Aerodynamic performance test system for centrifugal refrigeration compressor

Abstract

The invention relates to a pneumatic performance testing system for a centrifugal refrigeration compressor, which belongs to the technical field of refrigeration compressor testing and comprises a refrigeration pipeline communicated between an outlet of a second-stage centrifugal compressor and an inlet of a first-stage centrifugal compressor. A first adjusting valve CV1, a first gas cooler and a first electric heater are sequentially arranged on the refrigeration pipeline in the advancing direction of refrigerants, a second gas cooler is arranged on the middle pipeline, and a fourth adjusting valve CV4, a fifth gas cooler and a second electric heater are sequentially arranged on the air supplementing pipeline. According to the invention, the pressure and temperature of the refrigerant entering the first-stage centrifugal compressor can be adjusted, and the pressure and temperature of the refrigerant entering the second-stage centrifugal compressor can be adjusted, so that the refrigerant gas reaches the suction pressure and temperature required by the tested two-stage centrifugal refrigeration compressor; therefore, the performance of the two-stage centrifugal refrigeration compressor can be tested respectively, and the test effect of the high-speed centrifugal refrigeration compressor is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of refrigeration compressor testing, and in particular relates to a centrifugal refrigeration compressor pneumatic performance testing system. Background Art

[0002] The existing test device for high-speed centrifugal refrigeration compressors mainly uses pipelines and condensers and expansion valves installed on the pipelines to realize the circulation of refrigerant from the outlet to the inlet of the high-speed centrifugal refrigeration compressor, so as to test the performance of the high-speed centrifugal refrigeration compressor. The refrigerant enters the compressor inlet in a superheated gas state, becomes a high-temperature and high-pressure refrigerant after being compressed by the compressor, is partially cooled by the condenser, and then is reduced in pressure by the expansion valve, and then becomes a superheated gas state that meets the compressor inlet temperature and pressure requirements and re-enters the compressor. The cycle process is a closed cycle, and all the heat generated is taken away by the gas cooler to maintain the balance of the closed cycle system.

[0003] At present, high-speed centrifugal refrigeration compressors usually adopt two-stage compression. The outlet of the first-stage centrifugal compressor is connected to the inlet of the second-stage centrifugal compressor through a pipeline, and the outlet of the second-stage centrifugal compressor is connected to the inlet of the first-stage centrifugal compressor. After passing through the first-stage centrifugal compressor, the refrigerant enters the second-stage centrifugal compressor through a pipeline. After passing through the second-stage centrifugal compressor, the refrigerant enters the first-stage centrifugal compressor again through a pipeline to achieve circulation. Therefore, the performance of the first-stage centrifugal compressor and the second-stage centrifugal compressor will affect the performance of the refrigeration system. However, the existing test system can only test the performance of the first-stage centrifugal compressor or the two-stage series connection of the whole machine, and cannot test the aerodynamic performance of the first-stage centrifugal compressor and the second-stage centrifugal compressor separately. However, only testing the performance of the first-stage centrifugal compressor or the two-stage series connection results in poor testing results for the high-speed centrifugal refrigeration compressor, and it is difficult to optimize the performance of the high-speed centrifugal refrigeration compressor in an all-round way. Summary of the invention

[0004] In view of this, the present invention provides a centrifugal refrigeration compressor pneumatic performance testing system to address the deficiencies in the prior art. The testing system of the present invention can perform performance tests on two-stage centrifugal refrigeration compressors separately, thereby improving the testing effect on high-speed centrifugal refrigeration compressors.

[0005] The technical solution of the present invention is: a centrifugal refrigeration compressor pneumatic performance test system, which is used to test a compressor having a first-stage centrifugal compressor and a second-stage centrifugal compressor. The test system includes a refrigeration pipeline connected between the outlet of the second-stage centrifugal compressor and the inlet of the first-stage centrifugal compressor, and a first regulating valve CV1, a first gas cooler and a first electric heater are sequentially arranged along the refrigerant travel direction on the refrigeration pipeline. The refrigerant pressure entering the first-stage centrifugal compressor is regulated by the first regulating valve CV1, an intermediate pipeline is connected between the outlet of the first-stage centrifugal compressor and the inlet of the second-stage centrifugal compressor, a second gas cooler is arranged on the intermediate pipeline, an air supply pipeline is connected between the refrigeration pipeline and the intermediate pipeline, a connection between the air supply pipeline and the refrigeration pipeline is located on the front side of the first regulating valve CV1, and a connection between the air supply pipeline and the intermediate pipeline is located on the front side of the second gas cooler. A fourth regulating valve CV4, a fifth gas cooler and a second electric heater are sequentially arranged along the refrigerant travel direction on the air supply pipeline, and the refrigerant pressure of the air supply pipeline is regulated by the fourth regulating valve CV4.

[0006] Preferably, a third orifice flowmeter Qv3, a seventh temperature sensor T7 and a seventh pressure sensor P7 are sequentially arranged on the air supply pipeline along the direction of refrigerant travel, and the third orifice flowmeter Qv3, the seventh temperature sensor T7 and the seventh pressure sensor P7 are located on the rear side of the second electric heater.

