The Temperature Visualization and Investigation Inside a Pulsating Heat Pipe Using Temperature Sensitive Paint

Abstract

　　　The mechanism of Pulsating Heat Pipe (PHP) is still unclear because of its complex thermal fluid property. There are few researches that measured the temperature distribution inside the PHP. This study executed the visualization of temperature distribution inside a PHP. Temperature sensitive paint was painted on the optical window. The TSP was excited by UV LED light and the luminescence intensity was captured by CMOS camera. The fluid and wall temperature inside the PHP was measured instantaneously. We captured a thermal flow induced by the evaporation and oscillation. The measurement accuracy was 0.2 ° C. We measured the temperature of working fluid adhering to the wall surface that was colder than the ambient temperature. When the flow was oscillating, the temperature at an arbitrary point inside the channel was fluctuated. On the other hand, when the low was circulating, the temperature at the channel became stable apparently. Acquired data was qualitatively in agreement with known PHP properties. Temperature measurement by TSP is considered to be effective for PHP performance evaluation and flow mechanism investigation.