Loosely Coupled Numerical Modeling of Carbon-Based Ablative Material Response in Propulsion Applications

Date

2025-9-1

Author

Doğan, Fırat Cihan

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Ablative materials are extensively employed in propulsion applications to protect nozzle structural materials from the thermochemical and mechanical effects of high-enthalpy combustion gases. The open literature on ablative cooling is, with very few exceptions, limited to atmospheric re-entry applications or steady-state nozzle erosion. Computational tools for transient ablation in propulsion applications that combine the speed needed for design tasks with the fidelity required to accurately capture the underlying physics are scarce. In this thesis, a simulation tool for the estimation of the ablative and thermal response of carbon-based pyrolyzing and non-pyrolyzing materials in propulsion applications was developed. The material response in both cases requires modeling heat conduction within the material together with surface recession driven by finite-rate surface chemistry, while pyrolyzing carbon-based materials additionally require modeling thermal decomposition and the transport of pyrolysis gases within the porous char layer. A loosely coupled strategy was employed, which allowed for a limited bidirectional exchange of geometry, flow and thermal data between internal flow and material response calculations to maintain boundary conditions consistent with the evolving thermal and physical state, thereby achieving higher fidelity than conventional decoupled methods without the computational cost of fully coupled simulations. Validation against analytical cases, publicly available codes and nozzle firing test data confirmed the ability to capture experimental trends in surface recession, temperature distribution and char formation. The tool thus enables rapid, yet physically accurate, characterization and optimization of thermal protection systems.

Subject Keywords

Rocket propulsion, Thermal protection systems, Ablative cooling, Carbon-based ablative materials, Material response modeling

URI

https://hdl.handle.net/11511/116576

Collections

Graduate School of Natural and Applied Sciences, Thesis