[0007] Preferably, a first mass flowmeter Qm1, a first temperature sensor T1 and a first pressure sensor P1 are sequentially arranged along the direction of travel of the refrigerant between the first electric heater and the inlet of the first-stage centrifugal compressor, and a first orifice flowmeter Qv1, a second temperature sensor T2 and a second pressure sensor P2 are sequentially arranged along the direction of travel of the refrigerant between the connection point of the intermediate pipeline and the air supply pipeline and the outlet of the first-stage centrifugal compressor.

[0008] Preferably, a first flow balancing plate is provided on the intermediate pipeline, and the first flow balancing plate is located between the first orifice flowmeter Qv1 and the outlet of the first-stage centrifugal compressor.

[0009] Preferably, a third pressure sensor P3, a third temperature sensor T3 and a second mass flow meter Qm2 are sequentially arranged between the second gas cooler and the inlet of the second-stage centrifugal compressor along the direction of travel of the refrigerant, and a second orifice flow meter Qv2, a fourth temperature sensor T4 and a fourth pressure sensor P4 are sequentially arranged between the connection point of the air supply pipeline and the refrigeration pipeline and the outlet of the second-stage centrifugal compressor along the direction of travel of the refrigerant.

[0010] Preferably, a third flow equalizing plate is arranged between the outlet of the second-stage centrifugal compressor and the second orifice flowmeter Qv2, and a second regulating valve CV2, a third gas cooler and a liquid storage tank are arranged in sequence along the direction of refrigerant travel between the connection point of the air supply pipeline and the refrigeration pipeline and the fourth pressure sensor P4.

[0011] Preferably, an air intake pipeline is connected between the intermediate pipeline and the internal input interface of the compressor, and the connection between the air intake pipeline and the intermediate pipeline is located between the connection between the air supply pipeline and the intermediate pipeline and the second gas cooler, and a third regulating valve CV3 and a fourth gas cooler are sequentially arranged on the air intake pipeline along the direction of refrigerant travel, and an air outlet pipeline is connected between the internal output interface of the compressor and the refrigeration pipeline, and the connection between the air outlet pipeline and the refrigeration pipeline is located between the first regulating valve CV1 and the first gas cooler.

[0012] Preferably, a third mass flow meter Qm3, a fifth temperature sensor T5 and a fifth pressure sensor P5 are sequentially arranged along the direction of travel of the refrigerant between the fourth gas cooler and the internal input interface of the compressor, and a sixth pressure sensor P6, a sixth temperature sensor T6 and a fourth mass flow meter Qm4 are sequentially arranged along the direction of travel of the refrigerant on the outlet pipeline.

[0013] Preferably, a second flow balancing plate is provided on the intermediate pipeline, and the second flow balancing plate is located between the connection between the intake pipeline and the intermediate pipeline and the second gas cooler.

[0014] Preferably, a refrigerant recovery stop valve and a refrigerant filling joint are provided on the refrigeration pipeline, and the refrigerant recovery stop valve and the refrigerant filling joint are respectively located at the front and rear sides of the first regulating valve CV1.

[0015] Compared with the prior art, the present invention provides a centrifugal refrigeration compressor pneumatic performance test system, which can adjust the pressure and temperature of the refrigerant entering the first-stage centrifugal compressor through the cooperation of the first regulating valve CV1, the first gas cooler and the first electric heater on the refrigeration pipeline, and then adjust the pressure and temperature of the refrigerant entering the second-stage centrifugal compressor through the cooperation of the second gas cooler on the intermediate pipeline and the fourth regulating valve CV4, the fifth gas cooler and the second electric heater on the air supply pipeline, so that the refrigerant gas reaches the suction pressure and temperature required by the two-stage centrifugal refrigeration compressor to be tested, so that the performance of the two-stage centrifugal refrigeration compressor can be tested separately, thereby improving the test effect of the high-speed centrifugal refrigeration compressor, and optimizing the performance of the high-speed centrifugal refrigeration compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a diagram of the aerodynamic performance test system of the present invention; Figure 2is a cycle pressure-enthalpy diagram of the present invention; Figure 3 It is a working state diagram of the pneumatic performance testing system of the present invention. DETAILED DESCRIPTION

[0018] The present invention provides a centrifugal refrigeration compressor pneumatic performance test system. Figures 1 to 3 The present invention is described with reference to the structural schematic diagram of FIG.

