Transient thermal analysis of printed circuit boards and electronic packages.

A system level thermal analysis is performed by employing the computational fluid dynamics (CFD) method on a large telecommunication rack. Each rack consists of two identical shelves located on the top-to-bottom orientation. Each shelf includes one fan tray with 6 fans, 3 card cages with a total of 50 printed circuit boards (PCBs). Air enters from the front of the shelf, and then makes a 90-degree turn upwards through PCBs, and finally turns another 90-degree to exit the system from the back of the shelf. The system level analysis is performed independently on each shelf. The main purpose of the analysis is to determine the air flow rate to individual printed circuit boards as well as the air temperature distribution in the system. The computed flow rate for individual PCBs is then used for a detailed board analysis to predict the component temperatures of individual boards.

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Thermal analysis of microelectric packages and printed circuit boards using an analytic solution to the heat conduction equation

Advances in Engineering Software ◽

10.1016/0965-9978(94)00032-e ◽

1995 ◽

Vol 22 (2) ◽

pp. 99-111 ◽

Cited By ~ 14

Author(s):

Gordon N. Ellison

Keyword(s):

Thermal Analysis ◽

Heat Conduction ◽

Heat Conduction Equation ◽

Printed Circuit Boards ◽

Analytic Solution ◽

Conduction Equation ◽

Circuit Boards ◽

Printed Circuit

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A Simplified Thermal Analysis and Design Methodology for Printed Circuit Boards

Journal of Electronic Packaging ◽

10.1115/1.2909338 ◽

1993 ◽

Vol 115 (3) ◽

pp. 339-342

Author(s):

A. Hadim

Keyword(s):

Thermal Analysis ◽

Printed Circuit Boards ◽

Printed Circuit Board ◽

Simplex Algorithm ◽

Circuit Board ◽

Circuit Boards ◽

Analysis And Design ◽

Printed Circuit ◽

Squared Error ◽

Downhill Simplex

A simplified methodology is developed for thermal analysis and design of printed circuit boards. It combines the use of computer-aided thermal network modeling and a simplified experimental technique. In order to demonstrate its capabilities, this methodology is implemented to correlate natural convection on a printed circuit board oriented horizontally inside an enclosure. The empirical constants used in the correlation were determined through a numerical algorithm in which the sum of the squared error between calculated temperatures and experimental measurements is minimized using the downhill simplex algorithm.

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Optimal Package Design of Stacks of Convection-Cooled Printed Circuit Boards Using Entropy Generation Minimization Method

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 1 ◽

10.1115/ht2007-32195 ◽

2007 ◽

Author(s):

Wen Jei Yang ◽

Takahiro Furukawa ◽

Shuichi Torii

Keyword(s):

Reynolds Number ◽

Entropy Generation ◽

Printed Circuit Boards ◽

Junction Temperature ◽

Electronic Packages ◽

Circuit Boards ◽

Thermal Optimization ◽

Printed Circuit ◽

Entropy Generation Minimization ◽

Conductance Method

Thermal optimization of a stack of printed circuit boards using entropy generation minimization (EGM) method is presented. The study consists of two parts. One is focused on the entropy generation of a module in periodically fully-developed channel flow (PDF), while the other is the optimization applied to electronic packages composed of a stack of printed circuit boards. In the process of optimizing electronics packaging, consideration is given to two constraints which are the maximum junction temperature specified by a chip manufacturer and the allowable pressure difference across the channel maintained by cooling fans. The Reynolds number, block geometry and bypass flow area ratio are varied to search for an optimal channel spacing using the EGM method whose validity is borne out by comparing with those obtained by the conventional thermal optimization (or overall thermal conductance) method. A dimensionless optimal board spacing parameter C is derived which involves the relative migration speed (or time) of heat transfer and viscous friction over the PDF channel length. A correlation equation is derived which expresses C in terms of the Reynolds number and block geometry. This equation can be employed in the optimal design of electronic packages.

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