Dynamic Heat Transfer Inside Multilayered Packages with Arbitrary Heat Generations

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Dynamic Heat Transfer Inside Multilayered Packages with Arbitrary Heat Generations

Fakoor-Pakdaman, M. / Ahmadi, Mehran / Bagheri, Farshid / Bahrami, Majid

In most engineering applications, e.g., hybrid electric vehicles, the multilayered electronic packages generate arbitrary heat over a transient thermal duty cycle. In addition, the outer surface of such media endures time-dependent temperature as a result of variable coolant temperature during driving/duty cycles. As such, a new analytical model is developed to predict transient heat conduction inside multilayered composite media with arbitrary heat generation inside the layers. It is assumed that the temperature of the outer surface varies periodically over time. New compact closed-form relationships are developed for calculating 1) the temperature distribution inside multilayered media, 2) the average temperature of each layer, and 3) the interfacial heat flux. As an example, the methodology is applied to a two-concentric-cylinder composite. A detailed parametric study is conducted, and the critical values for the dimensionless parameters are evaluated; beyond these values, the temperature field inside the media is not affected considerably for any combination of other variables. It is shown that there is an optimum angular frequency that maximizes the amplitude of the interfacial heat flux. An independent numerical simulation is also performed using commercially available software ANSYS; the maximum relative difference between the obtained numerical data and the analytical model is less than 2%.