Kaiwei Chu

Shandong University | SDU · School of Qilu Transportation

Mini-hydrocyclones have been increasingly used as retention devices to separate mammalian cells in the continuous cell culture. However, the cell viability loss after running through mini-hydrocyclones varies even for the same cell, e.g., the most widely used Chinese hamster ovary (CHO) cells. The reasons behind this problem are unclear. This paper...

The utilization of hydrogen is gaining increasing attention due to its high heating value and environmentally friendly combustion product. The supercritical water circulating fluidized bed reactor is a promising and potentially clean technology that can generate hydrogen from coal gasification. Cyclone is a vital part of the reactor which can separ...

For ensuring safety during the construction and use of a super-large cross-section tunnel, it is essential to understand the lining structure failure pattern and the instability of the surrounding rock mass under a high burial depth. With the Letuan Tunnel of China as an engineering background, we conducted large-scale geo-mechanical model tests an...

Dust emission due to air entrainment in falling solids/particle plumes is a common and serious environmental issue in industry. The prediction of the flowrate of air induced by falling particles is pivotal for the design of dust removal equipment in practice but until now there is still limited reliable correlations available. In this work, the pro...

In this paper, the mechanism governing the particle-fluid flow characters in the stepped pipeline is studied by the combined discrete element method (DEM) and computational fluid dynamics (CFD) model (CFD-DEM) and the two fluid model (TFM). The mechanisms governing the gas-solid flow in the horizontal stepped pipeline are investigated in terms of s...

The separation performance of hydrocyclone is affected by many variables, the values of which have to be selected carefully for achieving the optimal design and operation of such a separator. This selection can be done by either empirical or numerical model. The empirical model provides convenience for industrial use by simply correlating cyclone p...

Hydrocyclones are widely used in various industries to classify particles mainly by size. In this work, two numerical models are developed to model the multiphase flow in hydrocyclones: one is a combined approach of volume of fluid (VOF) model and discrete element method (DEM) with the concept of the coarse-grained (CG) particle (CG VOF-DEM); the o...

A three-dimensional Eulerian Multi-Fluid Model (MFM) of biomass gasification in full-loop Circulating Fluidized Beds (CFBs) has been developed. The conservation equations of mass, momentum, and energy are solved by well-known Navier-Stokes formulation types. The Kinetic Theory of Granular Flow (KTGF), common chemical reactions in biomass gasificati...

Two-fluid model (TFM) has been widely used to simulate particle-fluid flows, with two model formulations available: Model A and Model B [1–3]. Previous studies have shown that both models generate comparable results for some flows, but their possible application limitations have not been well addressed. Recently, Zhou et al. [4] discussed this issu...

Industrial cyclones, such as gas, hydro and dense medium, are widely used in chemical, mineral and process industries to separate particles from fluids or classify particles by size, density or other solid properties. It is well known that the loading of particles can significantly affect fluid flow in such cyclones but the specific effect can be c...

Pharmaceutical powders used in inhalation therapy are in the size range of 1-5 microns and are usually cohesive. Understanding the cohesive behaviour of pharmaceutical powders during their transportation in human airway is significant in optimising aerosol drug delivery and targeting. In this study, the transport and deposition of cohesive pharmace...

Dense medium cyclone (DMC) is widely used to upgrade run-of-mine coal in modern coal preparation plants. The flow within it is very complicated, with multi-phases involved including air, water, coal and magnetic/non-magnetic particles of different sizes, densities and other properties. In this work, the effect of coal particle density distribution,...

Coal has been a major energy resource worldwide for many years and will continue to be in the foreseeing future. One of the major by-products of using coal is the redundant colliery spoil heaps that are harmful to environments. This problem can be overcome in a relatively economical way by using a newly developed technology, i.e., the Nature Medium...

The use of Pipe Belt Conveyor (PBC) has gained more and more popularity in bulk solids handling. Compared to the traditional trough conveyors, PBC can allow tighter curves and steeper gradients of conveyor routes and thus better suits the applications in difficult terrains. It has many unique mechanical characteristics which are not well understood...

Dense medium cyclone (DMC) is a high-tonnage device that is widely used to upgrade run-of-mine coal in the 0.5-50 mm size range. It is known that the performance of a DMC depends on the coal particle size distribution but quantitative relationships have not been established yet. In this work, the effect of the particle size distribution in a DMC is...

