Showing papers by "Annamalai Mani published in 2013"

Heat and mass transfer studies on a compact bubble absorber in R134a-DMF solution based vapour absorption refrigeration system

Abstract: Experimental investigations have been carried out to study heat and mass transfer characteristics of Tetrafluoro ethane (R134a) in Dimethyl formamide (DMF) solution in a compact bubble absorber of vapour absorption refrigeration system of 1 TR capacity. Plate heat exchangers have been used as system components. Bubble absorption principle is employed in the absorber and hot water supplies heat to the generator. Effect of operating parameters such as circulation ratio, absorber and generator temperatures on heat and mass transfer effectiveness, overall heat transfer coefficient and volumetric mass transfer coefficient are investigated. It is found that heat and mass transfer effectiveness of absorber are better at lower circulation ratios and higher generator temperatures. Experimental results are compared with those obtained from numerical model developed earlier by the authors and the agreement is generally fair. From the experimental data, a correlation has been obtained for volumetric mass transfer coefficient, using multi-linear regression analysis.

Effect of flame spray coating on falling film evaporation for multi effect distillation system

Abstract: Horizontal tube falling film evaporators find various applications like multi effect distillation for sea water desalination, power and process applications, refrigeration applications, etc. In this system, latent heat released inside the tube due to condensation is transferred to the falling film on the tube surface resulting in convective evaporation. Among many heat transfer enhancement techniques, thermal spray coatings enjoy diverse applications with economic advantage for commercial applications. This paper focuses on Computational Fluid Dynamic(CFD) analysis of falling film evaporation of water on horizontal tubes under the influence of gravity at vacuum. ANSYS Fluent with VOF two-phase model is used for the falling film studies on the horizontal tube. Half section of the tube is modeled with gravitational flow of sea water from the top. This model is used to predict the enhancement in convective evaporation on thermal spray coated tube surface with varying roughness. These CFD results are...