Testing device and method for measuring heat exchange performance of thermosyphon evaporator

Abstract

The invention provides a test device and method for measuring the heat exchange performance of a thermosyphon evaporator, and belongs to the technical field of heat exchangers. The device comprises a refrigeration compressor, an oil-gas separator, a high-pressure condenser, a cooling tower, a circulating water tank, a circulating water pump, a liquid reservoir, a gas-liquid separator, a thermosyphon evaporator, a secondary refrigerant water tank, a secondary refrigerant pump and a mixing tank which are communicated with one another, and monitoring the measuring instrument for the test according to a specified time interval and recording data through the computer, and calculating the total heat transfer coefficient of the thermosyphon evaporator. By adjusting the height of the gas-liquid separator and utilizing the ratio of the mass flow measured at the liquid inlet of the thermosyphon evaporator to the gas mass flow of the gas-liquid two-phase flow measured at the gas outlet of the thermosyphon evaporator, the refrigerant circulation multiplying power under different liquid column static pressure heads is measured and calculated, and better test data support can be provided for the pipeline design of the thermosyphon evaporator.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchangers, and relates to a test device for a heat exchanger, in particular to a test device and method for measuring the heat exchange performance of a thermosyphon evaporator. Background Art

[0002] The thermosyphon evaporator for air conditioners and refrigeration systems uses the density difference between the liquid refrigerant supply side and the gas refrigerant outlet side and the liquid column static head of the liquid refrigerant supply pipe as the driving force for the forced circulation of the refrigerant to perform heat exchange. After the refrigerant obtains heat, it vaporizes, and after the cooling medium obtains cold, its temperature drops. The main factors affecting the heat exchange performance of the thermosyphon evaporator include the liquid column static head, that is, the liquid column height of the supply pipe, the supply subcooling degree, and the structural design of the thermosyphon evaporator itself. To evaluate the heat exchange performance of a thermosyphon evaporator, tests are usually required under the liquid column static head specified in the design. When testing the thermosyphon evaporator, it is necessary to determine the liquid column static head according to the on-site installation conditions and working conditions. Therefore, the liquid column static heads of different thermosyphon evaporators are different, and it is impossible to design and build a test platform for each thermosyphon evaporator. This requires the test device for the thermosyphon evaporator to be universal. Summary of the Invention

[0003] An object of the present invention is to address the above problems existing in the prior art and propose a test device for measuring the heat exchange performance of a thermosyphon evaporator, which can evaluate the heat exchange performance of the thermosyphon evaporator for air conditioners and refrigeration systems under different supply subcooling degrees and different liquid column static heads of the supply liquid, and has universality.

[0004] The object of the present invention can be achieved by the following technical solutions: An experimental device for measuring the heat exchange performance of a thermosyphon evaporator, comprising a refrigeration compressor, an oil-gas separator, a high-pressure condenser, a cooling tower, a circulating water tank, a circulating water pump, a liquid receiver, a gas-liquid separator, a thermosyphon evaporator, a secondary refrigerant water tank, a secondary refrigerant pump and a mixing tank, characterized in that the suction port of the refrigeration compressor is communicated with the outlet pipe of the gas-liquid separator, the discharge port of the refrigeration compressor is communicated with the inlet port of the oil-gas separator, the outlet port of the oil-gas separator is communicated with the inlet port of the high-pressure condenser, the liquid outlet of the high-pressure condenser is communicated with the liquid inlet of the liquid receiver, the liquid outlet of the liquid receiver is communicated with the inlet port of the gas-liquid separator, and a throttle valve is communicated on the pipeline between the liquid outlet of the liquid receiver and the inlet port of the gas-liquid separator. The liquid outlet of the gas-liquid separator is communicated with the liquid inlet of the thermosyphon evaporator, the gas outlet of the thermosyphon evaporator is communicated with the inlet port of the gas-liquid separator, the water outlet of the high-pressure condenser is communicated with the water inlet of the cooling tower, the water outlet of the cooling tower is communicated with the water inlet of the circulating water tank, the water outlet of the circulating water tank is communicated with the water inlet of the mixing tank, the water outlet of the mixing tank is communicated with the water inlet of the circulating water pump, the water outlet of the circulating water pump is communicated with the water inlet of the high-pressure condenser, the secondary refrigerant outlet of the thermosyphon evaporator is communicated with the water inlet of the secondary refrigerant water tank, the water outlet of the secondary refrigerant water tank is communicated with the water inlet of the secondary refrigerant pump, and the water outlet of the secondary refrigerant pump is communicated with the secondary refrigerant inlet of the thermosyphon evaporator. Experimental measuring instruments are respectively arranged on the above-mentioned connected pipelines.

