Simulation of NO_x formation in turbulent swirling combustion using a USM turbulence-chemistry model

摘要

A unified second-order moment (USM) turbulence-chemistry model for simulating NO_x formation in turbulent combustion is proposed. All of correlations, including the correlation of the reaction-rate coefficient fluctuation with the concentration fluctuation, are closed by the transport equations in the same form. This model discards the approximation of series expansion of the exponential function or the approximation of using the product of several 1-D PDF's instead of a joint PDF. It is much simpler than other refined models, such as the PDF transport equation model and the conditional moment closure model. The proposed model is used to simulate methane-air swirling turbulent combustion and NO_x formation. The prediction results are in good agreement with the experimental results.