The combined computational fluid dynamics and discrete element method (CFD–DEM) approach has been proved to be an effective tool to study the fundamentals of different particle–fluid flow systems, but suffers high computational cost problem. Recently, various treatments such as parcel–particle concept, coarse-grained model, similar particle assembl...

The motion of coal particles and the “breakaway” effect in an industrial dense medium cyclone of body diameter 1000 mm are studied by a computational fluid dynamics model. In the model, mixture multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite contaminated with non-magnetic material in water)...

It has been widely reported that traditional circulating fluidized beds (CFBs) suffer from core–annulus flow structure which is characterized by severe solid back-mixing and non-uniform distribution of solids in both axial and radial directions. In this work, an S-shaped design of risers is proposed and its performance is examined first by numerica...

Dense medium cyclone (DMC) is a high-tonnage device that is widely used to upgrade run-of-mine coal in modern coal preparation plants. It is known that wear is one of the problems in the operation of DMCs, but it is not well understood. In this work, the wear rate of DMC walls due to the impact of coal particles is predicted by a combined computati...

In this work, an extended CFD-DEM approach is developed to study the gas-solids flow and heat transfer between bed and riser wall in three-dimensional full-loop circulating fluidized bed. The effects of some operational, such as superficial gas velocity and solids inventory, on the heat transfer coefficient between bed and riser wall are investigat...

a b s t r a c t The Dense medium cyclone (DMC) is a high-tonnage device that is widely used to upgrade run-of-mine coal in coal industry. Its complicated multiphase flow structure is difficult to investigate experimentally. In recent years, Computational Fluid Dynamics (CFD) and in particular, its combination with Discrete Ele-ment Method (DEM) hav...

This paper presents a numerical study on the piling processes of mono-sized wet particles by the discrete element method (DEM). The capillary force between particles due to liquid bridge is implemented in an existing DEM model. The effects of moisture content on the repose angle and structure of a pile are studied by a series of controlled numerica...

Dense medium cyclone (DMC) is widely used to upgrade the run-of-mine coal in the coal industry. It is known that the amount of near gravity material (NGM) fed into a DMC is an important parameter since it may cause problems such as vortex finder/spigot overloading, surging phenomenon, and system instability. Until now, the underlying mechanism of t...

The combined computational fluid dynamics and discrete element method (CFD-DEM) has been extended and used in recent years to study heat transfer between bed and an immersed cylinder in fluidized beds at the particle scale. The previous models usually assume the gas flow to be two-dimensional. This does not fully represent the reality in which both...

The effect of solids loading ratio or the medium-to-coal (M:C) ratio is the most important operational parameter of the Dense Medium Cyclones (DMC) that are widely used in the coal industry to upgrade the run-of-mine coal by separating gangue from product coal. However, its effect is still not well understood so far, since the flow pattern within a...

In this work, a numerical study of the gas-solids flow in a 3D gas-fluidized bed with an immersed horizontal cylinder is performed using the combined computational fluid dynamics (CFD) and discrete element method (DEM). In order to investigate the wall effect, a sensitivity study of bed thickness is performed first to obtain the critical bed thickn...

Dense medium cyclone (DMC) is widely used to upgrade run-of-mine coal in the coal industry. The flow dynamics/fluctuation in a DMC is important but has not been studied previously. In this work, the dynamics is studied by numerically with special reference to the effect of the fluctuation of solid mass flowrate. The simulation is carried out by use...

This work presents a numerical study of liquid–gas–solid flow in classifying hydrocyclones (CHs). In the numerical model, the turbulent flow of a liquid–gas–solid mixture is modelled using the Reynolds stress model. The interface between the liquid and air core, and the particle flow are both modelled using the mixture multiphase model under differ...

Dense medium cyclone (DMC) is widely used to upgrade run-of-mine coal in the coal industry. The flow within it is very complicated, with four phases (water, air, fine magnetite and coal) involved. To date, the underlying fundamentals are not well understood. In this work, the effect of particle density on the flow in a DMC is numerically studied to...

Dense medium cyclone (DMC) is widely used to upgrade run-of-mine coal in the coal industry. In practice, different designs of the outlet geometry of the vortex finder are used to achieve different purposes. However, the underlying mechanisms are not well understood. In this work, this phenomenon is studied numerically with reference to the effect o...

