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...]
Temperature measurement using optical fibers
Introduction Fiber optic temperature measurement has been in use for decades1.The most prevalent methods are fluorescent and radiation thermometry, also knownas pyrometry. Fluorescent temperature measurement is used for lower-rangemeasurements from -200°C to +450°C. Pyrometry best covers ranges from100°C to 4,000°C, and is based on the physics of Planck's blackbodyradiation … [Read more...]
Technical Data
In many cases, especially in the earliest phases of the product creation process, it may be necessary for the Designer to make rough calculations as to the thermal behavior of the proposed product. If a problem is identified, alternative cooling technologies should be considered in the next design phase. In such cases, it is useful to have some idea of the limits of the … [Read more...]
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