Differentially weighted direct simulation Monte Carlo method for particle collision in gas

He, Y., Zhao, H., Wang, H., & Zheng, C. (2015). Differentially weighted direct simulation Monte Carlo method for particle collision in gas–solid flows. Particuology, 21, 135-145. https://doi.org/10.1016/j.partic.2014.05.013

Differentially weighted direct simulation Monte Carlo method for particle collision in gas–solid flows

Yongxiang He, Haibo Zhao ^*, Haoming Wang, Chuguang Zheng

State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China

10.1016/j.partic.2014.05.013

Volume 21, August 2015, Pages 135-145

Received 13 December 2013, Revised 28 April 2014, Accepted 12 May 2014, Available online 16 November 2014, Version of Record 6 June 2015.

E-mail: hzhao@mail.hust.edu.cn; klinsmannzhb@163.com

Highlights

• A differentially weighted DSMC method was developed for particle collisions.

• Mono- and bidisperse high-inertia particle flows were simulated to validate the DW-DSMC method.

• The momentum conservation scheme proposed was able to conserve total mass, momentum and energy.

• Improved resolution was acquired using DW-DSMC, compared with equally weighted DSMC.

• Computational cost was largely reduced using DW-DSMC, compared to DNS.

Abstract

In gas–solid flows, particle–particle interaction (typical, particle collision) is highly significant, despite the small particles fractional volume. Widely distributed polydisperse particle population is a typical characteristic during dynamic evolution of particles (e.g., agglomeration and fragmentation) in spite of their initial monodisperse particle distribution. The conventional direct simulation Monte Carlo (DSMC) method for particle collision tracks equally weighted simulation particles, which results in high statistical noise for particle fields if there are insufficient simulation particles in less-populated regions. In this study, a new differentially weighted DSMC (DW-DSMC) method for collisions of particles with different number weight is proposed within the framework of the general Eulerian–Lagrangian models for hydrodynamics. Three schemes (mass, momentum and energy conservation) were developed to restore the numbers of simulation particle while keeping total mass, momentum or energy of the whole system unchanged respectively. A limiting case of high-inertia particle flow was numerically simulated to validate the DW-DSMC method in terms of computational precision and efficiency. The momentum conservation scheme which leads to little fluctuation around the mass and energy of the whole system performed best. Improved resolution in particle fields and dynamic behavior could be attained simultaneously using DW-DSMC, compared with the equally weighted DSMC. Meanwhile, computational cost can be largely reduced in contrast with direct numerical simulation.

Graphical abstract

Keywords

Direct simulation Monte Carlo; Differentially weighted method; Gas–solid flow; Particle–particle collision; Four-way coupling

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