不可凝結氣體中銅板表面滴狀凝結分析

Dropwise Condensation Analysis on the Copper Surface in Non-condensable Gas

高善豪(Shan-Hao Kao)

指導教授 ： 許政行

中原大學/工學院/機械工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200803

摘要

物質在溫度變化及相變化的過程中都伴隨著熱量的傳遞，溫度上的變化為顯熱熱傳，相變化則為潛熱熱傳。因為物質在相變化的過程中維持相同的溫度，故須改以物質濃度變化量的部分作運算處理。相變化過程中，又以冷凝熱傳的潛熱值較高，使多數的研究都採用冷凝熱傳進行實驗分析。故本研究亦採用冷凝熱傳過程來評估不同改質表面之熱傳效能。
本文以露點溫度原理於銅板表面產生冷凝液滴，並調整環境中乾、溼球溫度來評估不同改質表面之差異。研究結果顯示，疏水性較高的表面，其熱交換的效率會比其他表面來的高，而同一表面在不同角度下，傾斜角度越小其熱通量越高(h30° > h60° > h90°)，其數值之分布間隔也隨角度減少越趨於明顯。

關鍵字

滴狀凝結 ； 露點溫度 ； 濕盤管冷凝表面

並列摘要

Heat transfer always occurs in the process of temperature change or phase change of substances. Sensible and latent heat transfer are characterized respectively according to temperature change and phase change. Concentration change is used to analyze and compute latent heat transfer of the phase change process (i.e. vapor to liquid), because the temperature is kept constant within the phase change. Most previous studies or experiments analyzed phase change problems, especially condensation process, due to higher value of latent heat transfer in condensation. Therefore, condensation heat transfer process is used in the present study to evaluate heat transfer performance on different property-modified surfaces.
According to dew-point temperature principle, condensation droplets are present on three copper surfaces (reference, hydrophobic and hydrophilic surfaces), and the environment’s dry and wet bulb temperature are adjusted in the experiments to evaluate the performance of different property-modified surfaces. The results showed that the heat exchange on the hydrophobic surface has the highest efficiency. For same surface, the heat flux is higher with smaller inclined angle (h30° > h60° > h90°), and the distribution for the values also becomes more apparent with smaller inclined angle.

並列關鍵字

Dropwise condensation ； Dew point temperature ； Wet tube condensation surface

參考文獻

【13】 王啟川，熱交換設計，2007，五南出版社。

【19】 國立台灣大學碩士論文，邱豐彬，”濕空氣中表面性質對冷凝熱傳之影響”，民國100年6月。

【2】 Courtney, W.G., “Recent advances in condensation and evaporation , ” ARS Journal,June,p.751,1961.

【3】 Qi Baojin, Zhang Li, Xu Hong, Sun Yan,“Experimental stuty on condensation heat transfer of steam on vertical titanium plates with different surface energies,” Experimental Thermal and Fluid Science, Vol.35,pp.211-218,2011.

【4】 Rose J.W. ,“Effect of condenser tube material on heat transfer during dropwise condensation of steam,” International Journal of Heat and Mass Transfer, Vol.21,pp.163-168,1978.