APPLICATION OF DIFFERENT INTERPOLATION SCHEMES FOR REACTIVE FLOWS IN ROCKET NOZZLE ENGINES

Gabriel Vergara¹; Nicholas Dicati Pereira da Silva¹; Luciano Kiyoshi Araki¹

¹ Federal University of Paraná

doi:10.20906/CPS/COB-2015-0447

Resumo

The accuracy of a numerical solution is strongly related to which interpolation scheme is used to discretize a mathematical model. Two of the most used schemes are the UDS (Upstream Differencing Scheme) and the CDS (Central Differencing Scheme). Although the CDS presents second order of accuracy, it can exhibit numerical oscillations and even numerical divergence, depending of the studied problem. On the other hand, the UDS presents much easier convergence but it exhibits numerical diffusion. In order to avoid UDS and CDS problems, other approximations schemes were developed, such as the TVD (Total Variation Diminishing) ones. TVD is not a single interpolation scheme, but actually a family of schemes, which basically differs one to another by the limiting functions. In this work, different TVD schemes are employed for frozen and local equilibrium reactive flows in rocket nozzle engines. Such flows presents a strongly variation in gases speed: it starts with nearly null velocities and achieves supersonic flow in the exit region of the nozzle. Reactive models includes from three to eight chemical species for hydrogen/oxygen reactions, which are usually employed as propellants for high performance rocket engines. In order to evaluate numerical uncertainties of results, numerical verification techniques are used. By analyzing numerical results, one can identify which are the best choices of TVD schemes for compressible reactive flows.

Palavras-chave: TVD; frozen flow; local equilibrium flow; rocket nozzle engines; H2/O2