scholarly journals Laminar free convection due to a line source of heat

1952 ◽  
Vol 33 (5) ◽  
pp. 669 ◽  
Author(s):  
Chia-Shun Yih
Keyword(s):  
Free Convection ◽  
Line Source

scholarly journals Laminar free convection induced by a line heat source, and heat transfer from wires at small Grashof numbers

1998 ◽  
Vol 362 ◽  
pp. 199-227 ◽  
Author(s):  
AMABLE LIÑÁN ◽  
VADIM N. KURDYUMOV
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Line Source ◽  
Outer Region ◽  
Analytical Description ◽  
Temperature Fields ◽  
Thermal Plume ◽  
Line Heat Source ◽  
First Approximation ◽  
Wide Range

The buoyancy-induced laminar flow and temperature fields associated with a line source of heat in an unbounded environment are described by numerically solving the non-dimensional Boussinesq equations with the appropriate boundary conditions. The solution is given for values of the Prandtl number, the single parameter, ranging from zero to infinity. The far-field form of the solution is well known, including a self-similar thermal plume above the source. The analytical description close to the source involves constants that must be evaluated with the numerical solution.These constants are used when calculating the free convection heat transfer from wires (or cylinders of non-circular shape) at small Grashof numbers. We find two regions in the flow field: an inner region, scaled with the radius of the wire, where the effects of convection can be neglected in first approximation, and an outer region where, also in first approximation, the flow and temperature fields are those due to a line source of heat. The cases of large and small Prandtl numbers are considered separately. There is good agreement between the Nusselt numbers given by the asymptotic analysis and by the numerical analysis, which we carry out for a wide range of Grashof numbers, extending to very small values the range of existing numerical results; there is also agreement with the existing correlations of the experimental results. A correlation expression is proposed for the relation between the Nusselt and Grashof numbers, based on the asymptotic forms of the relation for small and large Grashof numbers.

scholarly journals Free and forced convection around line sources of heat and heated cylinders in porous media

2001 ◽  
Vol 427 ◽  
pp. 389-409 ◽  
Author(s):  
VADIM N. KURDYUMOV ◽  
AMABLE LIÑÁN
Keyword(s):  
Porous Media ◽  
Free Convection ◽  
Numerical Solution ◽  
Forced Convection ◽  
Line Source ◽  
Free Stream ◽  
Outer Region ◽  
Circular Cylinders ◽  
Stream Velocity ◽  
Wide Range

An analysis is presented for the steady, two-dimensional, free convection around line sources of heat and heated cylinders in unbounded saturated porous media. It is extended to account also for the effects of forced convection. The study is based on the Boussinesq equations, with the velocities calculated using Darcy's law.The analysis begins with the non-dimensional formulation and numerical solution of the problem of pure free convection around a line source of heat. When this analysis is extended to include the effects of forced convection, two parameters appear in the non-dimensional formulation: the non-dimensional value, V∞, of the free-stream velocity and its angle γ of inclination with respect to the vertical. We first describe the asymptotic form of the solution for large and small values of the distance to the source. The far-field description, which is also applicable to the flow around heated cylinders, is needed to facilitate the numerical solution of the problem. It includes a thermal wake, aligned with the free stream, and an outer irrotational flow with a sink and a vortex at the line source. The temperature distribution near the source involves a constant A0(V∞, γ), to be calculated with the numerical solution of the complete problem, which is used in the evaluation of the heat transfer from heated cylinders when the Rayleigh and Péclet numbers are small compared with unity. In this case we find an inner region where heat conduction is dominant, and an outer region where the cylinder appears as a line source of heat. The asymptotic analysis is complemented with the numerical solution of the general problem for circular cylinders with a wide range of Rayleigh numbers and some representative values of V∞ and γ. We give correlations for the Nusselt number in the limiting cases of pure free convection and pure forced convection.

Temperature Measurement in Laminar Free Convection Using Electro-Optic Holography

1997 ◽  
Vol 7 (9) ◽  
pp. 1893-1898 ◽  
Author(s):  
G. Schirripa Spagnolo ◽  
D. Ambrosini ◽  
A. Ponticiello ◽  
D. Paoletti
Keyword(s):  
Free Convection ◽  
Temperature Measurement ◽  
Electro Optic

Free convection in geophysical processes

1983 ◽  
Vol 141 (10) ◽  
pp. 311 ◽  
Author(s):  
V.V. Alekseev ◽  
A.M. Gusev
Keyword(s):  
Free Convection ◽  
Geophysical Processes
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