Multidisciplinary Thermal Analysis of Hot Aerospace Structures

Hypersonic flight introduces extreme heat loads into the leading edges of a vehicle. Determining these loads is challenging. It requires accounting for the aerothermodynamic features of both the flow and thermal state of the surface. These features can be influenced by pressure and viscous effects, real-gas and low density effects, inonization, radiative heating, surface-radiation cooling, and surface catalytic behavior. It also requires accounting for the complex layout of the structure and materials concept which includes high-temperature materials and coatings and internal thermal insulation, for gap and cove heating, and for active cooling. Hence, the accurate thermal analysis of hot structures requires not only a state-of-the-art nonlinear heat transfer tool for modeling temperature-dependent material properties, contact resistance between parts and across welds, and radiation within cavities, but also a tight coupling between aeroheating, thermal, and structural models. Incomplete forms of such an integration have been attempted in the past using loosely-coupled solution procedures that were either computationally inefficient or numerically unstable. The main objective of this proposal is to develop an alternative, higher-fidelity, multidisciplinary computational approach to thermal analysis of hot structures that is numerically stable, efficient, and compatible with the aerothermoelastic simulation environment AERO deployed at the Edwards Air Force Base to enable the accurate assessment of the effects of heat loads on structural integrity and aeroelastic stability. The proposed approach centers around a fourfield formulation of aerothermoelastic problems, a conservative discretization of appropriate transmission conditions on non-matching interfaces, and advanced steady and unsteady conjugate heat transfer algorithms for accelerating vehicles. The anticipated long-term out come of this research is the enabling of a state-of-the-art analysis tool for predicting steady and unsteady structural temperatures and their gradients, heat loads, and structural deformations and stresses associated with hypersonic systems in order to increase the safety and efficiency of their testing. *Phone: (650) 723-3840 Fax: (650) 725-3525 email: [email protected]