Free convection from a horizontal line source of heat

1974 ◽  
Vol 25 (6) ◽  
pp. 817-828 ◽  
Author(s):  
Norman Riley
Keyword(s):  
Free Convection ◽  
Line Source ◽  
Horizontal Line

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.

Mixed convection from a horizontal line source of heat

1986 ◽  
Vol 29 (2) ◽  
pp. 344-347 ◽  
Author(s):  
Ramesh Krishnamurthy ◽  
Benjamin Gebhart
Keyword(s):  
Mixed Convection ◽  
Line Source ◽  
Horizontal Line

An Experimental Investigation of the Plume Velocity Field Above a Horizontal Line Heat Source

1977 ◽  
Vol 99 (4) ◽  
pp. 609-613 ◽  
Author(s):  
H. J. Nawoj ◽  
R. S. Hickman
Keyword(s):  
Velocity Field ◽  
Heat Source ◽  
Vertical Velocity ◽  
Line Source ◽  
Lateral Diffusion ◽  
Similarity Function ◽  
Horizontal Line ◽  
Line Heat Source ◽  
Stream Functions ◽  
Energy And Momentum

The vertical velocity field of a natural convection plume arising from a horizontal line heat source was investigated experimentally in detail. The measured vertical velocities were found to be 20–25 percent less than that predicted by analysis. Various causative factors for the discrepancy between analytical and experimental results were investigated, and shown to have a minimal effect. The power law relationship between the plume vertical velocity and energy input to the line source was found to be substantially greater than that predicted by analysis. A normalized similarity function did provide an excellent representation of the lateral diffusion of energy and momentum in the plume, indicating the validity of the boundary layer approximation for the velocity field. It was postulated that further refinement of the stream functions defined by existing analyses is required to accommodate the effects of the upstream flow field that exists in the physical representation of a line source and is omitted from consideration in the development of the analyses.

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