CN110749115B - Multifunctional low-temperature vortex coil precooling heat exchanger - Google Patents

Abstract

The invention discloses a multifunctional low-temperature vortex coil precooling heat exchanger, which includes a middle slit structure, a threaded hole, a spiral groove, a U-shaped groove, a fixing hole, and a temperature measurement and heating threaded hole. This heat exchanger is used in the precooling unit of the precooling JT refrigerator in liquid helium and below temperature ranges. This heat exchanger can not only directly replace the cold head of the precooling machine, but also serve as the supporting bottom plate of the cold screen. The middle slit structure increases the heat exchange area and greatly improves the pre-cooling efficiency. The spiral groove is an interference fit with the high-pressure pipeline and is used to pre-cool high-pressure and high-temperature helium gas. The surface of the heat exchanger is plated with a micron-level thin gold layer to reduce radiation heat loss. The U-shaped groove facilitates the arrangement of pipelines and wires, and can also be used as a heat sink for wires from the liquid helium temperature zone to the room temperature zone. The invention integrates multiple functions of pre-cooling machine cold head, cold screen support, high-pressure fluid pre-cooling and wire heat sink. It has a compact structure, which not only reduces the contact thermal resistance between the pre-cooling machine and the heat exchanger, but also enhances the performance of the refrigerator. The pre-cooling effect improves the pre-cooling efficiency.

Description

A multifunctional low-temperature vortex coil pre-cooling heat exchanger

Technical field

The invention belongs to the field of low-temperature heat exchange, and specifically relates to a low-temperature vortex coil pre-cooling heat exchanger integrating multiple functions of pre-cooling machine cold head heat exchange, cold screen support, high-pressure fluid pre-cooling and wire heat sink.

Background technique

With the rapid development of aerospace technology, the requirements for space detectors are constantly increasing. In order to improve the sensitivity and observation accuracy of the detector, some detectors and their associated electronic equipment need to work in a stable and reliable liquid helium temperature zone or a lower mK-level low-temperature environment. The refrigeration technology in the space liquid helium temperature zone mainly includes liquid helium Dewar technology and J-T refrigeration technology. Among them, although the liquid helium Dewar technology is relatively mature, its lifespan is limited by the amount of liquid helium it carries, and the launch cost is also relatively high. The J-T refrigerator uses the Joule-Thomson effect for refrigeration. It has the advantages of small size, small vibration, compact structure, and high refrigeration efficiency, and can realize long-distance transmission of cold energy. Since the helium working fluid is throttled to generate heating at room temperature, the helium working fluid needs to be pre-cooled. At the same time, space application projects require the pre-cooling heat exchanger of the J-T refrigerator to be smaller, have less heat leakage, and have a more compact structure.

Contents of the invention

The invention provides a low-temperature vortex coil precooling heat exchanger that integrates multiple functions of precooler cold head heat exchange, cold screen support, high-pressure fluid precooling and wire heat sink. It reduces the need for precoolers and The contact thermal resistance of the heat exchanger also enhances the precooling effect of the precooling machine, improves the precooling efficiency, and has the advantages of compact structure and less heat leakage.

The technical solution of the present invention is:

The invention provides a multifunctional low-temperature vortex coil pre-cooling heat exchanger, which includes a middle slit structure 1, a threaded hole 2, a spiral groove 3, a U-shaped groove 4, a fixing hole 5 and a temperature measurement and heating threaded hole. 6. The heat exchanger structure is circular, and the surface is plated with a micron-level gold layer. There are temperature measurement and heating threaded holes 6 left on the surface of the heat exchanger for temperature measurement and heating element fixation; the middle slit structure 1 is made of a circular shape. The array is composed of pin ribs filled with fixed holes 5 around it for fastening the heat exchanger to the precooler; the threaded holes 2 are arranged around the edge of the heat exchanger for fixing the cold screen; so The spiral groove 3 is arranged on the upper surface of the heat exchanger, with the helium working fluid inlet and outlet at both ends; the U-shaped groove 4 is arranged on the edge of the heat exchanger;

The advantage of the present invention is that the multifunctional low-temperature vortex coil precooling heat exchanger can be applied to liquid helium and lower temperature zone precooling JT refrigerators. This heat exchanger can directly replace the cold head of the precooling machine, reducing the contact thermal resistance, improving the precooling effect, and increasing the precooling efficiency; the middle slit structure is composed of a circumferential array of pin ribs, which increases the heat exchange between the precooling machine and the The heat exchange area of the heat exchanger improves the heat exchange efficiency; the peripheral threaded holes of the heat exchanger are used for fixing the cold screen, and the surface of the heat exchanger is plated with a micron-level thin gold layer to reduce radiation heat loss; the upper surface of the heat exchanger There is a spiral groove pipeline for pre-cooling of helium working fluid, making full use of the limited floor area; a U-shaped groove is left on the edge of the heat exchanger to facilitate bypass pipelines, low-pressure pipelines, temperature measurement wires and heating The arrangement of the wires is also a heat sink for the wires from the liquid helium temperature zone to the room temperature zone; this heat exchanger integrates multiple functions of heat exchange at the cold head of the precooling machine, cold screen support, high-pressure fluid precooling and wire heat sink , compact structure, enhanced pre-cooling effect and improved pre-cooling efficiency

Description of drawings

Figure 1 is a schematic top view of the multifunctional low-temperature vortex coil pre-cooling heat exchanger of the present invention;

In the picture: 1. Middle slit structure; 2. Threaded hole; 3. Spiral groove; 4. U-shaped groove; 5. Fixing hole; 6. Threaded hole for temperature measurement and heating;

Figure 2 is a schematic front view of the multifunctional low-temperature vortex coil pre-cooling heat exchanger of the present invention;

Figure 3 is a schematic bottom view of the multifunctional low-temperature vortex coil pre-cooling heat exchanger of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and implementation examples.

