本文旨在以實驗方式，探討改變進口溫度對一水平圓管內氧化鋁/水奈米流體其紊流強制對流熱傳遞效益與壓降特性之影響。強制對流實驗所採用圓管尺寸為內徑3.4 mm，厚度0.3 mm與長度1300 mm，其中加熱段長度為400 mm，係以電阻加熱方式建構等熱通量管壁條件，而所探討相關參數及其範圍為：進口溫度 Tin = 25℃、37℃及50℃；雷諾數Renf = 3000-12000；及氧化鋁/水奈米流體之氧化鋁微粒質量分率ω_np = 0、2 、5和10 wt.% 。實驗結果顯示質量分率2 wt.%之奈米流體呈現最佳熱傳遞效益;當進口溫度從25 ℃提高至50 ℃，其紊流強制對流平均熱傳係數相較於純水之增益可從20%上升至30%，壓降亦同時呈現下降趨勢。

This study aims to explore experimentally the influence of inlet temperature on the turbulent forced convective heat transfer effectivenessof using alumina-water nanofluid over the pure water in an iso-fluxe heated horizontal circular tube. A copper circular pipe of inner diameter 3.4 mm was used in the forced convection experiments undertaken for the pertinent parameters in the following ranges: the inlet temperature, Tin = 25 ℃, 37 ℃ and 50℃; the Reynolds number, Renf = 3000 – 12000; the mass fraction of the alumina naoprticles in the nanofluid formulated, ωnp = 0, 2, 5 and 10 wt.%. The experimental results clearly showed that the turbulent convective heat transfer effectiveness of the alumina-water nanofluid over that of the pure water can be further uplifted by increasing the inlet temperature to the circular tube; specifically, an increase in the averaged heat transfer enhancement up to 30% arises for the nanofluid of ωnp = 2 wt.% with a significantly lower pressure drop as the inlet temprature is increased from 25C to 50C.

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