Two-dimensional Aerodynamic Loads of Thermal Protection System Considering Different Widths of the Strain Isolation Pad

Thermal Protection System (TPS) is widely adopted to prevent aircraft substructure from the high environment temperature which is assembled by the ceramic tile, the strain isolation pad (SIP) and the substrate structure. The surface of shuttle is covered by individual ceramic tiles which are bonded to the substrate. The structure of SIP is the significant component of TPS which has important influence on the aerodynamic loads of TPS. To reveal the effect of the width of SIP on the aerodynamic loads, the two-dimensional TPS models considering various widths of SIP, 0.5mm, 0.7mm, 1.0mm, 1.3mm and 1.5mm, are founded and are simulated by computational fluid dynamic (CFD) method. The models are established by combining SIP and the ceramic tile on the surface of NACA0012. The flow around TPS, including flow around NACA0012 and internal flow, is simulated by solving Navier-Stokes (N-S) equation and Spalart-Allmaras (S-A) model. The pressure distributions around TPS are obtained and numerical results show: (1) In X and Y direction, with the width of SIP, △w, being 1.0mm, the forces are minimum, 159.9N in X-direction and 313.3N in Y-direction, respectively; (2) The different force of tile-II is related to both the pressure distribution and the flow speed around tile-II. (paper)