test pump, in Pa, P s is the inlet pressure of the test pump, in Pa, γ d is the temperature specific gravity of the outlet of the test pump, γ s is the temperature specific gravity of the wellhead of the test pump, h is the vertical distance between the first pressure sensor and the second pressure sensor, in m, V d V is the outlet flow rate of the test pump, in m / s. s is the inlet flow rate of the test pump, in m / s, and g is the acceleration due to gravity.

[0016] In another implementation of the embodiment of the present disclosure, the test value includes at least the rated flow rate of the test pump, and the difference between adjacent test values ​​is less than or equal to 6% of the rated flow rate of the test pump.

[0017] In another implementation of the embodiment of the present disclosure, after fitting the performance curve based on the test value and the performance parameter, it also includes: installing a vacuum pumping device in the suction pipe; controlling the valve opening of the suction pipe to adjust the flow rate of the suction pipe to different test values; under different test values, controlling the vacuum pumping device to suck the suction pipe so that the pressure value of the suction pipe drops by a threshold value, and calculating the head of the test pump under different pressure values; if the difference in the head of the test pump under two adjacent pressure values ​​exceeds 3% of the larger pressure value, it is determined that cavitation has occurred.

[0018] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include at least:

[0019] In the liquid cargo pump test system provided by the embodiment of the present disclosure, the pump test tank and the storage tank are connected together through the suction pipe and the discharge pipe. In addition, the bottom of the storage tank is higher than the top of the pump test tank, so that the LNG in the storage tank can flow into the pump test tank through the suction pipe, and the test pump in the pump test tank sucks the LNG to the discharge pipe, and transports it from the discharge pipe to the storage tank, thereby forming a test loop for the test pump to transport LNG. The pump test tank is set to collect the LNG flowing out of the storage tank, and the test pump is placed in the pump test tank. Therefore, the test tank simulates the extremely cold working environment of the liquid cargo pump, so that the test results can conform to the actual working environment and have a high reference value.

[0020] At the same time, temperature sensors, pressure sensors and flow meters are installed on the suction pipe and the discharge pipe. Therefore, the temperature, pressure and flow parameters of the inlet and outlet of the test pump can be detected. In this way, the head of the test pump at different flow rates can be determined according to the detected parameters, so as to judge whether the test pump can meet the use requirements in this extremely cold working environment based on the head. It provides a test platform for realizing LNG transfer and transportation, ensuring that the liquid cargo pump can operate safely and efficiently under actual conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 is a schematic diagram of a liquid cargo pump test system provided by an embodiment of the present disclosure;

[0023] Figure 2 is a partial schematic diagram of a test system for a liquid cargo pump provided in an embodiment of the present disclosure;

[0024] Figure 3 is a partial schematic diagram of a test system for a liquid cargo pump provided in an embodiment of the present disclosure;

[0025] Figure 4 It is a flow chart of a test method of a liquid cargo pump provided in an embodiment of the present disclosure.

[0026] The descriptions of the marks in the figure are as follows:

[0027] 10. Pump test tank;

[0028] 20. Test pump;

[0029] 31. Suction pipe; 32. Discharge pipe;

[0030] 40. Storage tank;

[0031] 51. a first temperature sensor; 52. a second temperature sensor;

[0032] 61. A first pressure sensor; 62. A second pressure sensor;

[0033] 71. a first flow meter; 72. a second flow meter;

[0034] 81. Liquefaction converter; 82. Check valve;

[0035] 91. Differential pressure sensor; 92. Exhaust pipe; 93. Exhaust valve; 94. Filling valve; 95. Liquid level gauge; 96. Reflux pipe. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0037] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top", "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] Figure 1 Schematic diagram of a liquid cargo pump test system provided by an embodiment of the present disclosure. Figure 1 As shown, the liquid cargo pump test system includes: a pump test tank 10, a test pump 20, a suction pipe 31, a discharge pipe 32, a storage tank 40, a first temperature sensor 51, a second temperature sensor 52, a first pressure sensor 61, a second pressure sensor 62, a first flow meter 71 and a second flow meter 72.

