Confined growth of a vapour bubble in a capillary tube at initially uniform superheat: Experiments and modelling

Bubble growth was triggered in a capillary tube closed at one end and vented to the atmosphere at the other and initially filled with uniformly superheated water. Measurements of the rate of axial growth and the varying pressure at the closed end were used to test under these simplified conditions assumptions employed in one-dimensional models for bubble growth applicable to the more complex conditions of confined-bubble flow boiling in micro-channels. Issues included the thickness of the liquid films round confined bubbles and changes in saturation temperature due to the changes in pressure generated by bubble motion. Modelling features requiring further attention were identified, such as the possibility of “roll-up” of the liquid film due to a large dynamic contact angle.