Superconducting bulk cooling apparatus and cooling method for high-temperature superconducting magnetic levitation vehicle

Abstract

The present invention discloses a superconducting bulk cooling apparatus and cooling method for a high-temperature superconducting magnetic levitation vehicle. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle includes a refrigerating machine, a vacuum box and a Dewar tank. A condensing tank is arranged in the vacuum box, and the condensing tank is communicated with the Dewar tank through a nitrogen siphon pipe and a liquid nitrogen return pipe; a heat exchanger connected with the refrigerating machine is arranged in the condensing tank; and a flexible isolation pipe for thermally insulating and isolating the nitrogen siphon pipe and the liquid nitrogen return pipe is connected between the vacuum box and the Dewar tank. The present invention pumps the phase-change nitrogen out of the Dewar tank through a siphoning effect, so that the immersion cooling of high-temperature superconducting bulks is separated from the re-condensation of the nitrogen.

Claims

1. A superconducting bulk cooling apparatus for a high-temperature superconducting magnetic levitation vehicle, comprising a refrigerating machine (1), a vacuum box (2) and a Dewar tank (3), wherein a condensing tank (4) is arranged in the vacuum box (2), and the condensing tank (4) is thermally insulated from an external environment through the vacuum box (2); the Dewar tank (3) is communicated with the vacuum box (2) through a flexible isolation pipe (5), and a nitrogen siphon pipe (6) and a liquid nitrogen return pipe (7) that are independent from each other are arranged in the flexible isolation pipe (5); and the Dewar tank (3) is communicated with the condensing tank (4) through the nitrogen siphon pipe (6) and the liquid nitrogen return pipe (7) to form a closed nitrogen conversion and circulation loop; a heat exchanger (8) for performing heat exchange and condensation on gaseous nitrogen is arranged in the condensing tank (4), and the heat exchanger (8) is fixedly and thermally connected with the refrigerating machine (1); when the superconducting bulk cooling apparatus for a high-temperature superconducting magnetic levitation vehicle is in use, the high-temperature superconducting bulk is immersed in the liquid nitrogen of the Dewar tank (3), and the temperature of the liquid nitrogen increases in the process of cooling the high-temperature superconducting bulk, so that partial liquid nitrogen is phase-changed to the saturated nitrogen, and the pressure in the Dewar tank (3) increases continuously; the siphoning effect occurs between the condensing tank and the Dewar tank, the saturated nitrogen may overcome the surface tension thereof to automatically enter the condensing tank (4) through the nitrogen siphon pipe (6) and to contact the heat exchanger (8), the gaseous nitrogen is condensed into liquid, and the liquid nitrogen is returned to the Dewar tank (3) through the liquid nitrogen return pipe (7); the heat exchanger (8) comprises a connecting seat (81), and a plurality of cooling fins (82) are uniformly arranged on the connecting seat (81); and a cross section of each cooling fin (82) is in an inverted triangular shape or an inverted trapezoidal shape, and an oblique angle of a side surface is 0.25°-0.5°; and the cooling fin (82) is provided with a plurality of via holes, the nitrogen siphon pipe passes through the via holes to be inserted into the cooling fin (82), and a plurality of ventilation holes are uniformly arranged on a portion of the nitrogen siphon pipe located between the cooling fins (82).

2. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 1, wherein the flexible isolation pipe (5) comprises an inner pipe (51) and an outer pipe (52) made of a corrugated pipe, the inner pipe (51) and the outer pipe (52) are concentrically arranged, and a thermal insulation layer (53) is filled between the inner pipe (51) and the outer pipe (52); and a plurality of fixing sheets (54) having special structures for supporting the nitrogen siphon pipe (6) and the liquid nitrogen return pipe (7) are arranged in the inner pipe (51), and an isolation gap is reserved between any two of the nitrogen siphon pipe (6), the liquid nitrogen return pipe (7) and the inner pipe (51) through the fixing sheets (54).

3. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 2, wherein a plurality of pipeline supporting sheets (55) are uniformly arranged between the inner pipe (51) and the outer pipe (52), and the thermal insulation layer (53) is filled between pipeline supporting sheets (55).

4. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 1, wherein the vacuum box (2) comprises a box body (21) and a top cover (22) that are connected with each other; the refrigerating machine (1) is fixedly connected with the top cover (22) through a damper (9); the condensing tank (4) comprises a tank body (41), the top of the tank body (41) is provided with a heat exchanger (8), and a cold head (11) of the refrigerating machine (1) passes through the top cover (22) to be thermally connected with the heat exchanger (8).

5. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 4, wherein the cold head (11) is provided with a heating pipe (10) for controlling the output cold thereof, and the heating pipe (10) is also connected with a temperature controller for controlling the heating temperature.

6. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 1, wherein the condensing tank (4) is also provided with a liquid nitrogen replenishing pipe (12) communicated with an external liquid nitrogen source; the liquid nitrogen replenishing pipe (12) is provided with a regulating stop valve (13); and the liquid nitrogen replenishing pipe (12) is also provided with a corrugated compensation pipe (14).

7. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 1, wherein the condensing tank (4) is also connected with a safety pipe (15) communicated with the external environment; the safety pipe (15) is provided with a safety valve (16) for controlling a connection/disconnection state thereof; and the safety pipe is also connected with a first vacuum pipe (17) in parallel, and the vacuum pipe (17) is provided with a first stop valve (18).

8. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 1, wherein the vacuum box (2) is also provided with a detecting pipe (19) and a second vacuum pipe (20) that are communicated with the exterior; the detecting pipe (19) is connected with a vacuum gauge (23) and an aviation joint (24) respectively; a temperature sensor (25) connected with the aviation joint (24) is arranged in the vacuum box (2); and the second vacuum pipe (20) is provided with a second stop valve (26).

9. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle according to claim 1, wherein an outlet end of the nitrogen siphon pipe (6) is right opposite to the cooling fins (82).

10. A superconducting bulk cooling method for a high-temperature superconducting magnetic levitation vehicle, comprising the following steps: S1, placing high-temperature superconducting bulks into a Dewar tank; S2, connecting a vacuum pump with a first vacuum pipe, opening a first stop valve, vacuumizing a vacuum box through the vacuum pump, stopping relevant operations after the vacuum degree is qualified through the detection with a vacuum gauge, and closing the first stop valve; S3, connecting the vacuum pump with a second vacuum pipe, opening a second stop valve, vacuumizing a condensing tank, a nitrogen siphon pipe and a liquid nitrogen return pipe through the vacuum pump, and closing the second stop valve after finishing the S3 operation; S4, starting a refrigerating machine, reducing the internal temperature of the condensing tank through the refrigerating machine, and detecting the temperature through a temperature sensor to ensure that the temperature in the tank is stabilized at a nitrogen liquefied temperature; pumping saturated nitrogen generated by the phase change in a cooling process of the superconducting bulk into the condensing tank through a siphon effect, condensing the nitrogen into liquid nitrogen, and returning the liquid nitrogen into the Dewar tank through the liquid nitrogen return pipe to replenish the liquid nitrogen for cooling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a structural schematic diagram of the present invention;

(2) FIG. 2 is a rear structural schematic diagram of the present invention;

(3) FIG. 3 is a structural schematic diagram of a flexible isolation pipe of the present invention;

(4) FIG. 4 is a structural schematic diagram of a fixing sheet of the present invention.

(5) Reference numerals: 1, refrigerating machine; 2, vacuum box; 3, Dewar tank; 4, condensing tank; 5, flexible isolation pipe; 6, nitrogen siphon pipe; 7, liquid nitrogen return pipe; 8, heat exchanger; 9, damper; 10, heating pipe; 11, cold head; 12, liquid nitrogen replenishing pipe; 13, regulating stop valve; 14, corrugated compensation pipe; 15, safety pipe; 16, safety valve; 17, first vacuum pipe; 18, first stop valve; 19, detecting pipe; 20, second vacuum pipe; 21, box body; 22, top cover; 23, vacuum gauge; 24, aviation joint; 25, temperature sensor; 26, second stop valve; 41, tank body; 51, inner pipe; 52, outer pipe; 53, thermal insulation layer; 54, fixing sheet; 55, pipeline supporting sheet; 81, connecting seat; 82, cooling fin; 541, first installation hole; 542, second installation hole.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

(6) To make the purpose, technical solutions and advantages of embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below in combination with accompanying drawings in the embodiments of the present invention.

