The joint presumed PDF model of turbulent combustion

摘要

A joint pdf model of turbulent combustion is proposed. In this model, the fluctuating distribution of reactant concentration and temperature is described using a joint presumed pdf of three-dimensional Gaussian distribution based on the averaging variables of the mean reactant concentration and temperature, mean root square reactant concentration and temperature as well as all cross correlation. And then the mean reaction rate can be easily obtained by integral operation under the above joint presumed pdf. This model is verified by the xperiment of premixed turbulent combustion of sudden-expansion flow. It is shown that the contour temperature and maximum temperature predicted using joint presumed pdf model are in good agreement with the experimetn and are prior to that predicted using widely-used EBU-Arrhenius model. Furthermore, the joint pdf model is suitabel for most engineering application where both effects of turbulent diffusion and chemical dynamics are required to be considered, such as limit-reaction-rate flow and pollutant emission.