CN217717578U - Experimental device for testing flow heat transfer in high-temperature and high-pressure carbon dioxide pipe - Google Patents

Abstract

The utility model provides a high-temperature and high-pressure carbon dioxide inner flow heat transfer test experimental device, which belongs to the field of carbon dioxide thermal hydraulic testing and is used to solve the problem that the existing supercritical carbon dioxide power generation system is difficult to effectively measure the air-cooled wall and heat exchanger. Including high-pressure carbon dioxide pump, pressure sensor, main safety valve, airbag type regulator, system flow meter, regenerator, main armored thermocouple, pressure regulating valve, system shut-off valve and filter connected in sequence, and the regenerator is respectively The preheating system, the measurement system in the experimental section and the cooling system are connected. The cooling system is connected between the regenerator and the main armored thermocouple. The pressure regulating valve and the system shut-off valve are connected with the interconnected vacuum pumping and liquid injection system and The condensation liquid storage system is connected with a branch circuit; the utility model can perform supercritical carbon dioxide flow heat transfer and instability tests with different pressures, temperatures, pipe diameters and heating powers.

Description

An experimental device for testing flow and heat transfer in a high-temperature and high-pressure carbon dioxide tube

technical field

The utility model belongs to the technical field of thermal hydraulic testing of carbon dioxide, and relates to a flow heat transfer test experimental device, in particular to a flow heat transfer test experimental device in a high-temperature and high-pressure carbon dioxide tube.

Background technique

Supercritical fluid refers to a fluid that exceeds the critical temperature, critical pressure, and critical volume state of the gas-liquid of the substance. In a narrow sense, it refers to a gas or fluid that exceeds the critical temperature state. Supercritical carbon dioxide (scCO ₂ ) is one of the supercritical fluids. Its power cycle power generation uses carbon dioxide with ultra-high parameters as the circulating working medium, adopts Brayton cycle and possible compound cycle, and realizes high-efficiency thermal power conversion. When the steam temperature is higher than At 550 ^o C, the thermal efficiency of scCO2 is higher _than that of the water vapor Rankine cycle.

The power generation system operates at supercritical pressure, has a large carbon dioxide flow capacity, and doubles the size of the power generation system. It is a transformative technology in the energy field in recent years and is considered to be one of the most potential technical solutions in the future clean energy field. In the above application fields, carbon dioxide heat transfer occurs in various heat exchangers such as heaters, regenerators, and coolers. A comprehensive understanding of the flow and heat transfer laws of carbon dioxide is the basis for system and component design.

Based on this, we propose an experimental device for testing flow and heat transfer in a high-temperature and high-pressure carbon dioxide tube, which belongs to the technical field of resistance, convective heat transfer coefficient and flow instability testing. The experimental device consists of a vacuum injection system, a condensing liquid storage device, a preheating electric heating system, a cooling circuit, a _CO2 working medium circuit, and an experimental section. The above-mentioned systems and devices work together to convert low-temperature and low-pressure _CO2 into high-temperature and high-pressure Supercritical CO ₂ , and in order to reduce the total heating power of the test bench, the heat of high-temperature and high-pressure CO ₂ flowing out of the experimental section is fully absorbed by the low-temperature CO ₂ working fluid in the regenerator. The regenerator adopts sleeve type or printed Circuit plate heat exchanger; it can carry out flow heat transfer of different pressures (1~30 MPa), different temperatures (~600 ^o C), different pipe diameters (2-30 mm), different heating power (1-500 kW) and Instability testing. The experimental device solves the problems of data gaps and unrelated references in the design process of the air-cooled wall and heat exchanger of the supercritical _CO2 power generation system, which is of great significance to the development of a new generation of power generation technology.

Utility model content

The purpose of this utility model is to solve the above-mentioned problems in the existing technology, and proposes a flow heat transfer test device in a high-temperature and high-pressure carbon dioxide tube. The technical problem to be solved by this utility model is: how to realize , Heat transfer and instability tests of supercritical carbon dioxide under heating power.

The purpose of this utility model can be achieved through the following technical solutions:

A high-temperature and high-pressure carbon dioxide pipe flow heat transfer test experimental device, including a high-pressure carbon dioxide pump, a pressure sensor, a main pipe safety valve, an air bag regulator, a system flow meter, a regenerator, a main pipe armored thermocouple, and a pressure regulator connected in sequence Valve, system shut-off valve and filter, the regenerator is respectively connected with the preheating system, the measurement system of the experimental section and the cooling system, wherein the cooling system is connected between the regenerator and the main pipe armored thermocouple, the pressure regulating valve and The system shut-off valve is connected with a vacuum pumping liquid injection system and a condensate liquid storage system connected with each other, wherein the condensate liquid storage system is connected with a branch circuit, and the branch circuit is connected between the main safety valve and the air bag type regulator.

The high-pressure carbon dioxide pump is a plunger-type metering pump, the regenerator is a sleeve-type heat exchanger, and the inner and outer pipes of the regenerator are made of stainless steel.

