EXPERIMENTAL AND NUMERICAL STUDY TO ENHANCE HEAT TRANSFER ON A HEAT EXCHANGER AL2O3/WATER NANOFLUID USING AN AIR FLOW WITH WATER DROPLETS

A experimental and numerical study has been carried out on the enhancement of the heat exchanged on a tube and fin heat exchanger cooled by an air flow containing water droplets by using nozzle system. A numerical model representing the heat transfer has been presented and validated using the experimental data. The cooling of air due to water evaporation upstream in a channel to the exchanger (condenser fed with hot water with different temperature) and the supplementary evaporation of droplets while impacting or crossing the exchanger leads to enhance heat exchange. As additional to enhance heat exchange, adding a nanoparticle (Al2O3) to the water of the heat exchanger and studying the effect of the nanofluid with two volume concentrations (0.5 & 2 %). All the tests were carried out with working fluid flow rate (4, 6 and 8 L/min) and with temperature (40, 45 and 50 oC).The results obtained maximum Nusselt number ratio Image was (1.235) which occurred at nanofluid concentration 2% with using sprayed air.