複動式合成噴流腔體改良設計模擬分析

Abstract

發光二極體具備著低驅動電壓、不含汞、高色再現性等優點，將來取代冷陰極燈管已是必然的趨勢了，但為了要能達到高照度及提昇產品壽命等需求，二極體便產生高熱密度的問題，在空間與噪音的限制前提下，具備構造簡單、控制容易等特點的合成噴流便為極具發展潛力的主動式散熱元件。本文將致力於複動式合成噴流腔體的改良，由於複動式合成噴流腔體中冷熱流體的交換是利用主腔體與側邊腔體相反的相位差，將外界冷流體由側邊腔體導引入主腔體內。經分析後發現，將原本設計的主腔體與側邊腔體間的檔體完全截平後，有助於外界的冷流體導引入主腔體內，以維持每一次推出主腔體外的流體保持在一定低溫，在研究過程中也發現側邊腔體孔口處所產生的渦漩可以抵擋住主腔體在推出行程時，部分的流體經由側邊腔體流道流出腔體外，渦漩形成的時間將扮演兩腔體替換率高低的關鍵性角色。

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 spaces 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 proposes to design a chamber which can promote exchange rate between the central chamber and ambient. Annular chamber can induce cold fluid to central chamber because of the opposite phase between two chamber. We find that the block between central chamber and annular chamber we cut off is helpful to induce cold fluid from ambient to central chamber. That will keep the jet at low temperature during ejection every time. We also find that the vortex near the orifice of annular chamber plays an important role. The vortex can stop the fluid induce by annular chamber at pumping stroke.