At the 2017 Joint Propulsion Conference, Dr. Yu Daimon presented “Film Cooling Performance Analysis of a Full-scale Liquid Rocket Engine Combustion Chamber Based on a Coupled Combustion and Heat Transfer Simulation.”
Japan Aerospace eXploration Agency (JAXA) has investigated CFD techniques to predict regenerative cooling performance since 2009 using the unstructured and density-based solver CRUNCH CFD, which was developed by Combustion Research and Flow Technology (CRAFT Tech). In the past, CRUNCH CFD has been used for various applications in liquid rocket engines and extensively validated against key physical phenomena that occur in combustion chambers. Consequently, CRUNCH CFD was confirmed as an effective CFD tool to qualitatively and quantitatively predict key physical phenomena in regeneratively cooled combustion chambers. A combined combustion and heat transfer simulation methodology was recently proposed as a practical strategy to model fullscale combustion chambers and predict their regenerative cooling performance.
The chamber cooling system in expander bleed cycle engines is one of the key technologies to realize high-performance liquidrocket engines. LE-9, which has been developed as the first-stage engine of Japanese next flagship launch vehicle H3, adopts both film and regenerative cooling systems. To achieve high levels of efficiency and reliability, it is necessary to understand and make it possible to accurately predict the flow field and heat transfer characteristics of combustion chambers. In the current study, a fully coupled combustion and heat transfer simulation methodology for full-scale regeneratively cooled combustion chambers was validated against hot firing tests of a sub-scale multi-element combustor and a full-scale LE-9 combustion chamber. First, the hot-gas side simulation was validated in terms of the film cooling efficiency for the sub-scale combustion chamber, and showed good agreement with the measured wall heat flux with and without film cooling. Second, the coupled hot-gas and coolant side simulation was validated against the hot firing tests of the LE-9 combustion chamber. The computed results accurately predicted the pressure loss and temperature gain in the cooling channels within acceptable levels. These results confirmed that the current numerical approach is promising for predicting the regenerative cooling performance in full-scalecombustion chambers with film cooling.
Daimon, Y., Negishi, H. & Kawashima, H. (2017) Film Cooling Performance Analysis of a Full-scale Liquid Rocket Engine Combustion Chamber Based on a Coupled Combustion and Heat Transfer Simulation. 53rd AIAA/SAE/ASEE Joint Propulsion Conference. Atlanta, GA. AIAA 2017-4919.