Study on the heat transfer characteristics of Al2O3-CuO/Water hybrid nanofluids in a shell and rotating wavy tube heat exchanger

Abstract

The present study focuses on heat transfer and characteristics of fluid flow behaviour of a rotating wavy tube HEX using water and Al2O3-CuO/Water (0.3%) hybrid nanofluid as coolants. The shell and wavy tube were modelled in CATIA with a tube diameter of 9.3mm and shell diameter of 140mm. The heat transfer area of the rotating tube heat exchanger is 0.0476m2. Water is utilized as the hot fluid inside the shell and Al2O3-CuO/Water (0.3%) Hybrid nanofluid was used in tube side. The rotating wavy tube heat exchanger was fabricated by VMC and CNC machining process and tube is maintained at the speed of 57.5 rpm. The experiment was carried out by varying tube side mass flow rate and shell mass flow rate was kept constant. Experimental study reveals that the heat transfer rate of the rotating tube was higher when compared to the fixed tube by 10.5% when pure water is used. Similarly when Al2O3-CuO/Water (0.3%) Hybrid nanofluid is made to flow in tube side; the heat transfer rate was considerably higher than pure water by 9.15%. This is due to wavy rotating tube helps to increase the turbulence inside tube and shell side resulting in better heat transfer and a comparable pressure drop. So, this heat exchanger is found to be an optimal design and can be used in various applications.