Booster pump high-pressure test system

Abstract

The invention relates to the technical field of booster pump tests, in particular to a booster pump high-pressure test system. The system comprises a large circulation pipeline, a water storage assembly, a booster pump, a tested booster pump, a main pipeline adjusting valve and a pressurization adjusting valve are sequentially installed on the large circulation pipeline in the medium flowing direction, and a one-way backflow pipeline is connected to the large circulation pipeline in parallel. A first node and a second node of the one-way backflow pipeline are located at the output end of the main pipeline adjusting valve and the output end of the booster pump respectively, and media of the one-way backflow pipeline flow towards the output end of the booster pump. In the test process, a high-pressure condition can be provided for an inlet of the booster pump, continuous high-power operation of the booster pump is not needed, the cost in the test process is greatly reduced, and the service life of the booster pump is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of booster pump testing, in particular to a booster pump high-pressure testing system. Background Art

[0002] A booster pump is a pump commonly used to transport high-pressure media, boosting the high-pressure fluid to a higher pressure and transporting it to the destination. When the booster pump is working, the inlet pressure is very high. Compared with conventional imported low-pressure pumps, the local structure of the booster pump needs to be adaptively optimized and improved to meet the operating conditions of the imported high pressure, so as to increase the service life of the booster pump.

[0003] Therefore, during the test and inspection of the booster pump, the inlet high-pressure test conditions of the booster pump are often simulated to test the performance reliability of the booster pump under the inlet high-pressure working conditions and the high-pressure difference operation stability and other indicators.

[0004] like Figure 2 As shown, the existing booster pump test system mainly includes a test pipeline d connected end to end. Along the direction of medium flow, the test pipeline d is installed with a water tank a, a pre-pump 12, and a test booster pump 13. In addition, the outlet of the pre-pump 12 is provided with a branch b connected to the water tank a, and a control valve c is installed on branch b. During the test, the pre-pump 12 is used to boost the pressure and supply water to the inlet of the test booster pump 13, providing high-pressure test conditions at the inlet of the test booster pump 13. At the same time, the control valve c on branch b is used to distribute the flow of the pre-pump 12 through the test booster pump 13 and branch b, achieving precise regulation of the inlet pressure of the test booster pump 13. In this layout, the pre-pump 12 needs to provide medium not only to the test booster pump 13, but also to branch b. Therefore, the working flow of the pre-pump 12 will be much greater than the test flow of the test booster pump 13. Obviously, under long-term continuous testing, the tested booster pump 13 needs to operate continuously at high power, which not only greatly increases the test cost but also reduces the service life of the tested booster pump 13 , and thus needs to be solved urgently. Summary of the Invention

[0005] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides a high-pressure test system for a booster pump. The test process can not only provide high-pressure conditions for the inlet of the booster pump, but also does not require the continuous high-power operation of the pre-pump, which greatly reduces the cost of the test process and improves the service life of the booster pump.

[0006] To achieve the above object, the present invention provides the following technical solutions: A booster pump high-pressure test system includes a large circulation pipeline. Along the direction of medium flow, a water storage component, a pre-pump, a tested booster pump, a main line regulating valve and a boost regulating valve are installed in sequence on the large circulation pipeline. A one-way return pipeline is connected in parallel on the large circulation pipeline. The first node and the second node of the one-way return pipeline are respectively located at the output end of the main line regulating valve and the output end of the pre-pump, and the medium flow direction of the one-way return pipeline flows toward the output end of the pre-pump.

[0007] As a further solution of the present invention: the water storage component is a cooling tower, and the flow rate of the pre-pump in normal operation is controlled according to the following formula: ; Where, The flow rate of the pre-pump under normal operating conditions, in m 3 / h; is the power consumption correction empirical coefficient, dimensionless; is the flow rate of the tested booster pump, in m 3 / h; is the discharge pressure of the tested booster pump, in Pa; is the inlet pressure of the tested booster pump, in Pa; is the efficiency of the tested booster pump, dimensionless; is the length of the test pipe, in m; is the medium temperature in the test pipe, in °C; is the ambient temperature outside the test pipe, in °C; is the convection coefficient inside the test pipe, dimensionless; is the inner diameter of the test pipe, in m; is the outer diameter of the test pipe, in m; is the cooling temperature difference, in °C.

[0008] As a further solution of the present invention: the flow rate of the tested booster pump in the leakage operation state is controlled according to the following formula: ; Where, The flow rate of the pre-pump in the leakage operation state, the unit is m 3 / h; is the empirical correction coefficient, dimensionless; is the plunger diameter, in m; is the initial gap height of the filler, in m; is the compression coefficient, dimensionless; is the initial length of the filler, in m; is the length correction factor, dimensionless; is the dynamic viscosity of the medium, in Pa·s.

[0009] As a further solution of the present invention: the one-way reflux pipeline is provided with a one-way check valve for realizing one-way flow of the medium, and an exhaust port and a water injection port are respectively provided at the inlet and outlet of the one-way check valve, and valves are installed on the exhaust port and the water injection port.

[0010] As a further solution of the present invention: a first flow stabilizing device and a second pressure sensor are installed in sequence on the pipeline between the output end of the pre-pump and the second node on the large circulation pipeline, and a first pressure sensor is installed on the pipeline between the output end of the water storage component and the input end of the pre-pump on the large circulation pipeline.

[0011] As a further solution of the present invention: a third pressure sensor is installed on the pipeline between the second node and the input end of the tested booster pump on the large circulation pipeline, and a second flow stabilizing device and a fourth pressure sensor are installed in sequence on the pipeline between the output end of the tested booster pump and the main line regulating valve on the large circulation pipeline.

