Abstract
The impinging jet is widely used in the industrial field, as high heat transfer characteristics are obtained in the vicinity of a stagnation point on the object surface. In this paper, the heat transfer characteristics on the impinging wall after being blown off through a coaxial circular pipe were examined by changing the pipe-diameter ratio and the velocity ratio. As a result, the optimum values of the pipe-diameter ratio and the velocity ratio were found in the given conditions. The influence of the pipe-diameter ratio and the velocity ratio on the flow structure was clarified by the flow visualization.