Embodiment 1

(7) As shown in FIG. 1, the present embodiment provides a superconducting bulk cooling apparatus for a high-temperature superconducting magnetic levitation vehicle, which includes a refrigerating machine 1, a vacuum box 2 and a Dewar tank 3. The vacuum box 2 includes a box body 21 and a top cover 22 that are fixedly connected through a connecting flange. The refrigerating machine 1 is fixedly installed on the top cover 22. A damper 9 is also arranged between the refrigerating machine 1 and the top cover 22. The damper 9 adopts a rubber damping pad. The top cover 22 is also provided with a connecting hole, and a cold head 11 of the refrigerating machine 1 is inserted into the vacuum box 2 through the connecting hole.

(8) A condensing tank 4 is also arranged in the vacuum box 2. The condensing tank 4 includes a tank body 41. The top of the tank body 41 is provided with an installation hole. A heat exchanger 8 is fixedly arranged in the installation hole. The heat exchanger 8 includes a connecting seat 81. A plurality of cooling fins 82 are uniformly arranged on the bottom surface of the connecting seat 81. The connecting seat 81 is fixedly connected with the tank body 41 through the installation hole. The cooling fins 82 are inserted into the tank body 41. One end of the connecting seat 81 located outside the condensing tank 4 is fixedly and thermally connected with the cold head 11 of the refrigerating machine 1 in the vacuum box 2. In order to rapidly control the heat of the cold head 11, the cold head 11 is wound with a heating pipe 10. The heating pipe 10 is also connected with a temperature controller for controlling the heating temperature thereof.

(9) The side surface and the bottom surface of the tank body 41 are provided with a nitrogen inlet and a nitrogen outlet respectively. A nitrogen siphon pipe 6 and a liquid nitrogen return pipe 7 are also arranged between the Dewar tank 3 and the condensing tank 4. The Dewar tank 3 is provided with a nitrogen outlet and a liquid nitrogen return port. Two ends of the nitrogen siphon pipe 6 are connected with the nitrogen inlet and the nitrogen outlet of the condensing tank 4 and the Dewar tank 3 respectively in a closed manner. Two ends of the liquid nitrogen return pipe 7 are respectively connected with the liquid nitrogen outlet and the liquid nitrogen return port, and the outlet end of the liquid nitrogen return pipe 7 is immersed in liquid nitrogen in the Dewar tank 3. The condensing tank 4 and the Dewar tank 3 are communicated through the nitrogen siphon pipe 6 and the liquid nitrogen return pipe 7, and a closed nitrogen circulation loop is formed between the two.

(10) Further, the end of the nitrogen siphon pipe 6 connected with the tank body 41 is right opposite to a cooling fin 82. A cross section of the cooling fin 82 is in an inverted triangular shape or an inverted trapezoidal shape according to the actual running requirement of the high-temperature superconducting magnetic levitation vehicle, and an oblique angle of a side surface is 0.25°-0.5°. Meanwhile, in order to increase the diffusion speed of the nitrogen and improve the condensation effect, the cooling fin 82 may also be provided with a plurality of via holes. The nitrogen siphon pipe 6 passes through the via holes to be inserted into the cooling fin 82. A plurality of ventilation holes are uniformly arranged on a portion of the nitrogen siphon pipe 6 located between the cooling fins 82, so that the nitrogen is uniformly and rapidly conveyed to between the cooling fins 82, and the nitrogen is prevented from being concentrated at one side of a heat radiator 8.

