Wet air thermodynamic state parameter detection system and working method thereof

Abstract

The invention discloses a wet air thermodynamic state parameter detection system and a working method thereof, and belongs to the field of thermal engineering measurement. The system mainly comprises a water pump, a liquid flowmeter, a thermometer, a heater, a humidifier, a computer, a data acquisition module, a gas flowmeter, a fan, a first heat exchanger, a second heat exchanger and the like. The method is characterized in that the requirement and the problem of precise measurement of thermodynamic parameters in the existing humid air humidification process are fully considered, a thermodynamic method humidity measurement principle is combined, a combined measurement method is utilized, and on the basis that original thermodynamic parameters of fluid are not changed, the measurement precision is improved. According to the invention, an area (the relative humidity is between 0-10% and 90-100%) with large measurement precision deviation of instruments and meters is effectively avoided, the measurement precision of wet air parameters under all working conditions is improved, and a technical means is provided for the development of high-level humidification equipment. The whole measuring system adopts automatic data acquisition, and is convenient to operate, good in stability and high in accuracy.

Description

Technical Field

[0001] The invention designs a wet air thermodynamic state parameter detection system and a working method thereof, belonging to the field of thermal engineering measurement. Background Art

[0002] As a mixture of dry air and water vapor, wet air has the advantages of low density, large specific heat capacity, and high thermal conductivity compared to dry air. Due to its excellent moisture absorption and heat transfer properties, the wet air humidification process is widely used in many fields such as aerospace, thermal power generation, construction engineering, and food processing. It has attracted much attention in the development of new humidification and dehumidification seawater desalination technology and wet air turbine cycle applications. However, based on meteorological theory, the relative humidity of supersaturated wet air is greater than 100%, generally between 100-130%, while engineering thermodynamics defines the relative humidity of wet air as ranging from 0-100%.

[0003] At present, the main instruments for measuring the humidity of wet air, such as Testo605-H1, A2000-TS, Xima A-level and B-level hygrometers and AZ8746, have an accuracy range of: when the relative humidity is between 10-90%, the measurement accuracy is between ±2-±3%; when the relative humidity is between 0-10% and 90-100%, the measurement accuracy is between ±4-±5%. It can be seen that the measurement deviation will be further amplified when the wet air enters the supersaturated state.

[0004] Since the weakening treatment of the supersaturated phenomenon of moist air and the measurement error under the supersaturated state will seriously affect the calculation accuracy and design level of the humidification process, there is an urgent need to seek a more accurate method for measuring the thermodynamic parameters of moist air. Summary of the invention

[0005] Aiming at the problems of large measurement error of thermodynamic state parameters in the existing wet air humidification process and difficulty in thermodynamic state monitoring, the present invention proposes a wet air thermodynamic state parameter detection system with high stability and high measurement accuracy and a working method thereof.

[0006] A wet air thermodynamic state parameter detection system is characterized by comprising a humidifier, wherein the top of the humidifier is provided with a liquid inlet pipeline, the bottom is provided with a liquid outlet pipeline, the lower left side is provided with an air inlet pipeline, and the top right side is provided with an air outlet main pipeline.

[0007] The liquid inlet pipeline is provided with a water pump, a liquid flow meter, a first thermometer, a heater, and a second thermometer in sequence from the end farthest from the humidifier to the end closest to the humidifier;

[0008] A sixth thermometer is provided on the liquid outlet pipeline.

[0009] On the air inlet pipeline, from the end farthest from the humidifier to the end closest to it, a fan, a gas flow meter, a seventh thermometer, and a fourth thermometer are arranged in sequence;

[0010] On the main air outlet line, from one end close to the humidifier to the farthest end, a third thermometer, a first hygrometer, a fifth thermometer, and a third hygrometer are arranged in sequence, wherein a branch is connected in parallel between the first hygrometer and the fifth thermometer, and a check valve, a first heat exchanger, a fourth thermometer, a second hygrometer, and a second heat exchanger are arranged in sequence on the branch.

[0011] The humid air thermodynamic state parameter detection system is characterized in that the liquid flow meter, the first thermometer, the second thermometer, the third thermometer, the first hygrometer, the fourth thermometer, the second hygrometer, the fifth thermometer, the third hygrometer, the sixth thermometer, the fourth hygrometer, the seventh thermometer, and the gas flow meter are respectively connected to the data interface of the data acquisition module through their own signal output ports, and the data output ports of the data acquisition module are respectively connected to the computer data interface.

