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 Re-0.55. The paper also discusses the importance of defining appropriate characteristic length for the annular jet. (C) 2004 Elsevier Ltd. All rights reserved.