Surface Heat Transfer in a Stirred Boiling-Water Bath

摘要

A platinum resistance thermometer element was used to measure both temperature and heat transfer conditions in a stirred boiling water bath. The average heat transfer was affected strongly by stirring but only slightly by the boiling rate. For both room temperature stirred baths and stirred boiling baths, there were fluctuations about the mean heat transfer rate. The magnitude of the fluctuations increased with stirring rate and fluctuations had periods of 1 to 2 s. It is concluded that stirred water baths, whether boiling or room temperature, are not reproducible heat transfer systems and thus measurements of the thermal response time of temperature sensors in the baths will contain errors unless the heat transfer rate of the bath is measured during the response tests. (ERA citation 08:005846)