With the above structure, on the one hand, the high-pressure carbon dioxide pump provides power for the carbon dioxide fluid, and cooperates with the pressure regulating valve to adjust the pressure required by the system. On the other hand, it can realize precise control of the system flow through frequency conversion control. The inner and outer tubes of the regenerator are made of stainless steel, with low price, high stability and strong safety.

The vacuum pumping liquid injection system includes a busbar and a vacuum pump, the busbar and the vacuum pump are connected to the pressure regulating valve respectively, a number of carbon dioxide gas cylinders are connected to the busbar, and a vacuum stop valve is arranged between the carbon dioxide gas cylinders and the busbar. There are electric heating jackets on the gas cylinders.

With the above structure, the characteristic of the vacuum injection liquid injection system is that before filling carbon dioxide, in order to avoid the influence of non-condensable gas on the measurement, to ensure that the circuit is in the path, turn on the vacuum pump to vacuum the entire circuit until the vacuum degree of the entire system reaches 30 The vacuum pump is turned off below Pa, and the pressure of the carbon dioxide cylinder is usually about 8 MPa. When the pressure of the carbon dioxide cylinder is equal to the system pressure, the excess carbon dioxide in the carbon dioxide cylinder cannot continue to be filled into the system. To minimize the waste of carbon dioxide, an electric heating jacket is installed outside the carbon dioxide cylinder to increase the temperature of carbon dioxide, thereby increasing the pressure of the carbon dioxide cylinder and realizing rapid filling.

The condensate liquid storage system includes an industrial chiller and a condensate storage tank. A first flow meter, a first centrifugal pump, and a first shut-off valve are respectively arranged between the inlet and outlet ends of the industrial chiller and the condensate storage tank. The tank is connected to the vacuum injection system, the first armored thermocouple, the first pressure transmitter and the safety valve of the storage tank are connected to the condensate storage tank, and the exhaust valve is connected between the condensate storage tank and the system shut-off valve, industrial The water chiller is connected with the first cooling tower, the first water storage tank, the second centrifugal pump and the second flow meter in turn. The condensation storage tank is an integrated tank composed of a condenser and a liquid storage tank. It consists of a cooling water cylinder, a carbon dioxide storage liquid It consists of a tank, a condensing coil and a low-temperature cold water nozzle.

With the above structure, the carbon dioxide liquid storage tank is in the cooling water cylinder, the condensation coil is in the middle of the liquid storage tank and the cooling water cylinder, the low-temperature cold water nozzle is connected to the cold side outlet of the chiller, the temperature of the cold side outlet of the chiller is about 100 degrees Celsius, and the cold water nozzle Placed vertically and flowing from bottom to top, a certain number of through holes are opened in the axial and circumferential directions of the cold water nozzle pipe wall to enhance heat exchange. It is injected into the industrial chiller through the second flowmeter for heat exchange, and the obtained hot water enters the first cooling tower for cooling to form a circulating cooling mechanism. After heat exchange, the low-temperature medium is injected into the condensation storage tank through the first centrifugal pump. Cool down the system main line inside the condensate storage tank, thereby cooling the carbon dioxide fluid inside the system main line.

The preheating system includes a first current regulator and a U-shaped tube electric heating preheater, the U-shaped tube electric heating preheater is connected to the regenerator, and several first Copper electrode plates, the first current regulator and several first copper electrode plates are connected by first copper braids, the U-shaped tube electric heating preheater is made of stainless steel tubes, and the first current regulator is Thyristor low voltage high current voltage regulator.

With the above structure, by connecting to the power supply, the carbon dioxide fluid is heated by the resistance heating of the stainless steel tube of the U-shaped tube electric heating preheater. During the production process, the inlet section, middle section and outlet section are respectively soldered with silver brazing The copper electrode plate is welded. In order to prevent electric heating leakage from affecting the measurement of system instruments and meters, traditional electrical insulating flanges or insulating joints are difficult to realize in high-temperature and high-pressure systems. This embodiment adopts a three-point heating method, the so-called three-point heating method It is to lead out two wires from the positive pole of the DC low-voltage high-current transformer, one end is connected to the electrode plate of the inlet section, the other end is connected to the electrode plate of the outlet section, and the negative pole is directly connected to the electrode plate of the middle section, and the current forms a loop inside the U-shaped tube electric heating preheater , Effectively prevent leakage, the first current regulator is connected to a low-voltage high-current transformer, by continuously adjusting the voltage of the first current regulator, the electric heating power of the preheater can be changed, so as to reach the temperature required by the experiment.

The test system of the experimental section includes an experimental section and a second current regulator. The inlet and outlet ends of the experimental section are respectively connected to the U-shaped tube electric heating preheater and the reheater. There are two second armored thermocouples on the coupler seat, several wall thermocouple wires and some second copper electrode plates on the experimental section, two insulating joints on the experimental section, and the two insulating joints pass through the pressure induction tube A differential pressure transmitter is connected, a second pressure transmitter and a third pressure transmitter are respectively arranged on the pressure introduction tube, and several second copper electrode plates and the second current regulator are electrically connected through the second copper braided wire. Connection, the casing of the second armored thermocouple is made of 316L stainless steel, and the wall thermocouple wire is a K-type thermocouple.