[0012] As a further solution of the present invention: a flow meter is installed on the pipeline between the output end of the main pipeline regulating valve and the first node on the large circulation pipeline.

[0013] As a further solution of the present invention: the rear pipeline located at the second node on the large circulation pipeline and the pipeline between the tested booster pump and the main pipeline regulating valve are both equipped with safety overflow pipelines connected to the water storage assembly, and safety overflow valves are both installed on the safety overflow pipelines.

[0014] As a further solution of the present invention: the water storage component is connected to a water supply pipeline for replenishing the medium of the water storage component, and an automatic water supply valve is installed on the water supply pipeline.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. During the test, start the pre-pump first to allow the medium to circulate in the large circulation pipeline. Due to the pressure drop caused by the resistance in the large circulation pipeline, the pressure at the first node of the one-way return pipeline will be lower than the pressure at the second node, that is, the one-way return pipeline does not participate in the circulation of the medium. After that, reduce the opening of the boost regulating valve so that the pressure at the input end of the tested booster pump reaches the required set pressure. After that, start the tested booster pump. Since the pressure generated by the tested booster pump is much greater than the pressure drop value caused by the pressure drop, this causes the pressure at the first node of the one-way return pipeline to instantly exceed the pressure at the second node. As a result, the one-way return pipeline will circulate the medium at the outlet of the tested booster pump to the outlet end of the pre-pump. Finally, adjust the opening of the main pipeline regulating valve to adjust the pressure at the output end of the tested booster pump to the required set pressure value. The test process is clear, orderly, and smooth.

[0016] Based on the above test process, the present application utilizes a one-way return pipeline to circulate the medium gathered at the output end of the pre-pump and jointly supply it to the input end of the tested booster pump. The flow supplied by the pre-pump can be reduced so that the one-way return pipeline and the section of the pipeline where the tested booster pump is located in the large circulation pipeline are the main circulation pipelines for the medium; this significantly reduces the medium flow in the section of the pipeline where the pre-pump and the water storage component in the large circulation pipeline are located, and thus the pre-pump only needs to supply a smaller flow during the test, which significantly reduces the power of the pre-pump.

[0017] 2. The water storage component is a cooling tower that can be used to dissipate heat and cool the medium, avoiding the medium temperature increase caused by long-term continuous circulation testing in the large circulation pipeline and the one-way return pipeline, so as to avoid large fluctuations in the test temperature of the tested booster pump.

[0018] 3. This application also provides a flow control algorithm for the pre-pump, which optimizes the flow distributed to the cooling tower. On the basis of making the pre-pump flow as small as possible, it avoids large fluctuations between the medium temperature in the pipeline and the set temperature of the test, thereby achieving precise control of the medium temperature in the pipeline.

[0019] 4. This application also provides a flow control algorithm for the pre-pump in the pipeline leakage state, which can also achieve precise control of the medium temperature in the pipeline in the leakage state, avoiding the increase in test time due to shutdown maintenance due to leakage during the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the test system of the present invention.

[0021] Figure 2 Schematic diagram of a test system in the prior art.

[0022] In the figure: 10, large circulation pipeline; 11, cooling tower; 12, pre-pump; 121, first pressure sensor; 122, first flow stabilizing device; 123, second pressure sensor; 13, tested booster pump; 131, third pressure sensor; 132, second flow stabilizing device; 133, fourth pressure sensor; 14, main line regulating valve; 15, flow meter; 16, boost regulating valve; 17, safety overflow pipeline; 171, safety overflow valve; 20, one-way return pipeline; 21, one-way check valve; 22, exhaust port; 23, water injection port; e, first node; f, second node; a. Water storage tank; b. Branch line; c. Control valve; d. Detection pipeline. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] For ease of understanding, the specific structure and working mode of the present invention are further described below with reference to the accompanying drawings: The specific structure of the present invention refers to Figure 1 As shown, its main structure includes a large circulation pipeline 10. Along the medium flow direction, the large circulation pipeline 10 is sequentially installed with a water storage component, a pre-pump 12, a test booster pump 13, a main line regulating valve 14 and a booster regulating valve 16. A one-way return pipeline 20 is connected in parallel to the large circulation pipeline 10. The first node e and the second node f of the one-way return pipeline 20 are respectively located at the output end of the main line regulating valve 14 and the output end of the pre-pump 12, and the medium flow direction of the one-way return pipeline 20 flows to the output end of the pre-pump 12.

[0025] During the test, the pre-pump 12 is started first. At this time, the medium will circulate in the large circulation pipeline 10. Due to the pressure drop caused by the resistance in the large circulation pipeline 10, the pressure of the first node e of the one-way return pipeline 20 will be less than the pressure of the second node f, that is, the one-way return pipeline 20 does not participate in the circulation of the medium. At this time, the opening of the boost regulating valve 16 is reduced so that the pressure at the input end of the tested boost pump 13 reaches the required set pressure. After that, the tested boost pump 13 is started. Since the pressure generated by the tested boost pump 13 is much greater than the pressure drop value caused by the pressure drop, this causes the pressure of the first node e of the one-way return pipeline 20 to instantly exceed the pressure at the second node f, so that the one-way return pipeline 20 will circulate the medium at the outlet of the tested boost pump 13 to the outlet end of the pre-pump 12. Finally, adjust the opening of the main pipeline regulating valve 14 to adjust the pressure at the output end of the tested boost pump 13 to the required set pressure value.

