Improvement of cooling performance of impinging air by intermittent flow control : Relationship between nozzle diameter and cooling performance

This study describes a possibility of an improvement of cooling performance of electrical components by using an intermittent jet flow like a geyser in nature. In this report, a relationship between cooling performance of intermittent jet on the heating surface and the nozzle diameter was investigated through the experiment. Through the experiment, it was found that the level of the improvement of the cooling performance by the intermittent impingement jet was dependent on the nozzle diameter. However, when the diameter was smaller than 5 mm, the cooling performance was almost the same as that of the steady impingement jet regardless of the decrease of the time-averaged supply flow rate.