Development of Thrust Chamber Components for a System Analysis Tool

Abstract

In this paper a new thrust chamber component for the object oriented tool EcosimPro is presented. The numerical approach consists of a finite volume formulation of the unsteady quasi one-dimensional Euler equations for multispecies flow coupled with finite-rate chemistry. The inviscid convective fluxes are treated with two schemes, specifically formulated for multispecies flows: the approximate Riemann solver of Roe and the AUSM+ -up. Both the schemes are implemented with a spatial accuracy up to the third order by means of the Monotonic Upstream Centered Scheme for Conservation Laws (MUSCL). The reaction mechanism presented consists of six species and eight reactions for the combustion of hydrogen and oxygen while time integration is left to the DASSL implicit solver embedded in EcosimPro. After the description of the numerical model, some validation test cases for the schemes and the finite-rate chemistry mechanism are presented. The component is then tested on the Space Shuttle Main Engine (SSME) Main Combustion Chamber (MCC) and the results are compared against those obtained with an already validated software. The tests show that the component is able to reach the expected steady-state solution in terms of both evolution of the thermodynamic properties and mixture composition and that the implicit solver is able to deal with the stiffness introduced by the source terms representing the finite-rate chemistry. The SSME MCC and its regenerative cooling channel are then modelled in EcosimPro. Limitations related with the use of classical semi-empirical correlations for the hot gas side heat transfer coefficient are highlighted and overcome through a coupling procedure, in which the solution coming from a CFD analysis of the MCC is coupled with those obtained with EcosimPro for the cooling channels. The results of this iterative procedure are compared with those available in open literature, showing that wall heat flux and wall temperature profile are in line with those obtained by other methods. Furthermore, an accurate calculation of the wall heat flux allows the cooling channel component presently available in EcosimPro to obtain results that are comparable with those proposed by higher fidelity models