[0019] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0020] The compressor is the core component of the refrigeration system, responsible for compressing the refrigerant so that it circulates in the system. The refrigeration system performs performance testing on the compressor, which can not only detect the operating status of the compressor under different working conditions and ensure that it can work normally under various conditions, but also obtain the parameters such as the compressor's cooling capacity, power consumption, and exhaust temperature under different loads. These data provide an important basis for subsequent performance analysis and adjustment. Through the analysis and comparison of the test data, it can be evaluated whether the performance indicators of the compressor meet the design requirements, and whether there are problems of low energy efficiency or unstable operation, and then optimize its energy efficiency and stability by adjusting the load control method and operating parameters of the compressor. High-speed centrifugal refrigeration compressors are simple in structure and high in efficiency, so they have developed very rapidly. The performance test of high-speed centrifugal refrigeration compressors requires performance evaluation of the centrifugal impeller that mainly does the work. Since the performance of the centrifugal impeller is more sensitive to changes in the inlet pressure, inlet temperature, and speed, the design optimization of the centrifugal impeller performance is also more dependent on the actual measured parameters of the inlet and outlet pressures, temperatures, and speeds, and the centrifugal impeller may experience surge, which requires certain protection measures. In addition, high-speed centrifugal compressors also need to cool the inside of the compressor, and special cooling pipelines need to be designed. However, conventional refrigeration compressor test systems use direct measurement of the heat that the compressor can remove as a metric, and there is no additional cooling pipeline to cool the inside of the compressor. Therefore, existing conventional refrigeration compressor test systems are difficult to effectively test the performance of high-speed centrifugal refrigeration compressors.

[0021] At present, high-speed centrifugal refrigeration compressors usually adopt two-stage compression. The outlet of the first-stage centrifugal compressor is connected to the inlet of the second-stage centrifugal compressor through a pipeline, and the outlet of the second-stage centrifugal compressor is connected to the inlet of the first-stage centrifugal compressor. After passing through the first-stage centrifugal compressor, the refrigerant enters the second-stage centrifugal compressor through a pipeline. After passing through the second-stage centrifugal compressor, the refrigerant enters the first-stage centrifugal compressor again through a pipeline to achieve circulation. Therefore, the performance of the first-stage centrifugal compressor and the second-stage centrifugal compressor will affect the performance of the refrigeration system. However, the existing test system can only test the performance of the first-stage centrifugal compressor or the two-stage series connection of the whole machine, and cannot test the aerodynamic performance of the first-stage centrifugal compressor and the second-stage centrifugal compressor separately. However, only testing the performance of the first-stage centrifugal compressor or the two-stage series connection results in poor testing results for the high-speed centrifugal refrigeration compressor, and it is difficult to optimize the performance of the high-speed centrifugal refrigeration compressor in an all-round way.

[0022] The prior art discloses a centrifugal refrigeration compressor testing device, with publication number CN210715046U. The defects of its technical solution include: it is impossible to control the temperature and pressure of the gas in the air supply circuit, it is impossible to measure the gas flow rate of the air supply circuit, and thus it is impossible to verify the performance changes under different air supply states; it can only measure the performance of a single-stage centrifugal refrigeration compressor, and cannot measure the performance of a two-stage compression centrifugal refrigeration compressor; it is impossible to measure the pneumatic performance of the second-stage centrifugal compressor alone; and it is impossible to provide a compressor cooling circuit for a centrifugal refrigeration compressor with a high-speed motor.

[0023] The prior art discloses a performance test system and method for an air-suspended refrigeration compressor, with publication number CN118273940A. The technical solution defects include: being unable to measure the performance of a centrifugal refrigeration compressor containing a refrigeration cycle with air replenishment demand; being able to control only the temperature, pressure and flow rate of the first-stage inlet, being unable to control the pressure, temperature and flow rate of the second-stage inlet, and being unable to perform a separate measurement of the second-stage performance; and being unable to measure the flow rate consumed by the air-suspended bearing.

[0024] The prior art discloses a closed-cycle test device and a test method for the overheating zone of a centrifugal refrigeration compressor, with the publication number CN107701484A. The defects of the technical solution include: it is impossible to measure the performance of a centrifugal refrigeration compressor containing a refrigeration cycle with an air replenishment demand; it can only control the temperature, pressure and flow of the first-stage inlet, but cannot control the pressure, temperature and flow of the second-stage inlet, and cannot perform a separate measurement of the second-stage performance; it is impossible to measure the flow consumed by the air bearing; and it is impossible to provide a compressor cooling circuit for a centrifugal refrigeration compressor with a high-speed motor.

[0025] Reference Figure 1 , Figure 1 The aerodynamic performance test system diagram of this embodiment is shown in FIG. Figure 1As shown, a centrifugal refrigeration compressor pneumatic performance test system is used to test a compressor having a first-stage centrifugal compressor 13 and a second-stage centrifugal compressor 4. The test system includes a refrigeration pipeline connected between the outlet of the second-stage centrifugal compressor 4 and the inlet of the first-stage centrifugal compressor 13. A first regulating valve CV1, a first gas cooler 11 and a first electric heater 12 are sequentially arranged along the refrigerant travel direction on the refrigeration pipeline. The refrigerant pressure entering the first-stage centrifugal compressor 13 is adjusted by the first regulating valve CV1. The intermediate pipeline is connected to the first A second gas cooler 3 is arranged on the intermediate pipeline between the outlet of the first-stage centrifugal compressor 13 and the inlet of the second-stage centrifugal compressor 4. The air supply pipeline is connected between the refrigeration pipeline and the intermediate pipeline. The connection between the air supply pipeline and the refrigeration pipeline is located on the front side of the first regulating valve CV1, and the connection between the air supply pipeline and the intermediate pipeline is located on the front side of the second gas cooler 3. A fourth regulating valve CV4, a fifth gas cooler 15 and a second electric heater 16 are sequentially arranged on the air supply pipeline along the direction of refrigerant travel. The refrigerant pressure in the air supply pipeline is regulated by the fourth regulating valve CV4.