[0005] In the above test device for measuring the heat exchange performance of a thermosyphon evaporator, a circulating water outlet pressure gauge, a circulating water outlet thermometer and a circulating water mass flowmeter are connected to the pipeline between the outlet of the high-pressure condenser and the inlet of the cooling tower. The circulating water outlet pressure gauge and the circulating water outlet thermometer are infinitely close to the outlet of the high-pressure condenser. A circulating water inlet thermometer 1 is connected to the pipeline between the outlet of the circulating water tank and the inlet of the mixing tank. A circulating water inlet pressure gauge and a circulating water inlet thermometer 2 are connected to the pipeline between the outlet of the circulating water pump and the inlet of the high-pressure condenser. The circulating water inlet pressure gauge and the circulating water inlet thermometer 2 are infinitely close to the inlet of the high-pressure condenser. A refrigerant inlet thermometer, a refrigerant inlet pressure gauge and a refrigerant liquid mass flowmeter are connected to the pipeline between the liquid outlet of the gas-liquid separator and the liquid inlet of the thermosyphon evaporator. The refrigerant inlet thermometer and the refrigerant inlet pressure gauge are infinitely close to the liquid inlet of the thermosyphon evaporator. A refrigerant two-phase flow gas mass flowmeter, a refrigerant gas thermometer and a refrigerant gas pressure gauge are connected to the pipeline between the gas outlet of the thermosyphon evaporator and the gas inlet of the gas-liquid separator. The refrigerant gas thermometer and the refrigerant gas pressure gauge are infinitely close to the gas outlet of the thermosyphon evaporator. A coolant outlet mass flowmeter, a coolant outlet thermometer and a coolant outlet pressure gauge are connected to the pipeline between the coolant outlet of the thermosyphon evaporator and the inlet of the coolant tank. The coolant outlet thermometer and the coolant outlet pressure gauge are infinitely close to the coolant outlet of the thermosyphon evaporator. A coolant inlet thermometer and a coolant inlet pressure gauge are connected to the pipeline between the outlet of the coolant pump and the inlet of the thermosyphon evaporator. The coolant inlet thermometer and the coolant inlet pressure gauge are infinitely close to the coolant inlet of the thermosyphon evaporator.

[0006] In the above test device for measuring the heat exchange performance of a thermosyphon evaporator, the coolant outlet of the thermosyphon evaporator is also connected to the mixing tank through a branch pipeline. The branch pipeline is located after the outlets of the coolant outlet mass flowmeter, the coolant outlet thermometer and the coolant outlet pressure gauge. A switching valve is provided on the branch pipeline, and a coolant bypass thermometer is connected at a position infinitely close to the mixing tank.

[0007] In the above test device for measuring the heat exchange performance of a thermosyphon evaporator, the gas-liquid separator is arranged on a liftable platform or track. The barrel of the thermosyphon evaporator is provided with scales for measuring the distance dimension between the lowest position of the barrel of the thermosyphon evaporator and the liquid level position of the gas-liquid separator. The height of the gas-liquid separator can be adjusted as needed so that the relative height between the lowest position of the barrel of the thermosyphon evaporator and the liquid level position of the gas-liquid separator meets the static pressure of the supply liquid column of the thermosyphon evaporator. Setting the above scales can visually observe this relative height, which is convenient for monitoring, recording and adjustment.

[0008] In the above-mentioned test device for measuring the heat exchange performance of a thermosyphon evaporator, the test measuring instruments are controlled by a computer and data is recorded.

[0009] In the above-mentioned test device for measuring the heat exchange performance of a thermosyphon evaporator, at least one section of the liquid pipeline between the liquid storage tank and the gas-liquid separator is a flexible pipeline, at least one section of the liquid pipeline and the gas pipeline between the gas-liquid separator and the thermosyphon evaporator are each a flexible pipeline, and at least one section of the gas pipeline between the gas-liquid separator and the refrigeration compressor is a flexible pipeline.

[0010] In the above-mentioned test device for measuring the heat exchange performance of a thermosyphon evaporator, each of the flexible pipelines has an adjustable amount of at least 3 meters in length.

[0011] The object of the present invention can be achieved by the following another technical solution: A test method applied to the above-mentioned test device for measuring the heat exchange performance of a thermosyphon evaporator, characterized in that after the above-mentioned test device operates stably, the height of the gas-liquid separator is adjusted so that the vertical height of its liquid level from the lowest position of the thermosyphon evaporator cylinder body meets the liquid column static pressure head required by the design, and the test measuring instruments are monitored by a computer at a specified time interval and data is recorded.

[0012] In the above-mentioned test method applied to the above-mentioned test device for measuring the heat exchange performance of a thermosyphon evaporator, the computer monitors the coolant outlet mass flowmeter, coolant inlet thermometer, coolant inlet pressure gauge, coolant outlet thermometer, coolant outlet pressure gauge, refrigerant inlet thermometer, refrigerant inlet pressure gauge, refrigerant liquid mass flowmeter, refrigerant two-phase flow gas-phase mass flowmeter, refrigerant gas thermometer and refrigerant gas pressure gauge. First, the data of the coolant outlet mass flowmeter, coolant inlet thermometer, coolant inlet pressure gauge, refrigerant inlet thermometer, refrigerant outlet pressure gauge and refrigerant liquid mass flowmeter are recorded, and after a delay of T seconds, the data of the coolant outlet thermometer, coolant outlet pressure gauge, refrigerant two-phase flow gas-phase mass flowmeter, refrigerant gas thermometer and refrigerant gas pressure gauge are recorded, and the total heat transfer coefficient K of the thermosyphon evaporator is calculated through the above data.

