Next Article in Journal
The Thermodynamical Arrow and the Historical Arrow; Are They Equivalent?
Next Article in Special Issue
Second-Law Analysis of Irreversible Losses in Gas Turbines
Previous Article in Journal
Robust Automatic Modulation Classification Technique for Fading Channels via Deep Neural Network
Previous Article in Special Issue
Entropy Analysis of the Interaction between the Corner Separation and Wakes in a Compressor Cascade
Article Menu
Issue 9 (September) cover image

Export Article

Open AccessArticle
Entropy 2017, 19(9), 443; https://doi.org/10.3390/e19090443

A Numerical Study on Entropy Generation in Two-Dimensional Rayleigh-Bénard Convection at Different Prandtl Number

1,†,* , 2,†,* and 2
1
Faculty of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China
2
Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China
These authors contributed equally to this work.
*
Authors to whom correspondence should be addressed.
Received: 2 July 2017 / Revised: 16 August 2017 / Accepted: 21 August 2017 / Published: 30 August 2017
(This article belongs to the Special Issue Entropy in Computational Fluid Dynamics)
View Full-Text   |   Download PDF [5583 KB, uploaded 26 September 2017]   |  

Abstract

Entropy generation in two-dimensional Rayleigh-Bénard convection at different Prandtl number (Pr) are investigated in the present paper by using the lattice Boltzmann Method. The major concern of the present paper is to explore the effects of Pr on the detailed information of local distributions of entropy generation in virtue of frictional and heat transfer irreversibility and the overall entropy generation in the whole flow field. The results of this work indicate that the significant viscous entropy generation rates (Su) gradually expand to bulk contributions of cavity with the increase of Pr, thermal entropy generation rates (Sθ) and total entropy generation rates (S) mainly concentrate in the steepest temperature gradient, the entropy generation in the flow is dominated by heat transfer irreversibility and for the same Rayleigh number, the amplitudes of Su, Sθ and S decrease with increasing Pr. It is found that that the amplitudes of the horizontally averaged viscous entropy generation rates, thermal entropy generation rates and total entropy generation rates decrease with increasing Pr. The probability density functions of Su, Sθ and S also indicate that a much thinner tail while the tails for large entropy generation values seem to fit the log-normal curve well with increasing Pr. The distribution and the departure from log-normality become robust with decreasing Pr. View Full-Text
Keywords: entropy; Prandtl number; Rayleigh number; thermal; lattice Boltzmann method entropy; Prandtl number; Rayleigh number; thermal; lattice Boltzmann method
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).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Wei, Y.; Wang, Z.; Qian, Y. A Numerical Study on Entropy Generation in Two-Dimensional Rayleigh-Bénard Convection at Different Prandtl Number. Entropy 2017, 19, 443.

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]
Entropy EISSN 1099-4300 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top