[0012] The described humid air thermodynamic state parameter detection system is characterized in that the described first heat exchanger can be used for heating or cooling. When the relative humidity of the humid air at the humidifier outlet is low (less than 10%), the first heat exchanger is used for cooling; when the relative humidity of the humid air at the humidifier outlet is high (greater than 90%), the first heat exchanger is used for heating to allow the humid air to enter the high-precision detection area.

[0013] The described humid air thermodynamic state parameter detection system is characterized in that the described second heat exchanger can be used for heating or cooling. When the relative humidity of the humid air at the humidifier outlet is high (less than 10%), the second heat exchanger is used for heating; when the relative humidity of the humid air at the humidifier outlet is high (greater than 90%), the second heat exchanger can be used for cooling, so that the thermodynamic parameters of the humid air on the branch line remain consistent with those on the main line.

[0014] The working method of the wet air thermodynamic state parameter detection system is characterized in that it includes the following working process: first, the water side fluid flows into the system through the water pump, passes through the liquid flow meter and the first thermometer in sequence, flows out of the heater after being heated by the hot fluid, and then enters the humidifier through the second thermometer, forms a liquid film from top to bottom in the humidifier after being sprayed, and then flows out from the bottom of the humidifier and flows out of the system through the sixth thermometer;

[0015] Then, the humid air fluid enters the system through the fan, passes through the gas flow meter, the seventh thermometer and the fourth hygrometer in turn, and then enters the humidifier from the bottom of the humidifier to complete the humidification process, and then is discharged from the top of the humidifier into the humid air outlet parameter measurement subsystem, and then passes through the third thermometer and the first hygrometer in turn. The subsequent working process is divided into the following three situations: when the reading of the first hygrometer is between 0-10%, the main path and the branch path work at the same time. At this time, the check valve is opened, the first heat exchanger works as a cooler, and the second heat exchanger works as a heater. The main path humid air flows through the fifth thermometer and the third hygrometer in turn, and then is discharged from the system; the branch path humid air passes through the check valve into the first heat exchanger for cooling, and the cooled humid air passes through the fourth thermometer and the second hygrometer in turn, so that the reading of the second hygrometer is between 10-90%, and then enters the second heat exchanger for heating, and the heated humid air is mixed with the main path humid air The air is combined, and then passes through the fifth thermometer and the third hygrometer in sequence to be discharged from the system; when the reading of the first hygrometer is between 10-90%, the main road works and the branch road does not work, at this time, the check valve is closed, and the wet air flows through the fifth thermometer and the third hygrometer in sequence, and then is discharged from the system; when the reading of the first hygrometer is between 90-100%, the main road and the branch road work at the same time, at this time, the check valve is opened, the first heat exchanger works as a heater, and the second heat exchanger works as a cooler, and the wet air of the main road flows through the fifth thermometer and the third hygrometer in sequence, and then is discharged from the system; the wet air of the branch road enters the first heat exchanger through the check valve for heating, and the heated wet air passes through the fourth thermometer and the second hygrometer in sequence, so that the reading of the second hygrometer is between 10-90%, and then enters the second heat exchanger for cooling, and the cooled wet air merges with the wet air of the main road, and then passes through the fifth thermometer and the third hygrometer in sequence to be discharged from the system;

[0016] Finally, the data collected by the liquid flow meter, the first thermometer, the second thermometer, the third thermometer, the first hygrometer, the fourth thermometer, the second hygrometer, the fifth thermometer, the third hygrometer, the sixth thermometer, the fourth hygrometer, the seventh thermometer, and the gas flow meter are respectively transmitted to the data acquisition module through their respective signal output ports, and are imported into the computer for storage and analysis through the data output port of the data acquisition module; during the entire fluid parameter measurement process, the heat exchange rates of the first heat exchanger and the second heat exchanger are always kept the same, the readings of the third thermometer and the fifth thermometer are kept consistent, and the readings of the first hygrometer and the third hygrometer are kept consistent.