With the above structure, in order to prevent the influence of electric heating on the second armored thermocouple for fluid temperature measurement, the second armored thermocouple is a non-contact insulated armored thermocouple, and the second armored thermocouple passes through the high-pressure sealed thermocouple seat vertically Inserted into the center of the pipe, the second armored thermocouple realizes high-pressure sealing through a tapered seal, and the thermocouple wire on the wall is a K-type thermocouple, which is directly welded to the pipe wall of the experimental section by the principle of instantaneous high temperature generated by capacitive discharge.

The insulating joint includes a central column, and one end of the central column is screwed with a first fastening nut, and a compression ferrule and a tapered ferrule are sequentially arranged between the first fastening nut and the central column, and the central column is provided with two A symmetrically arranged polytetrafluoroethylene insulating sleeve, the polytetrafluoroethylene insulating sleeve is tapered, the central column is sleeved, the outer side of the polytetrafluoroethylene insulating sleeve is provided with a second fastening nut, and two polytetrafluoroethylene insulating sleeves The sleeve is located inside the second fastening nut, and the second fastening nut is screwed with a stud, and a rubber ring and a polytetrafluoroethylene flat pad are sequentially arranged between the second fastening nut and the stud.

With the above structure, the first fastening nut and stud are used to quickly connect the pressure induction pipe, the compression ferrule is matched with the tapered ferrule and the rubber ring is matched with the PTFE flat washer, and the second fastening nut and stud are used Cooperate and lock two PTFE insulating sleeves, rubber rings and PTFE flat pads to ensure the tightness of the connection and effectively prevent leakage.

The high-pressure sealed thermocouple seat includes a compression nut, a fixing nut and a conical sealing gasket, the compression nut and the fixing nut are screwed together, and the conical sealing gasket is engaged between the compression nut and the fixing nut.

With the above structure, the conical sealing gasket is stably engaged between the compression nut and the fixed nut to ensure the seal. The compression nut and the fixed nut are used to connect the second armored thermocouple, so that the second armored thermocouple is sealed by high pressure. The thermocouple seat is vertically inserted into the center of the pipe, and the second armored thermocouple is sealed through a cone to achieve high-pressure sealing.

The cooling system includes a cooler. The cooler is a shell-and-tube heat exchanger. A high-temperature and high-pressure carbon dioxide working medium is arranged inside the tube side, and normal-temperature cooling water is arranged inside the shell side. The inlet and outlet ends of the cooler are respectively connected to the regenerator It is connected with the main armored thermocouple, the cooler is connected with a heat exchange tube, and the heat exchange tube is provided with a second cooling tower, a second water storage bucket, a third centrifugal pump and a third flowmeter in sequence.

With the above structure, the cooling water in the second water storage tank is injected into the cooler through the third flowmeter through the third centrifugal pump, and exchanges heat with the main pipe of the system, and the hot water obtained enters the second cooling tower for cooling to form Circulating cooling mechanism, after heat exchange, the temperature of the carbon dioxide working fluid in the main pipe of the system decreases, and the low-temperature carbon dioxide working fluid passes through the main pipe armored thermocouple.

Compared with the prior art, this high-temperature and high-pressure carbon dioxide tube flow heat transfer test experimental device has the following advantages:

The vacuum pumping liquid injection system evacuates the whole system and injects carbon dioxide to realize rapid filling; through the condensing liquid storage system, the temperature of the carbon dioxide working fluid inside the system supervisor is cooled; and the air bag type regulator is used to stabilize the flow of carbon dioxide fluid in the loop The flow and pressure fluctuate; the regenerator is a casing heat exchanger, and its inner and outer tubes are made of stainless steel, which is low in price, high in stability and strong in safety; it is preheated by the preheating system, and the experimental section The test system is used to measure the inlet and outlet temperature of the working fluid in the experimental section. The wall thermocouple is directly welded on the corresponding experimental pipeline wall to measure the tube wall temperature for accurate measurement. The pressure sensor is used to measure the absolute pressure of the inlet working fluid. The pressure difference sensor is used to measure the pressure loss of the inlet and outlet working fluid; through the heat exchange between the cooling system and the system supervisor, the hot water obtained enters the second cooling tower for cooling to form a circulating cooling mechanism, and the carbon dioxide in the system supervisor after heat exchange The temperature of the working fluid decreases, and the low-temperature carbon dioxide working fluid enters the condensation storage tank to complete the cycle;

Lead out two wires from the positive pole of the DC low-voltage high-current transformer through an insulating joint, one is connected to the electrode plate of the inlet section, the other is connected to the electrode plate of the outlet section, and the negative pole is directly connected to the electrode plate of the middle section, and the current is inside the U-shaped tube electric heating preheater A loop is formed to effectively prevent leakage; by continuously adjusting the voltage of the first current regulator, the electric heating power of the preheater can be changed to achieve the temperature required for the experiment. This experimental device can be used for different pressures (1~30 MPa) , flow heat transfer at different temperatures (~600 ^o C), different pipe diameters (2-30 mm), different heating powers (1-500 kW), and instability tests.

