Augmented thermal performance in a non-uniform heat flux circular tube with twisted tape insert using hybrid nanofluid

¹ Department of Applied Mechanics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, UP, India.
² Department of Mechanical Engineering, National Institute of Technology Agartala, Agartala, India.
³ Department of Mechanical Engineering, Birla Institute of Technology and Science Pilani, Pilani Campus, Vidya Vihar, Rajasthan-, 333031, India.
⁴ Center of Flow Simulation (CFS), Department of Mechanical and Process Engineering, Duesseldorf University of Applied Sciences, D-40476 Duesseldorf, Germany.
⁵ Department of Mechanical Engineering, Mechatronics and Industrial Design, Tshwane University of Technology, Private Bag X860, Pretoria, 0001, South Africa.

Abstract

The influence of non-uniform heat transfer on a circular tube with a twisted tape insert using nanofluid (NF) is examined. The circular tube had an inner diameter 20 mm, with 0.5 mm thickness and 2 m of length. Wall heat flux conditions were examined for Reynolds number ranging from 5 000 to 25 000. Heat flux distribution included partial heating at different circumferential positions. Water was used as a base fluid, while single and multi-nano particles are used for simple and hybrid nanofluids (HNF). The goal of this study is to augment the thermal performance by incorporating non-uniform heating, using a twisted tape insert and by using nanoparticle of different volume fraction. NF act as a fluid additive and twisted tape act as a turbulence promoter and they enhance the heat transfer rate. However, major disadvantage in this investigation is the pressure drop incurred due to the twisted tape and NFs. Hence, a series of simulation are carried out to find out the optimum configuration of the set-up for which heat transfer will be enhanced with minimum pressure drop.