Paramertic Study of Effect on Heat Transfer Using Various Nanofluids in Tube in Tube Heat Exchanger

Abstract

There are many methods of enhancement of heat transfer coefficient including active and passive methods. Nanofluid is the passive method to increase the heat transfer. The present work deals with experimental investigation to enhance the heat transfer coefficient using nanofluid. Experiments are performed varying Reynolds number of hot water and flow rates of the base fluid. To know the effect of change of Prandtl number on heat transfer coefficient experiments are performed using three different base fluid by Distilled water. Experiments have been carried out experiments with Al2O3, CuO and SiO2 nanofluid. The average size of Al2O3, CuO and SiO2 nanoparticles used in this work was 40 nm with a rage of 30-100 nm . Experiment was carried out with 0.05%, 0.1%, 0.25%, 0.5%, 1% w/w concentrations of Al2O3, CuO and SiO2 nanoparticles in distilled water, for five Reynolds number in turbulant region. To avoid agglomeration of Nano particles in nanofluid a special treatment is required. For this SDBS(sodium dodecyl benzonyl sulphate) is selected for Al2O3, CuO and SiO2 type of nanofluid. Based on the present experimental investigation it is found that heat transfer coefficient increases with increase in Reynolds number for any type of fluid. The stability of nanouids was checked using Malvern Zetasizer and it was found that it was stable for 6 to 7 hours after synthesis. The experimental results shows that there were increament in the overall heat transfer coefficient. It was found that the nanofluids CuO, Al2O3 and SiO2have maximum of 40%, 30% and 23% higher heat transfer coefficient compared to base fluid at mass fraction of 1% concentration, respectively. The measurements also showed that the pressure drop of nanofluids was higher than that of the base fluid. The use of nanofluids CuO, Al2O3 and SiO2 increased the friction factor by 21%, 26% and 31% in comparison with pure water, respectively .As a result, the CuO nanofluid performed the best amongst the three metal oxide nanofluids at a given particle size, concentration, and temperature. According to the results, this nanofluids can be a good alternative in similar applications such as heat exchangers.