Experimental and CFD Evaluation of Humidity Management Methods of Ruggedizing a COTS Electronics System for a Severe Climatic Environment

• Main Author: ZHANG, YAFAN
• Format: Others
• Language: English
• Published: Tekniska Högskolan, Högskolan i Jönköping, JTH, Data- och elektroteknik 2007
• Subjects: humidity management; severe storage environment; electronics enclosure; environment test; comoputational fluid dynamics; enclosure heater; Electrical engineering; Elektroteknik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-1647

This master thesis is about an investigation of anti-moisture methods for a nonhermeticelectronics enclosure containing a number of printed circuit boards(PCB) and placed in a severe climatic environment. The relevant theoretical background was provided first. It included the impact of moisture on electronics, some useful psychrometrics concepts, heat transfer fundamentals, introduction of environmental test, temperature and humiditysensing techniques, computational fluid dynamics (CFD) modelling, antimoisture methods and commercial heaters in the current marketing. Then a CFD modelling methodology was developed and validated based on experiment data. An extra heater was added to the enclosure to prevent water adsorption on printed circuit assemblies (PCA) surfaces. The heat dissipation and switch-on period strategies were parametrically studied in order to maintain the internal relative humidity below 60% in the vicinity of PCA surfaces, according to the relative humidity control method. In the end, results obtained from the environmental tests and the CFD simulations were presented and analyzed. Conclusions and future work were also discussed.