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内容提要通常为了减少高温固体表面对环境大气的放热损失,除了采用热绝缘的办法外,亦可在其表面附近设置若干块黑度较小的薄板一遮热板。关于遮热板的隔热效果的论述,现有的文献[1—4],均假定两固体表面的温度恒为常数。事实上只有高温表面的温度近似不变,而低温表面的温度是随环境温度和遮热板的数目的改变而变化。本文就这种情况,对遮热板的隔热效果进行了理论推导,研究结果表明,遮热板的实际隔热效果远不如理想的那样显著。如果对带有扩展表面(园筒形或球形)的遮热板,若设置不当,不但不能减少热损失,有时还会适得其反。
Description In general, in order to reduce the exothermic loss of the ambient atmosphere from a high-temperature solid surface, in addition to the method of thermal insulation, a number of thin plate-heat shields with a relatively small blackness may be provided near the surface thereof. On the heat shield insulation discussion, the existing literature [1-4], both assume that the surface temperature of two solids constant. In fact, only the temperature of the high temperature surface is approximately the same, and the temperature of the low temperature surface changes with the change of the ambient temperature and the number of the heat shields. In this case, the heat insulation effect of the heat shield is theoretically deduced. The results show that the actual heat insulation effect of the heat shield is far less than ideal. If the shield with extended surface (cylindrical or spherical), if not properly set, not only can not reduce the heat loss, and sometimes will be counterproductive.