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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

THERMAL ANALYSIS OF A PRINTED CIRCUIT BOARD COOLED BY FORCED CONVECTION

Get access (open in a dialog) DOI: 10.1615/IHTC10.4000
pages 415-419

Resumo

The paper presents a finite-difference analysis of an air cooled printed circuit board (PCB) in an enclosure of a parallel plate channel geometry under constraints of weight, limited air flow and high inlet temperatures. In order to obtain an optimal thermal design under such conditions, the temperature of each component on the PCB must be predicted as accurately as possible. A conventional design based on average values of temperature differences and heat transfer coefficients is inadequate. Hence, a finite-difference analysis which yields local temperatures for the entire printed circuit board as well as the air flowing on both its sides has been carried out.
The components are arranged on the PCB in an irregular pattern. The air flow in the channels on both sides of the board is laminar and simultaneously developing throughout the length of the channels. By carrying out discrete finite-difference energy balances for the PCB and its substrate and for the air on both sides, local temperatures were computed for the PCB and the flowing air.
In order to validate the model and the algorithms used in the computations, experimental tests were performed on a dummy PCB, in which power resistors simulated the real components, under similar air flow conditions. The temperature measurements on the PCB were in good agreement with the computed values.
The computer program for the thermal analysis of printed circuit boards is interactive and enables the user to choose any arbitrary arrangement of components on the PCB as well as different values of all design parameters, e.g., type of substrate, channel dimension and flow inlet conditions. The program can serve as an important tool either for checking the performance of an existing PCB or for sensitivity analysis in designing the packaging of new printed circuit boards.