IGBT的微流道散熱分析與最佳化設計

Abstract

本研究針對絕緣柵雙極電晶體(Insulate Gate Bipolar Transistors, IGBT)，探討單層、雙層及三層的流道設計，在不同雷諾數下，改變流道高度、流道間距及流道寬度等對於微流道散熱效能的影響，以求得IGBT散熱的最佳化設計。在實際微流道散熱系統中，其入口端與出口端常有分流及匯流之流道結構，此處也是整體系統中最易形成氣泡的部分；若氣泡流入散熱流道中，將導致熱阻大幅上升而使得散熱效能下降。為避免此一情況發生，本文研究設計三種不同匯流角度之流道進行實驗研究，並比對出較不易產生氣泡之流道結構。研究結果顯示，多層微流道結構比起傳統單層微流道熱沉，其熱阻將至少降低15%；三層結構微流道之流道寬度與間距比(γ)為0.8時熱阻值為最低；晶片配置過於密集將降低散熱效率；交匯流道之匯流角度為240ﾟ時將包覆較大的氣泡。

This study purposes to investigate in detail the heat transfer at various values of Reynolds number, flow channel height and width, and channel spacing of double-tier and triple--tier flow channels, in order to achieve optimal design for heat dissipation of Insulate Gate Bipolar Transistors (IGBT). In practice, the divergence and/or convergence of fluid flows may occur in the micro-fluidic system, especially at the entrance and outlet of the channel structure of the systems, and the bubbles may be formed which will subsequently lead to significant decrease in the heat dissipation. In this study, we also address the issue of the bubbles formation in the micro-fluidic system, so that we may prevent the bubbles formation in the optimal design of heat dissipation for IGBT. We design the experiments in three different angles of convergence cannels and visualize the formation of the bubbles in channel structure. The results show that the multi-layer micro-fluidic structure, compared to the traditional single-layer micro-channel heat sink, may reduce the thermal resistance by at least 15%. At the ratio (γ) of three-tier structure of micro-flow channel width and spacing equal to 0.8; the heat resistance is the lowest. While the chips are too dense, the heat transfer rate would be depressed. The experimental results also show that at the convergence angle of the flow channel at the intersection equal to 240°, the volume of the bubble formed in the channel structure would be the largest.