氩氦刀探针的数值模拟研究.pdf

氩氦刀探针的数值模拟研究  王宏宇 张绍志 陈光明 （浙江大学制冷与低温研究所 杭州 310027） 摘 要:为了指导氩氦刀设计，本文对氩氦刀低温探针的内外部传热和J-T 节流过程进行了稳 态模拟，采用有限差分法，考虑了轴向传热和冷端低压流体的气液两相特征，在氩氦刀端部 假设与外界恒热流换热，对流体和壁面的温度分布进行了计算，对不同进气温度下氩氦刀的 制冷能力进行了比较。低压流体在换热器冷端存在气液两相，高压进气温度降低有利于制冷 量提高；当高压进气温度由291.49K 降至273.15K 后 ，在距刀端部2cm 处外壁温度维持170K 不变的情况下，外部热流qload 可提高12%左右；如利用半导体制冷来预冷高压进气，14L/min 氩气流量用6 片TESI-12704T125 型制冷片，冷却模块尺寸约20cm 5cm 5cm 即可满足要 求。 关键词: 氩氦刀 数值模拟 两相流 预冷 半导体制冷 A numerical study of the Ar-He Cryoprobe Wang Hongyu Zhang Shaozhi Chen Guangming (Institute of Refrigeration and Cryogenics，Zhejiang University ，Hangzhou 310027 ，China) Abstract ：To offer information for computer-aided design, a numerical study of steady-state characteristics for an Ar-He Cryoprobe is carried out in the present work. A simplified one-dimensional model of momentum and energy transport, which takes longitudinal heat conduction and gas-liquid two phase characteristics into consideration, is used to estimate the temperature distribution of the wall and fluid. The refrigeration capacities of the Cryoprobe at different inlet temperatures are compared. Low-pressure fluid is in two-phase state at the cold end of the heat exchanger, and decreasing inlet high pressure argon temperature leads to increasing refrigeration capacity. When argon source temperature decreases from 291.49 K to 273.15 K , the refrigeration capacity can be increased by 12% or so. Using semiconductors to cool the source argon, only six pieces of TESI-12704T125 are needed for a 14 L/min flow. The module size is estimated to be 20 cm×5cm×5cm. Keywords: Cryoprobe, numerical simulation, two-phase flow, Precooling;Semiconductor refrigeration  作 者：王宏宇，男，25 岁，硕士研究生，主要从事低温生物及传热传质研究。Email-zgd