Numerical investigation of heat transfer for elliptical tube in granular flow using DEM

Moving bed heat exchangers take important part in terms of extracting heat from granular materials. Circular tube is main part of heat exchanger in most studies and implements. Two heat transfer deterioration zone for circular tubes in granular flow is found and results in a low heat transfer coefficient. Elliptic tubes receive increase attention recent years for their better heat transfer performance for fluid. In this work numerical investigation based on DEM has been produced to obtain heat transfer performance of elliptic tubes in granular flow with different axis ratio. The result shows that elliptic tubes with axis ratio from 1.2 to 2.0 have a narrower area of heat transfer deterioration in granular flow and consequently a higher effective heat transfer coefficient from than circular tube (axis ratio =1.0) with the same long axis.