Optimum Arrangement of Rectangular Fins on Horizontal Surfaces for Free-Convection Heat Transfer

1970 ◽  
Vol 92 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Charles D. Jones ◽  
Lester F. Smith
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Design Method ◽  
Convection Heat Transfer ◽  
Transfer Coefficients ◽  
Maximum Heat ◽  
Heat Transfer Coefficients ◽  
Maximum Heat Transfer ◽  
Optimum Arrangement ◽  
Free Convection Heat

Experimental average heat-transfer coefficients for free-convection cooling of arrays of isothermal fins on horizontal surfaces over a wider range of spacings than previously available are reported. A simplified correlation is presented and a previously available correlation is questioned. An optimum arrangement for maximum heat transfer and a preliminary design method are suggested, including weight considerations.

Optimum Geometry of Plate Fins

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
R. Karvinen ◽  
T. Karvinen
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Transfer Coefficients ◽  
Maximum Heat ◽  
Geometrical Properties ◽  
Heat Transfer Coefficients ◽  
Fixed Volume ◽  
Maximum Heat Transfer ◽  
Heat Transfer Theory ◽  
Approximate Analytical Solutions

A method and practical results are presented for finding the geometries of fixed volume plate fins for maximizing dissipated heat flux. The heat transfer theory used in optimization is based on approximate analytical solutions of conjugated heat transfer, which couple conduction in the fin and convection from the fluid. Nondimensional variables have been found that contain thermal and geometrical properties of the fins and the flow, and these variables have a fixed value at the optimum point. The values are given for rectangular, convex parabolic, triangular, and concave parabolic fin shapes for natural and forced convection including laminar and turbulent boundary layers. An essential conclusion is that it is not necessary to evaluate the convection heat transfer coefficients because convection is already included in these variables when the flow type is specified. Easy-to-use design rules are presented for finding the geometries of fixed volume fins that give the maximum heat transfer. A comparison between the heat transfer capacities of different fins is also discussed.

Free Convection Heat Transfer Coefficients From Rectangular Vertical Fins

1965 ◽  
Vol 87 (4) ◽  
pp. 439-444 ◽  
Author(s):  
John R. Welling ◽  
C. B. Wooldridge
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Convection Heat Transfer ◽  
Preliminary Design ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Design Data ◽  
Heat Transfer Coefficients ◽  
Free Convection Heat ◽  
The Way

Vertical, rectangular, finned surfaces are used to effect heat transfer on much equipment. Lack of data showing the effect of various fin geometries on free-convection heat transfer prompted this experimentation. The results provide preliminary design data. For a given temperature, an optimum value of the ratio of fin height to the distance between fins is indicated. The way this ratio varies with fin temperature is also given.

Geometry of Plate Fins for Maximizing Heat Transfer

2010 ◽  
Author(s):  
Timo Karvinen ◽  
Reijo Karvinen
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Transfer Coefficients ◽  
Optimal Point ◽  
Maximum Heat ◽  
Geometrical Properties ◽  
Heat Transfer Coefficients ◽  
Maximum Heat Transfer ◽  
Approximate Analytical Solutions ◽  
Need To Evaluate

A method is presented for finding plate fin geometries for maximizing dissipated heat flux. The method is based on approximate analytical solutions of conjugated heat transfer which are utilized in optimization. As a result non-dimensional variables have been found that contain thermal and geometrical properties of the fin and the flow. These variables have a fixed value at the optimal point. The values are given for rectangular, convex parabolic, triangular, and concave parabolic fin shapes for natural and forced convection including laminar and turbulent boundary layers. An essential fact is that there is no need to evaluate convection heat transfer coefficients because they are already included in these variables. Easy-to-use design rules are presented for finding the geometry of fixed volume fins that gives the maximum heat transfer.

Finite Element Predictions of Free Convection Heat Transfer Coefficients of Simulated Electronic Circuit Boards

1989 ◽  
Vol 111 (2) ◽  
pp. 129-134 ◽  
Author(s):  
C. Rajakumar ◽  
D. Johnson
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Convection Heat Transfer ◽  
Circuit Board ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Heating Surfaces ◽  
Free Convection Heat ◽  
Microelectronic Components

A numerical simulation of the buoyancy-induced flow around microelectronic components mounted on a circuit board has been performed using the finite element method. The circuit board is modeled by a vertical plate on which rectangular strip heating surfaces are mounted. Computations have been performed in two-dimensional plane applying a simplifying assumption that the circuit board and the strip heating surfaces are infinitely long. The Navier-Stokes, the flow continuity and the energy equations for laminar flow have been considered in the finite element discretizations. Results of the computations are presented in the form of temperature contour plots and velocity vector plots in the flow field. The convection heat transfer coefficients at the surface of the microelectronic components are presented as a function of their height. The convection coefficients computed have been compared with experimental correlations of free convection heat transfer found in the literature.

scholarly journals Why heat transfer coefficients are unnecessary and undesirable, and how heat transfer problems are solved without them.