Description of drawings

Fig. 1 is a system schematic diagram of the present utility model;

Fig. 2 is a three-dimensional structural schematic diagram of an insulating joint in the utility model;

Fig. 3 is a schematic cross-sectional structure diagram of an insulating joint in the utility model;

Fig. 4 is a schematic diagram of an exploded structure of an insulating joint in the utility model;

Fig. 5 is a schematic diagram of the three-dimensional structure of the medium and high pressure sealed thermocouple seat of the present invention;

Fig. 6 is a schematic diagram of the decomposition structure of the medium and high pressure sealed thermocouple seat of the present invention;

In the figure: 1-High-pressure carbon dioxide pump, 2-Pressure sensor, 3-Director safety valve, 4-Air bag regulator, 5-System flow meter, 6-Regenerator, 7-Director armored thermocouple, 8- Pressure regulating valve, 9-system stop valve, 10-filter, 11-branch, 100-vacuumizing liquid injection system, 101-bus, 102-vacuum pump, 103-vacuum stop valve, 104-carbon dioxide cylinder, 105 -Electric heating mantle, 200-condensate storage system, 201-industrial chiller, 202-first flow meter, 203-first centrifugal pump, 204-first stop valve, 205-condensation storage tank, 206-first armor Install thermocouple, 207-first pressure transmitter, 208-tank safety valve, 209-first cooling tower, 210-first water storage bucket, 211-second centrifugal pump, 212-second flow meter, 213- Exhaust valve, 300-preheating system, 301-the first current regulator, 302-the first copper braid, 303-U-shaped tube electric heating preheater, 304-the first copper electrode plate, 400-experimental section Measuring system, 401-the second current regulator, 402-the second braided copper wire, 403-the second copper electrode plate, 404-the second pressure transmitter, 405-the second armored thermocouple, 406-the wall thermoelectric Even wire, 407-third pressure transmitter, 408-differential pressure transmitter, 409-insulated joint, 4091-first fastening nut, 4092-central column, 4093-second fastening nut, 4094-stud , 4095-compression ferrule, 4096-cone ferrule, 4097-polytetrafluoroethylene insulating sleeve, 4098-rubber ring, 4099-polytetrafluoroethylene flat gasket, 410-impression tube, 411-high pressure sealed thermocouple Seat, 4111-pressing nut, 4112-fixing nut, 4113-conical gasket, 412-experimental section, 500-cooling system, 501-cooler, 502-third flow meter, 503-third centrifugal pump, 504 - the second water storage tank, 505 - the second cooling tower.

Detailed ways

The technical solution of this patent will be further described in detail below in conjunction with specific embodiments.

Embodiments of the present patent are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are only used for explaining the patent, and should not be construed as limiting the patent.

Please refer to Figures 1-6, this embodiment provides a high-temperature and high-pressure carbon dioxide tube flow heat transfer test experimental device, including a high-pressure carbon dioxide pump 1, a pressure sensor 2, a main safety valve 3, an air bag regulator 4, System flow meter 5, regenerator 6, supervisor armored thermocouple 7, pressure regulating valve 8, system shut-off valve 9 and filter 10, regenerator 6 are respectively connected with preheating system 300, experimental section measurement system 400 and cooling System 500, wherein the cooling system 500 is connected between the regenerator 6 and the main pipe armored thermocouple 7, and the vacuum pumping liquid injection system 100 and the condensate liquid storage system are connected between the pressure regulating valve 8 and the system shut-off valve 9 200, wherein the condensate storage system 200 is connected with a branch 11, and the branch 11 is connected between the main safety valve 3 and the air bag regulator 4.

The high-pressure carbon dioxide pump 1 is a plunger-type metering pump, the regenerator 6 is a casing heat exchanger, and the inner and outer tubes of the regenerator 6 are made of stainless steel; on the one hand, the high-pressure carbon dioxide pump 1 provides Power, with the pressure regulating valve 8 to adjust the pressure required by the system, on the other hand, the system flow can be precisely controlled by frequency conversion control; the air bag regulator 4 is used to stabilize the flow and pressure fluctuation of the carbon dioxide fluid in the circuit, and the regenerator 6 The inner and outer tubes are made of stainless steel, which is low in price, high in stability and strong in safety.

The vacuum pumping liquid injection system 100 includes a bus bar 101 and a vacuum pump 102. The bus bar 101 and the vacuum pump 102 are connected to the pressure regulating valve 8 respectively. The bus bar 101 is connected with a number of carbon dioxide gas cylinders 104. Between the carbon dioxide gas cylinders 104 and the bus bar 101 Both are equipped with a vacuum stop valve 103, and the carbon dioxide gas cylinder 104 is equipped with an electric heating jacket 105; the characteristic of the vacuum pumping liquid injection system 100 is that before filling carbon dioxide, in order to avoid the influence of non-condensable gas on the measurement, ensure that the circuit is at Turn on the vacuum pump 102 to evacuate the entire circuit until the vacuum of the whole system reaches below 30 Pa. Close the vacuum pump 102. The pressure of the carbon dioxide gas cylinder 104 is usually about 8 MPa. When the pressure of the carbon dioxide gas cylinder 104 is equal to the system pressure , the excess carbon dioxide in the carbon dioxide cylinder 104 cannot continue to be charged into the system. In order to increase the filling speed and reduce the waste of carbon dioxide, an electric heating jacket 105 is installed outside the carbon dioxide cylinder 104 to raise the temperature of carbon dioxide, thereby increasing The pressure of the carbon dioxide cylinder 104 realizes fast filling.

