A robust and accurate algorithm of the ß-pdf integration and its application to turbulent methane-air diffusion combustion in a gas turbine combustor simulator

The beta-pdf has been widely assumed for the probability distribution of the mixture fraction in many turbulent mixing and turbulent nonpremixed combustion models in the literature. The numerical integration of the beta-pdf often encounters the singularity difficulties and only few publications have addressed this issue. An efficient, accurate and robust numerical treatment of the beta-pdf integration was proposed. The present treatment of the beta-pdf integration was implemented into a flamelet model to calculate turbulent methane-air combustion in a model gas turbine combustor. Numerical results obtained using the present beta-pdf integration method and those based on the properties of the beta and gamma functions were compared to illustrate the accuracy of the present method. Effect of assuming the beta-pdf to the mass-weighted pdf and unweighted pdf of the mixture fraction on the calculated density field was also investigated. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.