Comparative study on thermal performance of helical screw tape inserts in laminar flow using Al2O3/water and CuO/water nanofluids

This paper presents a comparison of thermal performance of helical screw tape inserts in laminar flow of Al2O3/water and CuO/water nanofluids through a straight circular duct with constant heat flux boundary condition. The helical screw tape inserts with twist ratios Y = 1.78, 2.44 and 3 were used in the experimental study using 0.1% volume concentration Al2O3/water and CuO/water nanofluids. Nanofluids with required volume concentration of 0.1% were prepared by dispersing specified amounts of Al2O3 and CuO nanoparticles in deionised water. The performance analysis of helical screw tape inserts in laminar flow of Al2O3/water and CuO/water nanofluids is done by evaluating thermal performance factor for constant pumping power condition. Thermal performance factor of helical screw tape inserts using CuO/water nanofluid is found to be higher when compared with the corresponding value using Al2O3/water. Therefore, the helical screw tape inserts show better thermal performance when used with CuO/water nanofluid than with Al2O3/water nanofluid.

► Helical screw tape inserts and alumina/water, copper oxide/water nanofluids have been used for heat transfer enhancement in circular tubes.
► Thermal performance analysis has been carried out for this compound technique of heat transfer enhancement for the two nanofluids and are compared.
► There is a very significant convective heat transfer enhancement with use of both helical screw tape inserts and nanofluids.
► Thermal performance factor of helical screw tape inserts using CuO/water nanofluid is higher than the value obtained using Al2O3/water.