Numerical simulation of gas-particle and liquid particle flows over a sudden expansion geometry

A detailed study into both the mean flow and the turbulent behaviour of dilute particulate flow under the influence of two carrier phases namely gas and liquid has been carried out behind a sudden expansion geometry. The major endeavour of the study is to ascertain the response of the particles within the carrier (gas or liquid) phase. The main aim prompting the current study is the density difference between the carrier and the dispersed phase. While the ratio is quite high in terms of the dispersed phase for the gas particle flows, the ratio is far more less in terms of the liquid-particle flows. Numerical simulations were carried out for both these classes of flows using an Eulerian two-fluid model with RNG based k-e model as the turbulent closure. An additional kinetic energy equation to better represent the combined fluid-particle behaviour is also employed in the current set of simulations. The numerical simulations are validated against the experimental data of Fessler and Eaton (1997) for Gas-Particle (GP) flows while experimental data from Founti and Klipfel (1998) was used to validate the Liquid-Particle (LP) flows. Qualitative results have been obtained for both these classes of flows with their respective experimental data, furthermore their response to their carrier phase has been investigated both at the mean and turbulence level for a range of Stokes number. While the particulate velocity seems to increase with the corresponding increase in Stokes number amidst both the carrier phases, the particulate turbulence shows entirely a different pattern