Experimental Studies on Internally Grooved Double Pipe Heat Exchanger Using Al2O3/TiO2 Nanofluids

This experimental study presents the heat transfer and pressure drop characteristics of internally grooved, double pipe heat exchanger using alumina (Al2O3) and titanium dioxide (TiO2) nanofluids. The inner pipe of the heat exchanger was modified with helical grooves on the inner surface, which will enhance the heat transfer due to increased turbulence in the flow. The Reynolds number was varied from 3,000 to 23,000 and the concentrations of nanofluid used were 0.1 to 0.2% by volume. The results of plain pipe were compared with the grooved pipe. Modified Wilson plot method was used to the determine heat transfer coefficients and subsequently, Nusselt number was determined. An increase in overall heat transfer coefficient was observed for plain pipe heat exchanger with increasing concentrations of nanofluid, but the increment rate was found to be much higher in helically grooved pipe heat exchanger with nanofluids. Pressure drop for grooved pipe with nanofluid increased by 36% compared to plain pipe with Deionized (DI) water.