Investigating the combined effect of square microgrooves and CNT coating on condensation heat transfer
Investigating the combined effect of square microgrooves and CNT coating on condensation heat transfer
复制标题
DOI：
10.1016/j.apsusc.2018.10.245
复制
发表时间：
2019-03
影响因子：
6.7
通讯作者：
G. U. Kumar;D. V. Krishnan;S. Suresh;M. Thansekhar;R. V. Prasanna;M. Jubal
中科院分区：
文献类型：
--
作者：
G. U. Kumar;D. V. Krishnan;S. Suresh;M. Thansekhar;R. V. Prasanna;M. Jubal
研究了皮秒激光处理制备的方形凹槽和冷凝表面浸涂技术沉积的碳纳米管涂层的综合效果。除了是一种高度省时的工艺之外，激光纹理技术的利用还可以精确控制凹槽尺寸。所制造的表面的表面形态和润湿性特征被表征，并且结果被适当地放置。设计并制作了冷凝实验装置，其中进行实验以分析改性铜表面的性能。从普通铜表面获得的值作为比较各种改性表面性能的参考。评估了方形凹槽和碳纳米管涂层的综合效果，并与同类产品进行了比较。使用接触角计测量改性表面的润湿性，这对于冷凝传热非常重要。发现与普通铜表面相比，与改性表面相对应的结果具有改进的性能。在表面改性的情况下，与同类产品相比，具有方形凹槽和碳纳米管涂层组合的样品具有优异的传热性能。与裸铜表面相比，凹槽、CNT 涂覆表面和凹槽 CNT 涂覆表面的热通量值分别提高了约 63%、29% 和 96%。同样，凹槽、CNT 涂覆表面和凹槽 CNT 涂覆表面的传热系数值分别提高了 29%、31% 和 58%。碳纳米管涂层表面本质上是疏水性的，而微米级凹槽减小了离开直径并增加了扫掠循环率，这对传热率有积极的影响。与裸铜表面相比，带凹槽的 CNT 涂层表面的液滴离开直径减少了近一半，离开频率增加了近 3 倍。
The combined effect of square grooves fabricated using picosecond laser treatment and CNT coating deposited using dip coating technique on the condensation surface was studied. Apart from being a highly time efficient process, the utilisation of laser texturing technique allows for precise control of the groove dimensions. The fabricated surface was characterized for its surface morphologies and wettability characteristics and the results are placed appropriately. A condensation experimental setup was designed and fabricated, in which the experiments were carried out to analyse the performance of modified copper surfaces. The values obtained from the plain copper surface served as a reference to compare the performance of various modified surfaces. The combined effect of square grooves and the CNT coating were evaluated and compared with its counterparts. Wettability of the modified surfaces was measured using contact angle meter which is very crucial for condensation heat transfer. Results corresponding to the modified surfaces were found to have improved performance as compared to the plain copper surface. In case of modified surfaces, the sample with the combination of square grooves and CNT coating was found to excel in heat transfer performance when compared to its counterparts. An enhancement of approximately 63%, 29% and 96% were obtained for grooved, CNT coated surface and grooved CNT coated surface respectively in the heat flux values, when compared against bare copper surface. Similarly, heat transfer coefficient values registered an improvement of 29%, 31% and 58% respectively for grooved, CNT coated surface and grooved CNT coated surface. The CNT coated surface was hydrophobic in nature, while the micron scale grooves reduced the departure diameter and increased the sweeping cycle rate, which has a positive effect on the heat transfer rate. Droplet departure diameter reduced by nearly half and departure frequency increased by nearly 3 times for grooved CNT coated surface, against the bare copper surface.