The cholesteric liquid crystal was adopted for the visualization of temperature distributions of viscous fluid about scraper blades. It was found that the scraper blades, which form a tail of scraped fluid from the horizontal wing on the rear part of the blade , bring faster uniform bulk temperature of viscous fluid by the visualization.
For each of three types of scraper blades, temperatures of the viscous bulk fluid were measured by 24 Cu-Co thermocouples in the Votator-type agitated vessel with the triple helical ribbon.
Heat transfer to the scraped vessel wall was investigated in very low mixing Reynolds number and it was confirmed that heat transfer coefficient was the most high value, for the scraper blade with the horizontal wing.