Adaptive Simulation of the Internal Flow in a Rocket Nozzle

GARELLI, L.; GUSTAVO A. RÍOS RODRIGUEZ; PAZ RODRIGO; STORTI, M.A.

LATIN AMERICAN APPLIED RESEARCH

PLAPIQUI(UNS-CONICET)

Lugar: Bahia Blanca; Año: 2013

0327-0793

xx This work is a first step in the understanding of the interactionprocess between internal shock waves and the flow transition inside ofa rocket nozzle that develops during the engine start-up phase or whenthe nozzle is operated at over-expanded conditions. In many cases,this transition in the flow pattern produces side loads in the nozzledue to an asymmetric pressure distribution on the wall, being harmfulfor the rocket´s integrity. To understand this phenomenon, a numericalsimulation is performed by solving the threedimensional Eulerequations on unstructured tetrahedral meshes. With this model thecomputational cost to solve the equations significantly increases,therefore parallel processing is required. Also, an unsteadyh-adaptive refinement strategy is used jointly with a StreamlineUpwind Petrov-Galerkin and a discontinuity capturing scheme, both tokeep the size of the fluid flow problem bounded and to sharply resolvethe shock wave pattern. The mesh adaptation strategy is introduced.Since its performance is a major concern in the solution of unsteadyflow problems, some implementation issues about the data structurechosen to represent the mesh are discussed. Average pressuredistributions computed at the wall and the axis of the nozzle forvarious pressure ratios are analyzed based on experimental andnumerical results from other authors.