Size Effects on the Entropy Production in Oscillatory Flow between Parallel Plates

Federico Vazquez,Sac Medina,Miguel Angel Olivares-Robles

doi:10.3390/e13020542

Federico Vazquez, Sac Medina + Show 1 more

Open Access

https://doi.org/10.3390/e13020542

Copy DOI

Journal: Entropy	Publication Date: Feb 18, 2011
Citations: 21	License type: CC BY 3.0

Affiliation: Universidad Autónoma del Estado de Morelos

Abstract

The heat transfer problem of a zero-mean oscillatory flow of a Maxwell fluid between infinite parallel plates with boundary conditions of the third kind is considered. The local and global time-averaged entropy production are computed, and the consequences of convective cooling of the plates are also assessed. It is found that the global entropy production is a minimum for certain suitable combination of the physical parameters and a discrete set of values of the separation between the parallel plates. The transferred heat at the plates also shows minima in the same discrete set of values of the plates separation.

Highlights

The design of many traditional heat removal engineering devices relies on heat transfer enhancement
The effective thermal diffusivity of a Newtonian fluid in a duct subjected to a zero-mean oscillatory flow may reach a maximum for a specific oscillation frequency and lead to heat transfer enhancement [2,3]
In the case of a viscoelastic fluid flowing in a tube, the dynamic permeability may be enhanced at given resonant oscillation frequencies [4,5,6,7,8,9,10]

Summary

Introduction

The design of many traditional heat removal engineering devices (such as heat exchangers and cooling modules) relies on heat transfer enhancement. The effective thermal diffusivity of a Newtonian fluid in a duct subjected to a zero-mean oscillatory flow may reach a maximum for a specific oscillation frequency and lead to heat transfer enhancement [2,3]. Oscillatory flows at high frequencies under conditions where inertial effects are negligible have been studied in microfluidics applications [11] In all these situations, the analysis of the entropy generation [12,13] has revealed as a tool for characterizing the associated irreversible processes, contributing to the enlightenment of the underlying physical processes and optimizing the performance of a given device. In this paper we examine the size effects on the flow and heat transfer problem of a zero-mean oscillatory flow of a Maxwell fluid between infinite parallel plates with boundary conditions of the third kind. Our findings may shed some light on the factors affecting the physical behavior of oscillatory flows and, we hope, will provide additional useful information for designing thermal devices

Basic Assumptions

Fundamental Equations

Velocity Field

Temperature Field

Results and Discussion

Summary and Conclusions