[0026] The present application utilizes the one-way return line 20 to circulate the medium that converges to the output end of the pre-pump 12 and supplies it to the input end of the tested booster pump 13. The flow rate supplied by the pre-pump 12 can be reduced so that the one-way return line 20 and the section of the pipeline where the tested booster pump 13 is located in the large circulation pipeline 10 become the main circulation pipelines for the medium. This significantly reduces the medium flow rate in the section of the pipeline where the pre-pump 12 and the water storage component in the large circulation pipeline 10 are located, and thus the pre-pump 12 only needs to supply a smaller flow rate during the test, which significantly reduces the power of the pre-pump 12.

[0027] In addition, since the flow rate through the large circulation pipeline 10 is very small, the water storage component does not need a large volume during the test, which reduces the space occupied by the water storage component.

[0028] Specifically, such as Figure 1 As shown, the one-way return pipeline 20 has a one-way check valve 21 for realizing one-way flow of the medium. An exhaust port 22 and a water injection port 23 are respectively provided at the inlet and outlet of the one-way check valve 21, and valves are installed on the exhaust port 22 and the water injection port 23.

[0029] In the pipeline structure, the exhaust port 22 and the water injection port 23 are respectively arranged at the inlet and outlet of the one-way check valve 21. By opening the valves of the exhaust port 22 and the water injection port 23 and injecting the medium into the water injection port 23, before the test, the large circulation pipeline 10 and the one-way return pipeline 20 can be filled with the medium to ensure that the air in the pipeline is exhausted.

[0030] On the basis of the above, if Figure 1As shown, a first flow stabilizing device 122 and a second pressure sensor 123 are sequentially installed on the pipeline between the output end of the pre-pump 12 and the second node f on the large circulation pipeline 10, and a first pressure sensor 121 is installed on the pipeline between the output end of the water storage component and the input end of the pre-pump 12 on the large circulation pipeline 10. The second pressure sensor 123 and the first pressure sensor 121 are respectively used to directly obtain the pressure conditions of the output end and the input end of the pre-pump 12. The first flow stabilizing device 122 can be a Wenturi-type flow stabilizer in the prior art, which is used for the working condition where the pre-pump 12 is a reciprocating pump, and is intended to eliminate turbulence, reduce eddies and uneven flow velocity distribution. If the pre-pump 12 is a centrifugal pump, the first flow stabilizing device 122 is not required.

[0031] On the basis of the above, if Figure 1 As shown, a third pressure sensor 131 is installed on the pipeline between the second node f and the input end of the test booster pump 13 on the large circulation pipeline 10, and a second flow stabilizing device 132 and a fourth pressure sensor 133 are installed in sequence on the pipeline between the output end of the test booster pump 13 and the main line regulating valve 14 on the large circulation pipeline 10. The fourth pressure sensor 133 and the third pressure sensor 131 are respectively used to directly obtain the pressure conditions at the output end and the input end of the test booster pump 13. The second flow stabilizing device 132 can also be a Venturi-type flow stabilizer in the prior art, which is used for the working condition where the test booster pump 13 is a reciprocating pump, and is intended to eliminate turbulence, reduce eddy currents and uneven flow velocity distribution. If the test booster pump 13 is a centrifugal pump, the second flow stabilizing device 132 does not need to be provided.

[0032] On the basis of the above, if Figure 1 As shown, a flow meter 15 is installed on the pipeline between the output end of the main pipeline regulating valve 14 and the first node e on the large circulation pipeline 10, which is used to quickly obtain the flow value of the tested booster pump 13 during the test.

[0033] In addition, to ensure the safety during the pipeline test, Figure 1 As shown, the rear pipeline at the second node f on the large circulation pipeline 10 and the pipeline between the tested booster pump 13 and the main pipeline regulating valve 14 are both equipped with a safety overflow pipeline 17 connected to the water storage component, and a safety overflow valve 171 is installed on the safety overflow pipeline 17.

[0034] In addition, if Figure 1 As shown, the water storage assembly is connected to a water supply pipeline for replenishing the medium of the water storage assembly. An automatic water supply valve is installed on the water supply pipeline, thereby realizing water replenishment in the case of leakage of the medium in the water storage assembly.

[0035] On the basis of the above, in order to prevent the medium from being subjected to a long-term continuous circulation test in the large circulation pipeline 10 and the one-way return pipeline 20, which may cause the medium temperature to rise and thus interfere with the test temperature of the tested booster pump 13, the water storage component in this application is a cooling tower 11, which can be used to dissipate heat and cool the medium. At the same time, in order to reduce the energy consumption of the pre-pump 12 while preventing large fluctuations in the medium temperature, the flow rate of the pre-pump 12 in normal operation is controlled according to the following formula: ; Where, The flow rate of the pre-pump 12 under normal operating conditions, in m 3 / h; is the power consumption correction empirical coefficient, dimensionless, ranging from 0.90 to 0.95; is the flow rate of the tested booster pump 13, in m 3 / h; is the discharge pressure of the tested booster pump 13, in Pa; is the inlet pressure of the tested booster pump 13, in Pa; is the efficiency of the tested booster pump 13, dimensionless; is the length of the test pipe, in m; is the medium temperature in the test pipe, in °C; is the ambient temperature outside the test pipe, in °C; is the convection coefficient inside the test pipe, dimensionless, ranging from 100 to 300; is the inner diameter of the test pipe, in m; is the outer diameter of the test pipe, in m; is the cooling temperature difference, in °C.

[0036] The derivation process of the above formula is as follows: (1) Overview Since the test is a process in which the test booster pump 13 consumes power continuously, most of this power consumption is converted into heat energy, and the test medium is continuously heated, which will inevitably cause the test medium to continue to rise. Since the main circulation system is a high-pressure system, direct heat exchange is inefficient, costly, and poses a safety hazard, it is best not to adopt a direct cooling method. Cooling can be achieved by using the pre-pump 12 to transport hot water from the cooling tower 11 for replacement to achieve thermal balance. In this way, another task of the pre-pump 12 is to provide sufficient cooling replacement liquid, so the cooling replacement amount of the pre-pump 12 also needs to be calculated.