The condensate liquid storage system 200 includes an industrial chiller 201 and a condensate storage tank 205. A first flow meter 202, a first centrifugal pump 203 and a first The shut-off valve 204, the condensate storage tank 205 are connected to the vacuum pumping liquid injection system 100, the first armored thermocouple 206, the first pressure transmitter 207 and the storage tank safety valve 208 are connected to the condensate storage tank 205, and the condensate storage tank 205 An exhaust valve 213 is connected to the system shut-off valve 9, and the industrial chiller 201 is sequentially connected to a first cooling tower 209, a first water storage bucket 210, a second centrifugal pump 211 and a second flow meter 212, and the condensation storage tank 205 is The integrated tank composed of the condenser and the liquid storage tank is composed of a cooling water cylinder, a carbon dioxide liquid storage tank, a condensation coil and a low-temperature cold water nozzle; the carbon dioxide liquid storage tank is in the cooling water cylinder, and the condensation coil is in the liquid storage tank and In the middle of the cooling water cylinder, the low-temperature cold water nozzle is connected to the cold side outlet of the chiller. The temperature of the cold side outlet of the chiller is about 1 degree Celsius. The cold water nozzle is placed vertically and flows from bottom to top. The axial and circumferential directions of the wall of the cold water nozzle are A certain number of through holes are opened in the direction to enhance heat exchange. The cooling water inside the first water storage bucket 210 is injected into the inside of the industrial chiller 201 through the second flowmeter 212 through the second centrifugal pump 211 for heat exchange, and the obtained The hot water enters the first cooling tower 213 for cooling, forming a circulating cooling mechanism. After the heat exchange, the low-temperature medium is injected into the condensation storage tank 205 through the first centrifugal pump 203, and the system main pipe inside the condensation storage tank 205 is cooled, thereby Cool down the carbon dioxide fluid inside the system mains.

The preheating system 300 includes a first current regulator 301 and a U-shaped tube electric heating preheater 303, the U-shaped tube electric heating preheater 303 is connected to the regenerator 6, and the U-shaped tube electric heating preheater 303 is provided with There are several first copper electrode plates 304, the first current regulator 301 and the several first copper electrode plates 304 are connected by the first copper braided wire 302, and the U-shaped tube electric heating preheater 303 is made of stainless steel tube The first current regulator 301 is a thyristor low-voltage high-current regulator; by connecting to the power supply, the resistance heating of the stainless steel tube of the U-shaped tube electric heating preheater 303 heats the carbon dioxide fluid, and the carbon dioxide fluid is heated during the production process. The inlet section, the middle section and the outlet section are respectively soldered with silver brazing to weld the copper electrode plate. In order to prevent electric heating leakage from affecting the measurement of system instruments and meters, traditional electrical insulating flanges or insulating joints are used in high temperature and high pressure systems. Difficult to realize, this embodiment adopts three-point heating method, the so-called three-point heating method is to lead out two lines from the positive pole of the DC low-voltage high-current transformer, one end is connected to the electrode plate of the inlet section, the other end is connected to the electrode plate of the outlet section, and the negative electrode is directly connected to the middle Segment electrode plate, the current forms a loop inside the U-shaped tube electric heating preheater 303, which effectively prevents leakage. The first current regulator 301 is connected to a low-voltage 0-60V high-current 0-5000A transformer, and continuously adjusts the first current The voltage of the voltage regulator 301 can change the electric heating power of the U-shaped tube electric heating preheater 303, so as to reach the temperature required by the experiment.

The experimental section test system 400 includes an experimental section 412 and a second current regulator 401, the inlet and outlet ports of the experimental section 412 are respectively connected to the U-shaped tube electric heating preheater 303 and the regenerator 6, and the two ends of the experimental section 412 Two second sheathed thermocouples 405 are provided respectively through the high-pressure sealed thermocouple seat 411, several wall thermocouple wires 406 and several second copper electrode plates 403 are provided on the experimental section 412, and two insulating thermocouples are provided on the experimental section 412. Connector 409, two insulating joints 409 are connected with differential pressure transmitter 408 through pressure introduction pipe 410, second pressure transmitter 404 and third pressure transmitter 407 are respectively arranged on pressure introduction pipe 410, several second The copper electrode plate 403 is electrically connected to the second current regulator 401 through the second copper braided wire 402, the casing of the second armored thermocouple 405 is made of 316L stainless steel, and the wall thermocouple wire 406 is a K-type thermocouple; Prevent electric heating from affecting the second sheathed thermocouple 405 for fluid temperature measurement. The second sheathed thermocouple 405 is a non-contact insulated sheathed thermocouple. The second sheathed thermocouple 405 is inserted vertically through a high-pressure sealed thermocouple seat 411 At the center of the pipe, the second armored thermocouple 405 realizes high-pressure sealing through a tapered seal, and the wall thermocouple wire 406 is a K-type thermocouple, which is directly welded to the pipe wall of the experimental section by the principle of instantaneous high temperature generated by capacitive discharge.

