Numerical Study on the Thermal Performance of a Substrate Integrated Thermal Buffer Heat Sink

Abstract

This report describes a parametric numerical study of a substrate integrated Thermal Buffer Heat Sink (TBHS) used to reduce transient temperature rise of power electronic devices. Linear and non-linear finite element models of the substrate unit cell are developed including a polynomial smoothing function to approximate phase change using the apparent capacity method (ACM). Parameters investigated include substrate geometry, convection rate and heat load. These parameters are examined for steady state and transient thermal loading conditions, and substrate thermal performance is evaluated for each case. Specifically the TBHS design tradeoff between thermal resistance and thermal capacity is quantified, and the ability of the TBHS structure to reduce peak temperature rise for certain transient load conditions is evaluated. It is demonstrated that for short thermal transients a particular TBHS design can suppress temperature rise by 19.6°C (35%) when compared to an equivalent standard microchannel heat sink.