航空航天电子设备的高空效应

本文以传热观点讨论了航空、航天电子设备故障的原因。文中指出,高空空气密度低于海平面空气密度,会使电子设备内部接触热阻增加;橡胶、环氧树脂、油脂、塑料、甚至于金属等材料逸出气体,自然对流放热系数降低。它们将导致温度升高,故障大量增加。除此之外,还推导了高空自然对流放热系数的计算公式,并对印刷电路上集成电路做了热设计计算。

High Altitude Effect of Electronic Equipment in the Air and Space

From the viewpoint of heat transfer,the reason why elec- tronic equipments in the air and space may be broken down is discussed in the paper.It is pointed out that at high altitude the air density is much lower than that at sea level conditions,so that the thermal con- tact resistance in the interior of electronic equipments will be increased, trapped gases of many common materials such as rubber epoxy resin, greases,plastics,and even metals will convert into gases,and escape from the solid materials.The neutral convection heat transfer coeffici- ent will be decreased.These can lead to temperature rising and a large increasing of failures. A formular for calculating the natural convection heattransfer coe- fficient at high altitudes has been derived,and a calculation for beat design of integrated circuits on the printed circuit board has been made in this paper.