[0017] The beneficial effects of the present invention are as follows: the present invention fully considers the needs and problems of accurate measurement of thermodynamic state parameters of the existing wet air humidification process, combines the humidity measurement principle of the thermodynamic method, and utilizes the combined measurement method. On the basis of not changing the basic thermodynamic parameters of the fluid, the present invention effectively avoids the area where the measurement accuracy of the instrument is large, improves the measurement accuracy of the wet air parameters under all working conditions, and provides a technical means for the development of high-level humidification equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a system for detecting thermodynamic state parameters of moist air;

[0019] Figure 2 This is the measurement accuracy distribution curve of a conventional industrial-grade humidity meter;

[0020] Names of the symbols in the figure: 1. Water pump, 2. Liquid flow meter, 3. First thermometer, 4. Heater, 5. Second thermometer, 6. Humidifier, 7. Third thermometer, 8. First hygrometer, 9. Check valve, 10. First heat exchanger, 11. Fourth thermometer, 12. Second hygrometer, 13. Second heat exchanger, 14. Fifth thermometer, 15. Third hygrometer, 16. Computer, 17. Data acquisition module, 18. Sixth thermometer, 19. Fourth hygrometer, 20. Seventh thermometer, 21. Gas flow meter, 22. Fan, A. Wet air outlet parameter measurement subsystem. DETAILED DESCRIPTION

[0021] Figure 1 It is a wet air thermodynamic state parameter detection system proposed by the present invention. Figure 2 This is the measurement accuracy distribution curve of conventional industrial-grade humidity meters in this field. The present invention can effectively reduce the area with large errors. Figure 1 Describe the specific implementation process of the system.

[0022] Liquid path: The liquid flows into the system through the water pump 1, passes through the liquid flow meter 2 and the first thermometer 3 in sequence, enters the heater 4, flows out of the heater 4 after being heated by the hot fluid, and then enters the humidifier 6 through the second thermometer 5. In the humidifier 6, a liquid film is formed from top to bottom after being sprayed, and then it is collected at the bottom, and then flows out from the bottom of the humidifier 6 and flows out of the system through the sixth thermometer 18;

[0023] Gas path: The wet air fluid enters the system through the fan 22, passes through the gas flow meter 21, the seventh thermometer 20 and the fourth hygrometer 19 in sequence, and then enters the humidifier 6 from the bottom to complete the humidification process, and then is discharged from the top of the humidifier 6 into the main air outlet line, and then passes through the third thermometer 7 and the first hygrometer 8 in sequence. The subsequent working process is divided into the following three situations:

[0024] S1: When the reading of the first hygrometer 8 is between 0-10%, the main outlet route and the branch route work at the same time. At this time, the check valve 9 is opened, the first heat exchanger 10 works as a cooler, and the second heat exchanger 13 works as a heater. The wet air in the main outlet route flows through the fifth thermometer 14 and the third hygrometer 15 in sequence, and then is discharged from the system; the branch route wet air passes through the check valve 9 and enters the first heat exchanger 10 for cooling. The cooled wet air passes through the fourth thermometer 11 and the second hygrometer 12 in sequence, so that the reading of the second hygrometer 12 is between 10-90%, and then enters the second heat exchanger 13 for heating. The heated wet air merges with the wet air in the main outlet route, and then passes through the fifth thermometer 14 and the third hygrometer 15 in sequence to be discharged from the system;

[0025] S2: When the reading of the first hygrometer 8 is between 10-90%, the main outlet pipe works and the branch pipe does not work. At this time, the check valve 9 is closed, and the wet air flows through the fifth thermometer 14 and the third hygrometer 15 in sequence, and then is discharged from the system;

[0026] S3: When the reading of the first hygrometer 8 is between 90% and 100%, the main outlet route and the branch route work at the same time. At this time, the check valve 9 is opened, the first heat exchanger 10 works as a heater, and the second heat exchanger 13 works as a cooler. The wet air in the main outlet route flows through the fifth thermometer 14 and the third hygrometer 15 in sequence, and then is discharged from the system; the branch route wet air passes through the check valve 9 and enters the first heat exchanger 10 for heating. The heated wet air passes through the fourth thermometer 11 and the second hygrometer 12 in sequence, so that the reading of the second hygrometer 12 is between 10% and 90%, and then enters the second heat exchanger 13 for cooling. The cooled wet air merges with the wet air in the main outlet route, and then passes through the fifth thermometer 14 and the third hygrometer 15 in sequence and is discharged from the system;