[0037] As the test medium circulates in the pipeline, it also continuously exchanges heat with the surrounding atmosphere through the pipeline, which will dissipate some heat.

[0038] Therefore, during the test, part of the heat generated by the operation of the tested booster pump 13 is naturally dissipated through the pipeline, and the remaining undissipated heat needs to be transported to the cooling tower 11 by the pre-pump 12 for direct cooling.

[0039] The following calculates the heating power, natural heat dissipation of the pipeline, and the cooling heat delivered to the cooling tower 11 by the pre-pump 12.

[0040] (2) Calculation of heating power In the test system of the test booster pump 13, the power consumption of the test booster pump 13 during operation is mainly to heat the test medium. (Unit: kW) can be calculated by the output power of the tested booster pump 13 (in kW) divided by the efficiency of the tested booster pump 13 get.

[0041] Right now: ; A portion of the operating power consumption of the test booster pump 13 is used to account for the temperature rise of the lubricating oil in the oil tank. This is corrected using the power consumption correction factor y, which is set between 0.95 and 0.98. Other factors, such as seal temperature rise, can be ignored in the calculation.

[0042] Output power of the tested booster pump 13 The standard calculation formula is: ; is the pressure difference between the inlet and outlet of the tested booster pump 13, that is, ; is the discharge pressure of the tested booster pump 13, in MPa; is the inlet pressure of the tested booster pump 13, in MPa; Then we can get: ; Since the right side of the equation is multiplied by 10 -6 Therefore, the discharge pressure of the tested booster pump 13 at this time is The unit is Pa; The inlet pressure of the tested booster pump 13 is , unit is Pa.

[0043] Power consumption for heating the test medium A portion of the heat is naturally dissipated through the surface of the pipe, and the other portion is transported to the cooling tower 11 through the front pump 12 for direct cooling.

[0044] (3) Natural heat dissipation of pipelines Calculation When the temperature of the medium in the test pipe exceeds the ambient temperature, the medium will exchange heat with the air in the environment through the pipe, and some energy will be naturally dissipated. Subtract the natural heat dissipation of the pipeline This is the energy that needs to be delivered to the cooling tower 11 by the front pump 12. .

[0045] The liquid in the pipe is at a higher temperature and dissipates heat to the surrounding environment through the pipe wall. This generally follows a process: heat from the liquid is transferred to the pipe wall, conducted through the pipe wall from the inner surface to the outer surface, and then dissipated from the outer surface to the surrounding environment through convection and radiation.

[0046] 1) Determination of basic calculation conditions A. The test pipe is circular.

[0047] B. Heat is lost in the following ways.

[0048] Internal convection: convection heat transfer between liquid and the inner wall of the pipe; Heat conduction through the pipe wall: heat is conducted through the pipe wall to the outer surface; External heat dissipation: The outer surface of the pipe dissipates heat to the environment through convection and radiation.

[0049] C. The calculation is based on the following basic boundary conditions.

[0050] Steady-state heat transfer: temperature distribution does not change with time; One-dimensional radial heat transfer: heat transfer only along the radial direction of the pipe, symmetrical in the circumferential and axial directions; Linearization of radiation heat dissipation: Equivalent radiation heat transfer to convection coefficient .

[0051] 2) Calculation of thermal resistance of each link Internal convection thermal resistance (Unit: K / W) Calculation (convection heat transfer thermal resistance between liquid and pipe inner wall): ; Where, is the heat exchange area in m², and ; is the internal convection coefficient, in W / (m²·K); is the inner radius of the pipe, in m; is the length of the test pipe in meters.

[0052] Thermal resistance of pipe wall (Unit K / W) Calculation: ; in, is the thermal conductivity of the pipe wall, in W / (m·K); is the outer radius of the pipe, in m.

[0053] External convection and radiation thermal resistance (Unit K / W) Calculation: ; is the external convection coefficient, in W / (m 2 K); is the radiation equivalent coefficient, the unit is W / (m 2 K): ; is the ambient temperature, in °C; is the pipe surface temperature, in °C; is the pipe surface emissivity; is the Stefan-Boltzmann constant; is the surface area of ​​the pipeline, in m²; ; is the outer diameter of the pipe, in meters.

[0054] 3) Thermal resistance of each link, total thermal resistance and heat transfer system A. Total thermal resistance of each link calculate The total thermal resistance is the sum of the thermal resistances in series: ; External convection and radiation are in parallel because they act simultaneously on the same temperature difference.

[0055] B. Heat transfer system calculation The natural heat dissipation of the pipeline is: ; is the medium temperature in the test pipe; at this time, The unit is W.

[0056] It is necessary to calculate the total heat transfer system and convert all thermal resistances to the same reference area, usually the outer surface as the reference, and convert each thermal resistance into a heat transfer coefficient based on the outer surface as the reference. The concatenation is: ; Therefore, the overall heat transfer coefficient for: ; Therefore, we can conclude that: ; Right now: ; Then we can conclude that: .

[0057] 4) Engineering simplification Since the above formula is relatively complex, we can refer to the actual working conditions and application experience corresponding to various parameters in the booster pump test practice to make corresponding engineering simplifications to the heat dissipation power formula.

