Heat Transfer and Combustion Simulation of Seven-Element / Rocket Combustor

Abstract

In the present Paper, the simulation of the flow inside an experimental rocket thrust chamber is undertaken. The combustor’s injector consists of seven individual coaxial injector elements, while the chamber and nozzle segments are water cooled. The results presented in this Paper are obtained with three-dimensional Reynolds-averaged Navier–Stokes simulations using an adiabatic flamelet formulation for the chemistry modeling. The main focus is placed on examining the effect of the different turbulence models on the flame structure and on the resulting pressure and wall heat flux. The obtained numerical values are compared to experimental measurements, delivering good agreement in the heat flux profile at the combustion chamber wall and a slight underestimation of the pressure profile of approximately 2.5%. Greater discrepancies are observed in the heat flux of the nozzle segment but are largely attributed to the experimental setup. A conjugate heat transfer simulation of the structure and cooling channel flow confirms this assumption, and results for both one-way and two-way couplings are shown. It is demonstrated that a one-way coupling between hot gas and structure is sufficient due to the low sensitivity of the wall heat flux on the wall temperature. The azimuthal variation of the heat flux is also examined, and interestingly the heat flux showcases a local minimum at the position directly above the injector element. It is shown that an increased concentration of colder fuel-rich gas directly above the injector due to a strong vortex system leads to the local minimum in heat flux values and is strongly influenced by the injector/injector interaction near the face plate.