暫態液晶技術量測陣列噴流衝擊於溝槽之熱傳研究

Abstract

本論文主要是以實驗的方式來分析衝擊冷卻技術，運用暫態液晶量測方法，應用在測試目標表面為平滑及具有溝槽(Groove)情形下之熱傳效應，得知衝擊目標面各局部區域的熱傳分布。實驗中主要的參數：雷諾數設定為2500、5100及7700等三種。本實驗主要測試(1)衝擊目標面溝槽的排列方式為橫向(transverse)及縱向(longitudinal)此兩種，(2)對正(in-line)及交錯(staggered)排列的溝槽形式，藉此了解衝擊冷卻應用於不同排列方式之溝槽的熱傳效應。實驗結果發現在單一出口方向下且流體流出方向與流體流入方向相同時，局部熱傳分佈情形會受到溝槽之排列形式影響而不同，而橫向交錯及縱向交錯在後半段靠近出口之熱傳有提升的效果，但整體平均熱傳係數在平滑及各種溝槽情形下並無明顯差異。

Detailed heat transfer distributions over a jet impingement target surface with grooves were presented. Transient liquid crystal method was used to measure the detailed heat transfer coefficients with the average jet Reynolds numbers of 2500, 5100 and 7700.Grooves were machined on the target surfaces with either parallel or orthogonal to the exit flow direction. These grooves were either aligned with the jet holes (inline) or between the jet holes (staggered). Results showed local heat transfer coefficient increases with an increase of average jet Reynolds number over the entire impingement target surface. Local heat transfer distributions were affected by the groove configuration and staggered grooves can enhance local heat transfer coefficient near the exit. Four different grooved types in this study didn’t have significant effect on the overall heat transfer coefficient on the target plate.