低温绝热管道漏热量测试方法研究

Study of Heat-leak Rate Measurement for Vacuum Insulation Cryogenic Tube

低温绝热管道的漏热量是衡量其性能的重要参数,准确有效测试低温绝热管道的漏热量至关重要。依照GB/T 18443.6-2010《真空绝热深冷设备性能试验方法第6部分:漏热量测量》的要求,通过借鉴和改进设计,搭建了基于流量计测量法和表面温度测量法进行低温绝热管道漏热量测量的试验平台。通过试验分析发现:流量计测量法是一种准确度比较高的漏热量测量方法,基于该法的漏热量测试系统对大管径的低温绝热管道能够提供较为理想的测试结果。但当低温绝热管道的管径较小时,测试系统就很难达到标准中所要求的测试条件了。利用表面温度测量法测量漏热率的准确度不高,原因在于测温元件的精度很难满足要求,另外,还在于数据处理方法还不完善。

Heat-leak rate is a crucial property for vacuum insulation cryogenic tube, so searching an effective testing method to get it becomes urgent. Based on GB/T 18443.6 （testing method of performance for vacuum insulation cryogenic equipment-Part 6：heat-leak rate measurement）, two systems for the testing of heat-leak rate were built up-one was according to the evaporation rate and the other was to the surface temperature. The experimental results have shown：With the method of evaporation rate, the testing equipment can execute an accurate measurement for the heat-leak rate of the tubes with large diameter, whereas for the small diameter tubes the testing equipment cannot give a satisfying result. Moreover, the method of surface temperature was verified not an accurate method to testing the heat-leak rate of cryogenic tubes, because of the inadequate precision of the thermocouples and the defective calculation of the heat-leak rate.