IMPINGEMENT HEAT TRANSFER AUGMENTATION DUE TO LARGE SCALE EDDIES
This paper deals with the mechanism and technology for augmentation of impingement heat transfer. Much attention is focused on the role of large scale eddies in jet impingement heat transfer. Owing to their strong unsteadiness and three-dimensionality, large scale turbulent coherent structures are discussed making a statistical analysis with conditional sampling of the turbulence measurements in the jet impingement region. It is emphasized that the surface renewal effect of large scale eddies impinging on heat transfer surfaces is dominant in the mechanism for enhancement of the stagnation-point heat transfer It is also demonstrated that to strike the large scale artificially-induced eddies against heat transfer surfaces is a very effective means to raise further the impingement heat transfer.