The 2018 AIAA Propulsion and Group selected Dr. Hideyo Negishi’s presentation and paper, titled “Computational Analysis of Supercritical and Transcritical Flows in Cooling Channels with Rough Surface,” as a Best Paper Award. JAXA used CRUNCH CFD’s surface roughness model extensively to study heat transfer in a regeneratively-cooled combustion chamber. Experiments were carried out in a sub-scale hydrogen-cooled combustion chamber to validate CFD simulations.
Regenerative cooling technology remains a key technology in thedevelopment of high performance liquid-fuel rocket engines. To achieve high levelsof efficiency and reliability, it is necessary to understand and be able to accurately predict the flow field and heat transfer characteristics of regeneratively-cooled combustion chambers. Among important parameters affecting the regenerative cooling performance, surface roughness is one of key important factors. In the current study, a new extension to k-ε turbulence model to take into account the effect of surface roughness in Reynolds-averaged Navier-Stokes simulation was proposed and validated relative to a variety of test cases. First, fundamental test cases were performed to validate both skin friction and heat transfer predictions using data from the classical experiment by Nikuradse on rough pipes and experiments by Hosni on flat plates. Second, electrically heated circular tube and curved rectangular duct cases were carried out
to validate pressure drop and wall temperature predictions under supercritical and transcritical pressure conditions with relatively high heat flux environment. Then, cooling channel flows in a sub-scale combustion chamber was simulated in order to evaluate the capability of the proposed model on the prediction of pressure drop and wall temperatures under combustion chamber environments of actual interest. In all the test cases, the computed results showed reasonable agreement with the experimental results. Those results confirmed that the proposed surface roughness model is promising for predicting the regenerative cooling performance in liquid rocket combustion chambers.