Modelling Heat transfer Coefficient in Nanofluids in Gravity based Pipe Flow

Abstract

Heat transfer is one of the most important processes in many industrial. The inherently poor thermal performance of common fluids put a limitation and restricted in developing energy efficient heat transfer fluid. With a strong needed by industry in developing energy efficient, advance heat transfer fluid called nanofluid is introduced. Nanofluid is prepared by two step technique in this study by diluting Alumina CuO, and TiO2 Nanoparticle with water at concentration of .01% The heat transfer coefficient was investigated experimentally in a flow in three tubes of diameters 15.875mm,12.7mm and 9.52mm respectively with Reynolds no. in range of 1000-4500. Initial experiments were conducted with pure water for experiment validation and accuracy. The experimental results, represented in Nusselt number (Nu) are compared to classical Gnielinski equation and Dittus-Boelter equation and observed that both equations are applicable in turbulent flow range for single phase fluid but some deviation 0f 5-10% was observed. The model developed from use of 3 different nanofluids at 0.01%volume fraction is dependent on ratio of particle diameter to pipe diameter and on the ratio of particle density to fluid density. So the derived model is dependent on different parameters than found in most of literature. It gives error of 5-15% when compared with other models dependent on different parameters. To eradicate this error further research can be done on to find other parameters that influence the convection heat transfer coefficient