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ARTICLE

Experimental Study on Flow and Heat Transfer Characteristics of Nanofluids in a Triangular Tube at Different Rotation Angles

by Cong Qi, Chengchao Wang, Jinghua Tang, Dongtai Han

1 Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology and Equipments, China University of Mining and Technology, Xuzhou, 221116, China
2 School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou, 221116, China

* Corresponding Author: Cong Qi. Email:

Energy Engineering 2020, 117(2), 63-78. https://doi.org/10.32604/EE.2020.010433

Received 04 March 2020; Accepted 14 April 2020; Issue published 23 April 2020

Abstract

Because of the poor thermal performance of ordinary tubes, a triangular tube was used to replace the smooth channel in the heat transfer system, and nanofluids were used to take the place of ordinary fluids as the heat transfer medium. High stability nanofluids were prepared, and an experimental set on flow and heat exchange was established. Effects of triangular tube rotation angles (α = 0°, 30°, 60°) as well as mass fractions of nanofluids (ω = 0.1%, 0.3%, 0.5%) on heat exchange and flow performance were experimentally considered at Reynolds numbers (Re = 800–8000). It was shown that the triangular tube with a rotation angle α = 0° possesses the most excellent thermal property, followed by a rotation angle α = 60° triangular tube, and a rotation angle α = 30° triangular tube has the worst heat exchange property. Results also revealed that resistance coefficients of the triangular tube with rotation angles α = 0° and α = 30° are close to each other, and a rotation angle α = 60° triangular tube shows the minimal resistance coefficient. It could be also seen that higher nanoparticle mass fraction can augment the thermal performance. However, higher nanoparticle mass fraction can also lead to an increment in resistance coefficient. A comprehensive performance evaluation index was introduced to appraise the augment in Nusselt number and flow resistance coefficient. The experiment revealed that the highest index emerges with nanofluids (ω = 0.5%) in the triangular tube with a rotation angle α = 0°.

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