[0039] like Figure 1 As shown, the first end of the suction pipe 31 is connected to the bottom of the storage tank 40, the second end of the suction pipe 31 is connected to the side wall of the pump test tank 10, the test pump 20 is located in the pump test tank 10, the first end of the discharge pipe 32 is connected to the output port of the test pump 20, the second end of the discharge pipe 32 is connected to the side wall of the storage tank 40, and in the vertical direction, the bottom of the storage tank 40 is higher than the top of the pump test tank 10.

[0040] like Figure 1 As shown, the first temperature sensor 51 , the first pressure sensor 61 and the first flow meter 71 are connected to the suction pipe 31 , and the second temperature sensor 52 , the second pressure sensor 62 and the second flow meter 72 are connected to the discharge pipe 32 .

[0041] In the liquid cargo pump test system provided by the embodiment of the present disclosure, the pump test tank 10 and the storage tank 40 are connected together through the suction pipe 31 and the discharge pipe 32. In addition, the bottom of the storage tank 40 is higher than the top of the pump test tank 10, so that the LNG in the storage tank 40 can flow into the pump test tank 10 through the suction pipe 31, and the test pump in the pump test tank 10 sucks the LNG to the discharge pipe 32, and transports it from the discharge pipe 32 to the storage tank 40, thereby forming a test loop for the test pump to transport LNG. The pump test tank 10 is set to collect the LNG flowing out of the storage tank 40, and the test pump is placed in the pump test tank 10. Therefore, the test tank simulates the extremely cold working environment of the liquid cargo pump, so that the test results can conform to the actual working environment and have a high reference value.

[0042] At the same time, temperature sensors, pressure sensors and flow meters are set on the suction pipe 31 and the discharge pipe 32. Therefore, the temperature, pressure and flow parameters of the inlet and outlet of the test pump can be detected. In this way, the head of the test pump at different flow rates can be determined according to the detected parameters, so as to judge whether the test pump can meet the use requirements in such an extremely cold working environment based on the head. A test platform is provided for realizing LNG transfer and transportation, ensuring that the liquid cargo pump can operate safely and efficiently under actual conditions.

[0043] Optionally, both the suction pipe 31 and the discharge pipe 32 include an outer tube and an inner tube that are concentrically distributed, and a heat insulation material layer is provided between the outer tube and the inner tube.

[0044] By setting each pipe in the liquid cargo pump test system as a double-layer pipe and setting a heat insulation material layer between the outer pipe and the inner core pipe, the rapid transfer of heat can be effectively blocked. This prevents the LNG at minus 165℃ in the inner core pipe from absorbing heat and causing temperature changes, which affects the working environment of the test pump.

[0045] Exemplarily, the heat insulating material may be at least one of melamine resin foam, glass fiber wool board and rubber powder polystyrene particle insulation slurry.

[0046] Exemplarily, a melamine resin foam layer is sandwiched between the outer tube and the inner core tube.

[0047] Alternatively, if Figure 1 As shown, the space between the inner wall and the outer wall of the storage tank 40 is filled with a heat insulating material.

[0048] Exemplarily, the storage tank 40 may include an inner tank body and an outer tank body, and the heat insulation material is located between the inner tank body and the outer tank body, which can prevent rapid heat transfer and improve the heat preservation effect of the storage tank 40.

[0049] Exemplarily, the outer wall of the storage tank 40 is provided with a plurality of grooves, and the plurality of grooves are arranged at intervals. The heat insulating material is filled in the grooves, so that the heat insulating material can be attached to the surface of most of the storage tank 40, thereby improving the heat preservation effect.