[0013] In the above-mentioned test method applied to the above-mentioned test device for measuring the heat exchange performance of a thermosyphon evaporator, it consists of the following steps:

[0014] Step 1. Record instrument data: The data recorded by the coolant outlet mass flowmeter is the coolant mass flow M2, the data recorded by the coolant inlet thermometer is the coolant inlet temperature T 2-1 , the data recorded by the coolant inlet pressure gauge is the coolant inlet pressure P 2-1 , the data recorded by the coolant outlet thermometer is the coolant outlet temperature T2-2 , the data recorded by the secondary refrigerant inlet pressure gauge is the secondary refrigerant outlet pressure P 2-2 , the data recorded by the refrigerant liquid mass flowmeter is the refrigerant liquid mass flow M L , the data recorded by the refrigerant inlet pressure gauge is the refrigerant liquid inlet temperature T L , the data recorded by the refrigerant inlet thermometer is the refrigerant liquid inlet pressure P L , the data recorded by the refrigerant two-phase flow gas mass flowmeter is the two-phase flow refrigerant gas mass flow M G , the data recorded by the refrigerant gas thermometer is the two-phase flow refrigerant temperature T G , the data recorded by the refrigerant gas pressure gauge is the two-phase flow refrigerant pressure P G ;

[0015] Step 2. Calculate the heat transfer quantity Q: The cooling capacity released by the refrigerant in the thermosyphon evaporator is Q C , Q C = M L * (h1 - h2), where h1 is the enthalpy value at the refrigerant liquid inlet temperature and h2 is the enthalpy value at the two-phase refrigerant outlet temperature. h1 and h2 can be obtained from relevant literature;

[0016] The heat released by the secondary refrigerant in the thermosyphon evaporator is Q H , Q H = M2 * Cp2 * (T 2-11 - T 2-2 ), where Cp2 is the specific heat of the secondary refrigerant at the average temperature and can be obtained from relevant literature;

[0017] The average temperature of the secondary refrigerant is equal to T 2-1 + T 2-2 / 2;

[0018] When the values of Q C and Q H differ by no more than 5%, take the heat transfer quantity Q = Q C + Q H / 2 as the heat transfer quantity of the thermosyphon evaporator; when the values of Q C and Q H differ by no more than 5%, check whether the test device is abnormal, and after troubleshooting, re-measure the above parameters and recalculate until the Q value meets the requirements;

[0019] Step 3. Calculate the overall heat transfer coefficient K of the thermosyphon evaporator: A is the heat transfer area of the thermosyphon evaporator, A = π * d i * L * N, where π is a constant, d i is the inner diameter of the heat exchange tube, L is the effective heat exchange length of the heat exchange tube, N is the number of heat exchange tubes, and △Tm is the average logarithmic heat transfer temperature difference, the average logarithmic heat transfer temperature difference The pressure loss △P of the thermosyphon evaporator = P 2-1 -P 2-2 .

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. By adjusting the height of the gas-liquid separator, the refrigerant circulation ratio under different liquid column static heads is calculated by using the ratio of the mass flow rate measured at the liquid inlet of the thermosyphon evaporator to the gas mass flow rate of the gas-liquid two-phase flow measured at the gas outlet, which can provide better experimental data support for the pipeline design of the thermosyphon evaporator.

[0022] 2. By adjusting the height of the gas-liquid separator to meet the experimental conditions of different liquid column static heads, the test device has strong versatility and avoids the repeated construction of the test device.

[0023] 3. The overall heat transfer coefficient of the thermosyphon evaporator is checked by the heat balance method, and the calculated overall heat transfer coefficient has higher accuracy.

[0024] 4. The flow rate, pressure and temperature parameters of the liquid refrigerant inlet, gas-liquid two-phase refrigerant outlet, coolant inlet and coolant outlet of the thermosyphon evaporator are recorded by computer control, avoiding errors caused by flow fluctuations.

[0025] 5. Introducing the coolant outlet branch into the mixing tank can reduce the temperature of the circulating water entering the condenser (the temperature of the mixed circulating water is lower than the temperature of the circulating water in the circulating water tank, that is, the temperature measured by the second circulating water inlet thermometer is lower than the temperature measured by the first circulating water inlet thermometer), and reduce the outlet liquid temperature (condensation temperature) of the high-pressure condenser, so that the refrigerating capacity of the same refrigeration compressor will increase, broadening the application range of the test device. Brief Description of the Drawings

[0026] Figure 1 is the system flow chart of the first embodiment of the present invention.

[0027] Figure 2 is the system flow chart of the second embodiment of the present invention.

