X-33 Base Region Thermal Protection System Design Study

The X-33 is an advanced technology demonstrator for validating critical technologies and systems required for an operational Single-Stage-to-Orbit (SSTO) Reusuable Launch Vehicle (RLV). Currently under development by a unique contractor/government team led by Lockheed- Martin Skunk Works (LMSW), and managed by Marshall Space Flight Center (MSFC), the X-33 will be the prototype of the first new launch system developed by the United States since the advent of the space shuttle. This paper documents a design trade study of the X-33 base region thermal protection system (TPS). Two candidate designs were evaluated for thermal performance and weight. The first candidate was a fully reusable metallic TPS using Inconel honeycomb panels insulated with high temperature fibrous insulation, while the second was an ablator/insulator sprayed on the metallic skin of the vehicle. The TPS configurations and insulation thickness requirements were determined for the predicted main engine plume heating environments and base region entry aerothermal environments. In addition to thermal analysis of the design concepts, sensitivity studies were performed to investigate the effect of variations in key parameters of the base TPS analysis

Analytical and Numerical Solutions for Transient Forced Convection in Fluid with Vanishing Prandtl Number

The analytical solution of transient heat transfer from incompressible laminar boundary layer flows over a curved surface when the Prandtl number is zero was attempted by Soliman and Chambre (1969) using Fourier transforms and the method of characteristics. The same problem was addressed by Biasi (1971) using the von Karman-Pohlhausen intergral method. A conceptual error in both papers was detected by Sucec (1978) and was found to cause significant error in the formulation of the response function for wall heat flux and wall temperature, as well as the temperature distribution in the fluid. In correcting the earlier works, Sucec unfortunately, due to a slight oversight, obtained an erroneous solution for the time-varying wall heat flux. Because the papers considered by those investigators represent a class of important transient forced convective heat transfer problems involving liquid metals, it is believed that the problem warrants further investigation and rectification