Abstract: A two-dimensional mathematical model was developed for predicting the temperature and velocity field in a cylindrical combustion chamber. The two-equation turbulent model and Monte-Carlo method were used to simulate the turbulence and radiative heat transfer. Three different turbulence combustion models were considered. The differential equations were solved by a SIMPLE algorithm. The distribution of fuel and oxygen concentration, velocity, temperature and heat flux in a crude oil heater were predicted. The comparison between the calculated and measured temperature distributions showed that the prediction was successful.