<p dir="ltr">Ablation is the process by which material is removed from a system due to phase changes, chemical reactions, or mechanical erosion.&nbsp; Ablative processes are an important factor in many problems of scientific and engineering interest, including glacial erosion, fire protection, medical procedures, combustion of solid fuel, and industrial manufacturing processes.&nbsp; Because the removed material carries heat energy with it, ablative materials have been used since the 1950s as sacrificial heat shields in weapon applications, rocket nozzle coatings, and hypersonic reentry vehicles.&nbsp; Accurate prediction of the rate of mass and energy loss allows the designer to minimize the weight and cost of the heat shield while ensuring adequate thermal protection of the underlying structure, payload, and/or vehicle occupants.&nbsp; Furthermore, prediction of changes in the outer mold line due to surface erosion is important in the context of hypersonic flight, where the aerodynamic forces and incident heat flux are intrinsically linked to the shape of the vehicle.&nbsp; Therefore, the development of accurate, robust, and efficient models for the simulation of ablating materials is a critical component of the design of future transportation and weapons systems.</p><p>In this presentation, we present a nonintrusive approach to manufacturing solutions for ablation.&nbsp; The ablation code relies heavily on external data, which serve as problem parameters.&nbsp; These parameters include the material properties (e.g., specific heat capacity and thermal conductivity), as well as the heating conditions (e.g., char ablation rate, heat transfer coefficient, wall enthalpy, and recovery enthalpy).&nbsp; We begin this process by optionally transforming the governing equations, then determining the boundary condition dependencies that are most general and representative of the ablation boundary condition dependencies while permitting an exact solution to be derived.&nbsp; We then map the artificial boundary conditions to the ablation boundary conditions to determine the parameter dependencies.&nbsp; Subject to these dependency constraints, we manufacture the parameters.&nbsp; Like traditional manufactured solutions, certain desirable properties of the underlying functions, such as infinite nonzero derivatives, smoothness, and elementary function composition, take precedence over being physically realizable.&nbsp; Through this approach we can modify the external data to obtain a nontrivial known solution, rather than by modifying the code to introduce a forcing term.</p>

Nonintrusive Manufactured Solutions for Ablation

Paper Proceedings: https://asmedigitalcollection.asme.org/VVS/VVS2021/volume/84782

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