Figure 1. AFT description Fin pitch = 25.01 per in = 985 per mPlate spacing, b = 0.200 in = 5.08 x 10-3 m Fin Length = 0.111 in = 2.8 x 10-3 m Flow passage hydraulic diameter 4rh = 0.004905 ft = 1.50 x 10-3 m Fin metal thickness = 0.004 in = 0.102 x 10-3 m Total heat transfer area/volume between plates, ß = 719.4 ft2 / ft3 = 2,360 m2 / m3 Fin area / total area = … [Read more...]
Calculating interface resistance
Figure 1. Ceramic Package - Aluminum Heat SinkAssembly Introduction The exposed surface area of many of today's high powered electronic packagesis no longer sufficient for the removal of the heat generated during normaloperation. Heat sinks are a commonly-used, low cost means of increasing theeffective surface area for dissipating heat by means of convective air cooling.While … [Read more...]
A simple method to estimate heat sink air flow bypass
Introduction After selecting or designing a heat sink based upon a given air velocity orvolumetric flow rate through the fins, the thermal designer needs to determinethe total amount of flow which must be delivered in the duct or card passagecontaining the module w with heat sink. As shown in Figure 1, some of the flowwill go around or bypass the heat sink. In fact, depending … [Read more...]
Microthermal imaging in the infrared
John McDonald, Latigo Optics and Grant Albright EDO/Barnes Engineering Division Introduction Infrared imaging methods provide unequaled ease and flexibility forinvestigating micro-circuit temperatures. The researcher need only slide thecircuit under the objective lens and power it up in order to measure thetemperatures throughout the micro-circuit at once, precisely and … [Read more...]
Measuring chip temperatures with thermochromic liquid crystals
Introduction Measurement of the temperature distribution of an operating electroniccomponent, including its junction and case temperatures, is necessary tocompletely characterize the thermal and electrical performance of today's highpower density electronic components. As part of the characterization process,thermal designers must be able to predict and verify the … [Read more...]
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