Entrainment by a Jet at a Density Interface in a Thermally Stratified Vessel

Abstract

A study was conducted to determine the thermal behavior and upward movement of the density interface resulting from entrainment by an impinging jet in a thermally stratified vessel. Experiments were performed using a cylindrical vessel with water as the test fluid. The upward movement of the interface was detected by vertical strings of closely spaced thermocouples. As the interface passed a given thermocouple location, the temperature was observed to drop abruptly while oscillating in the process. It was found that vigorous entrainment and mixing maintain a relatively sharp temperature “step” in the impingement region. Using the theory of free submerged jets, a correlation was developed for the rise rate of the interface in terms of the Froude number based on local jet impingement parameters.