Numerical investigations of heat transfer from impinging annular jet

Numerical investigations were performed to predict heat transfer characteristics of laminar annular jets impinging on a surface. An axi-symmetric formulation was used for solving the mass, momentum and energy equations with SIMPLE algorithm. The performance of an annular jet was compared with a standard circular jet having the same values of mass and momentums efflux at the nozzle exit. It was found that heat transfer from the annular jet was about 20% less compared to the circular jet. The distribution pattern of the Nusselt number over the impinging surface scales with Re0.55. The paper also discusses the importance of defining appropriate characteristic length for the annular jet.