Simulation of a GOx-GCH4 Rocket Combustor and the Effect of the GEKO Turbulence Model Coefficients

In this study, a single injector methane-oxygen rocket combustor is numerically studied. The simulations included in this study are based on the hardware and experimental data from the Technical University of Munich. The focus is on the recently developed generalized k–w turbulence model (GEKO) and the effect of its adjustable coefficients on the pressure and on wall heat flux profiles, which are compared with the experimental data. It was found that the coefficients of ‘jet’, ‘near-wall’, and ‘mixing’ have a major impact, whereas the opposite can be deduced about the ‘separation’ parameter Csep, which highly influences the pressure and wall heat flux distributions due to the changes in the eddy-viscosity field. The simulation results are compared with the standard k–# model, displaying a qualitatively and quantitatively similar behavior to the GEKO model at a Csep equal to unity. The default GEKO model shows a stable performance for three oxidizer-to-fuel ratios, enhancing the reliability of its use. The simulations are conducted using two chemical kinetic mechanisms: Zhukov and Kong and the more detailed RAMEC. The influence of the combustion model is of the same order as the influence of the turbulence model. In general, the numerical results present a good or satisfactory agreement with the experiment, and both GEKO at Csep = 1 or the standard k–# model can be recommended for usage in the CFD simulations of rocket combustion chambers, as well as the Zhukov–Kong mechanism in conjunction with the flamelet approach

COLD FLOW TESTING OF DUAL-BELL NOZZLES IN ALTITUDE SIMULATION CHAMBERS

DLR studied various subscale cold flow dual-bell nozzles at test facility P6.2. To fulfill future test requirements the facilitywas modified. This paper gives an overview about the upgrading and its results

Heat Accumulators for Cryogenic In-Space Propulsion

In this work, the preparations for the experimental study of ISP-1 [1] work package 5 dealing with low temperature heat accumulators (LTA) for possible cryogenic in-space propulsion are presented. The functional principle of the LTA which is based on water and which is able to operate within the temperature range from -200°C to +80°C is quantitatively outlined. A prototype for the experimental validation of the numerical simulation of the phase change behaviour of both the heat transfer fluid and the heat storage material is shown

Relation between shock unsteadiness and the origin of side-loads insidea thrust optimized parabolic rocket nozzle

This paper reports the results from tests carried out on a thrust optimized parabolic (TOP) nozzle to study the influence of the unsteady characteristics of fluctuating separation and reattachment shocks towards the possible origin of lateral forces in rocket nozzle flows. The study was conducted using wall pressure measurements both in axial and circumferential directions, surface oil visualization technique and from strain gauges installed on the nozzle bending tube. Experiments reveal that the nozzle pressure ratios, at which the peaks in maximum rms values occur for separation and reattachment shocks, to coincide with the nozzle pressure ratios at which peaks in strain gauge signal are observed. This indicates that the fluctuating nature of separation and reattachment shocks as directly responsible for origin of side-loads in rocket nozzle flows