微米级余弦槽表面疏水性及冷凝传热实验研究

发布时间：2018-05-14 12:28

本文选题：滴状冷凝 + 微槽　；参考：《西安交通大学学报》2016年05期

【摘要】：为了研究余弦微槽结构的疏水性和冷凝传热性能,首先制备了不同槽峰高度和槽距的微米级余弦槽结构表面,实验研究了不同结构微槽表面的静态接触角及其对滴状冷凝传热性能的影响,并对冷凝传热过程中液滴在微槽表面合并、脱落过程进行实验研究和热力学分析。结果表明,液滴在微槽表面的疏水性和传热性能都呈现明显的各向异性,横向静态接触角θ⊥明显高于纵向接触角θ∥。同时,冷凝传热过程中竖直纵槽阻碍液滴的横向合并,但其对液滴脱落过程起到极大促进作用,传热性能较光滑表面提高30%~50%,且峰距比越大液滴的脱落半径越小、脱落频率越高,表面传热效率也越高。水平横槽则相反,虽然增大峰距比促进了液滴合并,但却对其脱落过程产生不利影响,导致整体传热性能较纵向槽表面大幅下降,与光滑表面接近。引入表面润湿率对微槽表面的液滴脱落半径进行热力学计算,计算值与实验结果吻合较好,误差在20%以内。
[Abstract]:In order to study the hydrophobicity and condensing heat transfer performance of cosine microgrooves, the surface of micron cosine grooves with different peak height and slot spacing was prepared. The static contact angle of microgroove surface with different structure and its influence on the heat transfer performance of droplet condensation were studied experimentally. The experimental study and thermodynamic analysis of droplets merging and shedding on the surface of microgroove during condensation heat transfer were carried out. The results show that the hydrophobicity and heat transfer properties of the droplets on the surface of the microgrooves show obvious anisotropy, and the transverse static contact angle 胃 _ (1) is obviously higher than that of the longitudinal contact angle 胃 _ (1) /. At the same time, the vertical longitudinal slot obstructs the transverse merging of the droplets during condensation heat transfer, but it greatly promotes the drop off process, and the heat transfer performance is 30% higher than that on the smooth surface, and the larger the peak-to-distance ratio, the smaller the drop radius of the droplets, the higher the shedding frequency. The surface heat transfer efficiency is also higher. On the contrary, the increase of the peak-to-distance ratio promotes the droplet merging, but it has a negative effect on the shedding process, which leads to the decrease of the overall heat transfer performance compared with the longitudinal groove surface, which is close to the smooth surface. The surface wettability was introduced to calculate the drop radius of the microgroove surface. The calculated values were in good agreement with the experimental results, and the error was less than 20%.
【作者单位】：西安交通大学化学工程与技术学院;西安交通大学动力工程多相流国家重点实验室;
【基金】：国家自然科学基金资助项目(51306141) 教育部高等学校博士学科点专项科研基金资助项目(20120201120068)
【分类号】：TK124

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