[0058] In actual engineering, the test pipeline is generally made of low carbon steel, and the thermal conductivity k is selected as 45W / (m·K); during the pump test, the flow rate in the pipeline is generally controlled within 1m / s-5m / s, and its internal convection coefficient is Can be selected within 100-500; the booster pump test pipeline is generally indoors, with automatic convection of horizontal pipes, and the external convection coefficient Select 50W / (m²·K); Under normal circumstances, the booster pump test pipeline is to ensure safety, the temperature difference between the pipeline and the environment is very small, the heat radiation is very small, and the radiation equivalent coefficient is 3W / (m²·K) is generally selected.

[0059] In summary, Can be simplified to: ; is the convection coefficient inside the test pipe, dimensionless, ranging from 100 to 300; Since the right side of the equation is divided by 1000, The unit is kW.

[0060] (4) Cooling tower cooling calculation 1) Balancing equations A. Thermodynamic equilibrium equation Cooling energy of cooling tower 11 (Unit: kW) is discharged from the process system and needs to be dissipated through water evaporation and air temperature rise: ;

[0061] Where: is the mass flow rate of circulating water, in kg / s; is the specific heat capacity of water, in kJ / kg·℃; is the cooling tower inlet water temperature, in °C; is the cooling tower outlet water temperature, in °C; is the evaporation loss mass flow rate, in kg / s; is the latent heat of vaporization of water, in kJ / kg.

[0062] B. Mass balance equation Evaporation loss is equal to the amount of moisture absorbed by the air: ; Where: is the dry air mass flow rate, in kg / s; is the humidity content of air inlet, in kg / kg dry air; It is the moisture content of air outlet, in kg / kg dry air.

[0063] 2) Air side enthalpy difference equation The total heat absorbed by the air includes sensible heat and latent heat ,but ; Enthalpy of moist air (Unit is kJ / kg) The calculation formula is: ; in, is the air dry bulb temperature, in °C; W is the moisture content, the mass of water vapor contained in the air.

[0064] 3) Calculation of circulating water volume Substituting the mass balance equation into the heat balance equation: ; At the same time, the enthalpy difference equation on the air side is: ; but: ; Where Q is the total heat transfer.

[0065] This equation needs to be solved iteratively in combination with air parameters, and a simplified method is often used in engineering.

[0066] 4) Engineering Simplification Formula In the design, the sensible heat part of the latent heat of evaporation is ignored (the error is about 5%), and the circulating water volume is approximately calculated using only the sensible heat: ; is the cooling temperature difference, in °C; The above formula can be converted into the following units: ; is the specific heat capacity, the specific heat capacity of water is 4200 J / (kg·℃); The flow rate of the pre-pump 12 under normal operating conditions, in m 3 / h.

[0067] It can be further simplified to: .

[0068] (5) Calculation of flow rate of pre-pump 12 From the above formula, we can get: ; Also because ; The above and The calculation result is brought in, and the flow rate of the pre-pump 12 under normal operation is finally obtained. for: ; The above flow rate for cooling in the cooling tower 11 is obtained, that is, the flow rate sucked from the cooling tower 11 at the inlet of the pre-pump 12 under normal operating conditions. .

[0069] During practice, practice conditions are divided into three groups: In the first group of practices, the efficiency of the tested booster pump 13 The convection coefficient inside the test pipe is 87%. Take 300, the power consumption correction coefficient Take 0.92; the flow rate of the tested booster pump 13 30m 3 / h; discharge pressure of the tested booster pump 13 The inlet pressure of the tested booster pump 13 is 32000000Pa. 15000000Pa; test pipe length 30m; the medium temperature in the test pipeline The ambient temperature outside the test pipe The difference is 10℃; the inner diameter of the test pipe 0.0325m; outer diameter of test pipe 0.043m; cooling temperature difference It is 10.00℃.

[0070] Calculate the cooling flow in the cooling tower 11, that is, the flow rate sucked from the cooling tower 11 at the inlet of the pre-pump 12 under normal operating conditions Specifically 12.52m 3 / h. If the traditional pipeline layout is adopted, the flow rate of the pre-pump 12 must be greater than the flow rate of the tested booster pump 13 , i.e. greater than 30m 3 / h, and obviously, with the pipeline layout of the present application, the flow rate of the pre-pump 12 under normal operating conditions is Significantly reduced.

[0071] In addition, when the pipeline is in normal operation, in practice, the front pump 12 is 12.52m 3 The flow rate of the test medium is 1 / h, and the temperature of the medium near the test booster pump 13 in the large circulation pipeline 10 is measured in real time, forming a comparison table of the real-time temperature range of the first medium and the expected test temperature at different operating times in normal operation as shown in Table 1 below: Table 1 Comparison of the real-time temperature range of the first medium and the expected test temperature ; In the second group of practice, the efficiency of the tested booster pump 13 The convection coefficient inside the test pipe is 88%. 300; power consumption correction empirical coefficient is 0.92; the flow rate of the tested booster pump 13 35m 3 / h; discharge pressure of the tested booster pump 13 The inlet pressure of the tested booster pump 13 is 39000000Pa. 17000000Pa; test pipe length 30m; the medium temperature in the test pipeline The ambient temperature outside the test pipe The difference is 10℃; the inner diameter of the test pipe 0.0325m; outer diameter of test pipe 0.043m; cooling temperature difference It is 10.00℃.

[0072] Calculate the cooling flow in the cooling tower 11, that is, the flow rate sucked from the cooling tower 11 at the inlet of the pre-pump 12 under normal operating conditions Specifically 18.87m 3 / h. If the traditional pipeline layout is adopted, the flow rate of the pre-pump 12 must be greater than the flow rate of the tested booster pump 13 , i.e. greater than 35m 3 / h, and obviously, with the pipeline layout of the present application, the flow rate of the pre-pump 12 under normal operating conditions is Significantly reduced.

