Dynamic behavior investigation of capillary rising at various dominant forces using free energy lattice Boltzmann method

A Free Energy Lattice Boltzmann Method has been developed to characterize dominant forces and regimes involved in the capillary rise imbibition process. The comparison of the capillary rise behavior at the initial stages, reveals significant differences between numerical and theoretical models. This...

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Bibliographic Details
Published in:Meccanica (Milan) 2021-12, Vol.56 (12), p.2961-2977
Main Authors: Moradi, Bijan, Ghasemi, Shahab, Hosseini Moghadam, Amir, Rasaei, Mohammad Reza, Sajjadi, Mozhdeh
Format: Article
Language:English
Subjects:
Automotive Engineering
Capillary pressure
Capillary tubes
Civil Engineering
Classical Mechanics
Contact angle
Engineering
Free energy
Imbibition
Mathematical analysis
Mathematical models
Mechanical Engineering
Pressure loss
Sensitivity analysis
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Summary:A Free Energy Lattice Boltzmann Method has been developed to characterize dominant forces and regimes involved in the capillary rise imbibition process. The comparison of the capillary rise behavior at the initial stages, reveals significant differences between numerical and theoretical models. This is attributed to the simplifying assumptions, ignoring the entrance region, dynamic contact angle, and inertial term in the theoretical model. By relaxing these assumptions in numerical formulations, the proposed model prevails the theoretical model limitations and shows closer results to the experimental records. However, as the capillary tube size decreases, the capillary force overcomes the inertia and the theoretical and numerical curves converge. Comparing the numerical curves and the experimental results indicates that the dynamics of the capillary ascent predicted by the present model is similar to the dry tube data. It should be mentioned that the inertial regime, the viscous regime, and the gravity-viscous regime can be considered as the successive regimes involved. Further investigations reveal a transition regime at the beginning of the process, which appears due to singular pressure loss. Therefore, the capillary rise phenomenon develops during these regimes as h  ~  t 2 , h  ~  t , h  ~  t 1/2 and relaxing to a constant value, respectively. Finally, for better understanding of the phenomenon, sensitivity analysis on the dominant forces has been performed.
ISSN:0025-6455
1572-9648
DOI:10.1007/s11012-021-01426-z