Conjugate heat transfer measurements for air-cooled electronics - a new experimental method

A new method for performing conjugate heat transfer measurements from simulated electronic packages is presented. Using a thermal test component, consisting of a foil heater and two calibrated heat flux meters, this new technique provides a means for direct measurement of the heat flow rates in the two predominant paths: convection at the package cap and conduction into the board. A prototype thermal test component was constructed, mounted on four different substrate configurations, and tested in a wind tunnel to demonstrate the effects of varying board conductivity. An energy balance between the heat input and total output measured by the apparatus shows excellent agreement, between 2 and 5% RMS difference, over the full range of velocity and power settings. The proposed method will be used in future studies for heat transfer measurements for arrays of multiple components on thermally conductive substrates.