CN104697739B - Cryogen flow resistance and Temperature Distribution test device in adiabatic corrugated tube - Google Patents

Abstract

The invention relates to a low-temperature fluid flow resistance and temperature distribution test device in an adiabatic bellows. The test device includes a low-temperature self-pressurized storage tank connected by a metal hose, a two-stage subcooler, a bellows test section, a vaporizer and a gas The flowmeter, the bellows test section is connected with the filling and exhausting pipeline, the vacuum degree in the bellows testing section is adjusted through the filling and exhausting pipeline, and the temperature and pressure measuring unit and the vacuum degree measuring unit are set in the bellows testing section, The flow resistance and temperature distribution of cryogenic fluid in the adiabatic bellows are obtained through the temperature, pressure and vacuum data in the bellows test section. Compared with the prior art, the device of the present invention has simple structure, convenient operation, safety and reliability, and is suitable for the experimental measurement of the flow and heat transfer characteristics of various low-temperature fluid heat-insulating bellows under different inclination angles.

Description

Cryogenic fluid flow resistance and temperature distribution test device in adiabatic bellows

technical field

The invention relates to a low-temperature fluid flow and heat transfer characteristic testing device, in particular to a low-temperature fluid flow resistance and temperature distribution testing device in an adiabatic bellows, which belongs to the field of low-temperature engineering and low-temperature technology.

Background technique

Cryogenic fluid flow and heat transfer characteristics are the basic properties of energy development, chemical metallurgy, environmental protection, medical and health care, transportation, space technology and other fields. Newly developed products usually require related actual measurements. Especially in the process of superconducting cable power transmission, production, storage and transportation of liquefied natural gas and liquid hydrogen fuel, it is widely involved in the measurement of flow characteristics of various fluid devices such as pipelines, valves, and variable diameters. The transportation of cryogenic fluid and the circulation as a cooling medium are inseparable from vacuum insulated pipes, and flexible bellows account for a large proportion of such vacuum insulated pipes. It is of great value to design a simple and reliable device that can realize the standardized measurement of the flow and heat transfer characteristics of various cryogenic fluids under specific conditions in the bellows.

The patent with the publication number CN102435632A discloses a test system for the flow boiling heat transfer characteristics and pressure drop characteristics of low temperature fluid. The system installs electric heating equipment in the vacuum dewar, mainly for the low temperature fluid flow boiling in the heat exchanger pipeline. Carry out heat transfer and pressure drop characteristics research under specific conditions; it only measures the temperature at the inlet and outlet of the heat exchanger pipe, and cannot realize the temperature measurement along the pipe. In addition, its subcooler cannot achieve fluid precooling in the temperature range below 77K. The journal paper "Experimental Research on Flow Characteristics in Bellows" (Journal of Engineering Thermophysics, 2008, 10:1725-1727) discloses an experimental device for measuring the flow resistance of liquid nitrogen in bellows. The stable pressure and flow of the fluid in the tube has certain advantages. However, this device is inconvenient to replace the tested samples of bellows of different specifications, cannot change the inclination angle, does not measure the temperature distribution along the bellows, does not change and detect performance measurement under different vacuum degrees of heat leakage, etc.

Contents of the invention

The purpose of the present invention is to provide a low-temperature fluid flow resistance and temperature distribution test device in the heat-insulated bellows in order to overcome the above-mentioned defects in the prior art. , safe and reliable, can realize experimental measurement under various conditions, can easily replace the tested sample pipeline sample, not only gives the pressure drop characteristics under different heat leakage conditions, but also simultaneously measures the temperature distribution of the experimental section, and more importantly, realizes The measurement function of the tested pipeline under different inclination angles is realized.

