Numerical simulation on the flow patterns/the velocity profiles was conducted and predicted. The test conditions and input boundary conditions are summarized. The flow patterns of the side view/top view are predicted along with stream lines. When the flow reached to the secondary air input of the lower air injection nozzles, the flow pattern was changed from a laminar flow to a turbulent flow. The velocity profiles at various locations of the combustor chamber was predicted. The velocity at the center of the combustor is greater than that of the wall region. The velocity of the top section is also greater than that of the lower section. The swirling velocity is reduced in both directions of the wall and the center of the combustor chamber. The velocity increased from the wall region to the center region at the top section of the secondary air injectors. Numerical modeling/simulation will be continued to determine the species profiles, temperature profiles, mass fraction profiles, and heat flux and heat transfer coefficient profiles. In addition, experimental test on the hot combustor model will be conducted and analyzed to compare with the numerical simulation results.