Study on the heat and mass transfer performance of a tubular still enhanced by hydrophilic surface modification

Tubular still is one of the most promising desalination devices. This paper presents hydrophilic modification of the outer surface of the seawater trough in a tubular still, so that the hydrophilically modified outer surface can serve as an evaporation surface when it is wetted with the overflowing seawater from the trough. To experimentally verify and examine the effect of hydrophilic surface modification, a small tubular still was constructed with a seawater trough of 63 mm in diameter and 1.9 m in length. The experimental results show that at the operating temperature of 80 degrees C, the hydrophilically modified surface can increase the yield rate by 24.9%. Under the condition with a constant input power of 100 W, the hydrophilically modified surface can increase the gained output ratio (GOR) of the tubular still by 44.4%. In addition, a heat and mass transfer model of tubular still is also presented for a theoretical performance prediction of the effect of hydrophilic surface modification. A comparison exhibits the maximum deviation of 18.7% between the theoretical and experimental results.