2020 ◽  
Author(s):  
EUGENE ADIUTORI
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Thermal Behavior ◽  
Convection Heat Transfer ◽  
Nonlinear Function ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Transfer Problems

Abstract Heat transfer coefficients (h) are unnecessary and undesirable . They are unnecessary because heat transfer problems are readily solved without them. They are undesirable because they greatly complicate problems that concern nonlinear thermal behavior. In order to understand why heat transfer coefficients are unnecessary and undesirable, it is necessary to know precisely what h is. The nomenclature in every heat transfer text should state “ h is a symbol for q/ D T ”. (Note that q = h D T and h = q/ D T are identical .) Problems in convection heat transfer are conventionally solved using q, h, and D T —ie using q, q/ D T, and D T . It is self-evident that any problem that can be solved using q, q/ D T , and D T can also be solved using only q and D T . Therefore h (ie q/ D T ) is unnecessary. h (ie q/ D T ) is undesirable because, when q is a nonlinear function of DT (as in free convection, condensation, and boiling), h (ie q/ D T ) is a third variable , and it greatly complicates problem solutions. The text includes example problems that support the conclusion that h (ie q/ D T ) is unnecessary and undesirable.

Spatial Variation of Heat Transfer to Pistons and Liners of Some Medium Speed Diesel Engines

1970 ◽  
Vol 185 (1) ◽  
pp. 203-218 ◽  
Author(s):  
W. J. Seale ◽  
D. H. C. Taylor
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling Water ◽  
Radial Variation ◽  
Transfer Coefficients ◽  
Air Concentration ◽  
Maximum Heat ◽  
Heat Transfer Coefficients ◽  
Maximum Heat Transfer

Heat transfer coefficients have been measured on the gas side of pistons and liners, the water side of liners, and the oil side of pistons. A significant radial variation in heat transfer across the piston crown has been found. The position of the maximum heat transfer coefficient appears to be coincident with the maximum air concentration, or the position the tips of the fuel sprays have reached at the time of ignition, and the radial variation of heat transfer is possibly related to the amount of fuel burnt at each radius. For four-stroke engines, equations are presented to describe this variation. Heat transfer coefficients at the exposed section of the liner have been found to be similar to the values at the outer edge of the piston. Heat transfer between piston undercrown and cooling oil has been measured for various types of cooling arrangement and, for jet cooling, an expression has been suggested for the heat transfer coefficient. Equations have also been derived to enable coefficients to be predicted for heat transfer from liner to cooling water.

scholarly journals Heat transfer through the regular polyhedrons with asymmetric boundary conditions

2012 ◽  
Vol 33 (3) ◽  
pp. 117-125
Author(s):  
Ewa Pelińska-Olko
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Extreme Values ◽  
Regular Polyhedron ◽  
Transfer Coefficients ◽  
Maximum Heat ◽  
Heat Transfer Coefficients ◽  
Maximum Heat Transfer

Abstract During heat transport through the walls of a hollow sphere, the heat stream can achieve extreme values. The same processes occur in regular polyhedrons. We can calculate the maximum heat transfer rate, the so-called critical heat transfer rate. We must assume here identical conditions of heat exchange on all internal and external walls of a regular polyhedron. The transfer rate of heat penetrating through the regular polyhedron with different heat transfer coefficients on the walls is called the heat transfer rate with asymmetric boundary conditions. We show that the heat transfer rate in this case will grow up if we replace those coefficients with their average values.

An Experimental Investigation of Free-Convection Heat Transfer From Rectangular-Fin Arrays

1963 ◽  
Vol 85 (3) ◽  
pp. 273-277 ◽  
Author(s):  
K. E. Starner ◽  
H. N. McManus
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Convection Heat Transfer ◽  
Parallel Plates ◽  
Transfer Coefficients ◽  
Three Dimensional Flow ◽  
Fin Efficiency ◽  
Heat Transfer Coefficients ◽  
Vertical Arrays ◽  
Free Convection Heat

Average heat-transfer coefficients are presented for four fin arrays positioned with the base vertical, 45 degrees, and horizontal while dissipating heat to room air. The fins are analyzed as constant-temperature surfaces since the lowest fin efficiency encountered was greater than 98 percent. It was found that coefficients for the vertical arrays fell 10 to 30 percent below those of similarly spaced parallel plates. The 45-degree arrays yielded results 5 to 20 percent below those of the vertical. Two flow patterns were investigated for the horizontal arrays, and it was found that the coefficients could be reduced sharply by preventing three-dimensional flow.

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