ISSN Online: 2377-424X
International Heat Transfer Conference 5
LOCAL ENHANCEMENT OF THE RATE OF HEAT−TRANSFER IN AN IMPINGING ROUND JET BY FREE−STREAM TURBULENCE
Sinopsis
The effect of free-stream turbulence on the local rate of heat-transfer in an impinging round jet was studied for large Prandtl numbers by the electrochemical method. The rate of heat-transfer for large Prandtl numbers was much more enhanced by the amplified turbulence of free-stream than skin friction in the impingement region. The local enhancement of heat-transfer can be explained with the following two contributions (1) the penetration of mixing-induced turbulence across the laminar boundary
layer in the presence of negative pressure gradients and (2) the subsequent transition from laminar to turbulent boundary layer by the disappearance of the pressure gradients.