[0073] In addition, when the pipeline is in normal operation, in practice, the front pump 12 is 18.87m 3 The flow rate of the test medium is 1 / h, and the temperature of the medium near the test booster pump 13 in the large circulation pipeline 10 is measured in real time, forming a comparison table of the real-time temperature range of the second medium and the expected test temperature at different operating times in normal operation as shown in Table 2 below: Table 2 Comparison of the second medium real-time temperature range and the expected test temperature ; In the third group of practice, the efficiency of the tested booster pump 13 The convection coefficient inside the test pipe is 89%. 300; power consumption correction empirical coefficient is 0.92; the flow rate of the tested booster pump 13 40m 3 / h; discharge pressure of the tested booster pump 13 The inlet pressure of the tested booster pump 13 is 44000000Pa. 21000000Pa; length of test pipe 30m; the medium temperature in the test pipeline The ambient temperature outside the test pipe The difference is 10℃; the inner diameter of the test pipe 0.0325m; outer diameter of test pipe 0.043m; cooling temperature difference It is 10.00℃.

[0074] Calculate the cooling flow in the cooling tower 11, that is, the flow rate sucked from the cooling tower 11 at the inlet of the pre-pump 12 under normal operating conditions Specifically 22.35m 3 / h. If the traditional pipeline layout is adopted, the flow rate of the pre-pump 12 must be greater than the flow rate of the tested booster pump 13 , i.e. greater than 40m 3 / h, and obviously, with the pipeline layout of the present application, the flow rate of the pre-pump 12 under normal operating conditions is Significantly reduced.

[0075] When the pipeline is in normal operation, in practice, the front pump 12 is 22.35m 3 The flow rate of the test medium is 1 / h, and the temperature of the medium near the test booster pump 13 in the large circulation pipeline 10 is measured in real time, forming a comparison table of the real-time temperature range of the third medium and the expected test temperature at different operating times in normal operation as shown in Table 3 below: Table 3 Comparison of the third medium real-time temperature range and the expected test temperature ; As can be seen from Table 1, the pre-pump 12 operates at a flow rate obtained according to the flow calculation formula under normal operating conditions provided in this application, which can stably maintain the temperature of the medium in the pipeline, thereby avoiding excessive temperature fluctuations in the pipeline and causing a reduction in the accuracy of the test results of the tested booster pump 13.

[0076] On the basis of the above, we further consider the leakage in the pipeline. Since the test booster pump 13 requires a long time of test operation, leakage may occur during the test. If the test pump is shut down for maintenance and retested at this time, it will obviously greatly increase the test time. Therefore, in this application, the leakage of the test booster pump 13 is taken into consideration, and the following flow calculation formula for the test booster pump 13 in the leakage operation state is provided: ; Where, The flow rate of the pre-pump 12 in the leakage operation state, in m 3 / h; is the empirical correction coefficient, dimensionless, ranging from 0.7 to 1.0; is the plunger diameter, in m; is the initial gap height of the filler, in m; is the compression coefficient, dimensionless; is the initial length of the filler, in m; is the length correction factor, dimensionless; is the dynamic viscosity of the medium, in Pa·s.

[0077] The derivation process of the above formula is as follows: (1) Overview The flow rate of the pre-pump 12 of the existing traditional booster pump test system must be greater than the flow rate of the tested booster pump 13, that is, it must provide the same flow rate for the tested booster pump 13 and also provide sufficient flow rate for the bypass boosting. It is generally configured to be 1.5 times the flow rate of the tested pump to ensure the normal progress of the test.

[0078] There is no necessary connection between the flow rate of the pre-pump 12 of the present invention and the tested booster pump 13. The flow rate is designed mainly for obtaining the replaced cooling test medium through the cooling tower 11. In addition, it is also used to ensure that the loss of the tested booster pump 13 during the process is replenished.

[0079] (2) Calculation of flow rate to compensate for losses during the test of the booster pump 13 The tested booster pump 13 is a reciprocating pump, and there are mechanical losses, hydraulic losses and volumetric losses during its operation. The mechanical losses and hydraulic losses do not affect the flow rate of the pump, and are not considered in this calculation. The volumetric losses include volumetric losses caused by liquid compression and expansion, volumetric losses caused by delayed closing of the one-way valve, volumetric losses caused by lax valve closure, and volumetric losses caused by leakage through the seal, etc. The first three are the main reasons for the decrease in pump volumetric efficiency, but they are all internal losses and will not cause a decrease in pump flow rate, so they are not considered in the calculation. The volumetric loss caused by seal leakage is an external leakage. Although it accounts for a small proportion, once it occurs, the system flow rate will decrease accordingly, which will destroy the flow balance and pressure balance of the test system. The test process will become complex, changeable, difficult to control, and unstable, so the system loss must be supplemented. The present invention only needs to carry out calculations for the volumetric loss caused by the fourth type of over-seal leakage.

[0080] 1) Determination of basic calculation conditions A. The leakage gap can be regarded as an annular gap, and the velocity distribution is parabolic, with the maximum velocity in the middle. The coordinate system is established with the seal as the calculation and research object. The plunger is cylindrical, and the radius is set to (Unit: m), inner radius of stuffing box (Unit is m), then the gap , total length of packing (Unit: m), leakage along the axial direction z.

[0081] B. Geometric parameters Plunger diameter (Unit: m), the packing gap height is (unit: m), initial filler gap height (Unit: m), pressing force (Unit: N), elastic modulus of filler material , Poisson's ratio , the initial length of the filler is (Unit: m).

[0082] C. Dynamic conditions Plunger reciprocating speed ; Pressure difference on both sides of the seal , since the leakage was measured as atmosphere during the test, , .

