The design of a space launcher requires some considerations about the unsteady loads and heat transfer occurring at the base of the structure. In particular, these phenomena are predominant during the early stage of the flight. This paper aims to evaluate the ability of the unstructured, high order finite-volume CFD solver FLUSEPA, developed by Airbus Safran Launchers, to accurately describe these phenomena.
This paper first performs a steady simulation on a base flow around a four-clustered rocket configuration. Results are compared with NASA experiments and Loci-CHEM simulations. Then, unsteady simulations of supersonic H2/air reacting mixing layer based on the experiment of Miller, Bowman and Mungal are performed. Three meshes with different cells number are used to study the impact of spatial resolution. Instantaneous and time-averaged concentrations are compared with the combined OH/acetone planar laser-induced fluorescence imaging from the experiment.
FLUSEPA satisfactorily predicts the base heat flux at the base of a four-clustered rocket configuration. NASA Loci-CHEM reactive simulations indicate that afterburning plays an important role and should not be neglected. The unsteady reactive computation of a supersonic mixing layer shows that FLUSEPA is also able to accurately predict flow structures and interactions. However, the complexity of the experiment and the lack of details concerning the facility prevents from obtaining satisfactory converged results.
This study is the first step on the development of a cost-effective method aiming at predicting unsteady loads and heat transfer on space launchers using an unsteady and reactive model for the CDF calculations. It uses original techniques such as conservative CHIMERA-like overset grids, local re-centering of fluxes and local adaptive time-stepping to reduce computational cost while being robust and accurate.
Charrier, L., Charrier, L., Jubera, M., Pont, G., Marié, S., Brenner, P. and Grasso, F. (2021), "Simulations of reactive supersonic/subsonic flow interactions for space launcher applications", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/HFF-09-2016-0356
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