The purpose of the present invention can be achieved through the following technical solutions:

A low-temperature fluid flow resistance and temperature distribution test device in an adiabatic bellows, the test device includes a low-temperature self-pressurized storage tank connected by a metal hose, a two-stage subcooler, a bellows test section, a vaporizer and a gas flow meter,

The bellows test section includes an inner bellows, an outer bellows, a large-diameter operating chamber and an inner filling core, the outer bellows is sleeved outside the inner bellows, and the inner filling core is filled inside At the core of the bellows, the large-diameter operating chamber is located at both ends of the outer bellows, wherein the two ends of the inner bellows communicate with the metal hose for delivering low-temperature fluid,

A vacuum insulation cavity is formed between the inner bellows and the outer bellows, and the vacuum insulation cavity is connected with the filling and exhausting pipelines, and the vacuum degree in the vacuum insulation cavity is adjusted through the charging and exhausting pipelines.

A temperature and pressure measurement unit and a vacuum degree measurement unit are installed in the bellows test section, and the low temperature fluid flow resistance and temperature distribution in the adiabatic bellows are obtained through the temperature, pressure and vacuum data in the bellows test section.

A pressure regulating valve, a flow regulating valve, a back pressure regulating valve and an on-off valve are arranged on the metal hose. The regulating valve is set between the two-stage subcooler and the bellows test section, the back pressure regulating valve is set between the bellows test section and the vaporizer, and the on-off valve is set between the vaporizer and the gas flow meter.

The two-stage subcooler is divided into a first-stage subcooler and a second-stage subcooler, and the first-stage subcooler is formed by placing a first-stage coil in an open heat-insulating stainless steel tank; the second-stage overcooler The cooler consists of a closed wide-mouth Dewar, a second-stage coil placed in the wide-mouth Dewar, and a mechanical pump connected to the interior of the wide-mouth Dewar. The first-stage coil and the second-stage The coils are sequentially connected in series on the metal hose. The low-temperature fluid in a supercooled state is obtained according to two-stage subcoolers, wherein the first-stage subcooler completes most of the heat exchange under normal pressure, and the second-stage subcooler can achieve further supercooling under vacuum conditions. Cold heat exchange.

The inner filling core is used to simulate the insert in the inner bellows, and the inner filling core is fixed to the core of the inner bellows through a polytetrafluoroethylene spiral support structure, which is not only temperature-resistant, but also has a very small resistance to flow. It is more convenient to disassemble and replace.

The large-diameter operating chamber is connected to the outer bellows through a clamp, so that the interior of the large-diameter operating chamber communicates with the vacuum insulation cavity formed between the inner bellows and the outer bellows, and the two ends of the inner bellows It is connected with the connecting pipe in the large-diameter operating chamber through a ferrule joint, and the connecting pipe in the large-diameter operating chamber communicates with the metal hose, and the vacuum insulation cavity formed between the inner bellows and the outer bellows is filled with multi-layer insulation Material. By opening the large-diameter operation chamber, the ferrule connection operation of the inner bellows can be realized, so as to flexibly disassemble and replace the tested bellows and core samples, so as to realize the replacement experiment of different specifications of the tested bellows and core samples.

The inflation and exhaust pipeline is connected with the inside of the large-diameter operation chamber, and a vacuum pump and a vacuum valve are arranged on the inflation and exhaust pipeline, and an inflation stop valve is arranged on the inflation and exhaust pipeline.

The temperature and pressure measuring unit includes a differential pressure transmitter, a bottom temperature sensor and a top temperature sensor, the two ends of the differential pressure transmitter communicate with the two ends of the inner bellows, and the differential pressure transmitter The device realizes micro-pressure difference measurement, the bottom temperature sensors are evenly installed on the outer surface of the bottom of the inner bellows in the vertical direction at equal intervals, and the top temperature sensors are evenly installed at equal intervals on the vertical top of the inner bellows The outer surface;

The vacuum degree measuring unit includes a vacuum gauge and a digital display vacuum gauge connected to the large-diameter operating chamber, and the vacuum of the vacuum insulation cavity formed between the inner bellows and the outer bellows is obtained through the vacuum gauge and the digital display vacuum gauge. By changing the degree of vacuum to change the insulation of the bellows, simulating the different degrees of air leakage conditions of the low-temperature pipelines that have been operating all year round, it can be used to monitor the flow and heat transfer characteristics in the test bellows under different vacuum degrees.