[0028] In the figure, 1 is a refrigeration compressor; 2 is an oil-gas separator; 3 is a high-pressure condenser; 4 is a cooling tower; 5 is a circulating water tank; 6 is a circulating water pump; 7 is a liquid receiver; 8 is a gas-liquid separator; 9 is a thermosyphon evaporator; 10 is a secondary refrigerant water tank; 11 is a secondary refrigerant pump; 12 is a circulating water outlet pressure gauge; 13 is a circulating water outlet thermometer; 14 is a circulating water mass flowmeter; 15 is a circulating water inlet thermometer I; 16 is a circulating water inlet pressure gauge; 17 is a circulating water inlet thermometer II; 18 is a secondary refrigerant bypass thermometer; 19 is a secondary refrigerant outlet mass flowmeter; 20 is a secondary refrigerant inlet thermometer; 21 is a secondary refrigerant inlet pressure gauge; 22 is a secondary refrigerant outlet thermometer; 23 is a secondary refrigerant outlet pressure gauge; 24 is a refrigerant inlet thermometer; 25 is a refrigerant inlet pressure gauge; 26 is a refrigerant liquid mass flowmeter; 27 is a refrigerant two-phase flow gas mass flowmeter; 28 is a refrigerant gas thermometer; 29 is a refrigerant gas pressure gauge; 30 is a mixing tank; 31 is a throttle valve; 32 is a switching valve. Specific Embodiments

[0029] The following are specific embodiments of the present invention and, in conjunction with the accompanying drawings, further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0030] Refer to Figure 1, the first embodiment is an experimental device for measuring the heat exchange performance of a thermosyphon evaporator, including a refrigeration compressor 1, an oil-gas separator 2, a high-pressure condenser 3, a cooling tower 4, a circulating water tank 5, a circulating water pump 6, a liquid receiver 7, a gas-liquid separator 8, a thermosyphon evaporator 9, a secondary refrigerant tank 10, a secondary refrigerant pump 11, and a mixing tank 30. The suction port of the refrigeration compressor 1 is connected to the outlet pipe of the gas-liquid separator 8, the discharge port of the refrigeration compressor 1 is connected to the inlet port of the oil-gas separator 2, the outlet port of the oil-gas separator 2 is connected to the inlet port of the high-pressure condenser 3, the liquid outlet of the high-pressure condenser 3 is connected to the liquid inlet of the liquid receiver 7, the liquid outlet of the liquid receiver 7 is connected to the inlet port of the gas-liquid separator 8, and a throttle valve 31 is connected to the pipeline between the liquid outlet of the liquid receiver 7 and the inlet port of the gas-liquid separator 8. The liquid outlet of the gas-liquid separator 8 is connected to the liquid inlet of the thermosyphon evaporator 9, the gas outlet of the thermosyphon evaporator 9 is connected to the inlet port of the gas-liquid separator 8, the water outlet of the high-pressure condenser 3 is connected to the water inlet of the cooling tower 4, the water outlet of the cooling tower 4 is connected to the water inlet of the circulating water tank 5, the water outlet of the circulating water tank 5 is connected to the water inlet of the mixing tank 30, the water outlet of the mixing tank 30 is connected to the water inlet of the circulating water pump 6, the water outlet of the circulating water pump 6 is connected to the water inlet of the high-pressure condenser 3, the secondary refrigerant outlet of the thermosyphon evaporator 9 is connected to the water inlet of the secondary refrigerant tank 10, the water outlet of the secondary refrigerant tank 10 is connected to the water inlet of the secondary refrigerant pump 11, and the water outlet of the secondary refrigerant pump 11 is connected to the secondary refrigerant inlet of the thermosyphon evaporator 9. Test measuring instruments are respectively arranged on the above-mentioned connected pipelines.

[0031] The specific test measuring instruments arranged on each connected pipeline are as follows: A circulating water outlet pressure gauge 12, a circulating water outlet thermometer 13, and a circulating water mass flowmeter 14 are connected to the pipeline between the water outlet of the high-pressure condenser 3 and the water inlet of the cooling tower 4. The circulating water outlet pressure gauge 12 and the circulating water outlet thermometer 13 are infinitely close to the water outlet of the high-pressure condenser 3. A circulating water inlet thermometer 15 is connected to the pipeline between the water outlet of the circulating water tank 5 and the water inlet of the mixing tank 30. A circulating water inlet pressure gauge 16 and a circulating water inlet thermometer 2 17 are connected to the pipeline between the water outlet of the circulating water pump 6 and the water inlet of the high-pressure condenser 3. The circulating water inlet pressure gauge 16 and the circulating water inlet thermometer 2 17 are infinitely close to the water inlet of the high-pressure condenser 3. A refrigerant inlet thermometer 24, a refrigerant inlet pressure gauge 25, and a refrigerant liquid mass flowmeter 26 are connected to the pipeline between the liquid outlet of the gas-liquid separator 8 and the liquid inlet of the thermosyphon evaporator 9. The refrigerant inlet thermometer 24 and the refrigerant inlet pressure gauge 25 are infinitely close to the liquid inlet of the thermosyphon evaporator 9. A refrigerant two-phase flow gas mass flowmeter 27, a refrigerant gas thermometer 28, and a refrigerant gas pressure gauge 29 are connected to the pipeline between the gas outlet of the thermosyphon evaporator 9 and the gas inlet of the gas-liquid separator 8. The refrigerant gas thermometer 28 and the refrigerant gas pressure gauge 29 are infinitely close to the gas outlet of the thermosyphon evaporator 9. A coolant outlet mass flowmeter 19, a coolant outlet thermometer 22, and a coolant outlet pressure gauge 23 are connected to the pipeline between the coolant outlet of the thermosyphon evaporator 9 and the water inlet of the coolant tank 10. The coolant outlet thermometer 22 and the coolant outlet pressure gauge 23 are infinitely close to the coolant outlet of the thermosyphon evaporator 9. A coolant inlet thermometer 20 and a coolant inlet pressure gauge 21 are connected to the pipeline between the outlet of the coolant pump 11 and the inlet of the thermosyphon evaporator 9. The coolant inlet thermometer 20 and the coolant inlet pressure gauge 21 are infinitely close to the coolant inlet of the thermosyphon evaporator 9. The term "infinitely close" described in the first embodiment of the present invention means that each test measuring instrument is as close as possible without contact, aiming to minimize the temperature change caused by the pipeline length and make the measured temperature closer to the temperature of the internal medium of the heat exchanger.