(11) A flexible isolation pipe 5 is also connected between the vacuum box 2 and the Dewar tank 3. The flexible isolation pipe 5 includes an inner pipe 51 and an outer pipe 52. Both the inner pipe 51 and the outer pipe 52 are made of a corrugated pipe and are concentrically arranged. A plurality of pipeline supporting sheets 55 are uniformly arranged between the inner pipe 51 and the outer pipe 52. A distance among the pipeline supporting sheets 55 is preferably 20 cm. Two sides of the pipeline supporting sheets 55 contact the inner wall of the outer pipe 52 and the outer wall of the inner pipe 51 respectively, thereby providing support in a radial direction, and ensuring that the inner pipe 51 and the outer pipe 52 are arranged concentrically. A thermal insulation layer 53 is filled between two pipeline supporting sheets 55, thereby improving the thermal insulation effect of the flexible isolation pipe 5. The nitrogen siphon pipe 6 and the liquid nitrogen return pipe 7 pass through the inner pipe 51 to be connected with the condensing tank 4 and the Dewar tank 3 respectively. A plurality of fixing sheets 54 are uniformly arranged in the inner pipe 51. A distance among the fixing sheets 54 is preferably 25 cm. The periphery of the fixing sheet 54 uniformly contacts the inner wall of the inner pipe 51, thereby providing the support in the radial direction. The fixing sheet 54 is provided with a first installation hole 541 and a second installation hole 542 that are separated from each other, and the nitrogen siphon pipe 6 and the liquid nitrogen return pipe 7 pass through the first installation hole 541 and the second installation hole 542 respectively, so that the nitrogen siphon pipe 6 and the liquid nitrogen return pipe 7 are fixed, and a sufficient isolation gap is ensured to be reserved between the nitrogen siphon pipe 6 and the liquid nitrogen return pipe 7, between the nitrogen siphon pipe 6 and the inner pipe 51 and between the inner pipe 51 and the liquid nitrogen return pipe 542, thereby avoiding the heat transfer caused by the mutual contact.

(12) Further, the top cover 22 of the vacuum box 2 is also provided with a detecting pipe 19 and a second vacuum pipe 20. The interior of the vacuum box 2 is communicated with the exterior through the detecting pipe 19 and the second vacuum pipe 20. The detecting pipe 19 is connected with an aviation joint 24 and a vacuum gauge 23 for detecting a vacuum degree in the box in parallel. A temperature sensor 25 connected with the aviation joint 24 is arranged in the vacuum box 2. The second vacuum pipe 20 is provided with a second stop valve 26, and the connection and disconnection state of the second vacuum pipe is controlled by the second stop valve 26. When in use, the vacuum pump vacuumizes the vacuum box 2 through the second vacuum pipe 20.

(13) A liquid nitrogen replenishing pipe 12, a safety pipe 15 and a first vacuum pipe 17 are also arranged in the vacuum box 2. One end of each of the liquid nitrogen replenishing pipe 12, the safety pipe 15 and the first vacuum pipe 17 passes through the top cover 22 to extend out of the vacuum box 2. A regulating stop valve 13 is arranged on one end of the liquid nitrogen replenishing pipe 12 located outside the vacuum box 2. A safety valve 16 and a first stop valve 18 are arranged respectively on one end of each of the safety pipe 15 and the first vacuum pipe 17 located outside the vacuum box 2. One end of each of the liquid nitrogen replenishing pipe 12, the safety pipe 15 and the first vacuum pipe 17 located in the vacuum box 2 are communicated with the condensing tank 4 respectively. Meanwhile, a corrugated compensation pipe 14 is also arranged at one section of the liquid nitrogen replenishing pipe 12 located in the vacuum box 2, thereby compensating the pipeline shrinkage caused by the temperature change.

(14) Further, the liquid nitrogen replenishing pipe 12 and the safety pipe 15 are communicated with the condensing tank 4 through a three-way pipe.

Embodiment 2

(15) As a basic embodiment of the present invention, the present embodiment discloses a superconducting bulk cooling method for a high-temperature superconducting magnetic levitation vehicle, which includes the following steps:

(16) S1, high-temperature superconducting bulks are placed into a Dewar tank;

(17) S2, liquid nitrogen is poured into the Dewar tank until the high-temperature superconducting bulk is completely immersed, and all pipelines are closed by stop valves;

(18) S3, a vacuum pump is connected with a first vacuum pipe, a first stop valve is opened at the same time, and a vacuum box is vacuumized by the vacuum pump, after a vacuum degree is qualified through the detection of a vacuum gauge, relevant operations are stopped, and the first stop valve is closed; then the vacuum pump is connected with a second vacuum pipe, a second stop valve is opened at the same time, the condensing tank, a nitrogen siphon pipe and a liquid nitrogen return pipe are vacuumized by the vacuum pump, and the second stop valve is closed after the operation is finished;

(19) S4, a refrigerating machine is started, the temperature in the condensing tank is reduced by the refrigerating machine, and the temperature in the tank is ensured to be stabilized at a nitrogen liquefied temperature through the detection of a temperature sensor; and saturated nitrogen generated by the phase change in a cooling process of the high-temperature superconducting bulk is pumped into the condensing tank through a siphon effect, the heat-exchanged re-condensed liquid nitrogen is returned to the Dewar tank through the liquid nitrogen return pipe to replenish the liquid nitrogen for cooling.