Described differential pressure transmitter, bottom temperature sensor and top temperature sensor are all connected with data acquisition card, and this data acquisition card is connected with computer, and computer is according to the temperature obtained by differential pressure transmitter, bottom temperature sensor and top temperature sensor. , pressure data, and obtain the flow resistance and temperature distribution of the cryogenic fluid in the adiabatic bellows.

The bellows test section is placed on the support base, and the support base is a two-stage liftable support, including a base, a middle telescopic support and a stretchable hinge, and the middle telescopic support is located on In the middle of the base, there are two stretchable hinges, one end of which is connected to the left or right end of the base, and the other end is hinged to the top of the middle telescopic bracket at the same time; the support base is realized by adjusting the angle of the stretchable hinge Bend deformation, used for flow resistance and temperature distribution test of cryogenic fluid in adiabatic bellows at different inclination angles.

Compared with the prior art, the device of the present invention is suitable for testing the flow resistance and temperature distribution in a variety of low-temperature fluid adiabatic bellows. The device is simple, safe and reliable, and can realize experimental measurements under various conditions, and can conveniently replace the sample of the tested sample pipeline. , the device of the invention not only provides pressure drop characteristics under different heat leakage conditions, but also simultaneously measures the temperature distribution of the experimental section, and more importantly, realizes the measurement function of the tested pipeline under different inclination angles.

Description of drawings

Fig. 1 is the structural representation of testing device of the present invention;

Fig. 2 is the partially enlarged view of the bellows experiment section of the testing device of the present invention;

Fig. 3 is a schematic diagram of the lifting state of the supporting base of the testing device of the present invention.

Numbers in the figure: 1 is the low-temperature self-pressurized storage tank, 2 is the pressure regulating valve, 3 is the stainless steel tank, 4 is the first-stage coil, 5 is the wide-mouth Dewar, 6 is the second-stage coil, 7 is the mechanical Pump, 8 is a flow regulating valve, 9 is a large-diameter operating chamber, 10 is a ferrule joint, 11 is an inner bellows, 12 is a clamp, 13 is an outer bellows, 14 is a vacuum gauge, 15 is an internal filling core, 16 is a differential pressure transmitter, 17 is a bottom temperature sensor, 18 is a top temperature sensor, 19 is a back pressure regulating valve, 20 is a vaporizer, 21 is an on-off valve, 22 is a gas flow meter, 23 is an inflation stop valve, and 24 is a Vacuum valve, 25 is a vacuum pump, 26 is a data acquisition card, 27 is a computer, 28 is a base, 29 is a telescopic support in the middle, and 30 is a stretchable hinge.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

A low-temperature fluid flow resistance and temperature distribution test device in an adiabatic bellows, as shown in Figure 1 and Figure 2, the test device includes a low-temperature self-pressurized storage tank 1 connected by a metal hose, a two-stage subcooler, a corrugated Tube test section, vaporizer 20 and gas flow meter 22, on the metal hose are provided with pressure regulating valve 2, flow regulating valve 8, back pressure regulating valve 19 and switch valve 21, pressure regulating valve 2 is set in the low temperature self-pressurized storage Between the tank 1 and the two-stage subcooler, the flow regulating valve 8 is set between the two-stage subcooler and the bellows test section, the back pressure regulating valve 19 is set between the bellows test section and the vaporizer 20, and the switch valve 21 It is installed between the vaporizer 20 and the gas flow meter 22 .

The two-stage supercooler is divided into a first-stage supercooler and a second-stage supercooler. The first-stage supercooler is composed of a first-stage coil 4 placed in an open heat-insulating stainless steel tank 3; the second-stage supercooler The device consists of a closed wide-mouth Dewar 5, a second-stage coil 6 placed inside the wide-mouth Dewar 5, and a mechanical pump 7 communicated with the wide-mouth Dewar 5. The first-stage coil 4 and the second stage The secondary coils 6 are sequentially connected in series on the metal hose. The low-temperature fluid in a supercooled state is obtained according to the two-stage subcooler, wherein the first-stage subcooler completes most of the heat exchange under normal pressure, and the second-stage subcooler uses saturated vapor pressure corresponding to The principle of unique saturation temperature can realize further subcooling heat exchange.

