Numerical Investigation of Space Launch Vehicle Base Flows with Hot Plumes

Abstract

The flow field around generic space launch vehicles with hot exhaust plumes is investigated numerically. Reynolds-Averaged Navier-Stokes (RANS) simulations are thermally coupled to a structure solver to allow determination of heat fluxes into and temperatures in the model structure. The obtained wall temperatures are used to accurately investigate the mechanical and thermal loads using Improved Delayed Detached Eddy Simulations (IDDES) as well as RANS. The investigated configurations feature cases both with cold air and hot hydrogen/ water vapour plumes as well as cold and hot wall temperatures. It is found that the presence of a hot plume increases the size of the recirculation region and changes the pressure distribution on the nozzle structure and thus the loads experienced by the vehicle. The same effect is observed when increasing the wall temperatures. Both RANS and IDDES approaches predict the qualitative changes between the configurations, but the reattachment location predicted by IDDES is up to 7% further upstream than that predicted by RANS. Additionally, the heat flux distribution along the nozzle and base surface is analysed and shows significant discrepancies between RANS and IDDES, especially on the nozzle surface and in the base corner.

Plume and wall temperature impact on the subsonic aft-body flow of a generic space launcher geometry

“…The numerical model (Fig. 5) comprises the internal and external volumes of the aft-body geometry as already used in Schumann (2022). The external volume is extended around the lip of the wind tunnel nozzle in order to account also for potential effects routing from the wind tunnel nozzle shear layer.…”

“…Both setups employ a two-equation k-ω Shear Stress Transport (SST) turbulence model. More details on the numerical methods can be found in Schumann et al (2021a).…”

“…Here, the heat transfer coefficient was varied until heat flux convergence between flow and structure solver was obtained. Details on the approach are provided in Fertig et al (2019); Schumann et al (2021a).…”

“…In order to improve the knowledge on their driving mechanisms and consequently enhance predictability of qualitative and quantitative loads for future launcher design, these effects have been studied at the German Aerospace Center (DLR). It was achieved through a complementary experimental and numerical approach on a generic Ariane 5 geometry, using ambient temperature air (denoted 'cold') and hot gas generated from the combustion of gaseous hydrogen (GH2) and gaseous oxygen (GO2) for the exhaust jet (Kirchheck et al 2021;Schumann et al 2021a).…”