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TY - THES AU - König, Valentina TI - Effective boundary conditions for transpiration cooling applications PB - RWTH Aachen University VL - Dissertation CY - Aachen M1 - RWTH-2022-09672 SP - 1 Online-Ressource : Illustrationen, Diagramme PY - 2021 N1 - Englische und deutsche Zusammenfassung. - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2022 N1 - Dissertation, RWTH Aachen University, 2021 AB - Using transpiration cooling with carbon/carbon (C/C) thrust chamberliner is identified as a new innovative cooling concept that can lead to improvement in advanced rocket engines. In addition to experiments, computational fluid dynamics simulations offer an efficient and low costpossibility to investigate the physical phenomena of transpiration cooling. In the present work an effective model is developed that simulates transpiration cooling taking microscale effects at the interface between ahot gas flow and a porous medium flow into account without resolving the microscale pores. The derivation of our general strategy is based on upscaling and consists of three models: the multiscale model, the zeroth-order model and the effective model, where the latter two models operate on the macroscale. Here the multiscale model captures the local injection of a coolant through a large number of pore size injection channels. It is set up to derive appropriate cell problems on the microscale and to validate the effective model. For the latter effective boundary conditions are developed using an upscaling approach. To validate the effective model numerical computations are presented. Furthermore, the influence of the microscale characteristics on the heat transport in turbulent flow over a porous material is investigated. All computations are based on wind tunnel experiments performed at the ITLR Stuttgart with a porous C/C sample produced at the DLR Stuttgart. For the injection rate F = 0.1 LB - PUB:(DE-HGF)11 DO - DOI:10.18154/RWTH-2022-09672 UR - https://publications.rwth-aachen.de/record/854621 ER -