The structure of thermal field underneath an evaporative water surface

• Published in: International journal of thermal sciences 2011-06, Vol.50 (6), p.930-934
• Main Authors: Bukhari, Syed J.K., Siddiqui, Kamran
• Format: Article
• Language: English
• Subjects: Air–water interface; Convection; Convective and constrained heat transfer; Evaporation; Evaporative; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Heat flux; Heat transfer; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; LIF; Natural convection; Physics; Stratification; Temperature distribution; Temperature field; Temperature profiles; Thermal instruments, apparatus and techniques; Thermometry; Trends; Walls
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2011.01.001

The temperature field beneath an evaporating water surface during natural convection has been investigated using Laser Induced Fluorescence (LIF) technique. Experiments were conducted at two different surface heat flux conditions under thermally unstable stratification. The mean temperature profiles show three distinct regions beneath the water surface where the depth dependency of temperature is different. In the conduction layer, the temperature varied linearly with depth. In the intermediate region, the temperature varied as z −1 whereas, in the bulk region, the temperature varied as z −1/3. These depth dependencies are consistent with the theoretical predictions. The results also show that the relationship between the scales of conduction and convection layers for velocity and temperature defined for wall bounded natural convection are also valid for free surface natural convection however, the length scales ratio showed the opposite trend.