Heat transfer assessment of turbulent nanofluid flow in a circular pipe fitted with elliptical-cut twisted tape inserts
- PDF / 1,899,490 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 58 Downloads / 200 Views
Heat transfer assessment of turbulent nanofluid flow in a circular pipe fitted with elliptical‑cut twisted tape inserts Keyvan Ahmadi1 · Saber Khanmohammadi1 · Shoaib Khanmohammadi2 · Mehdi Bahiraei2 · Quang‑Vu Bach3 Received: 13 April 2020 / Accepted: 3 October 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In the present work, a numerical study is conducted to improve the thermal performance of a circular pipe fitted with the elliptical-cut twisted tape (ECT) inserts in presence of a nanofluid as the working fluid. A comparison between the pipe with and without ECTs in different cases is implemented. This investigation is accomplished for a 3D periodically turbulent flow with constant heat flux on the walls. The effect of inserting the ECTs with different parameters, namely the ratio of short diameter to twisted tape width (WA = a/W = 0.7, 0.8, 0.9) as well as the ratio of long diameter to short diameter of the twisted tape (BA = b/a = 2, 2.5, 3) is examined. In the case of WA = 0.7 and BA = 2 for Reynolds number of 7000, the Nusselt number and thermal efficiency factor (TEF) are maximum with the values about 117.25 and 1.392, which show 6.18% and 6.6% improvement compared to the case with the square-cut twisted tape. Moreover, the Cupric Oxide nanoparticlesenhanced fluid with the nanoparticle concentration ranging from 1 to 4% is used to study the effects of the nanofluid on the heat transfer performance of the different configurations. Based on the results, the highest Nusselt number and TEF occur at the concentration of 4%, which are equal to 177.81 and 1.7637, respectively. Moreover, the TEF for the case with the elliptical-cut twisted tape and nanofluid is 21% higher than the same geometry with water as the working fluid, and 26% higher than the square-cut twisted tape in the presence of water. Keywords Turbulent flow · Heat exchanger · Nanofluid · Elliptical-cut twisted tape · Cupric oxide nanoparticles · Thermal efficiency
Introduction Regarding the increasing use of heat exchangers in industries, enhancing the heat transfer coefficient of these components is important nowadays. Generally, improving the heat transfer can be implemented through active and passive methods. The Amplifying of heat transfer in the passive Corresponding author at: Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam * Quang‑Vu Bach [email protected] 1
Department of Mechanical Engineering, University of Kashan, Kashan, Iran
2
Department of Mechanical Engineering, Kermanshah University of Technology, Kermanshah, Iran
3
Sustainable Management of Natural Resources and Environment Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam
mode can be included in changing configuration, geometry or adding some additive materials. In addition, utilizing some external forces like electrical and magnetic forces is a kind of active mode enhancement. Using the twisted tape in tubes for enhancing the thermal efficie
Data Loading...
