论文部分内容阅读
使用非金属防热层的目的是防止气动加热引起结构强度降低和内部仪器失灵。在60年代初美国曾为“民兵”导弹研制了一种叫做Avcoat的防热涂层用于大面积防热目的。由于成本、工艺和防热效率的原因约在1964年就用软木贴片代替了这种涂料。“民兵”表面的几乎90％部份都用软木片所贴敷。由于我们一系列的基础条件不够充分,不能通过大量的飞行和气动试验对防热材料作细致完善的研究工作,不能结合具体的防热材料工作机理进行与空气动力学、附面层理论、烧蚀防热理论以及热传导理论有关的研究工作,因此,就不能为防热措施的设计与材料计算提供切实可靠的依据和方法,以及为这种方法所必要的全部物理参数。设计者们往往不得不采取极为粗略的甚至与防热设计的基本思想相违背的假定作为设计与计算的依据。相当程度上的盲目性使产品重量过剩。以这种与事实不符的计算结果作为辐射模拟试验的依据,其结果与实际飞行中所测得的数据不相符就是理所当然的事了。
The purpose of using a non-metallic heat shield is to prevent pneumatic heating from causing structural degradation and internal instrument failure. In the early 1960s, the United States developed a heat-resistant coating called Avcoat for “militia” missiles for large areas of heat-protection purposes. Due to cost, process and thermal efficiency, the coating was replaced with cork chip about 1964. Almost 90% of the surface of the “militia” is covered with cork sheets. Due to our lack of sufficient basic conditions, we can not make detailed research on the heat-proof materials through a large number of flight and aerodynamic tests, and can not be combined with the aerodynamic, surface-coating theory, Corrosion prevention theory and heat conduction theory. Therefore, it is impossible to provide a solid and reliable basis and method for the design and material calculation of the heat protection measures, and all the physical parameters necessary for the method. Designers often have to resort to the assumption that they are very rough or even contrary to the basic idea of thermal design as a basis for design and calculation. A considerable degree of blindness makes the product overweight. Taking this factual discrepancy as the basis for the radiation simulation test, the result is inconsistent with the data measured in actual flight, which is a matter of course.