A problem commonly encountered in the thermal analysis of electronic packages is that of thermal spreading resistance. Thermal spreading resistance occurs as heat flows by conduction between a source and a sink with different cross-sectional areas. Examples of two situations involving spreading heat flow are shown in Figure 1. One example is that of a chip mounted on the bottom … [Read more...]
Surface Flatness
Surface flatness is an important issue for thermal designers as it is directly related to thermal contact resistance between surfaces. In this column, the definitions of surface flatness related parameters are discussed. These definitions are presented here as in the ASME B46.1-1995 standard [1]. Surfaces are characterized by three main parameters: roughness, waviness, and … [Read more...]
CFD Prediction of Electronic Component Operational Temperature on PCBs
Introduction The thermal design of today's electronic equipment relies significantly on the use of Computational Fluid Dynamics (CFD) software for the prediction of electronics operational temperature. In the early to intermediate product design phase, CFD analysis is used to select a cooling strategy and refine a thermal design by parametric analysis. In the final design … [Read more...]
Critical Cooling Issues in High Power Radio Frequency Transmitter Amplifiers
Introduction While emerging methodologies correctly insist that thermal engineers should be involved right from the early conceptual stages of electronics product design [1], many situations still require thermal analysis well after the introduction of the product to its intended application. Military transmitters installed in the 1980's and 1990's and still in operation today … [Read more...]
Air Cooled Compact Heat Exchanger Design For Electronics Cooling
Introduction This article will discuss air-cooled compact heat exchanger design using published data. Kays & London's Compact Heat Exchangers [1] contains measured heat transfer and pressure drop data on a variety of circular and rectangular passages including circular tubes, tube banks, straight fins, louvered fins, strip or lanced offset fins, wavy fins and pin fins. … [Read more...]
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