[0026] A centrifugal refrigeration compressor pneumatic performance test system in the present embodiment is capable of performing performance tests on high-speed centrifugal refrigeration compressors. The temperature of the refrigerant when it enters the first-stage centrifugal compressor 13 is regulated by the first gas cooler 11 and the first electric heater 12, the intake pressure of the first-stage centrifugal compressor 13 is controlled by adjusting the first regulating valve CV1, the temperature of the refrigerant when it enters the second-stage centrifugal compressor 4 is regulated by the fifth gas cooler 15 and the second electric heater 16 of the air supply circuit, and the suction pressure of the second-stage centrifugal compressor 4 is controlled by regulating the fourth regulating valve CV4.

[0027] A centrifugal refrigeration compressor pneumatic performance test system in the present embodiment is capable of performing performance tests on high-speed centrifugal refrigeration compressors. The above-mentioned cycles in the present embodiment are all operated in the overheating zone. The entire process is simple, requires less equipment, is low in cost, and is simple and reliable to operate. While ensuring the service life of the overall components and operational safety, it can also ensure its convenient operability.

[0028] As a further optimization scheme, in this embodiment, a third orifice flow meter Qv3, a seventh temperature sensor T7 and a seventh pressure sensor P7 are sequentially arranged on the air supply pipeline along the direction of refrigerant travel. The third orifice flow meter Qv3, the seventh temperature sensor T7 and the seventh pressure sensor P7 are located on the rear side of the second electric heater 16.

[0029] In this embodiment, through the third orifice flowmeter Qv3, the seventh temperature sensor T7 and the seventh pressure sensor P7 on the air supply pipeline, the flow, temperature and pressure information of the refrigerant input from the air supply pipeline to the intermediate pipeline can be accurately collected, and the air supply pressure, air supply temperature and air supply flow related to the air supply pipeline can be controlled, thereby further improving the accuracy of the performance test of the high-speed centrifugal refrigeration compressor.

[0030] As a further optimization scheme, in this embodiment, a first mass flow meter Qm1, a first temperature sensor T1 and a first pressure sensor P1 are sequentially arranged along the direction of travel of the refrigerant between the first electric heater 12 and the inlet of the first-stage centrifugal compressor 13, and a first orifice flow meter Qv1, a second temperature sensor T2 and a second pressure sensor P2 are sequentially arranged along the direction of travel of the refrigerant between the connection point of the intermediate pipeline and the air supply pipeline and the outlet of the first-stage centrifugal compressor 13.

[0031] In this embodiment, the first mass flow meter Qm1, the first temperature sensor T1 and the first pressure sensor P1 on the refrigeration pipeline can collect the flow, temperature and pressure information of the refrigerant entering the first-stage centrifugal compressor 13. The first orifice flow meter Qv1, the second temperature sensor T2 and the second pressure sensor P2 on the intermediate pipeline can collect the flow, temperature and pressure information of the refrigerant when it is output from the first-stage centrifugal compressor 13. Based on the above collected information, the performance of the first-stage centrifugal compressor 13 can be accurately tested, further improving the accuracy of the performance test of the high-speed centrifugal refrigeration compressor.

[0032] As a further optimization solution, in this embodiment, a first flow balancing plate 1 is provided on the middle pipeline, and the first flow balancing plate 1 is located between the first orifice flowmeter Qv1 and the outlet of the first-stage centrifugal compressor 13 .

[0033] In this embodiment, the use of the first flow equalizing plate 1 can evenly distribute the refrigerant airflow output by the first-stage centrifugal compressor 13, avoid uneven distribution of the refrigerant, improve the stability of the refrigerant entering the second-stage centrifugal compressor 4, and further improve the accuracy of performance testing of high-speed centrifugal refrigeration compressors.

[0034] As a further optimization scheme, in this embodiment, a third pressure sensor P3, a third temperature sensor T3 and a second mass flow meter Qm2 are sequentially arranged between the second gas cooler 3 and the inlet of the second-stage centrifugal compressor 4 along the direction of travel of the refrigerant, and a second orifice flow meter Qv2, a fourth temperature sensor T4 and a fourth pressure sensor P4 are sequentially arranged between the connection point of the air supply pipeline and the refrigeration pipeline and the outlet of the second-stage centrifugal compressor 4 along the direction of travel of the refrigerant.

