Convective Heat Transfer in the Reusable Solid Rocket Motor of the Space Transportation System

This simulation involved a two-dimensional axisymmetric model of a full-motor initial grain of the reusable solid rocket motor of the Space Transportation System. It was conducted with the computational fluid dynamics (CFD) commercial code FLUENT^®. This analysis was performed to maintain continuity with most related previous analyses; serve as a non-vectored baseline for any three-dimensional vectored nozzles; provide a relatively simple application and test for various CFD solution schemes, grid sensitivity studies, turbulence modeling, and heat transfer; and calculate nozzle convective heat transfer coefficients. The theoretical prediction of turbulent convective heat transfer in supersonic nozzles is scarce and challenging. The accuracy of the present results and the selection of the numerical schemes and turbulence models were based on matching the rocket ballistic predictions of mass flow rate, head end pressure, measured chamber pressure drop and vacuum thrust, and specific impulse. The matching for these ballistic predictions was found to be good. This study was limited to convective heat transfer, and the results compared favorably with some of the methods cited. Good agreement with the backed-out data of the ratio of the convective heat transfer coefficient to the specific heat at a constant pressure was made at the nozzle throat. Qualitative agreement was achieved upstream and downstream of the nozzle throat due to effects that are absent in this study. These backed-out data were devised to match nozzle erosion that resulted from the combination of heat transfer (convective, radiative, and conductive), chemical (transpiration), and mechanical (shear and particle impingement forces) effects. To the author's knowledge, these effects have not been investigated/reported simultaneously.