Among them, the bellows experimental section includes an inner bellows 11, an outer bellows 13, a large-diameter operating chamber 9 and an inner filling core 15, the outer bellows 13 is set outside the inner bellows 11, and the inner filling core 15 is used for simulating The insert in the inner bellows 11, the inner filling core 15 is fixed to the core of the inner bellows 11 through the polytetrafluoroethylene spiral support structure, which is not only temperature-resistant, but also has a very small entry flow resistance, and is more convenient for disassembly and replacement. The large-diameter operating chamber 9 is located at both ends of the outer bellows 13, and the large-diameter operating chamber 9 is connected to the outer bellows 13 through a clamp 12, so that the inside of the large-diameter operating chamber 9 is formed between the inner bellows 11 and the outer bellows 13. The two ends of the inner bellows 11 are connected with the connecting pipe in the large-diameter operating chamber 9 through a ferrule joint 10, and the connecting pipe in the large-diameter operating chamber 9 communicates with the metal hose, and the inner bellows The vacuum insulation cavity formed between the pipe 11 and the outer bellows 13 is filled with multiple layers of insulation material. By opening the large-diameter operation chamber 9, the ferrule connection operation of the inner bellows 11 can be realized, so that the bellows and core samples under test can be flexibly disassembled and replaced, so as to realize the replacement experiment of different specifications of the bellows and core samples under test .

A vacuum insulation cavity is formed between the inner bellows 11 and the outer bellows 13, and the vacuum insulation cavity is connected with the filling and exhausting pipeline, and the vacuum degree in the vacuum insulation cavity is adjusted through the filling and exhausting pipeline, and the filling and exhausting The pipeline communicates with the inside of the large-diameter operating chamber 9, and a vacuum pump 25 and a vacuum valve 24 are arranged on the inflation and exhaust pipeline, and an inflation stop valve 23 is arranged on the inflation and exhaust pipeline.

A temperature and pressure measurement unit and a vacuum degree measurement unit are arranged in the bellows experiment section, and the temperature and pressure measurement unit includes a differential pressure transmitter 16, a bottom temperature sensor 17 and a top temperature sensor 18, and two of the differential pressure transmitter 16 The two ends of the inner bellows 11 are connected, the differential pressure transmitter 16 realizes micro-pressure difference measurement, the bottom temperature sensors 17 are evenly installed on the bottom outer surface of the vertical direction of the inner bellows 11, and the top temperature sensors 18, etc. Installed evenly on the top outer surface of the vertical direction of the inner bellows 11;

The vacuum degree measuring unit includes a vacuum gauge 14 and a digital display vacuum gauge connected to the large-diameter operating chamber 9. The vacuum insulation cavity formed between the inner bellows 11 and the outer bellows 13 is obtained by the vacuum gauge 14 and the digital display vacuum gauge. The degree of vacuum can be changed by changing the vacuum degree to change the insulation of the bellows, simulating different degrees of air leakage conditions, and can be used to monitor the flow and heat transfer characteristics in the test bellows under different vacuum degrees.

Differential pressure transmitter 16, bottom temperature sensor 17 and top temperature sensor 18 are all connected with data acquisition card 26, and this data acquisition card 26 is connected with computer 27, and computer 27 is according to by differential pressure transmitter 16, bottom temperature sensor 17 and The temperature and pressure data obtained by the top temperature sensor 18 obtain the flow resistance and temperature distribution of the cryogenic fluid in the adiabatic bellows.

In this embodiment, the experimental section of the bellows is placed on the supporting base, and the supporting base is shown in Figure 3. Telescopic support 29 is located at the middle part of base 28, and stretchable hinge 30 is provided with two, and its one end is connected on the left end or the right end of base 28, and the other end is hinged with the top of middle flexible support 29 simultaneously; The angle of 30° realizes the bending deformation of the support base, which is used for the flow resistance and temperature distribution test of the cryogenic fluid in the adiabatic bellows at different inclination angles.

