Coupled simulation method of CG-DPM and MP-PIC for gas-solid system

doi:10.11949/0438-1157.20250599

Abstract

Abstract:

The simulation of industrial-scale gas-solid particle systems always faces computational challenges. Coarse-graining methods, which group real particles into coarse-grained particle or parcel, improve the scalability of numerical simulations. As typical coarse-graining methods for gas-solid systems, coarse-grained discrete particle model (CG-DPM) and multiphase particle-in-cell (MP-PIC) each have their advantages. CG-DPM offers high simulation accuracy but is computationally expensive, while MP-PIC is faster but suffers from accuracy loss in dense systems due to simplified description of interparticle interactions. A coupled method based on domain decomposition, where CG-DPM is used in dense regions to maintain accuracy and MP-PIC is used in sparse regions to accelerate calculations, is proposed in this work. The accuracy and speed of the coupled method are validated in the simulation of bubbling fluidized bed, providing new insights into accelerated simulation methods for gas-solid particle systems.

Key words: fluidization, coarse-graining, coupled model, multiscale, CFD

摘要：

工业规模气固系统的模拟研究始终面临着计算量巨大的问题，粗粒化方法将真实颗粒群打包为粗颗粒或颗粒包，提高了数值模拟方法可以处理的粒子规模。作为典型的两类气固系统粗粒化模拟方法，粗粒化离散颗粒法（coarse-grained discrete particle model，CG-DPM）和多相质点网格法（multiphase particle-in-cell，MP-PIC）具有各自的优势，CG-DPM模拟精度高但计算量较大，MP-PIC模拟速度快，但因颗粒间碰撞处理的简化在稠密系统中精度不足。本工作基于空间计算域分解策略将CG-DPM与MP-PIC耦合，在密相区域使用CG-DPM保证精度，在稀相区域使用MP-PIC加速计算，并在鼓泡床模拟中验证了耦合方法的计算精度及速度，为气固颗粒系统的加速模拟方法提供了新思路。

关键词: 流态化, 粗粒化, 耦合方法, 多尺度, 计算流体力学

CLC Number:

TQ 021.1

Shuai ZHANG, Jiayu XU, Leina HUA, Wei GE. Coupled simulation method of CG-DPM and MP-PIC for gas-solid system[J]. CIESC Journal, 2025, 76(9): 4412-4424.

张帅, 徐嘉宇, 华蕾娜, 葛蔚. 气固系统的CG-DPM与MP-PIC耦合模拟方法[J]. 化工学报, 2025, 76(9): 4412-4424.

Figures/Tables 13

Fig.1 Schematic diagram of EMMS-DPM (modified from Ref.[19])

Fig.2 Schematic diagram of coupling strategy

Fig. 3 Schematic diagram of computational domain partitioning

Table 1 Simulation parameters

参数	数值
计算域尺寸/m³	0.025×0.28×1.0
CFD网格数	4×45×160
气相密度 $ρ g$ /(kg/m³)	1.225
气相黏度 $μ g$ /(Pa∙s)	1.8×10^-5
气速 $u g$ /(m/s)	0.03, 0.10, 0.38, 0.46, 0.51
CFD时间步长 $Δ t c f d$ /s	5×10^-4
真实颗粒粒径 $d r$ /m	2.75×10^-4
粗化率（粗粒化倍数）a	10
粗颗粒内部空隙率 $ε C G P$	0.4
颗粒密度 $ρ p$ /(kg/m³)	2500
杨氏模量Y/(N/m²)	5×10⁷
恢复系数e_r	0.9
滑动摩擦系数 $μ$	0.1
DEM/PIC时间步长 $Δ t$ /s	5×10^-5
模拟总时长/s	30
统计时间/s	5~30

Table 1 Simulation parameters

参数	数值
计算域尺寸/m³	0.025×0.28×1.0
CFD网格数	4×45×160
气相密度 $ρ g$ /(kg/m³)	1.225
气相黏度 $μ g$ /(Pa∙s)	1.8×10^-5
气速 $u g$ /(m/s)	0.03, 0.10, 0.38, 0.46, 0.51
CFD时间步长 $Δ t c f d$ /s	5×10^-4
真实颗粒粒径 $d r$ /m	2.75×10^-4
粗化率（粗粒化倍数）a	10
粗颗粒内部空隙率 $ε C G P$	0.4
颗粒密度 $ρ p$ /(kg/m³)	2500
杨氏模量Y/(N/m²)	5×10⁷
恢复系数e_r	0.9
滑动摩擦系数 $μ$	0.1
DEM/PIC时间步长 $Δ t$ /s	5×10^-5
模拟总时长/s	30
统计时间/s	5~30

Fig. 4 Comparison of bubbling behavior predicted by different simulation methods with experiment

Fig. 5 Comparison of bed expansion ratio between experiment and simulation

Fig.6 Comparison of bed pressure drop between experiment and simulation

Fig.7 Comparison of instantaneous local voidage at bed height of 0.2 m between experiment and simulation

Table 2 Comparison of bubbling frequency at bed height of 0.2 m between experiment and simulation

数据来源	鼓泡频率/Hz
实验	1.8
TFM	2.2
CG-DPM	1.6
Coupled	1.8

Fig.8 Comparison of time mean radial voidage profile at bed height of 0.2 m between experiment and simulation

Fig. 9 Comparison of time mean axial voidage profile predicted by CG-DPM and Coupled method

Fig.10 Comparison of wall time between the Coupled method and CG-DPM

Fig.11 Comparison of wall time in local region between the Coupled method and CG-DPM

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