In the field of heat transfer and fluid flow, the application of numerical simulations using commercial CFD (Computational Fluid Dynamics) software for development of combustion equipment has become widespread with the improvement of power and the fall in price of computers. However, there are few reports concerning the examination of CFD performance through comparison with experimental data or other CFD software. This paper reports the numerical simulation of the turbulent air jet in a cylindrical combustor using commercial CFD software and comparison of the calculated results with the results obtained with our original CFD software and the experimental data reported previously. The velocity profiles estimated with the commercial software were found to differ from those calculated with our original software, though almost the same turbulence model, boundary conditions, numerical grid and discretization scheme were used in both. Moreover, the employment of a higher order discretization scheme and finer grid with the commercial software did not always produce good results compared to our original software. The results reported here will be useful in applying commercial CFD software to the development of combustion equipment.