Numerical Analysis of Chamber Wall Heat Transfer in a GH2/GO2 Sub-Scale Combustor

摘要

Chamber wall heat transfer is critical to lifetime and reliability goals in all engine cycles but design margins included to account for uncertainty of predictive methods and allow for system growth can have detrimental effects on performance. Ensuring that critical objectives will be achieved requires accurate predictive methods; however, in many cases, CFD tools used to predict chamber wall heat transfer have never been validated for rocket chamber conditions. AFRL has a program for assessing the current capability of CFD tools and as necessary, and where possible, making improvements. As a part of our ongoing efforts, a sensitivity analysis was performed to identify key parameters that dominate the overall uncertainty in hot-gas-side chamber wall heat transfer to guide decision making in the experimental effort. Numerical simulations of heat transfer in a sub-scale combustor were carried out using FLUENT over a range of boundary and initial conditions in order to determine sensitivity coefficients. These results were combined with estimates of the uncertainty in experimental measurements to determine an initial estimate for the uncertainty in heat flux prediction. The results indicate that the most critical parameters for chamber wall heat flux are surface roughness, turbulence intensity, and gas temperature.