The course of work of the device of the present invention is:

Using liquid nitrogen as the working medium, first pass the low-temperature self-pressurized storage tank 1, the two-stage subcooler, the bellows test section, the vaporizer 20, and the gas flow meter 22 through the pressure regulating valve 2, the flow regulating valve 8, and the back pressure regulating valve in sequence. Valve 19, on-off valve 21 and metal hose are connected. Place the bellows test section on the support base.

Vacuumize the bellows experimental section, the process is: connect the vacuum pump 25 to the bellows experimental section through the vacuum valve 24, close the inflation stop valve 23, open the vacuum valve 24, vacuum the inner and outer bellows, and wait until the vacuum degree After reaching and stabilizing at 10 ^-3 Pa, close the vacuum valve 24.

The test device is precooled, specifically: a small amount of liquid nitrogen is poured into the open-top insulated stainless steel tank 3 and the wide-mouth Dewar 5 . Open the back pressure regulating valve 19, open the pressure regulating valve 2, wait until the pressure in the pipe rises to the gauge pressure of 0.1 MPa, slightly open the flow regulating valve 8, and pass a small amount of liquid nitrogen from the low-temperature self-pressurized storage tank 1 to the bellows experimental section , and discharged directly.

Formal testing is carried out: the open insulation stainless steel tank 3 and the wide-mouth Dewar 5 are filled with liquid nitrogen, the mechanical pump 7 is turned on, and the wide-mouth Dewar 5 is evacuated. Open the pressure regulating valve 2, the back pressure regulating valve 19, and the switch valve 21, and control the appropriate liquid nitrogen flow through the flow regulating valve 8 to continue passing through the test device.

The computer 27 records the real-time test data of the differential pressure transmitter 16, the bottom temperature sensor 17, and the top temperature sensor 18. Use a digital display vacuum gauge to record the vacuum degree of the cavity between the inner bellows and the outer bellows measured by the vacuum gauge 14. The flow resistance and temperature distribution of the cryogenic fluid in the adiabatic bellows can be obtained by collating the calculated data.

The above descriptions of the embodiments are for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative effort. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (9)

