In this paper the three dimensional confined and unconfined turbulent air jets impinging on a simple heated flat plate were simulated numerically, using an elliptic relaxation turbulence model ( 2  f Model). The flow was assumed to be incompressible. Both the radiation heat transfer and buoyancy effects were neglected. The Reynolds number was equal to 23000. Different turbulence models were also used to compare their abilities in prediction of the experimental data of surface heat transfer coefficients. Comparing the numerical and experimental results it was concluded that the results of the  2  f turbulence model were more accurate than those of the other models. A range of jet-to-target distances (0.25, 0.5, 1 and 2 times the jet diameter) for both cases were simulated to study the effect of the confinement on the flow field and local heat transfer characteristics. The results showed that the confinement didn’t change the stagnation heat transfer coefficient but it caused a decrease in the average heat transfer rates. The effect of confinement was significant at low nozzle-to-plate distances and moving away from the stagnation point, the differences between the heat transfer and velocity magnitude of the free and confined jets were more obvious

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