(20) When the present invention is in use, the Dewar tank is filled with the liquid nitrogen for cooling, and the high-temperature superconducting bulk is immersed in the liquid nitrogen of the Dewar tank for cooling, and the temperature of the liquid nitrogen increases in the process of cooling the high-temperature superconducting bulk, so that partial liquid nitrogen is phase-changed to the saturated nitrogen, and the pressure in the Dewar tank increases continuously; at the same time, the condensing tank is isolated from the external environment through a vacuum cooling method, and the cooling fins of the condensing tank are cooled through the refrigerating machine, so that the temperature of the cooling fins is reduced to the nitrogen liquefied temperature through the refrigeration of the refrigerating machine. Because of the pressure difference between the condensing tank and the Dewar tank, the siphoning effect occurs between the condensing tank and the Dewar tank, the saturated nitrogen may overcome the surface tension thereof to automatically enter the condensing tank through the nitrogen siphon pipe and to contact the cooling fins, after the heat exchange, the gaseous nitrogen is condensed into liquid, and the liquid nitrogen is returned to the Dewar tank through the liquid nitrogen return pipe on the bottom of the condensing tank.

(21) The present invention ingeniously utilizes the siphoning effect to naturally separate the saturated nitrogen from the liquid nitrogen; and the saturated nitrogen is re-condensed through the external refrigerating equipment, and in the working process of the equipment, the saturated nitrogen and the liquid nitrogen are always in a process of dynamic circulation.

(22) Compared with the traditional liquid nitrogen immersion cooling method, the saturated nitrogen may be pumped in time, so that the high-temperature saturated nitrogen is prevented from affecting the internal temperature of the Dewar tank; and at the same time, the re-condensed liquid nitrogen is returned to the Dewar tank to ensure the stability of the liquid nitrogen quantity in the Dewar tank. Through the above measures, the temperature in the Dewar tank can be ensured to be stable relatively, and it is unnecessary to replenish additional liquid nitrogen regularly, thereby improving the working efficiency of the equipment greatly, and improving the running efficiency of the high-temperature superconducting magnetic levitation vehicle greatly.

(23) Compared with the traditional refrigerating machine cooling mode, the present invention changes a traditional heat conduction method that the refrigerating machine is directly connected with the superconducting bulk, and adopts the nitrogen and liquid nitrogen as refrigerant, so that compared with the direct connection method, the mobility of the nitrogen and liquid nitrogen is better and can better contact the cold head of the refrigerating machine and the superconducting bulk, the contact area is increased, and the heat efficiency is further improved; and meanwhile, it is unnecessary to add the additional equipment to increase the contact area between the refrigerating machine and the superconducting bulk, thereby greatly simplifying the structure of the equipment, and improving the overall structural compactness of the high-temperature superconducting magnetic levitation vehicle.

(24) Therefore, by pumping the nitrogen through the siphoning effect and through the working method of the refrigerating machine for re-condensing the nitrogen, the present invention integrates the advantages of good cooling effect of the liquid nitrogen immersion cooling and good working continuity of the refrigerating machine cooling, overcomes the main defects of the two, and can ensure the continuous stable work of the high-temperature superconducting bulk. At the same time, the structural design and parameter selection of all components in the present invention are based on the high-temperature superconducting magnetic levitation vehicle, so that the manual maintenance period of the high-temperature superconducting magnetic levitation vehicle can be shortened on the premise of ensuring the normal running of the high-temperature superconducting magnetic levitation vehicle, the manual maintenance difficulty is reduced, and the running efficiency of the high-temperature superconducting magnetic levitation vehicle is improved greatly, thereby further promoting the engineering application of the high-temperature superconducting magnetic levitation vehicle.