MODELING AND SIMULATION OF ABLATION IN A MULTI-LAYER TPS VIA AN INTERFACE TRACKING METHOD
- Paper number
IAC-09.C2.6.3
- Author
Dr. Humberto Araujo Machado, Institute of Aeronautics and Space/ CTA, Brazil
- Year
2009
- Abstract
The objective of this work is to present a computational simulation of the ablative process in the vicinity of the stagnation point during the flight of SARA Sub-orbital platform via the interface tracking method, applied to a multilayer region. Such procedure will allow applying more complex models for ablation, taking into account the presence of various ablative and structural layers, providing a more accurate dimensioning of the TPS. The SARA Sub-orbital Platform has being developed by the Institute of Aeronautics and Space (IAE) of Brazil, to be employed as a low-cost alternative for micro-gravity research, and is equipped with an ablative external shield (TPS) for protection against aerodynamic heating during the atmospheric flight. Until the ablation temperature is reached, we have a transient heat conduction problem. Once the TPS surface gets to the ablation temperature, its thickness is reduced; therefore, a transient, coupled conduction-moving boundary problem appears. The technique used in this work allows for the finding of the instantaneous position and velocity of the moving boundary. The moving boundary problem is solved by the Interface Tracking Method, introduced by Unverdi and Trygvason (1992), and employed by Juric (1996) in the solution of phase change problems. In this method, a fixed uniform Eulerian grid is generated, where the conservation laws are applied over the complete domain. The interface acts as a Lagragean referential, where a moving grid is applied. The instantaneous placement of the interface occurs through the constant remeshing of the moving grid, and each region of the domain is characterized by the Indicator Function, that identifies the properties of the wall and the air around. This method allows the representing of any geometry used in the TPS, and also the characterization of every wall layer separately. It is accomplished without a high increase in the computational cost and does not need any pre-processing (construction of unstructured grid or coordinate transformation). In this work, the method is extended to a multi-layer problem (structure plus TPS), in order to estimate the ablative performance of the TPS, considering a two-dimensional approach in both, the heat conduction and the moving boundary problem. After validation, results demonstrated that the method is able to capture the temperature peak and to represent the ablation process as a moving boundary problem, for more than one single layer. This analysis can be easily extended to more regions, more layers and other shapes.
- Abstract document
- Manuscript document
IAC-09.C2.6.3.pdf (🔒 authorized access only).
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