Study on Force Schemes in Pseudopotential Lattice Boltzmann Model for Two-Phase Flows

Abstract

Multiphase flows are very important in industrial application. In present study, the force schemes in the pseudopotential LBM for two-phase flows have been compared in detail and the force schemes include Shan-Chen, EDM, MED, and Guo's schemes. Numerical simulations confirm that all four schemes are consistent with the Laplace law. For Shan-Chen scheme, the smaller is, the smaller the surface tension is. However, for other schemes, has no effect on surface tension. When 0.6 < ≤ 1, the achieved density ratio will reduce as reduces. During this range of , the maximum density ratio of EDM scheme will be greater than that of other schemes. For a constant , the curves of the maximum spurious currents ( ) has a minimum value which is corresponding to except for EDM schemes. In the region of < ≤ 1, will reduce as decreases. On the other hand, in the area of ≤ , will increase as decreases. However, for EDM scheme, will increase as increases.

Three-Dimensional Aerators: Characteristics of the Air Bubbles

“…Those data were classified according to two categories, air and water signals. The air concentration ( C ) was computed as the encountering air's probability at the leading tip of the probe, which can be expressed as [26]…”

“…A simplified analogy would be to consider on aeration flows past a fixed probe, as a series of discrete one-dimensional air and water The number of data (N) can be obtained by multiplying the frequency (f ) of the measurement instrument with the sampling time T, i.e., N = f × T. Those data were classified according to two categories, air and water signals. The air concentration (C) was computed as the encountering air's probability at the leading tip of the probe, which can be expressed as [26]…”

“…Some researchers [20][21][22][23][24] also established analytical equations to predict the air concentration distributions at the aerators' downstream. Numerical models such as the lattice Boltzmann method were found to successfully simulate two-phase flows and free-surface flows [25][26][27]. These models may be used to complement physical models and experimental measurements after careful validation and verification of model parameters such as the void fraction distribution, velocity, and air-bubble chord sizes.…”

Three-Dimensional Turbulence Numerical Simulation of Flow in a Stepped Dropshaft

“…With the rapid development of computer technology, numerical methods have been applied more and more to complex flows of industrial relevance [25][26][27][28][29][30]. The most widely used approach in both academia and industry for the modeling of turbulent flows is Reynolds-averaged Navier-Stokes (RANS) methods that solve additional transport equations for turbulence and introduce the turbulence eddy viscosity to simulations to mimic the effect of turbulence.…”

Numerical Investigation on the Hydraulic Properties of the Skimming Flow over Pooled Stepped Spillway

“…Physical models were established by Zhang and Chanson [11] to examine the effect of step edge and cavity geometry on the air entrainment and energy loss performance in stepped chutes. Apart from experimental studies, thanks to the advances in the computational performance of computers, numerical methods have also been successfully used to study the detailed flow properties in complex contexts [12][13][14][15]. Baylar et al [16] numerically examined the energy loss and aeration efficiency of the stepped chutes and found that both of them in nappe flow regime were greater than that of the skimming flow regime.…”