1. A low-temperature fluid flow resistance and temperature distribution test device in an adiabatic bellows, characterized in that the test device comprises a low-temperature self-pressurized storage tank (1) connected by a metal hose, a two-stage subcooler, and a bellows Experiment section, vaporizer (20) and gas flow meter (22), The bellows test section includes an inner bellows (11), an outer bellows (13), a large-diameter operating chamber (9) and an inner filling core (15), and the outer bellows (13) is sleeved on Outside the inner bellows (11), the inner filling core (15) is filled at the core of the inner bellows (11), and the large-diameter operating cavity (9) is located at both ends of the outer bellows (13) , wherein, the two ends of the inner bellows (11) communicate with the metal hose for conveying cryogenic fluid, A vacuum insulation cavity is formed between the inner bellows (11) and the outer bellows (13), and the vacuum insulation cavity is connected with the filling and exhausting pipelines, and the vacuum degree in the vacuum insulation cavity is adjusted through the charging and exhausting pipelines , A temperature and pressure measurement unit and a vacuum degree measurement unit are installed in the bellows test section, and the low temperature fluid flow resistance and temperature distribution in the adiabatic bellows are obtained through the temperature, pressure and vacuum data in the bellows test section. 2. The low-temperature fluid flow resistance and temperature distribution test device in a heat-insulated bellows according to claim 1, characterized in that a pressure regulating valve (2), a flow regulating valve (8), a back Pressure regulating valve (19) and on-off valve (21), described pressure regulating valve (2) is arranged between the low-temperature self-pressurized storage tank (1) and two-stage supercooler, described flow regulating valve (8 ) is located between the two-stage subcooler and the bellows test section, the back pressure regulating valve (19) is set between the bellows test section and the vaporizer (20), and the on-off valve (21) is located at Between vaporizer (20) and gas flow meter (22). 3. The low-temperature fluid flow resistance and temperature distribution test device in an adiabatic bellows according to claim 1, wherein the two-stage subcooler is divided into a first-stage subcooler and a second-stage subcooler The first-stage subcooler is composed of the first-stage coil (4) placed in an open heat-insulating stainless steel tank (3); the second-stage subcooler is composed of a closed wide-mouth Dewar (5), placed in a wide-open The second-stage coil (6) in the wide-mouth Dewar (5) and the mechanical pump (7) communicated with the wide-mouth Dewar (5), the first-stage coil (4) and the second The stage coils (6) are serially connected in series on the metal flexible pipes. 4. A test device for flow resistance and temperature distribution of low temperature fluid in an adiabatic bellows according to claim 1, characterized in that the inner filling core (15) is used to simulate the inner bellows (11) insert , the inner filling core (15) is fixed to the core of the inner bellows (11) through a polytetrafluoroethylene support. 5. A test device for flow resistance and temperature distribution of low-temperature fluid in an adiabatic bellows according to claim 1, characterized in that the large-diameter operating chamber (9) is connected to the outer bellows (13) by a clamp (12) ) connection, so that the inside of the large-diameter operating chamber (9) communicates with the vacuum insulation cavity formed between the inner bellows (11) and the outer bellows (13), and the two ends of the inner bellows (11) are connected to the The connecting pipe in the large-diameter operating chamber (9) is connected through a ferrule joint (10), and the connecting pipe in the large-diameter operating chamber (9) communicates with the metal hose. The vacuum heat insulation cavity formed between the inner bellows (11) and the outer bellows (13) is filled with multiple layers of heat insulating material. 6. A test device for flow resistance and temperature distribution of low-temperature fluid in an adiabatic bellows according to claim 5, characterized in that, the inflation and exhaust pipeline communicates with the inside of the large-diameter operating chamber (9), A vacuum pump (25) and a vacuum valve (24) are arranged on the exhaust pipeline, and an inflation stop valve (23) is arranged on the inflation and exhaust pipeline. 7. The low-temperature fluid flow resistance and temperature distribution test device in a heat-insulated bellows according to claim 1, wherein the temperature and pressure measurement unit includes a differential pressure transmitter (16), a bottom temperature sensor ( 17) and the top temperature sensor (18), the two ends of the differential pressure transmitter (16) communicate with the two ends of the inner bellows (11), and the bottom temperature sensors (17) are evenly spaced on the The bottom outer surface of the vertical direction of the inner bellows (11), and the top outer surface of the vertical direction of the inner bellows (11) is uniformly installed with the top temperature sensors (18) at equal intervals; The vacuum degree measuring unit includes a vacuum gauge (14) and a digital display vacuum gauge connected to the large-diameter operating chamber (9), and the inner bellows (11) and the outer bellows (11) and the outer bellows (11) are obtained by the vacuum gauge (14) and the digital display vacuum gauge. The vacuum degree of the vacuum insulation cavity formed between the bellows (13). 8. A test device for flow resistance and temperature distribution of low temperature fluid in an adiabatic bellows according to claim 7, characterized in that said differential pressure transmitter (16), bottom temperature sensor (17), top temperature sensor (18) are all connected with data acquisition card (26), and this data acquisition card (26) is connected with computer (27), and computer (27) is according to by differential pressure transmitter (16), bottom temperature sensor (17) and top The pressure and temperature data obtained by the temperature sensor (18) obtain the flow resistance and temperature distribution of the low-temperature fluid in the adiabatic bellows. 9. A test device for flow resistance and temperature distribution of low-temperature fluid in an adiabatic bellows according to claim 1, characterized in that, the bellows test section is placed on a support base, and the support base is two The section-type liftable support includes a base (28), a middle telescopic support (29) and a stretchable hinge (30), and the middle telescopic support (29) is located at the middle part of the base (28). There are two stretchable hinges (30), one end of which is connected to the left or right end of the base (28), and the other end is hinged with the top of the middle telescopic support (29); by adjusting the stretchable hinge (30) The angle realizes the bending deformation of the support base, which is used for the flow resistance and temperature distribution test of the cryogenic fluid in the adiabatic bellows at different inclination angles.