Numerical study of particle interaction in gas-particle and liquid-particle flows: part II particle response

In this paper the numerical model, which was presented in the first paper (Mohanarangam & Tu; 2009) of this series of study, is employed to study the different particle responses under the influence of two carrier phases namely the gas and the liquid. The numerical model takes into consideration the turbulent behaviour of both the carrier and the dispersed phases, with additional equations to take into account the combined fluid particle behaviour, thereby effecting a two-way coupling. The first paper in this series showed the distinct difference in particulate response both at the mean as well as at the turbulent level for two varied carrier phases. In this paper further investigation has been carried out over a broad range of particle Stokes number to further understand their behaviour in turbulent environments. In order to carry out this prognostic study, the backward facing step geometry of Fessler and Eaton (1999) has been adopted, while the inlet conditions for the carrier as well as the particle phases correspond to that of the experiments of Founti and Klipfel (1998). It is observed that at the mean velocity level the particulate velocities increased with a subsequent increase in the Stokes number for both the GP (Gas-Particle) as well as the LP (Liquid-Particle) flow. It was also observed that across the Stokes number there was a steady increase in the particulate turbulence for the GP flows with successive increase in Stokes number. However, for the LP flows, the magnitude of the increase in the particulate turbulence across the increasing of Stokes number is not as characteristic as the GP flow. Across the same sections for LP flows the majority of the trend shows a decrease after which they remain more or less a constant.