On the comparison between probability density function models for CFD applications

Computational fluid dynamics (CFD) for modelling, turbulent reacting flows is based on the Reynolds-average approach and requires a micro-mixing model, for the chemical source that appears in an unclosed form. Three different approaches are presented in this work: full PDF, finite-mode PDF and beta PDF The comparison was carried out in an ideal perfectly mixed batch reactor, that corresponds to the cell considered by, CFD codes; competitive-consecutive and competitive-parallel reaction schemes were used to test model performances. The comparison showed that the disagreements between the,approaches in a certain range of operative conditions are, acceptable The prediction obtained by using the Finite-Model PDF model and the Beta PDF model are. comparable. Nevertheless the Finite-Mode PDF model presents the main advantage of being simpler and faster.