往復式冷卻渠道之熱流實驗

Abstract

本研究於層流模式下進行ㄇ型渠道的往復運動，以觀察其流場可視化，並於紊流模式下搭配不同的振動頻率與雷諾數進行分析，探討渠道頂部的熱傳效率，最後並將實驗結果與數值計算相互驗證，以完備實驗結果的可信度。 當ㄇ型渠道進行往復運動時，將導致內部的渠道流與頂部壁面相互撞擊，此為增進熱傳效率的主要機制，從實驗的結果可得知，渠道頂部的熱傳效率皆以前段加熱區域為最佳、中段加熱區域次之、後段加熱區域為最差。此外在固定的振動振幅下，渠道頂部的熱傳效率並不會因為振動頻率增加而提高，故推斷渠道內部流場存在一自然頻率，因此必須利用頻率共振的原理才能有效地提升渠道頂部的熱傳效率。

The aim of this study is to investigate heat transfer rate of a cooling ㄇ-shaped channel when reciprocating motion experimentally. Three separate heat regions are selected at former、middle and later position and used to indicate variations of heat transfer phenomenon. A method of flow visualization is adopted to indicate the flow field in the cooling channel qualitatively. The parameters of Reynolds number、frequency are varied and the amplitude is fixed due to the experimental apparatus. The results show that at the frequency being equal to 0.05 the maximum heat transfer rate is obtained. Both the experimental and numerical results are consistent well under the conditions conducted in this study.