[0050] Exemplarily, the outer wall of the storage tank 40 is surrounded by a layer of heat-insulating material. This method of laying the heat-insulating material can more comprehensively wrap the storage tank 40, which not only reduces the difficulty of preparing the storage tank 40 but also effectively improves the thermal insulation performance of the storage tank 40.

[0051] Optionally, the length L1 of the suction pipe 31 is equal to 2n×(8-10)×D1, wherein n is the number of valves on the suction pipe 31, and D1 is the diameter of the suction pipe 31.

[0052] Since the length of the pipeline has a significant impact on the test of the test pump, especially the suction effect, the suction pipeline 31 of the liquid cargo pump test system is left 8 to 10 times the diameter before and after the valve. Keeping the pipeline short can reduce the pressure drop at the suction port as much as possible, and the straight pipe section can make the flow rate of the fluid in the pipeline uniform.

[0053] In addition, the flow pattern in the pipeline before and after the valve is relatively turbulent under rated and large flow conditions. In order to maintain a better inlet flow pattern and achieve better pump testing results, the length of the suction pipeline 31 must be 8 to 10 times the diameter and must also be multiplied by twice the number of valves, so that the flow pattern in the suction pipeline 31 is more stable and easier to test.

[0054] Exemplarily, the diameter of the suction pipe 31 is 400 mm. In order to balance the cost and friction loss, the suction pipe 31 adopts a pipe of equal diameter.

[0055] Figure 2 FIG. 1 is a partial schematic diagram of a test system for a liquid cargo pump provided by an embodiment of the present disclosure. Figure 2 As shown, in the test system, a valve is provided on the suction pipe 31. Therefore, the length of the suction pipe 31 is L1 = 2n×(8-10)×D1 = 2×(8-10)×0.4 = 6.4m to 8m.

[0056] Optionally, the length L2 of the discharge pipe 32 is 2N×(8-10)×D2, wherein N is the number of valves on the discharge pipe 32, and D2 is the diameter of the discharge pipe 32.

[0057] Since the length of the pipeline has a significant impact on the test of the test pump, the discharge pipeline 32 of the liquid cargo pump test system is left 8 to 10 times the diameter before and after the valve. Keeping the pipeline short can reduce the pressure drop at the suction port as much as possible, and the straight pipe section can make the flow rate of the fluid in the pipeline uniform.

[0058] In addition, the flow pattern in the pipeline before and after the valve is relatively turbulent under rated and large flow conditions. In order to maintain a better flow pattern, the test pump is discharged to achieve a better test effect. In addition to being 8 to 10 times the diameter, the length of the discharge pipeline 32 also needs to be multiplied by twice the number of valves, so that the flow pattern in the discharge pipeline 32 is more stable and convenient for testing.

[0059] Exemplarily, the diameter of the discharge pipe 32 is 350 mm. In order to balance the cost and friction loss, the discharge pipe 32 adopts a pipe of equal diameter.

[0060] Figure 3 FIG. 1 is a partial schematic diagram of a test system for a liquid cargo pump provided by an embodiment of the present disclosure. Figure 3 As shown, in the test system, two valves are provided on the discharge pipe 32. Therefore, the length of the discharge pipe 32 is L2 = 2N x (8 to 10) x D2 = 4 x (8 to 10) x 0.35 = 11.2 m to 14 m.

[0061] Alternatively, if Figure 1 As shown, the liquid cargo pump test system also includes: a liquefaction converter 81 and a one-way valve 82, the air inlet of the liquefaction converter 81 is connected to the top of the storage tank 40 through a pipeline, the discharge port of the liquefaction converter 81 is connected to the top of the storage tank 40 through a pipeline, and the one-way valve 82 is connected to the pipeline between the discharge port of the liquefaction converter 81 and the top of the storage tank 40.

[0062] Exemplarily, the liquefaction converter 81 may be a liquefier, which can reliquefy the vaporized LNG, thereby recovering the vaporized LNG.