[0035] In this embodiment, the third pressure sensor P3, the third temperature sensor T3 and the second mass flow meter Qm2 on the intermediate pipeline can collect the flow rate, temperature and pressure information of the refrigerant entering the second-stage centrifugal compressor 4. The second orifice flow meter Qv2, the fourth temperature sensor T4 and the fourth pressure sensor P4 on the refrigeration pipeline can collect the flow rate, temperature and pressure information of the refrigerant when it is output from the second-stage centrifugal compressor 4. Based on the above collected information, the performance of the second-stage centrifugal compressor 4 can be accurately tested, further improving the accuracy of the performance test of the high-speed centrifugal refrigeration compressor.

[0036] As a further optimization scheme, in this embodiment, a third flow equalizing plate 5 is arranged between the outlet of the second-stage centrifugal compressor 4 and the second orifice flowmeter Qv2, and a second regulating valve CV2, a third gas cooler 6 and a liquid storage tank 8 are arranged in sequence along the direction of refrigerant travel between the connection point of the air supply pipeline and the refrigeration pipeline and the fourth pressure sensor P4.

[0037] In this embodiment, the refrigerant gas output by the second-stage centrifugal compressor 4 is made uniform by the third flow equalizing plate 5, and the second regulating valve CV2 and the third gas cooler 6 are used to adjust the pressure and temperature of the refrigerant gas output by the second-stage centrifugal compressor 4. After the adjustment, the refrigerant enters the liquid storage tank 8.

[0038] In this embodiment, the high-temperature and high-pressure refrigerant vapor at the outlet of the second-stage centrifugal compressor 4 to be tested is first cooled by the third gas cooler 6, and then gas throttling is performed according to demand to obtain the suction pressure required by the refrigeration compressor.

[0039] More importantly, since the centrifugal refrigeration compressor pneumatic performance test system of the present invention adopts a multi-point stepped cooling method instead of the traditional one-time cliff-type direct condensation operation method, the third gas cooler 6 no longer directly and drastically cools the temperature, but after the first gas cooling and throttling, it still keeps the refrigerant gas in a relatively high suction superheat state, and then passes through the first gas cooler 11 and the first electric heater 12 at the inlet of the first-stage centrifugal compressor for more precise temperature control, so that any suction temperature conditions can be obtained at the inlet of the compressor under test, and ensure that the refrigerant gas at the suction temperature is always in a specified superheated gas state rather than a vapor-liquid two-phase state.

[0040] As a further optimization scheme, in this embodiment, an air intake pipeline is connected between the middle pipeline and the internal input interface of the compressor. The connection between the air intake pipeline and the middle pipeline is located between the connection between the air supply pipeline and the middle pipeline and the second gas cooler 3. The third regulating valve CV3 and the fourth gas cooler 14 are sequentially arranged on the air intake pipeline along the direction of refrigerant travel. An air outlet pipeline is connected between the internal output interface of the compressor and the refrigeration pipeline. The connection between the air outlet pipeline and the refrigeration pipeline is located between the first regulating valve CV1 and the first gas cooler 11.

[0041] In this embodiment, the third regulating valve CV3 and the fourth gas cooler 14 on the intake pipe can adjust the pressure and temperature of the refrigerant entering the compressor for cooling, thereby cooling the compressor.

[0042] The air inlet pipeline and the air outlet pipeline in this embodiment can directly provide internal cooling for the air-floating high-speed compressor or the magnetic-floating high-speed compressor during a closed cycle.

[0043] In addition, the cooling pressure and flow rate of the cooling refrigerant can be controlled by regulating the fifth gas cooler and the fourth gas control valve, thereby conveniently adjusting the internal cooling flow rate and pressure required by different compressors.

[0044] In the above-mentioned embodiment, the fifth gas cooler 15 and the second electric heater 16 are used to control the temperature of the refrigerant at the outlet of the air supply circuit when it enters the second-stage centrifugal compressor 4. At the same time, when the fourth regulating valve CV4 is used to regulate the pressure of the refrigerant at the outlet of the air supply circuit, the third regulating valve CV3 can also be used to slightly reduce the pressure of the refrigerant entering the second-stage centrifugal compressor and adjust it to the target pressure to further meet the suction pressure of the second-stage centrifugal compressor 4. Through this control function, it is convenient to simulate different refrigeration cycle systems with intermediate throttling air supply, and it is convenient to measure the performance changes of the refrigeration compressor under different air supply temperatures and pressures.

[0045] As a further optimization scheme, in this embodiment, a third mass flow meter Qm3, a fifth temperature sensor T5 and a fifth pressure sensor P5 are sequentially arranged between the fourth gas cooler 14 and the internal input interface of the compressor along the direction of travel of the refrigerant, and a sixth pressure sensor P6, a sixth temperature sensor T6 and a fourth mass flow meter Qm4 are sequentially arranged on the outlet pipeline along the direction of travel of the refrigerant.

