Numerical investigations on combustion and emission characteristics of a novel elliptical jet-stabilized model combustor

In this study, a novel elliptical jet-stabilized combustor is developed; the combustion and emission characteristics are numerically investigated and compared with those of a circular jet-stabilized combustor. Five elliptical combustors with different semi-major/semi-minor axis ratios (1.00, 1.27, 1.56, 1.89, and 2.25) are considered, and an optimization method for adjustable stabilizer jet air supply is proposed. An Eulerian-Lagrangian approach is used for solving the liquid fuel spray. Employing the realizable k-e turbulence model and the finite-rate/eddy-dissipation model simulates the turbulent combustion. The discrete ordinate method is used to model thermal radiation, and the thermal and prompt NO formations are to be predictive of NO emissions. The numerical models are validated against available experimental data. The results show that the semi-major/semi-minor axis ratio significantly affects the performance of elliptical jet-stabilized combustors. To improve the temperature uniformity and to reduce NO emissions, the proposed optimization method is successfully applied. Compared with the circular combustor, the optimized elliptical combustor achieves strong mixing performance, resulting in improved combustion and emission performance. By adjusting the major/minor axis jet mass flow rate ratio (ma/mb = 0.6) in the elliptical combustor with semi-major/semi-minor axis ratio of 1.56, NO emissions are reduced by 50% compared with the circular combustor.