Heat Transfer Enhancement Using Augmented Tubes for Desalination Using Fuzzy-TOPSIS Approach

This paper deals with the falling film heat transfer across horizontal copper tubes at different tube surface geometries, mass flow rates, heat fluxes, and weight percentage of salt in water salt solutions at the atmospheric pressure. The falling film heat transfer coefficient is significantly affected by the heat flux, film Reynolds number, and water salt solutions for the three types of augmented tubes viz. spiral, splined, and smooth. This paper considers the influence of the operating parameters on the heat transfer coefficient using the Fuzzy-TOPSIS applications. The experimental results obtained reveal that the falling film heat transfer is greatly enhanced in case of the spiral tube when compared with the splined and smooth tubes. The spiral tube shows a significant heat transfer performance than the other two tubes for a given heat flux, and Reynolds number as the heat flux increases the surface temperature, and also increases and increment in the surface temperature of the smooth tube is greater than the spiral and spline tubes for a given heat flux and Reynolds number. As the mass flow rate increases, the surface temperature of all the three tubes decreases but for a given heat flux and Reynolds number, the smooth tube has a more surface temperature than the other two tubes.