TY - JOUR
TI - Numerical study on laminar free convection heat transfer between sphere particle and high pressure water in pseudo-critical zone
AU - Wei Liping
AU - Lu Youjun
AU - Wei Jinjia
JN - Thermal Science
PY - 2014
VL - 18
IS - 4
SP - 1293
EP - 1303
PT - Article
AB - Supercritical water fluidized bed reactor (SCWFBR) is a promising new  reaction vessel which can effectively gasify wet biomass and efficiently  produce hydrogen. Free convection heat transfer from particle in  supercritical water (SCW) is a major basic heat transfer mechanism in a  fixed bed or fluidized bed with low superficial velocity. In this paper,  numerical study on the steady free convection heat transfer around single  sphere particle in high pressure water of pseudo-critical zone was carried  out. Both the Boussinesq approximation method and real properties model  (considering variable specific heat, density, viscosity, and conductivity of  SCW) were incorporated to simulate the flow and temperature field. With  respect to Boussinesq approximation, real properties model shows higher  vorticity and temperature gradients in the vicinity of the sphere surface,  which shows variation of thermo-physical property has remarkable effect on  the free convection heat transfer process. High local Nusselt number and  high heat transfer rate were observed with real properties model.