The insulating joint 409 includes a central column 4092, and one end of the central column 4092 is screwed with a first fastening nut 4091, and a compression ferrule 4095 and a tapered ferrule 4096 are sequentially arranged between the first fastening nut 4091 and the central column 4092, The central column 4092 is provided with two symmetrically arranged polytetrafluoroethylene insulating sleeves 4097. The polytetrafluoroethylene insulating sleeves 4097 are tapered. Fastening nut 4093, two polytetrafluoroethylene insulating sleeves 4097 are located inside the second fastening nut 4093, the second fastening nut 4093 is screwed with stud 4094, between the second fastening nut 4093 and the stud 4094 Rubber ring 4098 and PTFE flat washer 4099 are provided; the first fastening nut 4091 and stud 4094 are used to quickly connect the pressure induction pipe 410, the compression ferrule 4095 is matched with the tapered ferrule 4096 and the rubber ring 4098 and The PTFE flat washer 4099 cooperates, the second fastening nut 4093 and the stud 4094 cooperate to lock the two PTFE insulating sleeves 4097, the rubber ring 4098 and the PTFE flat washer 4099 to ensure the tightness of the connection, Effectively prevent leakage.

The high-pressure sealed thermocouple seat 411 includes a compression nut 4111, a fixed nut 4112 and a conical gasket 4113. The compression nut 4111 is screwed to the fixed nut 4112, and the conical gasket 4113 is engaged between the compression nut 4111 and the fixed nut 4112. Between; the tapered sealing gasket 4113 is stably engaged between the compression nut 4111 and the fixed nut 4112 to ensure the seal, the compression nut 4111 and the fixed nut 4112 are used to connect the second armored thermocouple 405, so that the second armored thermocouple The couple 405 is vertically inserted into the center of the pipe through the high-pressure sealing thermocouple seat 411, and the second armored thermocouple 405 is sealed through a cone to realize high-pressure sealing.

The cooling system 500 includes a cooler 501. The cooler 501 is a shell-and-tube heat exchanger. The high-temperature and high-pressure carbon dioxide working medium is arranged inside the tube side, and normal-temperature cooling water is arranged inside the shell side. The inlet and outlet ends of the cooler 501 are respectively connected to the return The heater 6 is connected to the main pipe armored thermocouple 7, the cooler 501 is connected to a heat exchange tube, and the heat exchange tube is provided with a second cooling tower 505, a second water storage bucket 504, a third centrifugal pump 503 and a third flow meter in sequence 502: Use the third centrifugal pump 503 to inject the cooling water inside the second water storage tank 504 into the cooler 501 through the third flow meter 502, and exchange heat with the main pipe of the system, and the obtained hot water enters the second cooling tower 505 for cooling. Cooling to form a circulating cooling mechanism, the temperature of the carbon dioxide working medium in charge of the system after heat exchange is reduced, and the low-temperature carbon dioxide working medium passes through the main tube armored thermocouple 7 .

The working principle of the present utility model: firstly, the whole system is vacuumized and carbon dioxide is injected with the vacuum pumping liquid injection system 100, the condensing liquid storage system 200 liquefies the carbon dioxide, and the high-pressure carbon dioxide pump 1 is started to make the carbon dioxide flow into the air bag type regulator 4, System flow meter 5, regenerator 6, preheating system 300, test section measurement system 400, cooling system 500, and pressure regulating valve 8 complete a closed loop; on the one hand, high-pressure carbon dioxide pump 1 provides power for the carbon dioxide fluid, and cooperates with the pressure regulating valve 8. Adjust the pressure required by the system. On the other hand, the system flow can be precisely controlled by frequency conversion control; the air bag regulator 4 is used to stabilize the flow and pressure fluctuation of the carbon dioxide fluid in the loop; the system flow meter 5 is used to accurately measure the system flow flow;

The U-shaped tube electric heating preheater 303 is connected to the power supply, and the carbon dioxide fluid is heated by the resistance heating of the stainless steel tube itself. During the production process, the copper electrode plate is welded with silver brazing at the inlet section, the middle section and the outlet section respectively. go up;

In order to prevent leakage from affecting the measurement of system instruments and meters, traditional electrical insulating flanges or insulating joints are difficult to implement in high-temperature and high-pressure systems. This application adopts a three-point heating method, which is to lead out two lines from the positive pole of the DC low-voltage high-current transformer. One end is connected to the electrode plate of the inlet section, the other end is connected to the electrode plate of the outlet section, and the negative electrode is directly connected to the electrode plate of the middle section, so that the current forms a loop inside the U-shaped tube electric heating preheater 303, which effectively prevents leakage. The first current voltage regulation The regulator 301 is connected to a low-voltage 0-60V high-current 0-5000A transformer. By continuously adjusting the voltage of the first current regulator 301, the electric heating power of the U-shaped tube electric heating preheater 303 can be changed, thereby reaching the temperature required for the experiment;

The regenerator 6 is a sleeve-tube heat exchanger, the inner and outer tubes are made of stainless steel, the inner tube is low-temperature carbon dioxide, and the annulus channel is the high-temperature carbon dioxide fluid working fluid flowing out of the experimental section;

