All engineering surfaces exhibit some level of microscopic roughness. The resistance to heat flow through a contact interface occurs because only a small portion (usually 1-2%) [1] of the nominal surface area is actually in contact. Heat may pass through the interface via three paths: conduction through the contact spots, conduction through the gas present in the gap between … [Read more...]
Calculations for Thermal Interface Materials
It's no news to any of the readers of this publication that the increased power dissipation of integrated circuits has led to continuous refinement of package designs and component materials. This trend has increased the importance of thermal interface materials (TIMs) as a key factor in determining the thermal performance of packages intended for high-power applications. This … [Read more...]
Cooling Technology Options
(Editor's Note: Part 2 of this article will appear in the November 2003 issue of ElectronicsCooling.) Cooling electronic systems is one of the major focal points of the design process and the key to a successful product launch. Many options to attain successful operation are available, ranging from passive cooling to cryogenics. These options are obviously power dissipation … [Read more...]
E missivity in Practical Temperature Measurements
When making temperature measurements with infrared cameras and point detectors, we are always facing the question of the emissivity of our sample. In practice we would like to have a single number set in the IR device. To approach the question, let's first recall some fundamental definitions. Planck's radiation law gives the energy density emitted by a blackbody as a … [Read more...]
Hot Spots in Data Centers
Heat loads of data processing equipment continue to increase at a rapid rate. This increasing heat load has been documented by a Thermal Management Consortium of 17 companies [1] as shown in Figure 1. Also shown in this figure are measured heat fluxes (based on product footprint) of some recent product announcements. The most recent shows a rack dissipating 28,500 watts, … [Read more...]
- « Previous Page
- 1
- …
- 331
- 332
- 333
- 334
- 335
- …
- 366
- Next Page »