[0046] In this embodiment, the flow rate, temperature and pressure information of the refrigerant entering the compressor can be collected through the third mass flow meter Qm3, the fifth temperature sensor T5 and the fifth pressure sensor P5, and the amount, temperature and pressure information of the refrigerant flowing out of the compressor can be collected through the sixth pressure sensor P6, the sixth temperature sensor T6 and the fourth mass flow meter Qm4. Then, based on the collected information, the total amount of axial leakage of the centrifugal impeller of the compressor can be obtained, the internal leakage flow of the compressor can be measured, and corresponding data support can be provided for the development and design of the compressor, further improving the test effect of the high-speed centrifugal refrigeration compressor.

[0047] As a further optimization solution, in this embodiment, a second flow balancing plate 2 is provided on the middle pipeline, and the second flow balancing plate 2 is located between the connection between the intake pipeline and the middle pipeline and the second gas cooler 3 .

[0048] In this embodiment, the refrigerant gas output by the first-stage centrifugal compressor 13 and the refrigerant gas output by the air supply pipeline can be evenly mixed by the second flow equalizing plate 2, so that the two air flows are more uniform after merging.

[0049] As a further optimization scheme, in this embodiment, a refrigerant recovery stop valve 9 and a refrigerant filling connector 10 are provided on the refrigeration pipeline, and the refrigerant recovery stop valve 9 and the refrigerant filling connector 10 are respectively located on the front and rear sides of the first regulating valve CV1.

[0050] In this embodiment, the refrigerant recovery stop valve 9 and the refrigerant filling connector 10 are used to realize the refrigerant filling and recovery functions in the test system.

[0051] During the pneumatic performance test of the centrifugal refrigeration compressor, the refrigerant recovery stop valve 9 can also be opened to adjust the refrigerant filling amount of the entire system, thereby achieving the effect of regulating the inlet pressure of the compressor.

[0052] In this test system, by regulating the cooling water flow of each gas cooler, the cooling power of different coolers can be controlled, which is convenient for meeting the cooling needs of different positions in the system and is used to achieve different cooling effects on the refrigerant at different positions in the pipeline of the tested system.

[0053] The cooling of the cooling water in the above-mentioned embodiment can be replaced by a water chiller system or a cooling water temperature control system, so that the control accuracy of the water temperature is improved.

[0054] A centrifugal refrigeration compressor pneumatic performance testing system of the present invention can keep the refrigerant in a superheated gas state in the test system at all times, and can realize the active control function of any suction temperature and pressure conditions at the inlet of the multi-stage compressor being tested, alone or in combination, and can also add air supply gas circuit measurement and compressor internal cooling gas circuit measurement during the circulation process, thereby ensuring the overall service life and operational safety of the system while also ensuring its convenient operability.

[0055] In this embodiment, a test method for a centrifugal refrigeration compressor pneumatic performance test system is proposed to efficiently and quickly implement the performance test of the centrifugal refrigeration compressor, including the following steps: 1. Filling refrigerant: Before testing, open the refrigerant filling connector 10 to fill a specified amount of refrigerant into the compressor under test; 2. First gas throttling: the refrigerant gas passing through the liquid storage tank 8 is depressurized by the first regulating valve CV1. The opening of the first regulating valve CV1 makes the pressure of the refrigerant gas reach the suction pressure required by the first-stage centrifugal compressor 13; 3. First gas temperature adjustment: After passing through the first regulating valve CV1, the refrigerant gas that meets the suction pressure required by the compressor is cooled for the first time in the first gas cooler 11; the temperature of the refrigerant gas is adjusted to a preset temperature by adjusting the first gas cooler 11, or heated by the first electric heater 12, and the operating power of the first electric heater 12 is adjusted to more accurately adjust the superheat of the refrigerant; 4. Second gas throttling: The refrigerant gas compressed by the compressor is passed through the second regulating valve CV2 to adjust the compressor outlet pressure; by adjusting the opening of the second regulating valve CV2, the pressure of the refrigerant gas reaches the exhaust pressure required by the tested compressor; 5. Second gas temperature control: the refrigerant gas after the second gas throttling enters the third gas cooler 6, thereby realizing the second cooling operation; by adjusting the cooling flow through the third gas cooler 6, the temperature of the refrigerant gas is made to reach the suction temperature required by the compressor under test and the heat in the closed cycle pipeline is discharged.

[0056] In the above test method, the temperature, pressure and flow of the multi-stage compressor inlet can be regulated at the same time. By using the same compressor internal cooling method, the internal leakage flow of the compressor can be measured; by using the same compressor series air supply measurement method, the air supply pressure, air supply temperature and air supply flow related to the air supply circuit can be controlled; by using the same refrigerator cooling method, the required cooling function can be provided for the refrigerant at different positions in the pipeline, and the cooling effect can be adjusted by adjusting different cooling water flows; by using the same temperature adjustment method, an electric heater is used at the compressor inlet to increase the refrigerant temperature to ensure that the compressor inlet is in an overheated state; by using the same inlet pressure adjustment method, the compressor inlet pressure is adjusted by adjusting the compressor inlet valve or adjusting the cooling water temperature of the inlet heat exchanger.