The test system 400 in the experimental section uses the second armored thermocouple 405 to measure the inlet and outlet temperature of the working medium in the experimental section. The wall thermocouple wire 406 is welded on the corresponding experimental pipeline wall to measure the tube wall temperature. The second pressure changer The transmitter 404 and the third pressure transmitter 407 are used to measure the absolute pressure of the inlet working fluid, and the differential pressure transmitter 408 is used to measure the pressure loss of the inlet and outlet carbon dioxide fluid working fluid;

The cooler 501 is a shell-and-tube heat exchanger, the tube side uses high-temperature and high-pressure carbon dioxide fluid working medium, and the shell side uses normal temperature cooling water;

Condensation storage tank 205 is characterized by the integrated condenser and liquid storage tank, which is composed of a cooling water cylinder, a carbon dioxide liquid storage tank, a condensation coil, and a low-temperature cold water nozzle; the carbon dioxide liquid storage tank is in the cooling water cylinder, and the condensation coil Between the liquid storage tank and the cooling water cylinder, the low-temperature cold water nozzle is connected to the cold side outlet of the chiller. The temperature of the cold side outlet of the chiller is about 1 degree Celsius. The cold water nozzle is placed vertically and flows from bottom to top. A certain number of through holes are opened in the axial and circumferential directions to enhance heat transfer;

Working together to convert low-temperature and low-pressure carbon dioxide into high-temperature and high-pressure carbon dioxide and accurately measure its flow and heat transfer in the tube;

To sum up, the vacuum injection liquid injection system 100 vacuumizes the whole system and injects carbon dioxide to realize rapid filling; through the condensation liquid storage system 200, the carbon dioxide working medium inside the system supervisor is cooled; It is used to stabilize the flow and pressure fluctuations of the carbon dioxide fluid in the circuit; the regenerator 6 is a casing heat exchanger, and its inner and outer tubes are made of stainless steel, which is low in price, high in stability and strong in safety; The thermal system 300 is used for preheating, and the test system 400 in the experimental section is used to measure the temperature of the inlet and outlet of the working medium in the experimental section. The wall thermocouple is directly welded on the corresponding experimental pipeline wall to measure the tube wall temperature for accurate measurement. The pressure sensor It is used to measure the absolute pressure of the inlet working fluid, and the differential pressure sensor is used to measure the pressure loss of the inlet and outlet working fluid; through the heat exchange between the cooling system 500 and the system supervisor, the hot water obtained enters the second cooling tower 505 for cooling to form Circulating cooling mechanism, the temperature of the carbon dioxide working medium in charge of the system decreases after heat exchange, and the low-temperature carbon dioxide working medium enters the condensation storage tank to complete the cycle;

Lead out two wires from the positive pole of the DC low-voltage high-current transformer through the insulating joint 409, one is connected to the electrode plate of the inlet section, the other is connected to the electrode plate of the outlet section, and the negative pole is directly connected to the electrode plate of the middle section, and the current flows in the U-shaped tube electric heating preheater A loop is formed inside 303, which effectively prevents leakage. By continuously adjusting the voltage of the first current regulator 301, the electric heating power of the preheater can be changed to achieve the temperature required by the experiment. This experimental device can be used for different pressures (1~ 30 MPa), different temperatures (~600 ^o C), different pipe diameters (2-30 mm), different heating power (1-500 kW) flow heat transfer and instability tests.

The preferred implementation of this patent has been described in detail above, but this patent is not limited to the above-mentioned implementation, and within the knowledge of those of ordinary skill in the art, it can also be made without departing from the purpose of this patent. Variations.

Claims (9)

