Three-dimensional natural convection around an inner circular cylinder located in a cubic enclosure with sinusoidal thermal boundary condition

2016 ◽  
Vol 101 ◽  
pp. 807-823 ◽  
Author(s):  
Seong Han Lee ◽  
Young Min Seo ◽  
Hyun Sik Yoon ◽  
Man Yeong Ha
Keyword(s):  
Boundary Condition ◽  
Natural Convection ◽  
Circular Cylinder ◽  
Three Dimensional ◽  
Thermal Boundary Condition

Effect of circular cylinder location on three-dimensional natural convection in a cubical enclosure

2015 ◽  
Vol 29 (3) ◽  
pp. 1307-1318 ◽  
Author(s):  
Changyoung Choi ◽  
Hyun Woo Cho ◽  
Man Yeong Ha ◽  
Hyun Sik Yoon
Keyword(s):  
Natural Convection ◽  
Circular Cylinder ◽  
Three Dimensional ◽  
Cubical Enclosure

Three Dimensional Numerical Analysis of Laminar Slip-Flow Heat Transfer in Rectangular Microchannels

2008 ◽  
Author(s):  
H. D. Madhawa Hettiarachchi ◽  
Mihajlo Golubovic ◽  
William M. Worek
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Temperature Jump ◽  
Slip Flow ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Thermal Boundary Condition ◽  
Navier Stokes ◽  
Constant Wall Temperature ◽  
Rectangular Microchannels

Slip-flow and heat transfer in rectangular microchannels are studied numerically for constant wall temperature (T) and constant wall heat flux (H2) boundary conditions under thermally developing flow. Navier-Stokes and energy equations with velocity slip and temperature jump at the boundary are solved using finite volume method in a three dimensional cartesian coordinate system. A modified convection-diffusion coefficient at the wall-fluid interface is defined to incorporate the temperature-jump boundary condition. Validity of the numerical simulation procedure is stabilized. The effect of rarefaction on heat transfer in the entrance region is analyzed in detail. The velocity slip has an increasing effect on the Nusselt (Nu) number whereas temperature jump has a decreasing effect, and the combined effect could result increase or decrease in the Nu number. For the range of parameters considered, there could be high as 15% increase or low as 50% decrease in fully developed Nu is plausible for T thermal boundary condition while it could be high as 20% or low as 35% for H2 thermal boundary condition.

An Experimental Investigation of the Natural Convection of a Heat Generating Fluid within a Closed Vertical Cylinder

1970 ◽  
Vol 12 (5) ◽  
pp. 354-363 ◽  
Author(s):  
W. Murgatroyd ◽  
A. Watson
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Experimental Investigation ◽  
Natural Convection ◽  
Theoretical Model ◽  
Vertical Cylinder ◽  
Thermal Boundary Condition ◽  
Cylinder Wall ◽  
Uniform Temperature ◽  
Temperature Distributions

Experimental results are presented of the velocity and temperature distributions within a heat-generating fluid contained in a vertical closed cylinder, for the case in which the outer surface of the cylinder wall is maintained at a uniform temperature. Previous experimental data are compared and an earlier theoretical model for a different thermal boundary condition is reinterpreted for the present case.

Spatial and Temporal Stabilities of Flow in a Natural Circulation Loop: Influences of Thermal Boundary Condition

2003 ◽  
Vol 125 (4) ◽  
pp. 612-623 ◽  
Author(s):  
Y. Y. Jiang ◽  
M. Shoji
Keyword(s):  
Boundary Condition ◽  
Multiple Scales ◽  
Natural Circulation ◽  
Three Dimensional ◽  
Thermal Boundary Condition ◽  
Circular Loop ◽  
Thermal Boundary Conditions ◽  
Natural Circulation Loop ◽  
Control Of Flow ◽  
Multiple Scales Analysis

In a natural circular loop, the thermal convection demonstrates various spatial patterns and temporal instabilities. Problem consists in determining them with respects to thermal boundary conditions. To this end a multiple scales analysis is applied which resembles the inherent characteristic of the pattern formation in the Rayleigh-Be´nard convection. A three-dimensional nonlinear model is proposed by incorporating the flow modes derived along the analysis. The differences of thermal boundary condition are reflected by a coefficient δ. For small δ, numerical solution to the model shows that only temporal instability exists and Lorenz chaos is possible, otherwise, for large values both spatial and temporal instabilities occur leading to cellular flow and intermittency chaos. The model predicted some additional phenomena opening for experimental observation. It seems significant that this study proposes an algorithm for the control of flow stability and distribution by varying the thermal boundary condition.

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