Conduction Heat Transfer in Electronic Equipment

Abstract

Of the three modes of heat transfer (conduction, convection, and radiation), the convection mode has the most varied applications. Convection is actually the result of two energy transfer mechanisms: fluid motion and molecular motion. The molecular motion at the heat transfer interface is the result of conduction through the stagnant thermal boundary layer. Heat transfer through this layer is based upon Fourier’s Law [1], ΔT=qL/KA c . In convective heat transfer the engineer is faced with estimating the heat transfer coefficient, h c , for a surface. Usually this coefficient comes from texts of empirical formulas, which are based on actual experiments and observations. We cannot calculate the heat transfer coefficient exactly because we can analytically solve only the differential equations governing convection for the simplest flows and geometries.