Numerical Analysis of Double Acting and Single Synthetic Jet

• Main Authors: Chyi-Lin Lee, 李奇霖
• Other Authors: 顏瑞和
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/35604169853767157084

碩士 === 國立臺灣大學 === 機械工程學研究所 === 94 === In the backlight module industry, light emitted diode has already been an inevitable trend to replace the cold cathode light, because of characteristics such as the low voltage of urging, no mercury, and high color reproduction. In order to reach the demand for the high intensity of illumination, we should resolve the problem of density of high fever emerging in the diode which will influence the performance of LCD system. Because LCD has limited space and needs low noise, “synthetic jet” is an extremely potential active heat dissipation component possessing the characteristics such as simple structure and easy control. This article uses operating frequency and amplitude of moving boundary to define three main dimensionless parameters—Re,St,and S. After analyzing simulation results, we get two conclusions. On the one hand, increasing St will strengthen the structure of vortex ring and enhance thrusting efficiency. On the other hand, increasing S will enhance the intensity of vortex and increase the jet speed. Under the optimum premise, large amplitude and high frequency, the design of double acting for improving the steady jet region of single synthetic jet is limited. However, the near field of double acting synthetic jet has more concentrating velocity, higher speed, and longer high speed region than single synthetic jet. Therefore, it will have better performance on the application of impinging cooling. In addition, the reciprocal of St must be greater than a constant K to ensure jet formation. According to the results of this article, the values of K of double acting and single synthetic jet are 0.25 and 0.5 eventually.