ㄇ型槽往復運動之熱傳分析

Abstract

本研究主要目的在以實驗方法去探討混合對流在一振動ㄇ型渠道內對壁面熱傳效率之影響情形，並搭配數值模擬來提高實驗之可信度。實驗設備大致上可以分為三部份︰冷卻渠道、往復運動機構、溫度控制系統，工作流體為空氣。另外使用放煙線法進行流場可視化的拍攝，以實際流場變化情形與數值模擬之流線圖互相驗證，兩者結果非常吻合。 實驗主要針對不同的渠道振幅來進行討論，由結果得知熱傳效率會因為渠道振幅減小而降低。原因在於縮小振幅後導致對加熱區的擾動程度降低，流體所能帶走的熱也變少。至於熱傳增益則是動態優於靜態，所得到最大熱傳增益約在48.6%左右。

In order to investigate the heat transfer phenomena in a U-shaped channel with reciprocating motion, an experimental work is conducted and validated by an auxiliary computational procedure simultaneously. The experimental apparatus consist of three parts, a cooling channel, reciprocating mechanism and heating control. The working fluid is air and the parameters of Reynolds number , temperature and oscillating frequency are varied. In addition, a flow visualization using the Smoke-wire method is adopted to indicate the flow field and compared with the streamline of the numerical results. The comparisons between experimental and numerical results are consistent well. The main experiment for different channel amplitude to discuss the results that heat transfer efficiency, channel amplitude decreased resulting in heat transfer efficiency lower. The reason is that after reducing the amplitude of the fluid disturbance to the reduction in heating zone, the fluid can take away the heat has become less. The dynamic heat transfer gain is better than the static, and the heat transfer gain of about 48.6%