As shown in Figures 1, 2, and 3, the present invention provides a multifunctional low-temperature vortex coil pre-cooling heat exchanger. The low-temperature vortex coil heat exchanger is used for pre-cooling in liquid helium and below temperature zones. Type JT refrigerator. It includes a middle slit structure 1, a threaded hole 2, a spiral groove 3, a U-shaped groove 4, a fixing hole 5 and a temperature measurement and heating threaded hole 6. The heat exchanger is made of oxygen-free copper material and turned into a circular structure. The entire surface of the heat exchanger is plated with a micron-level gold layer to reduce the radiation leakage loss of the entire multi-functional low-temperature vortex coil pre-cooling heat exchanger, leaving a The temperature sensor and the heating plate fixed threaded port 6 are used to test the operating temperature and pre-cooling capacity of the heat exchanger respectively. In the middle of the heat exchanger is a circular array pin-rib slit structure 1, and the slits are made by wire cutting technology. There are fixing holes 5 left around the slit structure for fast connection with the precooling machine. The circumferential array of threaded holes 2 on the edge of the heat exchanger facilitates the fastening connection between the heat exchanger and the cold screen and serves as the supporting base plate of the cold screen. The upper surface of the heat exchanger is drilled with a low-temperature spiral groove 3. The high-pressure helium working fluid flows in from the entrance of the groove, fully exchanges heat with the bottom plate, and precools the helium working fluid to the same temperature as the bottom plate. A U-shaped groove 4 is carved on the edge of the heat exchanger to facilitate the arrangement of bypass pipelines, low-pressure pipelines, temperature measuring wires and heating wires. The U-shaped groove 4 is also a heat sink for the wire from the liquid helium temperature zone to the room temperature zone.

In actual use, the low-temperature vortex coil pre-cooling heat exchanger is tightly connected to the pre-cooling machine and placed in a vacuum tank. The vacuum degree of the vacuum tank is kept above 10-4Pa to reduce convection heat transfer in the device. . The heat exchanger is threaded and fixed with the precooling machine and then threaded with the gold-plated cold screen to reduce radiation heat loss from the pipeline and the precooling heat exchanger.

The working process of the present invention is carried out according to the following steps:

Vacuuming process:

In order to reduce the convective heat transfer loss between the low temperature zone and the high temperature zone, after the system is assembled, the entire system must be evacuated, and the vacuum degree of the external environment of the heat exchanger must be maintained above 10-4Pa. Then perform gas replacement in the pipeline to ensure that there is no impurity gas in the pipeline.

Cooling process:

When the multi-functional low-temperature vortex coil pre-cooling heat exchanger is running for pre-cooling, you first need to turn on the pre-cooling machine, let the pre-cooling machine work, and then pre-cool the pre-cooling heat exchanger.

Pre-cooling process:

After precooling, the temperature of the precooling heat exchanger decreases, and the high-pressure helium working fluid is precooled and cooled through the spiral groove 3.

(4) Temperature recovery process

The multifunctional low-temperature spiral coil precooler still has a lower temperature when the system ends. In order to protect the system components, it must be rewarmed first. First, shut down the pre-cooling machine, and use radiation heat exchange and high-pressure helium gas to take away the cooling energy and bring it back to temperature.

Finally, it should be noted that those skilled in the industry should understand that the present invention is not limited by the above-mentioned implementation examples. The above-mentioned embodiments and descriptions only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, The present invention will also have various changes and improvements, and these changes and improvements will fall within the scope of the claimed invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. A multifunctional low-temperature vortex coil precooling heat exchanger, including a middle slit structure (1), a threaded hole (2), a spiral groove (3), a U-shaped groove (4), and a fixing hole (5 ) and temperature measurement and heating threaded holes (6); which are characterized by: The heat exchanger structure is circular, and the surface is plated with a micron-level gold layer. There are temperature measurement and heating threaded holes (6) left on the surface of the heat exchanger for temperature measurement and heating element fixation. The middle slit structure (1) There are fixed holes (5) around for fast connection between the heat exchanger and the precooler; the middle slit structure (1) is composed of a circular array of pin ribs and is connected to the precooler; the thread Holes (2) are arranged around the edge of the heat exchanger for fixing the cold shield; the spiral groove (3) is arranged on the upper surface of the heat exchanger, with the helium working medium inlet and outlet at both ends; The U-shaped groove (4) is located at the edge of the heat exchanger.