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Keywords
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Geometric mass control loop, level set method, mass deviation, multiphase flows, oblique coalescence, interaction
of bubbles
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Abstract
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A geometrical mass control loop is proposed in this research to use in the level set method in order to simulation of
multiphase flows with complex topologies of the interface and a case study is investigated using proposed scheme. In this
regard oblique interaction and coalescence of bubbles in a liquid is investigated. The level set method is suffering from
poor mass conservation in the case of severe changes of interface and complex topologies encountered in a wide range
of problems which one of them is oblique coalescence of the bubbles. Despite the use of full re-initialization and
reconstruction approach of the level set method as well as application of fine mesh, deviation of mass conservation
of the method even becomes 100%. Therefore, simulation of such problems sometimes becomes impossible using this
method. So in the geometric mass control loop, mass deviation in each time step is calculated and is compensated in the
dispersed phase, which prevents the propagation of mass error entire the simulation. Efficiency of proposed geometrical
mass control loop is verified by simulation of oblique interaction and coalescence of gas bubbles in a liquid. The governing
equations are continuity and momentum equations which have been discretized using the finite volume method and the
SIMPLE algorithm. The results outlined in the present study well agree with the existing experimental and numerical
results. Results show that the maximum amount of mass dissipation was less than 4%. Therefore, the level set method
with proposed geometric mass control loop could be used properly for the simulation of multiphase flows with sharp
and high variations in the interface.
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