The process of multiphase flow and heat transfer in an entrained-flow coal gasification radiant syngas cooler (RSC) was simulated by coupling the multiphase flow model and heat transfer model.The gas phase flow field was calculated by realizable k-ε model with an Euler method while the discrete random walk (DRW) was applied to trace the particles

and the interaction between gas and particles was considered.The radiative properties of syngas mixture were calculated by Weighted-Sum-of-Gray-Gases (WSGG) model.The discrete ordinates model (DOM) was used for modeling the radiative heat transfer

and the effect of slag particles on radiative heat transfer was included.Results showed that the expanding angle of inlet jet is 10°

where the temperature and velocity are higher than other area’s.The recirculation region around the inlet jet has a higher particle concentration.Most of the slag particles are straightly dropped into the slag pool

and the larger the particle

the faster the dropping and the higher the temperature it will have.The temperature distribution in RSC is uniform except the inlet jet region

and the temperature increases with the increase in ash/slag deposition thickness.The mathematical models for numerical simulation are compared with experimental and literature data.Overall agreement between the predicted and experimental values is good and gives confidence in using these routines for RSC design calculations.