Bypass type low-temperature negative-pressure heat exchanger for pre-cooling type JT refrigerator and design method

Abstract

The invention discloses a bypass type low-temperature negative-pressure heat exchanger for a pre-cooling type JT refrigerating machine and a design method. The heat exchanger is composed of a high-pressure side pipeline, a low-pressure side pipeline, a bypass pipeline, a bypass element, a three-way element and a low-temperature negative-pressure dividing wall type heat exchanger. According to theinvention, the temperature and flow distribution of a fluid in the low-temperature negative-pressure heat exchanger are changed through the bypass pipeline, the irreversible loss of the pipeline and the pressure drop loss of the low-pressure pipeline side are reduced, the low-pressure pressure of the pre-cooling type JT refrigerating machine after throttling is reduced, and the final-stage refrigerating temperature of the pre-cooling type JT refrigerating machine is reduced; the flow velocity of a high-low pressure pipeline fluid in the low-temperature negative-pressure dividing wall type heatexchanger is increased, so that the heat exchange efficiency of the low-temperature negative-pressure heat exchanger is improved; the fluid temperature before throttling is reduced, and the refrigerating capacity of the pre-cooling type JT refrigerating machine is increased; and the overall efficiency of the pre-cooling type JT refrigerating machine is improved. The bypass type low-temperature negative-pressure heat exchanger for the pre-cooling type JT refrigerator and the design method have very positive significance for application of the pre-cooling type JT refrigerator in special fieldssuch as extremely low temperature areas, aerospace and the like.

Description

technical field [0001] The invention belongs to the field of refrigeration and low-temperature engineering, relates to a JT refrigerator, in particular to a bypass low-temperature negative pressure heat exchanger for a precooling JT refrigerator and a design method thereof. Background technique [0002] JT refrigerator (Joule-Thomson Cooler) is a typical partitioned refrigerator, and it can be used as an important technical means to realize refrigeration in the 1-4K deep low temperature zone when pre-cooling is used in the front stage. Its pre-cooling can be pre-cooled by GM refrigerator, Stirling refrigerator, GM pulse tube refrigerator or Stirling pulse tube refrigerator, which has important and wide application in the field of low temperature refrigeration. [0003] The low-temperature negative pressure partition wall heat exchanger is the core component of the pre-cooling JT refrigeration technology in the 1-4K deep-low temperature zone, and its heat transfer efficiency ...

AI Technical Summary

Problems solved by technology

Enlarging the heat exchange area can increase the amount of heat exchange and improve the efficiency of the low-temperature negative pressure partition wall heat exchanger, but the final low-temperature negative pressure partition wall heat exchanger usually works in the extremely low temperature region below 20K or even 1K, and the helium gas The non-ideality is becoming more and more obvious. The difference in specific heat capacity between the high and low pressure side of the partition wall heat exchanger is obvious, and the density drops sharply with the decrease of temperature, which leads to the insufficient cooling of the high pressure side gas before throttling, which affects the performance of the refrigerator.

At present, there are not many high-efficiency low-temperature negative-pressure partition wall heat exchangers that can be effectively used in pre-cooling JT refrigerators that work in the 1-4K temperature range.

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