TY - JOUR
T1 - Gravity-driven unsteady-state slug fall in capillaries – modeling and experimental verification
AU - Zhang, Kaiyin
AU - Wang, Qiuling
AU - Li, Shigang
AU - Wu, Shan
AU - Wallach, Rony
N1 - Publisher Copyright:
© 2016 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - Infiltration of liquid droplets into dry porous media often occurs in industrial and natural settings, which has been widely modeled as liquid slug flow in capillaries. This work focuses on gravity-driven slug motion in vertically oriented capillary tubes. To model the propagation and evolution of the slug, a mathematical model was set on the basis of Newton’s second law and the law of conservation of mass. The model includes terms like slug’s inertia, deposited film, dynamic contact angle, slug’s advancing and receding menisci hysteresis, and it particularly highlights the direct effect of the trailing film on the change of slug mass. In order to verify this model, experiments on water slug with different lengths of initial slugs were conducted in two Pyrex glass capillaries that are partially wettable. It was found that both the length and the velocity of the slug vary during the slug motion in every case. Then the experimental results were simulated with the established model by carefully presetting two fitting parameters, αa and αh, that are related to the dynamic contact angle at the advancing meniscus and the thickness of the trailing film, respectively. The good agreement between the experimental and theoretical results demonstrates that the present model is capable of describing the unsteady-state dynamics of slugs fall in porous media.
AB - Infiltration of liquid droplets into dry porous media often occurs in industrial and natural settings, which has been widely modeled as liquid slug flow in capillaries. This work focuses on gravity-driven slug motion in vertically oriented capillary tubes. To model the propagation and evolution of the slug, a mathematical model was set on the basis of Newton’s second law and the law of conservation of mass. The model includes terms like slug’s inertia, deposited film, dynamic contact angle, slug’s advancing and receding menisci hysteresis, and it particularly highlights the direct effect of the trailing film on the change of slug mass. In order to verify this model, experiments on water slug with different lengths of initial slugs were conducted in two Pyrex glass capillaries that are partially wettable. It was found that both the length and the velocity of the slug vary during the slug motion in every case. Then the experimental results were simulated with the established model by carefully presetting two fitting parameters, αa and αh, that are related to the dynamic contact angle at the advancing meniscus and the thickness of the trailing film, respectively. The good agreement between the experimental and theoretical results demonstrates that the present model is capable of describing the unsteady-state dynamics of slugs fall in porous media.
KW - Slug dynamics
KW - capillary
KW - trailing film
KW - unsteady-state
UR - http://www.scopus.com/inward/record.url?scp=84964478539&partnerID=8YFLogxK
U2 - 10.1080/01694243.2016.1176661
DO - 10.1080/01694243.2016.1176661
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AN - SCOPUS:84964478539
SN - 0169-4243
VL - 30
SP - 2146
EP - 2156
JO - Journal of Adhesion Science and Technology
JF - Journal of Adhesion Science and Technology
IS - 19
ER -