[0032] The gas-liquid separator 8 is arranged on a liftable platform or track. The cylinder body of the thermosyphon evaporator 9 is provided with a scale for measuring the distance dimension between the lowest position of the cylinder body of the thermosyphon evaporator 9 and the liquid level position of the gas-liquid separator 8. At least one section of the liquid pipeline between the liquid storage vessel 7 and the gas-liquid separator 8 is a flexible pipeline. At least one section of the liquid pipeline and the gas pipeline between the gas-liquid separator 8 and the thermosyphon evaporator 9 are each a flexible pipeline. At least one section of the gas pipeline between the gas-liquid separator 8 and the refrigeration compressor is a flexible pipeline. After being set as a flexible pipeline, the pipeline length can be adjusted to adapt to the lifting of the gas-liquid separator 8, so as to meet the need for establishing different liquid column static heads for the thermosyphon evaporator to supply liquid.

[0033] Each flexible pipe has an adjustable amount of at least 3 meters in length. The hydrostatic pressure of the liquid column in the thermosyphon evaporator is affected by the evaporator temperature of the material. The higher the evaporation temperature of the material, the greater the required hydrostatic pressure of the liquid column. According to simulation calculations, when the refrigerant evaporation temperature is about 15 °C, the optimal hydrostatic pressure of the liquid column is about 3.5 meters. After the flexible pipe has an adjustable amount of at least 3 meters in length, it can meet the requirements of this test device.

[0034] In the first embodiment, each test measuring instrument is controlled by a computer and data is recorded. Specifically, after the operation of the above test device is stable, the height of the gas-liquid separator 8 is adjusted so that the vertical height of its liquid level from the lowest position of the cylinder body of the thermosyphon evaporator 9 meets the hydrostatic head of the liquid column required by the design. The computer monitors the test measuring instruments at a specified time interval and records the data. Specifically, the computer monitors the coolant outlet mass flowmeter 19, the coolant inlet thermometer 20, the coolant inlet pressure gauge 21, the coolant outlet thermometer 22, the coolant outlet pressure gauge 23, the refrigerant inlet thermometer 24, the refrigerant inlet pressure gauge 25, and the refrigerant liquid mass flowmeter 26, the refrigerant two-phase flow gas mass flowmeter 27, the refrigerant gas thermometer 28, and the refrigerant gas pressure gauge 29. First, record the data of the coolant outlet mass flowmeter 19, the coolant inlet thermometer 20, the coolant inlet pressure gauge 21, the refrigerant inlet thermometer 24, the refrigerant inlet pressure gauge 25, and the refrigerant liquid mass flowmeter 26. After a delay of T seconds, record the data of the coolant outlet thermometer 22, the coolant outlet pressure gauge 23, the refrigerant two-phase flow gas mass flowmeter 27, the refrigerant gas thermometer 28, and the refrigerant gas pressure gauge 29.

[0035] In the first embodiment, the specific steps of the test method using the above test device for measuring the heat exchange performance of the thermosyphon evaporator are as follows:

[0036] Step 1: The computer monitors and records the instrument data: The data recorded by the coolant outlet mass flowmeter 19 is the coolant mass flow M2, and the data recorded by the coolant inlet thermometer 20 is the coolant inlet temperature T 2-1 , and the data recorded by the coolant inlet pressure gauge 21 is the coolant inlet pressure P 2-1 , and the data recorded by the coolant outlet thermometer 22 is the coolant outlet temperature T 2-2 , and the data recorded by the coolant inlet pressure gauge 21 is the coolant outlet pressure P 2-2 , and the data recorded by the refrigerant liquid mass flowmeter 26 is the refrigerant liquid mass flow M L , and the data recorded by the refrigerant inlet pressure gauge 25 is the refrigerant liquid inlet temperature T L , and the data recorded by the refrigerant inlet thermometer 24 is the refrigerant liquid inlet pressure P L, the data recorded by the refrigerant two-phase flow gas mass flowmeter 27 is the two-phase flow refrigerant gas mass flow M G , the data recorded by the refrigerant gas thermometer 28 is the two-phase flow refrigerant temperature T G , the data recorded by the refrigerant gas pressure gauge 29 is the two-phase flow refrigerant pressure P G ;

