實驗探討ㄇ型振動管之熱傳現象

Abstract

本文主要目的在以實驗方法探討冷卻流體在一振動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的可信度。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，實際觀測流場變化情形並與數值模擬之流線圖相互驗證，兩者結果一致。實驗針對不同的進口流體雷諾數和渠道無因次往復振動頻率來討論，由結果得知熱傳效率會因為渠道振動而提高，熱傳增益受到進口流體雷諾數增加影響較大，相較之下渠道低無因次振動頻率增加效果較不明顯。本實驗所得到最大熱傳增益在20%以內。

In order to investigate the heat transfer phenomena in a ㄇ-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 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 results show that the heat transfer rate is mainly dominated by Reynolds number, and less affected by increasing the low oscillating frequency. The enhancement of the heat transfer is confirmed and within 20% in this study.