scholarly journals AN ITERTIVE DESIGN METHOD TO REDUCE THE OVERALL THERMAL RESISTANCE IN A CONJUGATE CONDUCTION-FREE CONVECTION CONFIGURATION

2019 ◽  
Vol 13 ◽  
Author(s):  
Chadwick D. Sevart ◽  
Theodore L. Bergman
Keyword(s):  
Free Convection ◽  
Thermal Resistance ◽  
Design Method ◽  
Conjugate Conduction

Evolutionary Design Method for a Conducting Solid Cooled by Combined Free Convection and Radiation

2021 ◽  
Author(s):  
Chadwick Sevart ◽  
Theodore Bergman
Keyword(s):  
Free Convection ◽  
Thermal Resistance ◽  
Design Method ◽  
Relative Strength ◽  
Surface Radiation ◽  
Evolutionary Design ◽  
Design Algorithm ◽  
Iterative Design ◽  
First Order ◽  
Solid Geometry

Abstract An iterative design algorithm is used to adjust the shape of a conducting solid body that is subjected to a surface heat flux and cooled simultaneously by free convection and radiation in order to reduce the overall thermal resistance. Parametric simulations are carried out over a range of domain dimensions and emissivity values to determine the sensitivity of (i) the predicted solid shape and (ii) the overall thermal resistance to the relative strength of convection or radiation. Results show that, for the conditions considered, surface radiation has a first-order influence on the predicted optimal solid geometry and overall thermal resistance.

scholarly journals CONJUGATE CONDUCTION-FREE CONVECTION HEAT TRANSFER FROM A HORIZONTAL CYLINDER

2013 ◽  
Vol 36 (2) ◽  
pp. 155-166
Author(s):  
M. K. Bassiouny ◽  
F. M. Mahfouz ◽  
S. A. Wilson ◽  
Gamal H. Badawy
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Convection Heat Transfer ◽  
Horizontal Cylinder ◽  
Convection Heat ◽  
Free Convection Heat ◽  
Conjugate Conduction

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.

The Effect of Surface Radiation and Conjugate Conduction on Laminar Free Convection From a Vertical Flat Plate

2010 ◽  
Author(s):  
S. Prasanna ◽  
S. P. Venkateshan
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Flat Plate ◽  
Convection Heat Transfer ◽  
Vertical Surface ◽  
Surface Radiation ◽  
Flat Plates ◽  
Free Convection Heat ◽  
Conjugate Conduction ◽  
Vertical Flat Plate

The role of conduction and surface radiation on laminar free convection heat transfer from a heated vertical flat plate has been studied. Steady state experiments have been conducted on vertical flat plates, of different thermal conductivities and surface emissivities, with an embedded heater and the results have been reported in [1]. The plate dimensions were held fixed in all the experiments. An effort is made here to identify important parameters that are involved in wall conduction - free convection - radiation interaction phenomena. The convective heat transfer from a vertical surface is affected by the surface temperature of the plate and its variations which is influenced by two other modes of heat transfer, conduction within the plate and surface radiation. Hence, the present paper attempts to understand the interaction phenomenon between the three modes of heat transfer and explain the temperature distributions within the plate, observed both experimentally and in numerical simulations. It is found that radiation is very important as it significantly affects the temperature distribution along the plate.

Development of New Power MOSFETs Package With Double-Sided Cooling

2007 ◽  
Author(s):  
Kisho Ashida ◽  
Akira Muto ◽  
Ichio Shimizu ◽  
Kenya Kawano ◽  
Naotaka Tanaka ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Thermal Resistance ◽  
Fatigue Fracture ◽  
Design Method ◽  
Temperature Cycling ◽  
Optimum Structure ◽  
Packaging Technology ◽  
Experimental Design Method ◽  
Solder Fatigue ◽  
Number Of Cycles

We developed a new packaging technology, one that uses double-sided cooling to dramatically reduce the on-resistance and thermal resistance. The main features of this technology are as follows. Both sides of the chip are soldered to copper leadframes. After that, copper leadframes soldered to the top and bottom of the chip are exposed when transfer molding encapsulates the package. There were two development problems with packaging technology. The first is how to prevent chip crack in the reflow process. The second is how to improve the fatigue life of solder during the temperature cycling. To solve these problems, we designed our package structure using an experimental design method. In particular, for the second problem, we quantitatively calculated the amount of solder fatigue fracture and the number of cycles using the solder crack propagation analysis method, because the performance of the package depends on the amount of solder fatigue fracture. As a result, we could create a condition that prevented chip crack and improved the fatigue life of solder by the twice compared to the first prototype and determined the optimum structure. We assembled a new package based on this optimum structure, and confirmed this improvement of the reliability. In addition, we measured the on-resistance and thermal resistance of this package and that of the existing package available. We found that the new package’s on-resistance and thermal resistance decreased to about 70 and 80% that of the existing package respectively.

Free Convection Limits for Pin-Fin Cooling

1998 ◽  
Vol 120 (3) ◽  
pp. 633-640 ◽  
Author(s):  
T. S. Fisher ◽  
K. E. Torrance
Keyword(s):  
Analytical Solution ◽  
Free Convection ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Inviscid Flow ◽  
System Size ◽  
Total System ◽  
Pin Fin ◽  
Optimal Values

An analytical solution for a system consisting of a pin-fin heat sink and a chimney is presented. The result is applied to problems in which the size of the overall system is constrained. For a given heat dissipation and total system size, optimal values of the pin-fin diameter and heat-sink porosity are observed. The optima occur for systems with and without chimneys. The optimization is used to show that the minimum thermal resistance from a pin-fin heat sink is about two times larger than that of an idealized model based on inviscid flow.

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