[0083] D. Fluid properties In general, the test medium of the booster pump is water and the test pressure is less than 50MPa, so the compressibility of the test medium can be ignored and it can be considered as an incompressible Newtonian fluid. The dynamic viscosity of the medium is .

[0084] Under normal operating conditions where the seal has not failed, the test medium flows in the sealing gap in a laminar manner, with slight inertia at the edge of the plunger and an inertia term. The flow is both pressure-driven and shear-driven.

[0085] 2) Computational model establishment Assuming that the packing is evenly compressed to form an annular gap, the compression force The resulting gap height is , the length after compression is .

[0086] 3) Fluid flow analysis The flow in the gap is determined by the pressure difference and plunger speed (unit is m / s) are jointly driven. Assuming the flow is laminar and incompressible Newtonian fluid, the Navier-Stokes equations are simplified to: ; in is the flow velocity (in m / s), is the coordinate perpendicular to the flow direction (from the packing surface to the plunger surface), is the coordinate along the flow direction. The boundary conditions are: Department, (Packing is stationary); Department, (plunger movement speed); p is pressure.

[0087] Solving this equation, we can get the velocity distribution: ; From the above formula, it can be concluded that the flow rate is composed of the superposition of pressure-driven terms and shear-driven terms.

[0088] 4) Leakage calculation Leakage (The unit is m 3 / s) is the integral of the flow velocity over the gap cross-sectional area: ; Will Substituting the integral: ;

[0089] Calculate the integral: ; ;

[0090] This is the expression for instantaneous leakage, which includes leakage driven by pressure difference and leakage driven by plunger movement.

[0091] 5) Correction of packing compression effect A. Clearance height correction: The compaction force causes the gap height to decrease. According to material mechanics, the deformation after compaction can be approximated by Hooke's law to obtain the compression strain. (dimensionless). Among them, , where is the elastic modulus, in Pa; is the cross-sectional area of ​​the filler, in m 2 ,and .

[0092] Therefore, the gap height for: ; To simplify the calculation, the compression factor is introduced : .

[0093] B. Seal length correction: The effective length increases due to the lateral expansion of the filler. Due to the Poisson effect, the filler expands laterally when compacted, resulting in an increase in length: , therefore: ; To simplify the calculation, the length correction factor is introduced : ; The total length of the packing for: ; Substitution : .

[0094] C. Dynamic Effect Analysis The plunger moves back and forth at a speed For simple harmonic motion: ,in is the maximum speed, is the angular frequency, period .

[0095] Due to the leakage Contains The average value of the shear flow part is zero when the integral is averaged over the period because the positive and negative half cycles cancel each other out. Therefore, the average leakage Contributed only by the pressure difference term: .

[0096] D. Coefficient Correction In practical applications, due to factors such as packing wear, temperature changes, and non-Newtonian fluid characteristics, the theoretical formula needs to be modified. Usually, empirical coefficients are introduced. , and The unit conversion is m 3 / h, the corrected loss of the pre-pump 12 is as follows: ; The pre-pump 12 is used to supplement the flow required for consumption.

[0097] Thus, the flow calculation formula of the tested booster pump 13 in the leakage operation state is obtained: ; Right now: ; The flow rate of the pre-pump 12 in the leakage operation state, in m 3 / h.

[0098] In practice, follow the above The parameter conditions of the first, second and third groups of practice are obtained by inheriting the first, second and third groups of practice respectively. Specific results of 12.52m 3 / h、18.87m 3 / h and 22.35m 3 / h.

[0099] Among other parameters, the empirical correction coefficient 0.7; plunger diameter 0.085m; initial gap height of filler 0.0005m; compression coefficient 0.643; initial height of filler 0.05m; length correction factor is 4.122; the dynamic viscosity of the medium The test was conducted in three groups to simulate the leakage of the test pipeline under the above parameters.

[0100] With the aforementioned The first set of practices corresponds to the leakage of the fourth set of practices. The flow rate of the front pump 12 under the leakage operation state is calculated. 12.81m 3 / h. Obviously, under the leakage state, the flow rate of the pre-pump 12 is still much smaller than the flow rate of the tested booster pump 13 by 30m 3 / h.

[0101] When the pipeline is in a leaking state, in practice, the front pump 12 is 12.81m 3 The system was operated at a flow rate of 1 / 2 h, and the temperature of the medium near the test booster pump 13 in the large circulation pipeline 10 was measured in real time, resulting in a comparison table of the fourth medium's real-time temperature range and the expected test temperature at different operating times during the leakage operation as shown in Table 4 below: Table 4 Comparison of the fourth medium real-time temperature range and the expected test temperature ; Obviously, as shown in Table 4, even if the pipeline is in a leaking state, the temperature of the medium in the pipeline can be stably maintained. Not only does it not need to be shut down for maintenance and then measured again, but it also avoids excessive fluctuations in the temperature of the medium in the pipeline, which would lead to a decrease in the accuracy of the test results of the tested booster pump 13.

[0102] With the aforementioned The leakage of the second group of practice corresponding to the fifth group of practice is calculated to obtain the flow rate of the front pump 12 under the leakage operation state. 19.22m 3 / h. Obviously, in the leakage state, the flow rate of the pre-pump 12 is much smaller than the flow rate of the tested booster pump 13 by 35m 3 / h.

