Natural Convection Heat Transfer Around a Horizontal Circular Cylinder for the Case of Constant Surface Temperature of the Cylinder Near a Vertical Wall

Marcel Novomestský ,Andrej Kapjor,Helena Smatanová,Roman Bánovčan

doi:10.1051/matecconf/201816802002

Abstract

Natural convection heat transfer from a single horizontal cylinder near an isothermal wall is experimentally investigated in the environmental chamber. The cylinder is heated with constant temperature, the rising plum from the heated cylinder interacts with the side wall and significantly affects the surface heat transfer distribution. Thus, the distance between horizontal cylinder and side wall can influence the heat transfer. The heat transfer from heated cylinder with different distances were compared. Results are obtained for Ra = 104. It was found that natural convection heat transfer from horizontal cylinder depends on the distance between wall. Also, a heat transfer correlation has been proposed for a single horizontal cylinder near a wall and is compared with earlier work. The results indicate that the vertical wall affect the average Nusselt number at the cylinder. Therefore, the vertical wall has a positive effect on the Nusselt number at the cylinder.

Highlights

The natural convection flow in horizontal annuli has received increased attention in last decade because of their importance in engineering
The range of surface temperature was varied from 40 °C to 90 °C
Comparing Eq with the Eq for this study shown in the Figures 6-7, is proven that the distance between the wall and the cylinder has an effect on the heat transfer results

Summary

Introduction

The natural convection flow in horizontal annuli has received increased attention in last decade because of their importance in engineering. Horizontal cylinder has many engineering applications such as heat exchangers, radiators, thermal storage systems, and cooling of electronic components. Morgan [1], Churchill and Chu [2] have determined empirical correlation equations which focus mainly on Nusselt number. Kuehn and Goldstein [3] investigated natural convection around an isothermal circular cylinder for Rayleigh numbers of < 107 and have solved the full Navier –Stokes and energy equations. Kuehn and Goldstien have shown that the heat transfer is at its maximum at the bottom of the cylinder and decreases toward the top of the cylinder. The decrease in heat transfer is attributed to an increase of the thermal boundary layer thickness

Methods

Results

Conclusion