Two-way coupling effects in dilute gas-particle flows

A general analysis of gas-particle flows is presented using the hypotheses of a number of particles large enough to consider the solid phase as a continuum and of a volume fraction small enough to consider the suspension as dilute. It is found that the Stokes number (Sk) and the particle loading ratio (beta) are the basic parameters governing the flow. For small values of beta and large values of Sk it is possible to disregard the effect of the particles on the fluid field and simple numerical models based on one-way coupling may be used. However, for larger values of beta and lower Sk, both the fluid and the solid phase flow fields (and as a consequence the overall quantities such as pressure drop and energy dissipation) are determined to be substantially affected by the interphase coupling. A computational model accounting for two-way coupling is presented and found to provide for an accurate simulation. In addition, correlations are developed for determining the pressure drop which increases as a function of beta and Sk, and it is suggested that these correlations may be of practical interest for the investigation of flow metering systems.