本研究以實驗方法探討鰭柱散熱座於擺放角度為正向與45度角之圓形震盪衝擊噴流下的熱傳特性，鰭柱散熱座為直行排列之鋁合金圓形鰭柱陣列，四個矩形的鰭柱散熱座分別裝置於方形測試段的四個垂直側壁，另設有對稱之兩個圓形噴嘴於側向對準測試段，實驗結果指出，噴嘴與測試段為相對正向時的整體紐塞數(Nu)比噴嘴與測試段為傾斜45度角時為高，在目前測試的衝擊距離範圍下(L/d=1~11)，Nu平均高出約20%；其次，體積流率週期變化的震盪流其Nu都高於體積流率固定的穩態流，最大甚至可高出約100%；穩態衝擊流的Nu會先隨L/d上升、然後會衰退，但是此現象並未在震盪流時出現，震盪衝擊流的Nu均隨L/d增大而增加。本文對各項實驗觀察結果提出合理之解釋，可做為相關冷卻設計的重要參考基礎。

This work experimentally investigated the heat transfer characteristics of the pin-fin heat sinks with normal or 45-deg circular oscillating impinging jets. The pin-fin heat sink was made of aluminum-alloy circular-pin array with in-line arrangement. Four rectangular pin-fin heat sinks were installed at the four vertical walls of the square test section, respectively. In addition, two symmetrical circular nozzles laterally aligned with the test section. Experimental results indicate that the Nusselt number of the normal-jets system exceeded that of the 45 deg-jets system about by 20% at the present range of the relative impinging distance (L/d=1~11). Besides, the periodically volume rate-varying impinging jets promoted more heat transfer enhancement by maximum around 100% than the steady jets did. Finally, the Nusselt number of steady impinging jets firstly increased and then decreased with L/d. However, the Nusselt number of oscillating impinging jets increased with L/d at the present test range. This paper provided reasonable explanations for various experimental investigations. It can be the important base for the relevant cooling designs.