Next Article in Journal
Simulation Analysis and Experimental Study of the Cooker Hoods of High-Rise Residential Buildings
Previous Article in Journal
Longitudinal Seismic Response of Continuously Welded Track on Railway Arch Bridges
Previous Article in Special Issue
Three Flow Features behind the Flow Control Authority of DBD Plasma Actuator: Result of High-Fidelity Simulations and the Related Experiments
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle
Appl. Sci. 2018, 8(5), 776; https://doi.org/10.3390/app8050776

Heat Transfer and Friction Characteristics of Turbulent Flow through a Circular Tube with Ball Turbulators

1
Guangdong Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China
2
Department of Mechanical and Aerospace Engineering, University of California-Irvine, Irvine, CA 92697, USA
*
Author to whom correspondence should be addressed.
Received: 18 April 2018 / Revised: 9 May 2018 / Accepted: 12 May 2018 / Published: 13 May 2018
(This article belongs to the Special Issue Active Flow Control Technologies for Energy and Propulsive Systems)
View Full-Text   |   Download PDF [3141 KB, uploaded 13 May 2018]   |  

Abstract

One of the most commonly used methods of heat transfer enhancement is flow turbulization. This effect can be achieved, e.g., by placing special turbulizing elements into the channel. In this paper, the effects of ball turbulators (BTs) on the heat transfer and fluid friction characteristics in a circular tube are investigated through numerical simulation. The Reynolds number (Re) is in the range of 5000–35,000 under a condition of uniform heat-flux. BTs with different diameter ratios (e.g., 0.5, 0.75, and 1) and spacer lengths (40, 51.77, and 62.5 mm) are inserted in the circular tubes. The results show that the heat transfer rates in the tube equipped with BTs are around 1.26–2.01 times that of those in the plain tube. The BTs with a ball diameter ratio of one provide higher friction factors than 0.75 and 0.5 by about 34.6–46.2% and 51.1–63.4%, respectively. A smaller ball diameter ratio is more able to decrease the friction factor. The performance evaluation criterion (PEC) data indicate that the use of a smaller ball diameter ratio (BDR) and a smaller spacer length are preferred. The results also reveal that BTs with a larger diameter ratio and a smaller spacer length yield the highest heat transfer rate as well as the largest pressure loss. Compared with the plain tube, the fluid flow velocity near the tube wall is significantly improved when BTs are used at the same Reynolds number. View Full-Text
Keywords: ball turbulators; heat transfer; friction characteristics; numerical simulation; ball inserts ball turbulators; heat transfer; friction characteristics; numerical simulation; ball inserts
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Yuan, W.; Fang, G.; Zhang, X.; Tang, Y.; Wan, Z.; Zhang, S. Heat Transfer and Friction Characteristics of Turbulent Flow through a Circular Tube with Ball Turbulators. Appl. Sci. 2018, 8, 776.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Appl. Sci. EISSN 2076-3417 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top