This work attempts to establish the vision for Computational Fluid Dynamics as a rocket injector design tool. Simulations of a 5-kN thrust liquid rocket engine swirl atomizer, under cold flow conditions, using an open source CFD code is the immediate goal of this research. The governing equations are solved based on the laminar volume of fluid (VOF) interface capturing method. The oxidizer and fuel injector elements were analyzed for discharge coefficient, spray-cone angle, liquid film thickness as well as other design related parameters. Results from cold flow experiments and particle image velocimetry (PIV) are compared to the predictions of the swirl models and the numerical results. The VOF model was able to predict the spray angle with reasonable confidence, however, a deviation of 25% was observed in the mass flow rate and discharge coefficient. Although the laminar model has proven inadequate, it constitutes a good starting point in the procedure needed to assess swirl injector performance. Work is currently in progress to evaluate Reynolds Averaged (RANS) and Large Eddy (LES) turbulent numerical models.

Numerical modeling of premixed combustion is important for a wide range of machines and systems focusing on compliance with the increasing pollutants reduction requirements. However good industrial numerical combustion models need a practical requiring, in this way, a balance between speed and accuracy. The flamelet models are suitable for this purpose providing a decoupling of the reactive and fluid dynamic problems, and an important model of this family is the b-Ξ flame surface wrinkling model. A specially challenging experiment to test this combustion model is the ORACLES test rig whose two independent parallel inlet channels consistently influence the turbulent combustion, injecting fuel and oxydizer at different equivalence ratios. The b-Ξ flamelet combustion model is known by the sensibility to numerical schemes and boundary conditions and, based on this, the present study proposes to investigate the coupling with the important SST k-ω turbulence model and achieve good balance among accuracy, boundedness, stability and efficiency using the ORACLES experiment.

A turbulent reacting flow in a channel with an obstacle was simulated computationally with large eddy simulation turbulence modeling and the Xi turbulent combustion model for premixed flame. The numerical model was implemented in the open source software OpenFoam. Both inert flow and reactive flow simulations were performed. In the inert flow, comparisons with velocity profile and recirculation vortex zone were performed as well as an analysis of the energy spectrum obtained numerically. The simulation with reacting flow considered a pre-mixture of propane (C 3 H 8) and air such that the equivalence ratio was equal to 0.65, with a theoretical adiabatic flame temperature of 1,800 K. The computational results were compared to experimental ones available in the literature. The equivalence ratio, inlet flow velocity, pressure, flame-holder shape and size, fuel type and turbulence intensity were taken from an experimental set up. The results shown in the present simulations are in good agreement with the experimental data.

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