Abstract
The reliability of numerical simulations depends on the adequacy of modeling the relevant phenomena that are being analyzed. In the present seminar three sample cases will be discussed. The first two address wall heat flux predictions in LREs whereas the third one is focused on HRE regression rate predictions. The sample cases are briefly described in the following:| 1. Cooling of LRE thrust chamber walls to allowable solid material temperature induces near wall recombination which may add a non-negligible contribution to the heat transfer from the hot gas to the wall. Numerical results are compared to literature experimental data of wall heat flux in subscale calorimetric thrust chambers for both oxygen/methane and oxygen/hydrogen propellant combination. 2. Regeneratively cooled LRE heat flux evaluation requires adequate modeling of coupled heat transfer between hot gas and coolant fluid. Loosely coupled numerical results are discussed and compared with reference SSME-MCC literature data. 3. Numerical simulations of the flowfield in a GOX/HTPB hybrid rocket engine are carried out including detailed gas surface interaction modeling based on surface mass and energy balances. Results are compared with firing test data from a lab-scale hybrid rocket with HTPB cylindrical grain and axial injection of gaseous oxygen.

Bio
Barbara Betti is a post-doc fellow at Sapienza University. She took her PhD in 2012 at the same university defending a thesis on “Flowfield and heat transfer analysis of oxygen-methane liquid rocket engine thrust chambers”. Her research interest are: active cooling techniques, coupled heat transfer problems and heat transfer enhancement devices.

Francesco Nasuti is associate professor of aerospace propulsion at Sapienza University since 2004. He took his PhD at the same university in 1995 (Liquid rocket nozzle startup transients). Research subject during these years have been: Rocket nozzle over expanded operation, advanced nozzle concepts, fluid surface interface modeling in CFD (surface catalysis in reentry flows, ablative walls in SRM, hybrid rocket flows), cooling systems in LRE (film cooling, regenerative cooling heat transfer modeling, supercritical fluid modeling).