Simulation of Turbulent Combustion Using Various Turbulent Combustion Models

Abstract

The reynolds-averaged navier-stokes (RANS) method nowadays still is the major tool for gas turbine chamber (GTC) designers, but there is not a universal method in RANS GTC spray combustion simulation at present especially for the two- phase turbulent combustion. Usually there are two main steps in two-phase combustion: the liquid fuel evaporation and the gas mixture combustion. Thus, two widely used turbulent combustion models: the eddy-break-Up (EBU) and eddy- dissipation-concept (EDC) turbulent combustion models are firstly tested against a methane-air turbulent gas jet flame (Flame D) measured by Sandia Lab, then against two-phase turbulent swirl spray combustion in a complex GTC. In the jet flame simulation, the prediction results are in good agreement with the experimental results in most regions, while sometimes EBU model overestimated the turbulent effect. Though EDC model takes the chemistry effect into account, the turbulence seems be overestimated sometimes too. The simulated GTC performed well in experiments especially when the fuel-air mixture equivalence ratio (MER) in its main-reaction-zone (MRZ) is 0.7, so the two combustion models are all applied in this case, with the same 90deg spray angel, same material properties and the same discrete ordinates (DO) radiation model. Generally, the EBU and EDC results are good: the high temperature regions are mostly in MRZ when MER is 0.7. The EDC model also has good predictions of different MERs in MRZ. When MER is 1.3, the unburned kerosene continue reaction after primary-air-holes; when MER is 0.3, there is nearly no kerosene there. Additionally, effects of the spray angle, material property are studied.