Freon bubble rise measurements in a vertical rectangular duct

摘要

Isolated bubble rise experiments provide data on bubble drag as a function of size and fluid properties. This data is useful in obtaining drag models for higher void fraction bubbly flows. Previous experiments (Haberman and Morton, 1953) haveshown that the purity of the fluid affects the bubble rise velocity, and therefore the drag coefficient. For contaminated systems, impurities collecting at the liquid-vapor interface increase the effective viscous drag and decrease the rise velocity.In the current experimental work, Freon-114 is used to simulate high temperature environments. Freon is chosen as the modelling fluid because it boils at a lower temperature, and may be scaled appropriately. However, if the purity of the Freon test liquid is unknown, using it to model high temperature environments may lead to inaccurate results. The purpose of the bubble rise experiment is then (1) to identify the purity of the Freon test liquid, and (2) understand the bubble drag mechanism for singlebubbles as a building block for multiple bubble drag models.