| Optical moudule Heat Sink design | |
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Optical modules are the most temperature sensitive unit at each telecom system. For the majority of these units the maximum allowable case temperature is about 70°C. The ambient air which enters the telecom chassis is about 55°C . The result is a design with very narrow margins if any at all. This work shows a card/slot including 2 optic modules 3 x 4 in each, 3 power supply module and some electronic components. The total card power is about 42 W and the optic modules are 11 W and 14 W each. The airflow is 19 CFM at 55°C. Since the module is about 13 mm thick there is not enough room for fins height. The analysis provided a variety of 2 solutions - an innovative concept of "wing HS” - Heat Sink and combination of the "wing" HS and a base HS. The analysis result shows that the average module case temperatures are 68°C and 70.5°C for the 11W and 14 W respectively. The base HS addition reduced the average case temperature to 67°C and 69°C respectively. The sides HS influence is about 30%. |
  
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| Military Heat Exchanger Tracks Coolit Predictions | |
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CAS was requested to design a cooling system for a major aircraft manufacturer. The 250 watt computer, shown below, was housed in an aluminum chassis measuring 265 mm wide x 200 mm high x 365 mm deep. The chassis exterior was cooled by natural convection and radiation. The chassis interior held 12 cards that were fastened to a heat exchanger by Calmark wedge-locks. The plate-fin heat exchanger consisted of 31 horizontal fins mounted on each side of the chassis and cooled by forced air flow. Before building a prototype, the system was designed using Coolit. The Coolit model of the computer is shown at the right. Four analyses were performed using different mass flow rates (PPM) to represent the different flight conditions. The pressure drop was calculated as a function of the mass flow. Once the system prototype was designed and built, an experiment was conducted to determine the pressure drop. Airflow was varied and pressure readings were recorded on a manometer. Test data plotted against the Coolit predictions, showed an excellent accuracy throughout the entire pressure-flow range. A different test was performed at one of the designed mass flow rate, the temperature distribution across the "cold plate" predicted by Coolit was recorded at steady state. The "cold plate" temperatures not exceed 78°C, and meet the manufacturer's requirements Test data plotted against the Coolit predictions, showed a very good overall prediction |
 
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| Optics Die Thermal Evaluation | |
| In some cases of electro-optics component designs, the temperature characteristics and stability of the die is very important to the functionality of the complete component. The following is a representation of a thermal analysis done to one of our clients. The simulation inspects the temperature distribution over the die. Due to the large differences in dimension scaling the analysis was done in 2 phases:
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Optical moudule Heat Sink design
Design of Heat Sink for an optical module. In the design an otimization process was made to enable high heat dissipation from the module
Military Heat Exchanger Tracks Coolit Predictions
Heat Exchanger design under limitation of pressure drop and inlet air temperature followed by an actual test that approved the design
Optics Die Thermal Evaluation
Evaluating the sgnificanss of a local power dissipation phenomenon vs. the global one on an Optics Components Die