Particle-resolved numerical study of the forced convection heat transfer characteristics of an endothermic-biomass particle placed in supercritical water crossflow

Biomass gasification in supercritical water (SCW) for high energy density gas fuel is a promising method for the efficient usage of biomass resource. Researches have indicated that the gasification efficiency is greatly depended on the heat transfer rate during the practical process of cold biomass particle injected into SCW. So the study of the forced convection heat transfer characteristics of an endothermic-biomass particle placed in SCW crossflow is of great significance. Moreover, the study of the particle surface local heat transfer rate distribution is also necessary for the complete gasification of biomass particles in SCW. Therefore, this work performs particle-resolved direct numerical simulation study on SCW flow past an endothermic sphere. Results demonstrate that the heat transfer gets great enhancement when the heat transfer temperature range comprises the large specific heat capacity zone. For the particle surface local heat transfer distribution, the enhancement at the front of particle is much stronger than that at the rear. Furthermore, the heat transfer characteristics under different pressures are also studied. In the end, a new forced convection heat transfer correlation applicable for SCW flow past an endothermic sphere is obtained. (C) 2020 Elsevier Ltd. All rights reserved.