[0063] In the above implementation, the liquefaction converter 81 is connected to the top of the storage tank 40 through a pipeline, so that after the gasified LNG is collected at the top of the storage tank 40, it can flow into the liquefaction converter 81 along the pipeline, and after being liquefied by the liquefaction converter 81, the LNG is then converged to the storage tank 40 through the one-way valve 82. The one-way valve 82 is provided to prevent the gasified LNG from entering the liquefaction converter 81 from the outlet of the liquefaction converter 81, thereby affecting the liquefaction of the LNG.

[0064] For example, Figure 1 As shown, the liquid cargo pump test system further includes an exhaust pipe 92 and an exhaust valve 93. The first end of the exhaust pipe 92 is connected to the top of the storage tank 40, and the second end of the exhaust pipe 92 is provided with an exhaust valve 93. When the gasified LNG in the storage tank 40 is too large and the pressure is high, the exhaust valve 93 can be opened to discharge the gasified LNG.

[0065] For example, Figure 1 As shown, a filling valve 94 is also provided at the bottom of the storage tank 40 through a pipeline, and the filling valve 94 is used to inject LNG into the storage tank 40 .

[0066] For example, Figure 1 As shown, a liquid level gauge 95 is provided on both the storage tank 40 and the pump test tank 10 , and the volume of the LNG in the storage tank 40 and the pump test tank 10 can be observed in real time through the liquid level gauge 95 .

[0067] For example, Figure 1 As shown, a return pipe 96 is further provided between the pump test tank 10 and the storage tank 40, the first end of the return pipe 96 is connected to the top of the pump test tank 10, and the second end of the return pipe 96 is connected to the side wall of the storage tank 40. In this way, when the LNG in the pump test tank 10 overflows, the LNG can flow back to the storage tank 40 along the return pipe 96 to prevent the problem of LNG leakage.

[0068] Alternatively, if Figure 1 As shown, the liquid cargo pump test system also includes a differential pressure sensor 91 , which is connected to the discharge pipe 32 .

[0069] The pressure change of the fluid test section is checked by setting a pressure difference sensor 91 to determine the accuracy of the value of the outlet pressure sensor. If the pressure difference is zero, it means that the pressure fluctuation of the section is good and the data accuracy is high. Therefore, the closer the pressure difference is to zero, the higher the reliability of the data.

[0070] Figure 4 1 is a flow chart of a test method for a liquid cargo pump provided in an embodiment of the present disclosure. The test method is implemented using the liquid cargo pump test system as described above. Figure 4 As shown, the test method includes:

[0071] Step S11: Control the test pump to operate at a set speed.

[0072] Step S12: Control the valve opening of the suction pipe 31 to adjust the flow rate of the suction pipe 31 to different test values.

[0073] Step S13: Determine the performance parameters of the test pump under different test values.

[0074] The performance parameter includes at least one of lift, shaft power and efficiency.

[0075] Step S14: Fitting a performance curve based on the test values ​​and the performance parameters.

[0076] The performance curve is a curve about flow rate and performance parameters.

[0077] When testing the liquid cargo pump, the liquid cargo pump test system provided by the embodiment of the present disclosure can detect the temperature, pressure and flow parameters of the inlet and outlet of the test pump by using the temperature sensor, pressure sensor and flow meter arranged on the suction pipe 31 and the discharge pipe 32. In this way, the performance parameters of the test pump at different flow rates can be determined according to the detected parameters. Thus, the performance curve can be fitted according to the test value and the performance parameter. In this way, when the technician judges whether the test pump can meet the working requirements, he inputs the corresponding flow rate, that is, obtains the corresponding performance parameters, and thus determines whether the requirements are met according to the size of the performance parameters, which can ensure that the liquid cargo pump operates safely and efficiently under actual conditions.

[0078] In the embodiment of the present disclosure, liquid nitrogen (temperature -196°C, density 0.808 kg / m 3 ) can be used as the test medium, or LNG can be used as the test medium.