[0037] Step 2. Calculate the heat transfer quantity Q: The cooling capacity released by the refrigerant in the thermosiphon evaporator 9 is Q C , Q C = M L *(h1 - h2), where h1 is the enthalpy value at the refrigerant liquid inlet temperature and h2 is the enthalpy value at the two-phase refrigerant outlet temperature;

[0038] The heat released by the secondary refrigerant in the thermosiphon evaporator 9 is Q H , Q H = M2 * Cp2 * (T 2-1 - T 2-2 ), where Cp2 is the specific heat of the secondary refrigerant at the average temperature;

[0039] The average temperature of the secondary refrigerant is equal to T 2-1 + T 2-2 / 2;

[0040] When the values of Q C and Q H differ by no more than 5%, take the heat transfer quantity Q = Q C + Q H / 2 as the heat transfer quantity of the thermosiphon evaporator 9; when the values of Q C and Q H differ by no more than 5%, check whether the test device is abnormal, and after troubleshooting, re-measure the above parameters and recalculate until the Q value meets the requirements;

[0041] Step 3. Calculate the overall heat transfer coefficient K of the thermosiphon evaporator 9: A is the heat transfer area of the thermosiphon evaporator, A = π * d i * L * N, π is a constant, d i is the inner diameter of the heat exchange tube, L is the effective heat exchange length of the heat exchange tube, N is the number of heat exchange tubes, △T m is the average logarithmic heat transfer temperature difference, and the average logarithmic heat transfer temperature difference The pressure loss △P of the thermosiphon evaporator = P 2-1 - P 2-2 .

[0042] In addition, when applying this test method, it should be noted that the greater the pressure loss, the greater the fluid flow rate. Therefore, for the same thermosiphon evaporator, under the same operating conditions, comparison should be made under the same pressure loss to ensure the accuracy of the test data.

[0043] The first embodiment has the following advantages:

[0044] 1. By adjusting the height of the gas-liquid separator 8, the refrigerant circulation ratio under different liquid column static heads is calculated by the ratio of the mass flow rate measured at the liquid inlet of the thermosiphon evaporator 9 to the gas mass flow rate of the gas-liquid two-phase flow measured at the gas outlet, which can provide better test data support for the pipeline design of the thermosiphon evaporator 9.

[0045] 2. By adjusting the height of the gas-liquid separator 8 to meet the test conditions of different liquid column static heads, the test device has strong versatility and avoids the repeated construction of the test device.

[0046] 3. The overall heat transfer coefficient of the thermosiphon evaporator 9 is checked by the heat balance method, and the calculated overall heat transfer coefficient has higher accuracy.

[0047] 4. The flow rate, pressure, and temperature parameters of the liquid refrigerant inlet, gas-liquid two-phase refrigerant outlet, coolant inlet, and coolant outlet of the thermosiphon evaporator 9 are recorded by computer control, avoiding errors caused by flow fluctuations.

[0048] Embodiment 2:

[0049] Refer to Figure 2 , the test device structure of the second embodiment is similar to that of the first embodiment. The difference is that the coolant outlet of the thermosiphon evaporator 9 is also connected to the mixing tank 30 through a branch pipeline. After the outlets of the mass flowmeter 19 at the coolant outlet, the coolant outlet thermometer 22, and the coolant outlet pressure gauge 23 on the branch pipeline, a switching valve 32 is provided on the branch pipeline, and a coolant bypass thermometer 18 is connected at a position infinitely close to the mixing tank 30.

[0050] In addition to the advantages of the first embodiment, after the switching valve 32 is opened in the second embodiment, the coolant outlet branch can be introduced into the mixing tank, so that the temperature of the circulating water entering the high-pressure condenser 3 is reduced (the temperature of the mixed circulating water is lower than the temperature of the circulating water in the circulating water tank 5, that is, the temperature measured by the second circulating water inlet thermometer 17 is lower than the temperature measured by the first circulating water inlet thermometer 15), and the outlet liquid temperature (condensing temperature) of the condenser 3 is reduced, which can increase the refrigerating capacity of the same refrigeration compressor and broaden the application range of the test device.

