To explore the effect of discretization scheme on the simulation results,both the QUICK scheme and the hybrid scheme are applied to the numerical simulation of turbulent flow in a swirl combustor with coaxial jets. The computation adopts the k-εmodel for the closure of turbulence. It is seen that the gas axial and tangential velocities and the root mean square of gas axial fluctuating velocity calculated by utilizing the QUICK scheme agree well with the measured test data, while the calculated results by using the hybrid scheme show obvious deviations from the measurement.

For the purpose of developing swirl combustors with high combustion efficiency and low pollutant emission, a numerical simulation of swirling turbulent flows in a swirl combustor with coaxial jet interactions is performed. A new algebraic Reynolds stress model and the QUICK discretization scheme are utilized in the present calculations. The simulated results of swirling turbulent flows in the combustor for both cases of the coswirl jets and the counterswirl jets are in agreement with the experiment data in terms of the time-averaged gas axial velocity, tangential velocity and static pressure.

Using the Lagrangian analysis of particle motion and PDF(Probability Density Distribution Function) method,an improved the second-order-moment model of particle-phase is proposed.Based on the Lagrangian stochastic two-phase motion equations, using the stochastic-process analysis and the signal-system analysis, the obtained particle-phase PDF transport equation,the two-fluid model equations and the basic version of two-phase fluctuation velocity correlation are in agreement with those obtained by other investigators.However,significant improvement is made for the closure model.The crossing-trajectory effect,continuity effect,inertia effect and the anisotropic turbulence have been taken into account to simulate the interaction time between the particle and the fluid turbulence seen by the particles.