Natural convection heat transfer and fluid flow around a thick hollow vertical cylinder suspended in air: A numerical approach

2020 ◽  
Vol 152 ◽  
pp. 106312 ◽  
Author(s):  
Manoj Kumar Dash ◽  
Sukanta Kumar Dash
Author(s):  
Tunc Icoz ◽  
Qinghua Wang ◽  
Yogesh Jaluria

Natural convection has important implications in many applications like cooling of electronic equipment due to its low cost and easy maintenance. In the present study, two-dimensional natural convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel has been studied numerically. The fluid flow and temperature profiles, above the heating elements placed between an adiabatic lower plate and an isothermal upper plate, are obtained using numerical simulation. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated. Different configurations of channel dimensions and separation distances of heat sources are considered and their effects on natural convection heat transfer characteristics are studied. The results show that the channel dimensions have a significant effect on fluid flow. However, their effects on heat transfer are found to be small. The separation distance is found to be an important parameter affecting the heat transfer rate. The numerical results of temperature profiles are compared with the experimental measurements performed using Filtered Rayleigh Scattering (FRS) technique in an earlier study, indicating good agreement. It is observed that adiabatic upper plate assumption leads to better temperature predictions than isothermal plate assumption.


PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0188656 ◽  
Author(s):  
Ilyas Khan ◽  
Nehad Ali Shah ◽  
Asifa Tassaddiq ◽  
Norzieha Mustapha ◽  
Seripah Awang Kechil

1986 ◽  
Vol 108 (2) ◽  
pp. 310-316 ◽  
Author(s):  
Y. S. Lin ◽  
R. G. Akins

The SIMPLER numerical method was used to calculate the pseudo-steady-state natural convection heat transfer to a fluid inside a closed vertical cylinder for which the boundary temperature was spatially uniform and the temperatures throughout the entire system were increasing at the same rate. (Pseudo-steady state is comparable to the steady-state problem for a fluid with uniform heat generation and constant wall temperature.) Stream functions, temperature contours, axial velocities, and temperature profiles are presented. The range of calculation was 0.25 < H/D < 2, Ra < 107, and Pr = 7. This range includes conduction to weak turbulence. A characteristic length defined as 6 × (volume)/(surface area) was used since it seemed to produce good regression results. The overall heat transfer for the convection-dominated range was found to be correlated by Nu = 0.519 Ra0.255, where the temperature difference for both the Nusselt and Rayleigh numbers was the center temperature minus the wall temperature. Correlations using other temperature differences are also presented for estimating the volumetric mean and minimum temperatures.


Sign in / Sign up

Export Citation Format

Share Document