Effect of perforated concave delta winglet vortex generators on heat transfer augmentation of fluid flow inside a rectangular channel: An experimental study

Syaiful Syaiful,Nazaruddin Sinaga,Msk Tony Su,Myung-Whan Bae,Retno Wulandari,P Puspitasari,T Lenggo Ginta,A Ayu Permanasari,A.H Suryanto,A Dwi Astuti,Y Rohmat Aji Pradana,I Srikun,A Larasati,M Sharifi Jebeli,M Niaz Akhtar,D Zakariya Lubis

doi:10.1051/matecconf/201820404015

Syaiful Syaiful, Nazaruddin Sinaga + Show 14 more

Open Access

https://doi.org/10.1051/matecconf/201820404015

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Abstract

Compact heat exchanger with gas as a heat exchange medium is widely used in power plants, automotive, air conditioning, and others. However, the gas has a low thermal conductivity resulting in high thermal resistance causing a low rate of heat transfer. Therefore an improvement to the convection heat transfer coefficient is necessary. One way to enhance the convection heat transfer coefficient is to use a longitudinal vortex generator. However, the increase in convection heat transfer coefficient is followed by an increase in pressure drop. Therefore, this work aims to improve the convection heat transfer coefficient with a low pressure drop. To achieve this goal, experiments were carried out by perforating a longitudinal vortex generator with a diameter of 5 mm with variations in holes number one, two and three. Two types of longitudinal vortex generators are compared. The experimental results show that the convection heat transfer coefficient for the case of perforated concave delta winglet vortex generator is only decreased by 1% from that without a hole, while the pressure drop is decreased by 11.6%.

Highlights

The work on the use of vortex generators to increase the heat transfer of heat exchanger has been performed since the 90s as proposed by Martin Fiebig in the review paper [1]
From several previous literature studies, it can be concluded that the use of VG can increase the rate of heat transfer, but the use of VG impact on the increase of pressure drop
In the present study is focused on the effect of holes on VGs in lowering pressure drop and its impact on heat transfer rates

Summary

Introduction

The work on the use of vortex generators to increase the heat transfer of heat exchanger has been performed since the 90s as proposed by Martin Fiebig in the review paper [1]. M. Khoshvaght et al investigated in detail experimentally the effect of distance among delta winglet vortex generators [3]. Khoshvaght et al investigated in detail experimentally the effect of distance among delta winglet vortex generators [3] They used delta winglets to generate longitudinal vortices in the flow. Samer Ali et al used trapezoidal VG to improve heat transfer and fluid mixing [4] They found that the installation of both flexible and rigid trapezoidal VGs was able to improve the heat transfer by up to 118% against a non-VG pipe. Khoshvaght et al had previously studied the winglet VGs to enhance heat transfer in tubular heat exchangers [5]

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