On the comparison between presumed and full PDF methods for turbulent precipitation

Turbulent precipitation is an important topic in chemical reaction engineer ing because of its numerous industrial applications. Several modeling appro aches have been used in the past, but in recent years, computational fluid dynamics (CFD) coupled with micromixing models has been successfully applie d to predict the influence of mixing on the crystal size distribution (CSD) . The micromixing model is generally based on the presumed probability dens ity function (PDF) approach, such as finite-mode PDF or beta PDF, and the a im of thus work is to compare presumed PDF predictions and full PDF predict ions with experimental data. The experimental data were obtained from a tub ular reactor in which turbulent precipitation of barium sulfate is carried out from aqueous solutions of barium chloride and sodium sulfate. The imple mentation of the presumed PDF model was done using FLUENT user-defined subr outines, whereas the full PDF calculations were carried out with an in-hous e code based on Monte Carlo methods using the flow field prediction from FL UENT.