[0027] In S1 and S3, the heat exchange capacity of the first heat exchanger 10 and the second heat exchanger 13 are always kept the same, the reading of the third thermometer 7 is kept consistent with the reading of the fifth thermometer 14, and the reading of the first hygrometer 8 is kept consistent with the reading of the third hygrometer 15;

[0028] Data analysis: The data collected by the liquid flow meter 2, the first thermometer 3, the second thermometer 5, the third thermometer 7, the first hygrometer 8, the fourth thermometer 11, the second hygrometer 12, the fifth thermometer 14, the third hygrometer 15, the sixth thermometer 18, the fourth hygrometer 19, the seventh thermometer 20, and the gas flow meter 21 are transmitted to the data acquisition module 17 through their respective signal output ports, and are imported into the computer 16 through the data output port of the data acquisition module 17 for storage and analysis.

Claims

1. A humid air thermodynamic state parameter detection system, characterized in that: The humidifier comprises a humidifier (6), wherein the top of the humidifier is provided with a liquid inlet pipeline, the bottom is provided with a liquid outlet pipeline, the lower left side is provided with an air inlet pipeline, and the top right side is provided with an air outlet main pipeline; The liquid inlet pipeline is provided with a water pump (1), a liquid flow meter (2), a first thermometer (3), a heater (4), and a second thermometer (5) in sequence from the end farthest from the humidifier to the end closest to the humidifier; A sixth thermometer (18) is arranged on the liquid outlet pipeline; The air inlet pipeline is provided with a fan (22), a gas flow meter (21), a seventh thermometer (20), and a fourth thermometer (19) in sequence from the end farthest from the humidifier to the end closest to the humidifier; On the main air outlet line, from one end close to the humidifier to the far end, a third thermometer (7), a first hygrometer (8), a fifth thermometer (14), and a third hygrometer (15) are arranged in sequence, wherein a branch is connected in parallel between the first hygrometer (8) and the fifth thermometer (14), and a check valve (9), a first heat exchanger (10), a fourth thermometer (11), a second hygrometer (12), and a second heat exchanger (13) are arranged in sequence on the branch.

2. A humid air thermodynamic state parameter detection system according to claim 1, characterized in that: The liquid flow meter (2), the first thermometer (3), the second thermometer (5), the third thermometer (7), the first hygrometer (8), the fourth thermometer (11), the second hygrometer (12), the fifth thermometer (14), the third hygrometer (15), the sixth thermometer (18), the fourth hygrometer (19), the seventh thermometer (20), and the gas flow meter (21) are respectively connected to the data interface of the data acquisition module (17) through their own signal output ports, and the data output port of the data acquisition module (17) is respectively connected to the data interface of the computer (16).

3. A humid air thermodynamic state parameter detection system according to claim 1, characterized in that: The first heat exchanger (10) can be used for heating or cooling.

4. A wet air thermodynamic state parameter detection system according to claim 1, characterized in that: The second heat exchanger (13) can be used for heating or cooling.

5. The working method of a humid air thermodynamic state parameter detection system according to claim 1, characterized in that: The work process includes the following: The first step is to allow liquid to flow into the system through the water pump (1) and allow wet air to enter the system through the fan (22); Step 2: When the reading of the first hygrometer (8) is between 10% and 90%, the main outlet pipe works and the branch pipe does not work; When the reading of the first hygrometer (8) is not between 10-90%, the main outlet pipe and the branch pipe work at the same time, and the heat exchange rates of the first heat exchanger (10) and the second heat exchanger (13) are kept the same, the reading of the third thermometer (7) and the reading of the fifth thermometer (14) are kept consistent, the reading of the first hygrometer (8) and the reading of the third hygrometer (15) are kept consistent, and the reading of the second hygrometer (12) is kept between 10-90%. When the reading of the first hygrometer (8) is between 0-10%, the first heat exchanger (10) works as a cooler and the second heat exchanger (13) works as a heater; when the reading of the first hygrometer (8) is between 90-100%, the first heat exchanger (10) works as a heater and the second heat exchanger (13) works as a cooler; Step 3: The data collected by the data collection module (17) is processed and analyzed by the computer (16).

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