[0079] For example, the rated parameters of the test pump that can be selected are: speed 1800rpm, flow rate 1850m 3 / h, head 165m.

[0080] In step S11, the rotation speed of the test pump is controlled to be 1800 (±2%) r / min.

[0081] During the test, the working time of the test pump is controlled to be greater than or equal to 1.5h.

[0082] In step S12, the test value at least includes the rated flow rate of the test pump, and the difference between adjacent test values ​​is less than or equal to 6% of the rated flow rate of the test pump.

[0083] Optionally, the number of test values ​​may be greater than or equal to seven.

[0084] Exemplarily, the selected test value may include 185m 3 / h、370m 3 / h、555m 3 / h、740m 3 / h、925m 3 / h、1110m 3 / h、1295m 3 / h、1480m 3 / h、1665m 3 / h、1776m 3 / h、1850m 3 / h and 2220m 3 / h.

[0085] Since 1850m 3 / h is the rated flow rate of the test pump, so the test value needs to include the rated flow rate of the test pump.

[0086] In step S13, the shaft power of the test pump is determined using the following formula:

[0087]

[0088] In formula (1), H is the head of the test pump, P d The outlet pressure of the test pump, in Pa, P s is the inlet pressure of the test pump, in Pa, γ d is the temperature specific gravity of the outlet of the test pump, γ s is the temperature specific gravity of the wellhead of the test pump, h is the vertical distance between the first pressure sensor 61 and the second pressure sensor 62, in m, V d V is the outlet flow rate of the test pump, in m / s. s is the inlet flow rate of the test pump, in m / s, and g is the acceleration due to gravity.

[0089] For example, the outlet pressure of the test pump may be measured by a second pressure sensor 62 of the discharge conduit 32 .

[0090] Exemplarily, the inlet pressure of the test pump may be measured by a first pressure sensor 61 of the suction pipe 31 .

[0091] Among them, the temperature ratio is the relative density of liquid LNG at the current temperature.

[0092] For example, the temperature specific gravity of the outlet of the test pump can be obtained by looking up the table according to the temperature measured by the second temperature sensor 52 of the discharge pipe 32 .

[0093] Exemplarily, the temperature specific gravity of the inlet of the test pump can be obtained by looking up the table according to the temperature measured by the first temperature sensor 51 of the suction pipe 31 .

[0094] Illustratively, the outlet flow rate of the test pump may be measured by a second flow meter 72 of the discharge conduit 32 .

[0095] Illustratively, the wellhead flow rate of the test pump may be measured by a first flow meter 71 of the suction pipe 31 .

[0096] In step S13, the lift of the test pump is determined using the following formula: P = (n*N) / 9550 (2)

[0097] In formula (2), P is the shaft power, n is the speed, the unit is r / min, and N is the torque, the unit is N*m.

[0098] The efficiency of the test pump is determined in step S13 using the following formula: η = ρgQH / (1000*3600*P) (3)

[0099] In formula (3), η is efficiency; ρ is density, unit Kg / m 3 ; g is the acceleration due to gravity, unit: 9.8m 3 / s; Q is flow rate, unit is m 3 / h; H is the head, unit is m.

[0100] The head H can be calculated using formula (1):

[0101] The performance curves in step S14 may include H=f(Q) (flow-head curve), Pa=f(Q) (flow-shaft power curve) and η=f(Q) (flow-efficiency curve).

[0102] When it is necessary to judge the performance of the test pump based on the curve, firstly, it is determined whether the pump meets the performance index based on the design input parameters of the test pump.

[0103] For example, the design requires that the test pump reach a head of 165m and an efficiency of 78% at the rated flow rate. At this time, the rated flow rate is input into the flow-head curve to calculate the corresponding head value; the rated flow rate is input into the flow-efficiency curve to calculate the corresponding efficiency. By judging whether the head and efficiency of the test pump can reach the head and efficiency required by the design, it can be judged whether the test pump can meet the actual use requirements.

