Sinha, Nipun (2006-08). Design, fabrication, packaging and testing of thin film thermocouples for boiling studies. Master's Thesis. Thesis uri icon

abstract

  • Boiling is the most efficient form of heat transfer. Thermo-fluidic transport mechanisms at different length and time scales govern the nature of boiling. This study was conducted to enhance the understanding of the surface temperature variations and fluctuations during boiling. Microfabricated thin film thermocouples were used in this study. The main aim of this study was to develop a repeatable procedure for fabrication of thin film thermocouples and to test them by measuring surface temperatures during various boiling regimes. Since thin film thermocouples are known to provide reliable measurements at very fast response rates, they were selected for this study. Small temperature fluctuations at high sampling rates were studied in boiling experiments conducted using PF-5060 as the boiling medium. An experimental apparatus was fabricated for conducting these experiments and it contained a viewing chamber whichblock for sensing the temperature during boiling on its surface. The small size of these thermocouples was another big advantage as they were expected to cause minimal interference to the temperature distribution and the transport phenomenon during boiling. This thesis reports the design evolution of the thermocouples according to the need of packaging and describes the fabrication process with sufficient detail so that it can be easily reproduced given the same facilities and environment. The results of testing show that they can be used for monitoring and analyzing surface temperature variations and fluctuations during various boiling regimes with better temporal resolution. housed the copper block used for providing the heat for boiling. The substrate with thin film thermocouples was placed on top of this copper block for sensing the temperature during boiling on its surface. The small size of these thermocouples was another big advantage as they were expected to cause minimal interference to the temperature distribution and the transport phenomenon during boiling. This thesis reports the design evolution of the thermocouples according to the need of packaging and describes the fabrication process with sufficient detail so that it can be easily reproduced given the same facilities and environment. The results of testing show that they can be used for monitoring and analyzing surface temperature variations and fluctuations during various boiling regimes with better temporal resolution.

publication date

  • August 2006