Dynamics of liquid plugs in prewetted capillary tubes: from acceleration and rupture to deceleration and airway obstruction

TL;DR

This study explores how liquid plugs behave in prewetted capillary tubes, showing they can either rupture or cause airway obstruction depending on conditions, with models and experiments confirming the transition criteria.

Contribution

The paper introduces a simple nonlinear model and analytical criterion to predict the transition between rupture and obstruction regimes in liquid plug dynamics.

Findings

Behavior depends on prewetting film thickness and pressure head.

Model accurately reproduces experimental observations.

Transition criterion aligns with extensive experimental data.

Abstract

The dynamics of individual liquid plugs pushed at constant pressure head inside prewetted cylindrical capillary tubes is investigated experimentally and theoretically. It is shown that, depending on the thickness of the prewetting film and the magnitude of the pressure head, the plugs can either experience a continuous acceleration leading to a dramatic decrease of their size and eventually their rupture or conversely, a progressive deceleration associated with their growth and an exacerbation of the airway obstruction. These behaviors are quantitatively reproduced with a simple nonlinear model [Baudoin et al., Proc. Nat. Ac. Sci. USA, 2013, 110, 859] adapted here for cylindrical channels. Furthermore, an analytical criterion for the transition between these two regimes is derived and successfully compared with extensive experimental data. The potential implications of this work for pulmonary obstructive diseases are discussed.