Abstract
This paper presents flow visualization results obtained by using open-loop pulsating heat pipe made of pyrex glass tubes. The tubes have internal and external diameter of 1.8mm and 3.0mm, and the number of turns was 10. The PHP was tested at horizontal orientation. The working fluids employed were water and 1-Butanol aqueous solution (so-called self-rewetting fluids). Flow visualization results indicate that 1-Butanol aqueous solution showed anomalous liquid film behavior when liquid slug moved from heating section to cooling section. And the interface between the liquid film and vapor plug was unsteadily ruffled. Similar tendency was observed at vertical bottom heat mode.
