High-order modeling of multiphase flows: Based on discrete Boltzmann method

Wang, S. H.; Lin, Chin E.; Yan, Weiwei; Su, Xianli; Yang, Lichen

doi:10.1016/j.compfluid.2023.106009

Cited by 2 publications

(2 citation statements)

References 30 publications

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“…where the elements of R σ are given in appendix A. From equation (42), the expressions of reaction terms can be obtained =…”

Section: Reaction Termmentioning

confidence: 99%

“…It should be pointed out that the last aforementioned difference is the key reason why the DBM has been developed. The DBM is derived from the nonequilibrium statistical physics and has been successfully applied to investigate compressible reacting flows [7][8][9][10][11][12][13][14][15][16][17][18], multiphase [40][41][42][43], and fluid instabilities [44][45][46][47][48][49][50][51][52], etc. In 2013, the pioneering DBM for combustion was developed by using a hybrid scheme, and the hydrodynamic and thermodynamic nonequilibrium effects were investigated around the detonation wave [7].…”

Section: Introductionmentioning

confidence: 99%

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Discrete Boltzmann model with split collision for nonequilibrium reactive flows*

Lin,

Luo,

Lai

2024

Commun. Theor. Phys.

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A multi-relaxation-time discrete Boltzmann model (DBM) with split collision is proposed for both subsonic and supersonic compressible reacting flows, where chemical reactions take place among various components. The physical model is based on a unified set of discrete Boltzmann equations that describes the evolution of each chemical species with adjustable acceleration, specific heat ratio, and Prandtl number. On the righ-hand side of discrete Boltzmann equations, the collision, force, and reaction terms denote the change rates of distribution functions due to self- and cross-collisions, external forces, and chemical reactions, respectively. The source terms can be calculated in three ways, among which the matrix inversion method possesses the highest physical accuracy and computational efficiency. Through Chapman-Enskog analysis, it is proved that the DBM is consistent with the reactive Navier-Stokes equations, Fick's law and Stefan-Maxwell diffusion equation in the hydrodynamic limit. Compared with the one-step-relaxation model, the split collision model offers a detailed and precise description of hydrodynamic, thermodynamic, and chemical nonequilibrium effects. Finally, the model is validated by six benchmarks, including multicomponent diffusion, mixture in the force field, Kelvin-Helmholtz instability, flame at constant pressure, opposing chemical reaction, and steady detonation.

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“…where the elements of R σ are given in appendix A. From equation (42), the expressions of reaction terms can be obtained =…”

Section: Reaction Termmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Discrete Boltzmann model with split collision for nonequilibrium reactive flows*

Lin,

Luo,

Lai

2024

Commun. Theor. Phys.

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Droplet coalescence kinetics: Thermodynamic non-equilibrium effects and entropy production mechanism

Sun,

Gan,

et al. 2024

Physics of Fluids

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The thermodynamic non-equilibrium (TNE) effects and the relationships between various TNE effects and entropy production rate, morphology, kinematics, and dynamics during two initially static droplet coalescences are studied in detail via the discrete Boltzmann method. Temporal evolutions of the total TNE strength D¯* and the total entropy production rate can both provide concise, effective, and consistent physical criteria to distinguish different stages of droplet coalescence. Specifically, when the total TNE strength D¯* and the total entropy production rate reach their maxima, it corresponds to the time when the liquid–vapor interface length changes the fastest; when the total TNE strength D¯* and the total entropy production rate reach their valleys, it corresponds to the moment of the droplet being the longest elliptical shape. Throughout the merging process, the force contributed by surface tension in the coalescence direction acts as the primary driving force for droplet coalescence and reaches its maximum simultaneously with coalescent acceleration. In contrast, the force arising from non-organized momentum fluxes (NOMFs) in the coalescing direction inhibits the merging process and reaches its maximum at the same time as the total TNE strength D¯*. In the coalescence of two unequal-sized droplets, contrary to the larger droplet, the smaller droplet exhibits higher values for total TNE strength D¯*, merging velocity, driving force contributed by surface tension, and resistance contributed by the NOMFs. Moreover, these values gradually increase with the initial radius ratio of the large and small droplets due to the stronger non-equilibrium driving forces stemming from larger curvature. However, non-equilibrium components and forces related to shear velocity in the small droplet are consistently smaller than those in the larger droplet and diminish with the radius ratio. This study offers kinetic insights into the complexity of thermodynamic non-equilibrium effects during the process of droplet coalescence, advancing our comprehension of the underlying physical processes in both engineering applications and the natural world.

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High-order modeling of multiphase flows: Based on discrete Boltzmann method

Cited by 2 publications

References 30 publications

Discrete Boltzmann model with split collision for nonequilibrium reactive flows*

Discrete Boltzmann model with split collision for nonequilibrium reactive flows*

Droplet coalescence kinetics: Thermodynamic non-equilibrium effects and entropy production mechanism

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