The local heat transfer at the wall of a large vessel agitated by turbine impellers

Abstract The local heat transfer at the wall of an agitated, fully baffled vessel with a dished bottom has been ivestigated. This investigation was limited to six-bladed, disk-type turbine impellers in water. The influence of several geometrical factors was examined for Reynolds numbers varying from 10 5 up to 7 × 10 5 . A special heat flux meter has been developed for the measurement of the local heat transfer rate at the inside wall of the vessel and the bottom. The local heat transfer resistance at the vessel wall can also be calculated theoretically. The results of our experiments are in good agreement with the theory. The local heat transfer resistance appears to depend upon the vertical distance from the measuring point to the plane in which the agitator is rotating. The influence of the ratio of impeller diameter to vessel diameter is small. For the cylindrical wall above and below the agitator, the results are given by Eq. (11).