Enhancement the performance of swirl heat exchanger by using vortices and NanoAluminume

Walaa M Hashim,Hisham A Hoshi,Huda A Al-Salihi

doi:10.1016/j.heliyon.2019.e02268

Walaa M Hashim, Hisham A Hoshi + Show 1 more

Open Access

https://doi.org/10.1016/j.heliyon.2019.e02268

Copy DOI

Journal: Heliyon	Publication Date: Aug 1, 2019
Citations: 4	License type: cc-by

Affiliation: University of Technology- Iraq

Abstract

Heat exchangers are widely used in many industrial applications. It is well known that the effectiveness of these exchangers is normally measured by the amount of the heat transfer, which should be minimized as much as possible according to their size. Present study pays more attention to examine Taylor vortex which formed in the flow of the hot water of the smooth surface heat exchanger and a swirl flow of cold air. Also, an attempt was made to improve the result by replacing the heat transfer surface by Nanoaluminume metal. Experimental results revealed that the effectiveness of the exchanger at the ratio (Cmin/Cmax = 0.08) could be enhanced the effectiveness of the standard exchanger at the ratio (Cmin/Cmax = 0). Further, it was found that using nano Aluminume as a medium material for heat transfer increased the effectiveness (3.2%, 4.3% and 4.58%) for a rotational speed of inner cylinder which were used (0, 65and 80) rpm, respectively.

Highlights

It is generally accepted that one ways to increase the amount of the heat transfer through heat exchangers is generating vortices
In the present study it was utilized Taylor vortex flow of water in a hot water and the air swirl flow of cold fluid inside counter heat exchanger designed for this purpose
Aluminum & nanoparticles) in which represent a wall of heat transfer between Taylor vortex swirl flow measured at variable flow rates, various rotational speed of the internal cylinder and variable length of the slots in which swirl generating

Summary

Introduction

It is generally accepted that one ways to increase the amount of the heat transfer through heat exchangers is generating vortices. Vortices tend to increase the surface area of the heat transfer. These vortices decrease the effects of the boundary layer. That could lead to a sharp increase in the amount of heat transfer through the exchange [1, 2]. The finite swirl flow is another way to increase the time required for a fluid to heat transfer exchanging [3, 4, 5, 6] as well as using high conductivity heat transfer medium. The experimental results identified the two major mechanisms of heat transfer enhancement. first in high axial velocity near the wall to increase the wall heat flux and at high turbulence level improved the mixing in which lead to increased heat transfer

Methods

Results

Conclusion