[0057] The test method also includes a temperature and pressure adjustment step at the inlet of the second-stage centrifugal compressor 4. During the test, the fourth regulating valve CV4 of the air supply circuit is adjusted so that the pressure of the refrigerant gas reaches the intake pressure required by the inlet of the second-stage centrifugal compressor 4. The fifth gas cooler and the second electric heater of the air supply circuit are adjusted so that the temperature of the refrigerant gas reaches the suction temperature required by the inlet of the second-stage centrifugal compressor 4.

[0058] The test method also includes a step of adjusting the cooling pressure and temperature inside the compressor; during the test, the pressure of the refrigerant gas reaches the cooling pressure required for testing the inside of the compressor through the third regulating valve CV3 of the air intake pipeline. The temperature of the refrigerant gas reaches the cooling temperature required for testing the cooling inside the compressor by adjusting the fourth gas cooler of the air intake pipeline.

[0059] The test method also includes a pipeline internal pressure adjustment step; during the test, the refrigerant recovery stop valve 9 is opened to adjust the refrigerant charge in the system to adjust the exhaust pressure of the compressor under test.

[0060] In addition, the test method also includes a cooling and adjusting step of the refrigerant; during the test, the superheated refrigerant gas discharged from the second-stage centrifugal compressor will pass through the third gas cooler 6, the first gas cooler 11, the fifth gas cooler 15, the fourth gas cooler 14 and the second gas cooler 4. By adjusting the flow rate of the coolant of different gas coolers, the cooling function required by the refrigerant in different pipelines can be adjusted, thereby meeting the cooling requirements of the refrigerant at different positions in the pipeline.

[0061] Reference Figure 2 , Figure 2 is the cycle pressure-enthalpy diagram of this embodiment, as shown in Figure 2As shown, the solid line is the saturation curve of R134a, and the dotted line is a schematic diagram of various states of R134a in a closed cycle. Point 1 is the starting point of the first-stage compressor inlet, point 2 is the first-stage compressor outlet, point 2' represents the starting point of the second-stage centrifugal compressor inlet after mixing with the intermediate air supply, point 3 is the second-stage centrifugal compressor outlet, point 4 is the state after the pressure is reduced by the second-stage outlet expansion valve, point 5 is the gas after passing through the second-stage outlet gas cooler, point 7 is the branch point of the intermediate air supply state, point 6 is the gas after passing through the first-stage centrifugal compressor inlet expansion valve, and then returns to point 1 after being cooled by the first-stage inlet gas cooler.

[0062] Reference Figure 2 , Figure 2 is the cycle pressure-enthalpy diagram of this embodiment, as shown in Figure 2 As shown, Figure 3 exist Figure 1 On the basis of the above, a cooling water circulation pipeline is added, and a cooling water circulation pump P and various cooling valves are arranged in sequence on the water tank W along the water pipeline, among which: The cooling water returns to the water tank W through valve a; The cooling water passes through valve b and enters the third gas cooler 6, cools the refrigerant at the second stage outlet, passes through the cooling fan F and then returns to the water tank W; The cooling water passes through valve c and enters the second gas cooler 3, cools the refrigerant at the first-stage outlet, passes through the cooling fan F, and then returns to the water tank W; The cooling water passes through valve d and enters the fourth gas cooler 14, cools the refrigerant at the air-cooled inlet of the compressor, and then passes through the cooling fan F and returns to the water tank W; The cooling water passes through valve e and enters the first gas cooler 11, cools the refrigerant at the inlet of the first-stage centrifugal compressor, and then passes through the cooling fan F and returns to the water tank W; The cooling water passes through valve f, the fifth gas cooler 15, cools the refrigerant in the air supply path, and then passes through the cooling fan F and returns to the water tank W.

[0063] The cooling water circulation pipeline can first dissipate heat and take away the heat in the pipeline. At the same time, the working medium temperature at the outlet of each gas cooler can be controlled by adjusting the water valve. For example, if 50kw of heat is taken away, the water flow rate through different coolers can be controlled to take away 50kw of heat while adjusting and controlling the working medium temperature at the outlet of a gas cooler.

