This paper presents numerical simulation results of propane, propane-hydrogen blending diffusion flames in a combustion chamber. The numerical simulations using Fluent CFD code were carried out by changing fuel blending from pure propane (100% C3H8) to propane-hydrogen blending including 90% C3H8-10% H-2, 80% C3H8-20% H-2, 10% C3H8-90% H-2, 20% C3H8-80% H-2 by volume. A two-dimensional axis-symmetric numerical model was solved to investigate the effects of the turbulence and radiation models on the combustion characteristics such as temperature, and gas concentration distributions. The combustion reaction scheme in the flame region was modeled using eddy dissipation model with global reaction scheme. The effects of two turbulence models including RNG k-epsilon, and Reynolds Stress Model, RSM, and two different radiation models including P-I and discrete transfer model were examined on combustion characteristics. The predictions are validated and compared with the published experimental and simulation results. Numerical results show that the velocity profiles, temperature gradients, CO2 and O-2 concentrations profiles are overall agreement with published measurement and simulation results in the literature. (C) 2013 Elsevier Ltd. All rights reserved.