A flexible air-cooled loop heat pipe has been designed and built in production quantities for a high density avionics cooling application. Approximately 100 units of an ammonia / aluminum-nickel-stainless loop heat pipe were built and delivered over a 3 year period. The performance specification was 0.104 deg C/W at a load of 140W, when exposed to a worst case environment of 54 deg C ambient and 27 deg C cooling air flow. The average thermal performance was 0.098 deg C/W, with a 0.0036 deg C/W standard deviation. The unit is capable of a maximum power of 250W, in any orientation, at 9G's acceleration. The flexible transport lines of the heat pipe allow up to 0.4'' relative movement between the evaporator and condenser, while providing vibration isolation. Thermoelectric coolers were used in a novel way to improve performance. 4 TECs (Thermo Electric Cooler) were mounted between the evaporator and compensation chamber to provide 5-10W of cooling to the compensation chamber. This method overcame the cumulative sources of heat leak into the compensation chamber, and thus minimized the subcooling requirement from the condenser and allowed it to run at optimal performance. This technique not only improved the average performance by 50%, but drastically reduced standard deviation by a factor of 3.
Flexible air cooled loop heat pipe for high density avionics cooling
Flexibles, luftgekühltes Ringleitungswärmerohr für hochdichte Avionikkühlung
2006
12 Seiten, 13 Bilder, 1 Tabelle, 5 Quellen
Conference paper
English
Flexible Air Cooled Loop Heat Pipe for High Density Avionics Cooling
British Library Conference Proceedings | 2006
|Loop Heat Pipe for Avionics Thermal Control
SAE Technical Papers | 1996
|Loop heat pipe for avionics thermal control
Tema Archive | 1996
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