[0064] The above disclosure is only a preferred specific embodiment of the present invention, but the embodiments of the present invention are not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A centrifugal refrigeration compressor pneumatic performance test system, used for testing a compressor having a first-stage centrifugal compressor (13) and a second-stage centrifugal compressor (4), characterized in that: The test system includes: a refrigeration pipeline connected between the outlet of the second-stage centrifugal compressor (4) and the inlet of the first-stage centrifugal compressor (13); a first regulating valve CV1, a first gas cooler (11) and a first electric heater (12) are sequentially arranged on the refrigeration pipeline along the direction of travel of the refrigerant, and the pressure of the refrigerant entering the first-stage centrifugal compressor (13) is regulated by the first regulating valve CV1; an intermediate pipeline connected between the outlet of the first-stage centrifugal compressor (13) and the inlet of the second-stage centrifugal compressor (4), wherein a second gas cooler (3) is arranged on the intermediate pipeline; The air supply pipeline is connected between the refrigeration pipeline and the intermediate pipeline. The connection between the air supply pipeline and the refrigeration pipeline is located in front of the first regulating valve CV1. The connection between the air supply pipeline and the intermediate pipeline is located in front of the second gas cooler (3). The fourth regulating valve CV4, the fifth gas cooler (15), and the second electric heater (16) are sequentially arranged along the direction of refrigerant flow on the air supply pipeline. The refrigerant pressure in the air supply pipeline is regulated by the fourth regulating valve CV4.

2. A centrifugal refrigeration compressor pneumatic performance test system according to claim 1, characterized in that: A third orifice flow meter Qv3, a seventh temperature sensor T7 and a seventh pressure sensor P7 are sequentially arranged along the refrigerant travel direction on the air supply pipeline, and the third orifice flow meter Qv3, the seventh temperature sensor T7 and the seventh pressure sensor P7 are located on the rear side of the second electric heater (16).

3. A centrifugal refrigeration compressor pneumatic performance test system according to claim 1, characterized in that: A first mass flow meter Qm1, a first temperature sensor T1 and a first pressure sensor P1 are sequentially arranged between the first electric heater (12) and the inlet of the first-stage centrifugal compressor (13) along the direction of travel of the refrigerant, and a first orifice flow meter Qv1, a second temperature sensor T2 and a second pressure sensor P2 are sequentially arranged between the connection point between the intermediate pipeline and the air supply pipeline and the outlet of the first-stage centrifugal compressor (13) along the direction of travel of the refrigerant.

4. A centrifugal refrigeration compressor pneumatic performance test system according to claim 3, characterized in that: A first flow balancing plate (1) is provided on the intermediate pipeline, and the first flow balancing plate (1) is located between the first orifice plate flow meter Qv1 and the outlet of the first-stage centrifugal compressor (13).

5. A centrifugal refrigeration compressor pneumatic performance test system according to claim 1, characterized in that: A third pressure sensor P3, a third temperature sensor T3 and a second mass flow meter Qm2 are arranged in sequence between the second gas cooler (3) and the inlet of the second-stage centrifugal compressor (4) along the direction of travel of the refrigerant, and a second orifice flow meter Qv2, a fourth temperature sensor T4 and a fourth pressure sensor P4 are arranged in sequence between the connection point of the air supply pipeline and the refrigeration pipeline and the outlet of the second-stage centrifugal compressor (4) along the direction of travel of the refrigerant.

6. A centrifugal refrigeration compressor pneumatic performance test system according to claim 5, characterized in that: A third flow equalizing plate (5) is provided between the outlet of the second-stage centrifugal compressor (4) and the second orifice flowmeter Qv2, and a second regulating valve CV2, a third gas cooler (6) and a liquid storage tank (8) are provided in sequence along the refrigerant travel direction between the connection point of the air supply pipeline and the refrigeration pipeline and the fourth pressure sensor P4.

7. A centrifugal refrigeration compressor pneumatic performance test system according to claim 1, characterized in that: An air intake pipeline is connected between the intermediate pipeline and the internal input interface of the compressor. The connection between the air intake pipeline and the intermediate pipeline is located between the connection between the air supply pipeline and the intermediate pipeline and the second gas cooler (3). A third regulating valve CV3 and a fourth gas cooler (14) are sequentially arranged along the direction of travel of the refrigerant on the air intake pipeline. An air outlet pipeline is connected between the internal output interface of the compressor and the refrigeration pipeline. The connection between the air outlet pipeline and the refrigeration pipeline is located between the first regulating valve CV1 and the first gas cooler (11).

8. A centrifugal refrigeration compressor pneumatic performance test system according to claim 7, characterized in that: A third mass flow meter Qm3, a fifth temperature sensor T5 and a fifth pressure sensor P5 are sequentially arranged between the fourth gas cooler (14) and the internal input interface of the compressor along the direction of travel of the refrigerant, and a sixth pressure sensor P6, a sixth temperature sensor T6 and a fourth mass flow meter Qm4 are sequentially arranged on the outlet pipe along the direction of travel of the refrigerant.

9. A centrifugal refrigeration compressor pneumatic performance test system according to claim 7, characterized in that: A second flow balancing plate (2) is provided on the intermediate pipeline, and the second flow balancing plate (2) is located between the connection between the intake pipeline and the intermediate pipeline and the second gas cooler (3).

10. A centrifugal refrigeration compressor pneumatic performance test system according to claim 7, characterized in that: The refrigeration pipeline is provided with a refrigerant recovery stop valve (9) and a refrigerant filling joint (10), and the refrigerant recovery stop valve (9) and the refrigerant filling joint (10) are respectively located at the front and rear sides of the first regulating valve CV1.

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