Investigation of gas-solid two-phase flow across circular cylinders with discrete vortex method

Wang

Proceedings of the Institution of Mechanical Engineers, Part C:

2022

Angle-cutting elbows (ACEs) are important components of pipelines for fluid diversion and distribution. Severe erosion may occur on the internal walls of ACEs used to transport solid–gas/liquid flow. Erosion may cause pipeline failures. Therefore, the ACE erosion is a fundamental problem. However, the literature on the erosion characteristics and structural optimization of ACEs is rarely reported. This study conducts a numerical prediction of solid particle erosion in ACEs with gas–solid flow. Simulation models based on the two-way coupled Eulerian–Lagrangian approach and the E/CRC model are combined with particle-wall rebound models and a user defined function in the dispersed phase model. Simulation results are verified through a comparison with previously reported experimental results. The findings show that serious erosion occurs in the downstream part of the concave wall of ACE, whereas only slight erosion occurs on the convex wall of ACE. Therefore, anti-erosion measures should be adopted for the concave wall of ACEs. In addition, structural optimization of ACEs for erosion reduction is conducted. The optimal cutting angle is 40° > 50°, and the optimal non-dimensional cutting length is <1.05. The influence of fluid parameters on erosion characteristics is also determined. The erosion rate on the concave wall increases linearly with particle diameter and exponentially with inlet velocity.

Section: Introductionmentioning

confidence: 99%

Numerical prediction of solid particle erosion in angle-cutting elbows with gas–solid flow

Wang

Proceedings of the Institution of Mechanical Engineers, Part C:

2022

“…The results showed that additional pressure losses were generated in the horizontal pipe in the lower gas velocity range. Chen [27] used a discrete element method, Lagrangian-Lagrangian model to study the ow of liquid in the cylinder at high Reynolds coe cients and obtained the effect of St number on the distribution of solid particles. Li [28] combined the CFD model with ANSYS Fluent and MATLAB based A coupled ANSYS-Fluent-based framework was proposed, and the computational results showed that regulating the valve aeration rate could alleviate the problem of uneven solid distribution, demonstrating the versatility of the new method.…”

Section: Introductionmentioning

confidence: 99%

Analysis of gas-solid two-phase flow and structure optimization of mobile shot blasting machine recovery device

Zhang

Men

Pan

et al. 2022

Preprint

Purpose: To address the problem of low efficiency of recycling process waste by gas-solid two-phase flow of the shot blasting machine recycling device, a method and structure by increasing the negative pressure value and optimizing the outlet pipe position are proposed. Methods: Computational fluid dynamics (CFD), discrete element method (DEM) and discrete phase model (DPM) were used to study the waste recovery efficiency at different pressure outlet conditions and outlet pipe locations. The validity of the model was verified by velocity tests at the outlet and inlet compared with simulations. The effect of particle size and particle generation rate on solid particle recovery efficiency was further investigated by analyzing the flow field distribution of the recovery unit. The results show that: the maximum velocity of the gas phase in the recovery device increases with the increase of the absolute value of the outlet pressure, when the outlet pressure is -6500 Pa, the maximum velocity is 67.59 m/s. When the absolute value of the outlet pressure is greater than 6000 Pa, a small amount of steel shot particles is discharged from the recovery bin under the action of the outlet pressure, resulting in the loss of steel shot particles. After the outlet pipe position optimization, the steel shot particle recovery efficiency increased by 10% and the waste particle recovery efficiency increased by 18.9%.

Linköping Electronic Conference Proceedings

“…Both the solid and gas phases are treated as a continuous phases in the EE approach where two phases are differentiated by their volume fraction. This method lacks the discrete nature of solid particles and the transient information of the two-phase interactions (Bin et al, 2009). EL approach preserves the discrete nature of solid particles where the solid phase can exchange the mass, momentum, and energy with the fluid phase, i.e., strong coupling between the phases.…”

Section: Introductionmentioning

confidence: 99%

Study of gasification behavior for a biorefinery lignin waste in a fluidized bed gasification reactor

Ghosh¹,

Timsina²,

Moldestad³

2022

Lignocellulosic biorefineries, paper and pulp industries across the globe can convert cellulose and hemicellulose parts of the biomass into higher valued products. However, lignin from biomass is an underutilized biorefinery waste. Value-added applications of lignin waste should be investigated to produce low-molecular-weight compounds as an alternative to petrochemical compounds. Valorization and lignin recovery play an important role in ‘green shifts’ for such industries. In this work, the authors performed gasification of lignin pellets obtained from one biorefinery located in Finland. A 20-kW pilot-scale bubbling fluidized bed gasifier was used for the experiments. A computational particle fluid dynamics model based on a multi-phase particle in cell approach was developed for the same process. The developed model was validated against the experimental results.The experimental results showed good conversion of lignin pellets into permanent light gases such as carbon monoxide, hydrogen, methane, etc. The average production of product gas and the lower heating value were 5.74 Nm³/hr and 4.95 MJ/Nm³, respectively. The average molar gas compositions obtained from the experimental study were 0.04 for CH₄, 0.16 for CO, 0.15 for CO₂, 0.13 for H₂ and 0.51 for N₂.