Experimental investigation of heat transfer and pressure drop of SiO2/water nanofluid through conduits with altered cross-sectional shapes

The present study investigates experimentally the convective heat transfer and the friction factor of SiO2/water nanofluids through conduits with different cross-section shapes at constant heat flux. The effects of different parameters, such as cross-sectional shape, Reynolds number ranged from 10,000 to 35,000, and the concentration of nanoparticles on the heat transfer enhancement are studied experimentally. The experiments were carried out for different designs of conduits i.e., circular, rectangular, square, and triangular cross-section. The results show that the Nusselt number and friction factor are increased for particle concentration up to 3.0%. For circular conduit, at Reynolds number of 35,000 and 3.0% concentration of SiO2/water nanofluid, the Nusselt number and friction factor are greater than that of the based water by 18.7% and 19.6%, respectively. In addition, the results indicate that the Nusselt number through the conduit with a circular cross-section has better performance compared to other cross-section shapes. Furthermore, the conduit with triangular cross section has a highest value of the thermal enhancement factor than conduits with other shapes. In addition, the results reveal that for nanofluid of 3% concentration and at Reynolds number of 35,000, the thermal enhancement factor for triangular, square, circular and rectangular pipes is improved compared with the based water by 12.5%, 12.3%, 12.07%, and 11.9%, respectively.