1. An experimental device for testing flow and heat transfer in a high-temperature and high-pressure carbon dioxide pipe, including a high-pressure carbon dioxide pump (1), a pressure sensor (2), a main safety valve (3), an airbag regulator (4), and a system flow rate connected in sequence Meter (5), regenerator (6), supervisor armored thermocouple (7), pressure regulating valve (8), system shut-off valve (9) and filter (10), characterized in that the regenerator (6) The preheating system (300), the measurement system (400) and the cooling system (500) of the experimental section are respectively connected, wherein the cooling system (500) is connected to the regenerator (6) and the main armored thermocouple (7) Between the pressure regulating valve (8) and the system cut-off valve (9), there is a vacuum pumping liquid injection system (100) and a condensate liquid storage system (200) connected to each other, wherein the condensate liquid storage system (200) is connected with The branch circuit (11), the branch circuit (11) is connected between the main safety valve (3) and the air bag regulator (4). 2. A high-temperature and high-pressure carbon dioxide pipe flow heat transfer test experimental device according to claim 1, characterized in that the high-pressure carbon dioxide pump (1) is a plunger type metering pump, and the regenerator (6) is a casing Type heat exchanger, the inner and outer tubes of the regenerator (6) are all made of stainless steel. 3. The experimental device for testing flow and heat transfer in a high-temperature and high-pressure carbon dioxide tube according to claim 1, wherein the vacuum pumping liquid injection system (100) includes a bus bar (101) and a vacuum pump (102), and the bus bar (101) and the vacuum pump (102) are communicated with the pressure regulating valve (8) respectively, and several carbon dioxide gas cylinders (104) are connected on the busbar (101), and the carbon dioxide gas cylinders (104) and the busbar (101) are equipped with A vacuum stop valve (103) is arranged, and an electric heating mantle (105) is provided on the carbon dioxide cylinder (104). 4. The experimental device for testing flow and heat transfer in a high-temperature and high-pressure carbon dioxide pipe according to claim 1, characterized in that, the condensation liquid storage system (200) includes an industrial chiller (201) and a condensation storage tank (205), A first flow meter (202), a first centrifugal pump (203) and a first shut-off valve (204) are installed between the inlet and outlet ends of the industrial chiller (201) and the condensate storage tank (205). The tank (205) is connected to the vacuum pumping liquid injection system (100), and the first armored thermocouple (206), the first pressure transmitter (207) and the storage tank safety valve (208) are connected to the condensation storage tank (205). ), the exhaust valve (213) is connected between the condensate storage tank (205) and the system shut-off valve (9), and the industrial chiller (201) is connected with the first cooling tower (209) and the first water storage tank (210) in sequence , the second centrifugal pump (211) and the second flow meter (212), the condensation storage tank (205) is an integrated tank composed of a condenser and a liquid storage tank, and consists of a cooling water cylinder, a carbon dioxide liquid storage tank, and a condensation coil And low temperature cold water nozzle composition. 5. The experimental device for testing flow heat transfer in a high-temperature and high-pressure carbon dioxide tube according to claim 1, wherein the preheating system (300) includes a first current regulator (301) and a U-shaped tube electric heater The preheater (303), the U-shaped tube electric heating preheater (303) is connected to the regenerator (6), and the U-shaped tube electric heating preheater (303) is provided with several first copper electrode plates (304) , the first current regulator (301) and several first copper electrode plates (304) are connected by first copper braided wires (302), and the U-shaped tube electric heating preheater (303) is made of stainless steel tube In this way, the first current voltage regulator (301) is a thyristor low-voltage high-current voltage regulator. 6. A high temperature and high pressure carbon dioxide pipe flow heat transfer test experimental device according to claim 5, characterized in that the experimental section measurement system (400) includes an experimental section (412) and a second current regulator (401 ), the inlet and outlet ends of the experimental section (412) are respectively connected to the U-shaped tube electric heating preheater (303) and the regenerator (6), and the two ends of the experimental section (412) are respectively sealed by high-pressure thermocouple seats ( 411) is provided with two second armored thermocouples (405), and several wall thermocouple wires (406) and several second copper electrode plates (403) are provided on the experimental section (412). There are two insulating joints (409), and the two insulating joints (409) are connected to the differential pressure transmitter (408) through the pressure introduction tube (410), and the second pressure transmitter (410) is respectively provided device (404) and the third pressure transmitter (407), several second copper electrode plates (403) are electrically connected to the second current regulator (401) through the second copper braided wire (402), and the second armor The casing for installing the thermocouple (405) is made of 316L stainless steel, and the wall thermocouple wire (406) is a K-type thermocouple. 7. An experimental device for testing flow and heat transfer in a high-temperature, high-pressure carbon dioxide tube according to claim 6, wherein the insulating joint (409) includes a central column (4092), and one end of the central column (4092) is screwed with a The first fastening nut (4091), between the first fastening nut (4091) and the central column (4092) is provided with a compression ferrule (4095) and a tapered ferrule (4096), on the central column (4092) There are two symmetrically arranged polytetrafluoroethylene insulating sleeves (4097). The polytetrafluoroethylene insulating sleeves (4097) are tapered. There is a second fastening nut (4093), two polytetrafluoroethylene insulating sleeves (4097) are located inside the second fastening nut (4093), and the second fastening nut (4093) is screwed with a stud (4094) , a rubber ring (4098) and a polytetrafluoroethylene flat washer (4099) are sequentially provided between the second fastening nut (4093) and the stud (4094). 8. An experimental device for testing flow and heat transfer in a high-temperature, high-pressure carbon dioxide tube according to claim 7, wherein the high-pressure sealed thermocouple seat (411) includes a compression nut (4111), a fixing nut (4112) and The conical sealing gasket (4113), the compression nut (4111) and the fixing nut (4112) are screwed together, and the conical sealing gasket (4113) is engaged between the compression nut (4111) and the fixing nut (4112). 9. A high temperature and high pressure carbon dioxide pipe flow heat transfer test experimental device according to claim 1 or 8, characterized in that the cooling system (500) includes a cooler (501), and the cooler (501) is a tube shell Type heat exchanger, the tube side is equipped with high temperature and high pressure carbon dioxide working medium, and the shell side is equipped with normal temperature cooling water. The inlet and outlet ports of the cooler (501) are respectively connected with the regenerator (6) and the main pipe of the system. The cooler (501) is connected with a heat exchange tube, and the heat exchange tube is provided with a second cooling tower (505), a second water storage bucket (504), a third centrifugal pump (503) and a third flow meter (502) in sequence.

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