The recent progress in momentum, heat and mass transfer studies on pneumatic conveying: a review

Abstract

Pneumatic conveyors are broadly used in industry because transportation of solid can be performed instantaneously with heating and drying process. The present review focused on all the advancement executed in the field of pneumatic conveying considering the momentum, heat and mass transport phenomenon. The detailed analysis of each transport process like estimation and effects of hydrodynamic variables viz. slip velocity, pressure drop, friction factor, mass flow rate, flow types and particle velocity is summarized. The heat transfer phenomenon by considering the gas-solid heat transfer, as well as riser wall to the gas and particles is also discussed in detail. The mass transfer phenomenon becomes prominent while studying the pneumatic drying, thus the estimation of mass transfer coefficient and its variation with the hydrodynamics of the system is also addressed in brief. The special attention is given to the influence of hydrodynamic, heat and mass transfer parameters on the extent of pneumatic transport. The study also elaborates the empirical equations and assumptions considered while evaluating the unknown variables in each transport process in pneumatic conveying.