[0051] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains may make various modifications or supplements to the described specific embodiments or use similar means for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A test device for measuring the heat exchange performance of a thermosyphon evaporator, comprising a refrigeration compressor (1), an oil-gas separator (2), a high-pressure condenser (3), a cooling tower (4), a circulating water tank (5), a circulating water pump (6), a liquid storage tank (7), a gas-liquid separator (8), a thermosyphon evaporator (9), a refrigerant water tank (10), a refrigerant pump (11) and a mixing tank (30), characterized in that: The air intake of the refrigeration compressor (1) is connected to the air outlet pipe of the gas-liquid separator (8), the air outlet of the refrigeration compressor (1) is connected to the air inlet of the oil-gas separator (2), the air outlet of the oil-gas separator (2) is connected to the air inlet of the high-pressure condenser (3), the liquid outlet of the high-pressure condenser (3) is connected to the liquid inlet of the liquid reservoir (7), the liquid outlet of the liquid reservoir (7) is connected to the air inlet of the gas-liquid separator (8), and a throttle valve (31) is connected on the pipeline between the liquid outlet of the liquid reservoir (7) and the air inlet of the gas-liquid separator (8), the liquid outlet of the gas-liquid separator (8) is connected to the liquid inlet of the thermal siphon evaporator (9), the air outlet of the thermal siphon evaporator (9) is connected to the air inlet of the gas-liquid separator (8), and the high-pressure condenser (3) is connected to the liquid inlet of the liquid reservoir (7). The water outlet of the heat exchanger (3) is connected to the water inlet of the cooling tower (4), the water outlet of the cooling tower (4) is connected to the water inlet of the circulating water tank (5), the water outlet of the circulating water tank (5) is connected to the water inlet of the mixing tank (30), the water outlet of the mixing tank (30) is connected to the water inlet of the circulating water pump (6), the water outlet of the circulating water pump (6) is connected to the water inlet of the high-pressure condenser (3), the refrigerant outlet of the thermosiphon evaporator (9) is connected to the water inlet of the refrigerant water tank (10), the water outlet of the refrigerant water tank (10) is connected to the water inlet of the refrigerant pump (11), the water outlet of the refrigerant pump (11) is connected to the refrigerant water inlet of the thermosiphon evaporator (9), and the above-mentioned connected pipelines are respectively provided with test measuring instruments.

2. The test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 1, characterized in that: A circulating water outlet pressure gauge (12), a circulating water outlet thermometer (13) and a circulating water mass flow meter (14) are connected to the pipeline between the water outlet of the high-pressure condenser (3) and the water inlet of the cooling tower (4), and the circulating water outlet pressure gauge (12) and the circulating water outlet thermometer (13) are infinitely close to the water outlet of the high-pressure condenser (3), a circulating water inlet thermometer (15) is connected to the pipeline between the water outlet of the circulating water tank (5) and the water inlet of the mixing tank (30), and a circulating water inlet thermometer (15) is connected to the pipeline between the water outlet of the circulating water pump (6) and the water inlet of the high-pressure condenser (3). The pipeline is connected with a circulating water inlet pressure gauge (16) and a circulating water inlet thermometer (17), and the circulating water inlet pressure gauge (16) and the circulating water inlet thermometer (17) are infinitely close to the water inlet of the high-pressure condenser (3), and the pipeline between the liquid outlet of the gas-liquid separator (8) and the liquid inlet of the thermosiphon evaporator (9) is connected with a refrigerant inlet thermometer (24), a refrigerant inlet pressure gauge (25) and a refrigerant liquid mass flow meter (26), and the refrigerant inlet thermometer (24) and the refrigerant inlet pressure gauge (25) are infinitely close to the thermosiphon evaporator. The liquid inlet of the thermosiphon evaporator (9) is connected to the pipeline between the gas outlet of the thermosiphon evaporator (9) and the gas inlet of the gas-liquid separator (8), and a refrigerant two-phase flow gas phase mass flow meter (27), a refrigerant gas thermometer (28) and a refrigerant gas pressure gauge (29) are connected to the pipeline between the gas outlet of the thermosiphon evaporator (9) and the water inlet of the refrigerant water tank (10), and the refrigerant gas thermometer (28) and the refrigerant gas pressure gauge (29) are infinitely close to the gas outlet of the thermosiphon evaporator (9), and a refrigerant outlet mass flow meter is connected to the pipeline between the refrigerant outlet of the thermosiphon evaporator (9) and the water inlet of the refrigerant water tank (10). (19), a refrigerant outlet thermometer (22) and a refrigerant outlet pressure gauge (23), and the refrigerant outlet thermometer (22) and the refrigerant outlet pressure gauge (23) are infinitely close to the refrigerant outlet of the thermosyphon evaporator (9), and a refrigerant inlet thermometer (20) and a refrigerant inlet pressure gauge (21) are connected to the pipeline between the outlet of the refrigerant pump (11) and the inlet of the thermosyphon evaporator (9), and the refrigerant inlet thermometer (20) and the refrigerant inlet pressure gauge (21) are infinitely close to the refrigerant inlet of the thermosyphon evaporator (9).

3. The test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 2, characterized in that: The refrigerant outlet of the thermosyphon evaporator (9) is also connected to the mixing tank (30) via a branch pipeline, the branch pipeline is located after the outlets of the refrigerant outlet mass flow meter (19), the refrigerant outlet thermometer (22) and the refrigerant outlet pressure gauge (23), and a switch valve (32) is provided on the branch pipeline. A refrigerant bypass thermometer (18) is connected at a position infinitely close to the mixing tank (30).

4. The test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 1, 2 or 3, characterized in that: The gas-liquid separator (8) is arranged on a liftable platform or track, and the cylinder of the thermosyphon evaporator (9) has a scale for measuring the distance between the lowest position of the cylinder of the thermosyphon evaporator (9) and the relative height of the liquid level of the gas-liquid separator (8).

5. The test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 1, 2 or 3, characterized in that: The test measuring instruments are controlled by computers and perform data recording.