[0103] Pre-pump 12 according to 19.22m3 The system was operated at a flow rate of 1 / 2 h, and the temperature of the medium near the test booster pump 13 in the large circulation pipeline 10 was measured in real time, resulting in a comparison table of the fifth medium's real-time temperature range and the expected test temperature at different operating times during the leakage operation as shown in Table 5 below: Table 5 Comparison of the fifth medium's real-time temperature range and the expected test temperature ; The pre-pump 12 is 22.75m 3 / h flow rate operation, other parameters are still based on the empirical correction coefficient 0.7; plunger diameter 0.085m; initial gap height of filler 0.0005m; compression coefficient 0.643; initial height of filler 0.05m; The length correction factor is 4.122; and the leakage under the above parameter conditions is simulated in practice.

[0104] With the aforementioned The third set of practices corresponds to the sixth set of practices, and the leakage is obtained Specific results of 22.75m 3 / h. Obviously, in the leakage state, the flow rate of the pre-pump 12 is much smaller than the flow rate of the tested booster pump 13 by 40m 3 / h.

[0105] Pre-pump 12 according to 22.75m 3 / h flow rate operation, and real-time measurement of the medium temperature at the location near the test booster pump 13 in the large circulation pipeline 10, resulting in a comparison table of the sixth medium's real-time temperature range and the expected test temperature at different operating times during leakage operation as shown in Table 6 below: Table 6 Comparison of the sixth medium's real-time temperature range and the expected test temperature ; Similarly, as shown in Table 6, even if the pipeline is in a leaking state, the temperature of the medium in the pipeline can be stably maintained. Not only does it not need to be shut down for maintenance and then measured again, but it also avoids excessive fluctuations in the temperature of the medium in the pipeline, which would lead to a decrease in the accuracy of the test results of the tested booster pump 13.

[0106] Of course, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also encompasses the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that fall within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0107] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0108] The technology, shape, and structure not described in detail in the present invention are all well-known technologies.

Claims

1. A booster pump high pressure test system, characterized in that: The invention comprises a large circulation pipeline (10), wherein a water storage component, a pre-pump (12), a test booster pump (13), a main line regulating valve (14) and a booster regulating valve (16) are sequentially installed on the large circulation pipeline (10) along the medium flow direction, and a one-way return pipeline (20) is connected in parallel to the large circulation pipeline (10), wherein a first node (e) and a second node (f) of the one-way return pipeline (20) are respectively located at the output end of the main line regulating valve (14) and the output end of the pre-pump (12), and the medium flow direction of the one-way return pipeline (20) flows toward the output end of the pre-pump (12).

2. A booster pump high pressure test system according to claim 1, characterized in that: The water storage component is a cooling tower (11), and the flow rate of the pre-pump (12) in normal operation is controlled according to the following formula: ； Where, is the flow rate of the pre-pump (12) under normal operating conditions, in m 3 / h; is the power consumption correction empirical coefficient, dimensionless; is the flow rate of the tested booster pump (13), in m 3 / h; is the discharge pressure of the tested booster pump (13), in Pa; is the inlet pressure of the tested booster pump (13), in Pa; is the efficiency of the tested booster pump (13), dimensionless; is the length of the test pipe, in m; is the medium temperature in the test pipe, in °C; is the ambient temperature outside the test pipe, in °C; is the convection coefficient inside the test pipe, dimensionless; is the inner diameter of the test pipe, in m; is the outer diameter of the test pipe, in m; is the cooling temperature difference, in °C.

3. A booster pump high pressure test system according to claim 2, characterized in that: The flow rate of the tested booster pump (13) in the leakage operation state is controlled according to the following formula: ； Where: is the flow rate of the pre-pump (12) in the leakage operation state, in m 3 / h; is the empirical correction coefficient, dimensionless; is the plunger diameter, in m; is the initial gap height of the filler, in m; is the compression coefficient, dimensionless; is the initial length of the filler, in m; is the length correction factor, dimensionless; is the dynamic viscosity of the medium, in Pa·s.

4. A booster pump high pressure test system according to claim 1, 2 or 3, characterized in that: The one-way return flow pipeline (20) is provided with a one-way check valve (21) for realizing one-way flow of the medium. An exhaust port (22) and a water injection port (23) are respectively provided at the inlet and outlet of the one-way check valve (21), and valves are installed on the exhaust port (22) and the water injection port (23).

5. A booster pump high pressure test system according to claim 1, 2 or 3, characterized in that: A first flow stabilizing device (122) and a second pressure sensor (123) are sequentially installed on the pipeline between the output end of the pre-pump (12) and the second node (f) on the large circulation pipeline (10), and a first pressure sensor (121) is installed on the pipeline between the output end of the water storage component and the input end of the pre-pump (12) on the large circulation pipeline (10).

6. A booster pump high pressure test system according to claim 1, 2 or 3, characterized in that: A third pressure sensor (131) is installed on the pipeline between the second node (f) and the input end of the tested booster pump (13) on the large circulation pipeline (10), and a second flow stabilizing device (132) and a fourth pressure sensor (133) are installed in sequence on the pipeline between the output end of the tested booster pump (13) and the main pipeline regulating valve (14) on the large circulation pipeline (10).

7. A booster pump high pressure test system according to claim 1, 2 or 3, characterized in that: A flow meter (15) is installed on the large circulation pipeline (10) between the output end of the main pipeline regulating valve (14) and the first node (e).

8. A booster pump high pressure test system according to claim 1, 2 or 3, characterized in that: A safety overflow pipeline (17) connected to the water storage assembly is installed on the rear pipeline located at the second node (f) on the large circulation pipeline (10) and the pipeline between the tested booster pump (13) and the main pipeline regulating valve (14), and a safety overflow valve (171) is installed on the safety overflow pipeline (17).

9. A booster pump high pressure test system according to claim 1, 2 or 3, characterized in that: The water storage component is connected to a water supply pipeline for replenishing the medium of the water storage component, and an automatic water supply valve is installed on the water supply pipeline.

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