预防热循环试验中试件结露的方法及其除湿效果试验验证

结露现象在航天电子产品热循环试验中十分常见。如不采取除湿措施，则在试验过程中可能对部分电子产品造成不必要的损坏。文章分析了热循环试验中试件结露的原因，并设计试验对蒸发器除湿及充氮气除湿进行验证。结果表明，蒸发器除湿方法不能解决升温阶段相对湿度及含水量明显升高的问题，而常温阶段充入氮气降低相对湿度后再进行试验是更为有效的除湿方法。

Methods for preventing condensation on test piece in thermal cycling test and the experimental verification

The condensation phenomenon is very common in the thermal cycling test of aerospace electronic products. Undesirable damage of some electronic products would be caused during the test without dehumidification measures. In this paper, the causes of the condensation in the thermal cycling test are analyzed, two methods of dehumidification are proposed, namely, the use of the evaporator, and the nitrogen filling method, and they are validated by designed tests. It is shown that the dehumidification effect of the evaporator is not satisfactory in view of the significant increase of the relative humidity and the moisture content in the heating stage; while the more effective dehumidification method is to fill the nitrogen in the normal temperature stage to reduce the relative humidity before carrying out the test.