6. The test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 1, 2 or 3, characterized in that: At least one section of the liquid pipeline between the liquid storage tank (7) and the gas-liquid separator (8) is a flexible pipeline, at least one section of the liquid pipeline and the gas pipeline between the gas-liquid separator (8) and the thermal siphon evaporator (9) are each a flexible pipeline, and at least one section of the gas pipeline between the gas-liquid separator (8) and the refrigeration compressor is a flexible pipeline.

7. The test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 6, characterized in that: Each of the flexible pipes has an adjustable length of at least 3 meters.

8. A test method using the above test device for measuring the heat exchange performance of a thermosyphon evaporator, characterized in that: When the operation of the above-mentioned test device is stable, the height of the gas-liquid separator (8) is adjusted so that the vertical height between the liquid surface and the lowest position of the cylinder of the thermosyphon evaporator (9) meets the design requirements for the static pressure head of the liquid column, and the test measuring instruments are monitored and data are recorded by a computer at prescribed time intervals.

9. The test method for the test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 8, characterized in that: The computer monitors the refrigerant outlet mass flow meter (19), the refrigerant inlet temperature meter (20), the refrigerant inlet pressure meter (21), the refrigerant outlet temperature meter (22), the refrigerant outlet pressure meter (23), the refrigerant inlet temperature meter (24), the refrigerant inlet pressure meter (25), the refrigerant liquid mass flow meter (26), the refrigerant two-phase flow gas phase mass flow meter (27), the refrigerant gas temperature meter (28) and the refrigerant gas pressure meter (29), and first records the refrigerant outlet mass flow meter (19), the refrigerant inlet temperature meter (22), the refrigerant outlet pressure meter (23), the refrigerant inlet temperature meter (24), the refrigerant inlet pressure meter (25), the refrigerant liquid mass flow meter (26), the refrigerant two-phase flow gas phase mass flow meter (27), the refrigerant gas temperature meter (28) and the refrigerant gas pressure meter (29). The data of the refrigerant inlet thermometer (20), the coolant inlet pressure gauge (21), the refrigerant inlet thermometer (24), the refrigerant inlet pressure gauge (25) and the refrigerant liquid mass flow meter (26) are recorded, and then the data of the coolant outlet thermometer (22), the coolant outlet pressure gauge (23), the refrigerant two-phase flow gas phase mass flow meter (27), the refrigerant gas thermometer (28) and the refrigerant gas pressure gauge (29) are recorded after a delay of T seconds, and the total heat transfer coefficient K of the thermosyphon evaporator (9) is calculated based on the above data.

10. The test method for the test device for measuring the heat exchange performance of a thermosyphon evaporator according to claim 9, characterized in that: It consists of the following steps: Step 1: Computer monitoring and recording instrument data: the data recorded by the refrigerant outlet mass flow meter (19) is the refrigerant mass flow rate M2, and the data recorded by the refrigerant inlet thermometer (20) is the refrigerant inlet temperature T 2-1 The data recorded by the coolant inlet pressure gauge (21) is the coolant inlet pressure P 2-1 , the data recorded by the coolant outlet thermometer (22) is the coolant outlet temperature T 2-2 The data recorded by the refrigerant outlet pressure gauge (23) is the refrigerant outlet pressure P 2-2 The data recorded by the refrigerant liquid mass flow meter (26) is the refrigerant liquid mass flow rate M L , the data recorded by the refrigerant inlet pressure gauge (25) is the refrigerant liquid inlet pressure P L , the data recorded by the refrigerant inlet thermometer (24) is the refrigerant liquid inlet temperature T L The data recorded by the refrigerant two-phase flow gas phase mass flow meter (27) is the two-phase flow refrigerant gas mass flow rate M G , the data recorded by the refrigerant gas thermometer (28) is the two-phase flow refrigerant temperature T G , the data recorded by the refrigerant gas pressure gauge (29) is the two-phase flow refrigerant pressure P G ; Step 2: Calculate the heat exchange amount Q: The cooling amount released by the refrigerant in the thermosyphon evaporator (9) is Q C ,Q C =M L *(h1-h2), h1 is the enthalpy value at the refrigerant liquid inlet temperature, h2 is the enthalpy value at the two-phase refrigerant outlet temperature; The heat released by the refrigerant in the thermosyphon evaporator (9) is Q H , Q H =M2*Cp2*(T 2-1 -T 2-2 ), Cp2 is the specific heat of the coolant at the average temperature; The average temperature of the coolant is equal to (T 2-1 +T 2-2 ) / 2; When Q C and Q H When the difference between the values ​​of C +Q H ) / 2 is the heat transfer capacity of the thermosyphon evaporator (9); when Q C and Q H When the value difference does not exceed 5%, check whether the test device is abnormal, and re-measure the above parameters after eliminating the fault, and recalculate to meet the required Q value; Step 3: Calculate the total heat transfer coefficient K of the thermosyphon evaporator (9): A is the heat transfer area of ​​the thermosyphon evaporator, A = π*d i *L*N,π is a constant, d i is the inner diameter of the heat exchange tube, L is the effective heat exchange length of the heat exchange tube, N is the number of heat exchange tubes, △T m is the average logarithmic heat transfer temperature difference, the average logarithmic heat transfer temperature difference The pressure loss of the thermosyphon evaporator △P=P 2-1 -P 2-2 .

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