Heat Transfer Enhancement of Launch Tube Using Free Convection: Parametric Design and Investigation

To alleviate the damages on launch tube surface from high temperature the rocket exhaust gas during firing the missile, we thus propose the heat transfer enhancement mechanism for the tube wrapped with metal sheet providing the small space, so-called air gap. The idea of the augmentation is by creating the free convection flow pattern in the narrow gap making by wrapping the metal sheet around the launch tube. In this present work, design of experiment is applied to parametrically design the launch tube with metal cover sheet configuration (cylindrical annulus with fins). The objective is to parametrically design and investigate the configuration of the metal-sheet-wrapped launcher. To predict the free convection in narrow cylindrical annulus heated from the below surface (launch tube) including the rotating effect, the CFD investigation of the time-variant axissymmetric flow is conducted. The influences of three design factors, diameter and position of exit channels and air gap thickness on the flow field and the heat transfer are investigated.