[0104] Then, for the flow-head curve, you can observe whether the performance curves are smooth. If the curve is smoother and has no obvious twists and turns, it means that the head variation of the test pump is smaller and the performance is higher. For the flow-efficiency curve, you can observe the width of the high-efficiency zone. If the high-efficiency zone is wider, it means that the test pump has a high working efficiency.

[0105] After fitting the performance curve in step S14, the test method further includes a cavitation test. Specifically, the following steps may be included:

[0106] First, a vacuum device is installed on the suction pipe 31 .

[0107] Exemplarily, the vacuum pump may be a vacuum pump or other equipment, and the vacuum pump may be connected to the suction pipe 31 through a pipeline. The vacuum pump may be used to extract the gas in the suction pipe 31, so that the pressure in the suction pipe 31 can be reduced.

[0108] Then, the valve opening of the suction pipe 31 is controlled to adjust the flow rate of the suction pipe 31 to different test values.

[0109] For example, the rated speed of the test pump is 1800 (±2%) r / min, and the test values ​​may include three, namely, 1480m / min and 3 / h、1850m 3 / h and 2220m3 / h.

[0110] Next, under different test values, the vacuum device is controlled to suck the suction pipe 31 so that the pressure value of the suction pipe 31 drops by a threshold value, and the lift of the test pump under different pressure values ​​is calculated.

[0111] The threshold value may be 0.1 atm. The vacuum device controls the pressure in the suction pipe 31 to drop by 0.1 atm at a time.

[0112] Then, a judgment is made: if the difference in the head of the test pump at two adjacent pressure values ​​exceeds 3% of the larger pressure value, it is determined that cavitation occurs.

[0113] Finally, record the data and draw the H-NPSH (head-cavitation margin) and NPSHr-Q (cavitation margin-flow) curves, and repeat each test value 3 times.

[0114] For example, NPSHr = (p-1026.42) / ρg, where p is the pressure of the suction pipe 31, in Pa; ρ is the density, in Kg / m 3 ; g is the acceleration due to gravity, unit: 9.8m 3 / s.

[0115] Optionally, the test method also includes a starting current test.

[0116] Specifically, it may include: at the beginning of the performance test, a dual-channel oscilloscope is used to observe and record the starting current. The test should be conducted at 100% voltage and in the test liquid. If the starting current is less than 4400A, it is qualified.

[0117] Optionally, the test method further includes disassembly and inspection before and after the test.

[0118] The LNG pump is disassembled and inspected after factory testing to check the wear of various operating parts of the LNG pump.

[0119] Specifically, it can include: checking the matching size between the impeller and the lower ring; checking the matching size between the impeller and the upper ring; checking the matching size between the bearing and the bearing sleeve. There should be no obvious signs of bite or excessive wear on the surface of the parts, and the structural dimensions and matching clearance of each part are still within the required range.

[0120] The above does not limit the present disclosure in any form. Although the present disclosure has been disclosed as above through the embodiments, it is not used to limit the present disclosure. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present disclosure. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present disclosure without departing from the content of the technical solution of the present disclosure still falls within the scope of the technical solution of the present disclosure.

Claims

1. A liquid cargo pump test system, characterized in that: The liquid cargo pump test system comprises: a pump test tank (10), a test pump (20), a suction pipe (31), a discharge pipe (32), a storage tank (40), a first temperature sensor (51), a second temperature sensor (52), a first pressure sensor (61), a second pressure sensor (62), a first flow meter (71) and a second flow meter (72); The first end of the suction pipe (31) is connected to the bottom of the storage tank (40), the second end of the suction pipe (31) is connected to the side wall of the pump test tank (10), the test pump (20) is located in the pump test tank (10), the first end of the discharge pipe (32) is connected to the output port of the test pump (20), the second end of the discharge pipe (32) is connected to the side wall of the storage tank (40), and in the vertical direction, the bottom of the storage tank (40) is higher than the top of the pump test tank (10); The first temperature sensor (51), the first pressure sensor (61) and the first flow meter (71) are connected to the suction pipe (31), and the second temperature sensor (52), the second pressure sensor (62) and the second flow meter (72) are connected to the discharge pipe (32).

