초음속 비행체의 공력가열에 의한 선두부 내부열전달 및 단열에 대한 연구

Abstract

Boundary layer occurs on the surface of all flying objects that fly at high speed on air due to compressibility of air. When speed of fluid decreases rapidly due to friction between surface of an object and air, surface is heated or property of surface material is changed or melt which causes electronic components of payload to be damaged while decrease of kinetic energy changes thermal energy.[1, 2] Temperature boundary layer refers to area that free flow reaches surface of flying object as temperature begins to rise from temperature that free flow has. Liquid temperature raised within temperature layer boundary causes heat to be transferred to surface of an object which phenomenon is called aerodynamic heating. Therefore, it is advisable for engineers to create optimum design considering above mentioned matters. There are coating of external surface using insulation film, internal insulation treatment using caulk and minimization of heat transfer by using layer structure as heat resistant system to protect guided missile from aerodynamic heating. Coating of external surface requires a high degree of technology and may result in a fatal flaw because wrinkle occurs on coating film depending on shape.[3] Lots of researchers have proposed formula of calculating aerodynamic heating. Boundary condition required for calculation is characteristic of flow at the end of speed boundary layer. In this study, what does not affect external heat transfer and temperature but has a great influence on internal temperature for internal heat transfer process that calculates convection and radiation out of internal heat transfer was indicated. In this study, radiation heat transfer into payload inside from internal surface and heat transfer from external surface of guided missile to internal surface were examined by analyzing mass per unit area and highest temperature in each case under the same initial condition after making analysis of single material, composite material and composite material that heat insulating material of 2mm, 4mm and 6mm was added. In chapter Ⅱ, heat transfer equation and method of numerical analysis were described. In chapter Ⅲ, heat modeling and external heat inflow were analyzed. In chapter Ⅳ, simulation and its result were studied. In chapter Ⅴ, conclusion was described.