2. The liquid cargo pump test system according to claim 1, characterized in that: The suction pipe (31) and the discharge pipe (32) both comprise an outer tube and an inner tube which are concentrically distributed, and a heat insulation material layer is provided between the outer tube and the inner tube.

3. The liquid cargo pump test system according to claim 1, characterized in that: The space between the inner wall and the outer wall of the storage tank (40) is filled with heat insulation material.

4. The liquid cargo pump test system according to any one of claims 1 to 3, characterized in that: The length L1 of the suction pipe (31) = 2n×(8-10)×D1, wherein n is the number of valves on the suction pipe (31), and D1 is the diameter of the suction pipe (31); The length L2 of the discharge pipe (32) = 2N×(8-10)×D2, wherein N is the number of valves on the discharge pipe (32), and D2 is the diameter of the discharge pipe (32).

5. The liquid cargo pump test system according to any one of claims 1 to 3, characterized in that: The liquid cargo pump test system further comprises: a liquefaction converter (81) and a one-way valve (82); an air inlet of the liquefaction converter (81) is connected to the top of the storage tank (40) via a pipeline; a liquid discharge port of the liquefaction converter (81) is connected to the top of the storage tank (40) via a pipeline; and the one-way valve (82) is connected to the pipeline between the liquid discharge port of the liquefaction converter (81) and the top of the storage tank (40).

6. The liquid cargo pump test system according to any one of claims 1 to 3, characterized in that: The liquid cargo pump test system further comprises a differential pressure sensor (91), wherein the differential pressure sensor (91) is connected to the discharge pipe (32).

7. A test method for a liquid cargo pump, characterized in that: The test method is implemented by using the liquid cargo pump test system according to any one of claims 1 to 6, comprising: Control the test pump to work at a set speed; Controlling the valve opening of the suction pipeline (31) to adjust the flow rate of the suction pipeline (31) to different test values; Determining the performance parameters of the test pump under different test values, wherein the performance parameters include at least one of head, shaft power and efficiency; A performance curve is fitted based on the test value and the performance parameter, where the performance curve is a curve about flow rate and performance parameter.

8. The test method according to claim 7, characterized in that: The head of the test pump is determined using the following formula: In formula (1), H is the head of the test pump, P d The outlet pressure of the test pump, in Pa, P s is the inlet pressure of the test pump, in Pa, γ d is the temperature specific gravity of the outlet of the test pump, γ s is the temperature specific gravity of the wellhead of the test pump, h is the vertical distance between the first pressure sensor (61) and the second pressure sensor (62), in m, V d V is the outlet flow rate of the test pump, in m / s. s is the inlet flow rate of the test pump, in m / s, and g is the acceleration due to gravity.

9. The test method according to claim 7, characterized in that: The test value at least includes the rated flow rate of the test pump, and the difference between adjacent test values ​​is less than or equal to 6% of the rated flow rate of the test pump.

10. The test method according to any one of claims 7 to 9, characterized in that: After fitting the performance curve based on the test value and the performance parameter, the method further includes: A vacuum device is installed on the suction pipe (31); Controlling the valve opening of the suction pipe (31) to adjust the flow rate of the suction pipe (31) to different test values; Under different test values, controlling the vacuum pump to suck the suction pipe (31) so that the pressure value of the suction pipe (31) drops by a threshold value, and calculating the head of the test pump under different pressure values; If the difference in lift of the test pump at two adjacent pressure values ​​exceeds 3% of the larger pressure value, it is determined that cavitation occurs.

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