In this work, a numerical study of the gas–solid flow in a gas cyclone is carried out by use of the combined discrete element method (DEM) and computational fluid dynamics (CFD) model where the motion of discrete particles phase is obtained by DEM which applies Newton’s equations of motion to every individual particle and the flow of continuum flui...

This paper presents a numerical study of the gas–liquid–solid flow in 1000mm dense medium cyclones (DMCs) with different body dimensions, which includes the spigot diameter, cylinder length, cone length and inlet size by means of a computer model which we recently proposed. In this model, mixture multiphase model is used to describe the flow of the...

This paper presents an investigation of powder dispersion based on a combined computational fluid dynamics (CFD) and discrete element method (DEM) approach. Agglomerates of different particle sizes and polydispersities are dispersed in a cyclonic flow at different flow velocities. The analysis of flow field and agglomerate properties indicates that...

The approach of combining computational fluid dynamics (CFD) for continuum fluid and the discrete element method (DEM) for discrete particles has been increasingly used to study the fundamentals of coupled particle–fluid flows. Different CFD–DEM models have been used. However, the origin and the applicability of these models are not clearly underst...

A mathematical model is proposed to describe the multiphase flow in a 1000 mm industrial dense medium cyclone (DMC). In this model, a Mixture Multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite contaminated with non‐magnetic material in water) and the air core, where the turbulence is described...

Gas cyclones are widely used in industries to separate solids from gas stream. It is well known that solids loading will significantly affect the performance of gas cyclones. In this work, a numerical study of the gas‐solid flow in a gas cyclone at different solid loadings is carried out by means of Combined Continuum and Discrete Method (CCDM). In...

The paramount importance of dense medium cyclones (DMCs) has led to their continued development since their invention and commercialisation by the Dutch State Mines in the immediate post-war period. The size of DMC units has grown significantly in recent times, with 1500mm units now commercially available. Given the high level of technical difficul...

A mathematical model is developed to study the coal-medium flow in a dense medium cyclone (DMC) of 1000 mm body diameter. In the model, the motion of coal particles is obtained using the Discrete Element Method (DEM) facilitated with the concept of “parcel–particle” while the flow of medium as a liquid-magnetite mixture Computational Fluid Dynamics...

A mathematical approach is proposed to describe the multiphase flow in a 1000 mm industrial dense medium cyclone. A mixture multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite contaminated with non-magnetic material in water) and the air core, where the turbulence is described by the well establ...

Dense medium cyclone (DMC) is a high-tonnage device that is widely used to upgrade run-of-mine coal in coal preparation. It is simple in design but the flow pattern within it is complex due to the size and density distributions of the feed and process medium solids, and the turbulent vortex formed. This paper presents a mathematical model to descri...

A mathematical model is proposed to describe the multiphase flow in a dense-medium cyclone (DMC). In this model, the volume of fluid multiphase model is first used to determine the shape and position of the air core, and then the mixture multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite in wat...

Sputnik coal distributors are widely applied in coal separation plants and biased outputs are frequently encountered. The present paper aims to develop a numerical model for simulating the flow of the carrier liquid within a distributor chamber. The model uses simple homogeneous multi-phase flow model and performs well in terms of successfully pred...

The laden gas-solid flow in a pneumatic conveying bend is featured with intensive gas-solid, particle-particle, and particle-wall interactions, which are however difficult to quantify experimentally. In this work, these interactions are obtained by use of a three-dimensional combined continuum and discrete model. The model is achieved by combining...

This paper presents a numerical simulation of the liquid–solid flow in a 12-way coal distributor used in a coal preparation plant. The liquid flow, coupled with gas-flow, is determined by a homogeneous multiphase model by computational fluid dynamics (CFD). A strong swirling and non-uniform flow is obtained. The fluid–solid interaction is determine...

This paper presents a numerical study of the particle cluster behavior in a riser/downer reactor by means of combined computational fluid dynamics (CFD) and discrete element method (DEM), in which the motion of discrete particles is obtained by solving Newton's equations of motion and the flow of continuum gas by the Navier–Stokes equations. It is...

Dense-phase pneumatic transportation of bulk materials in the form of slug flow has become a very important technology in industry. In order to understand the underlying mechanisms of slug flow, this paper presents a numerical study of slug flow in horizontal pneumatic conveying by means of discrete particle simulation. To be computationally effici...

This paper presents a numerical study of particle–fluid flow in complex three-dimensional (3D) systems by means of Combined Continuum and Discrete Method (CCDM). In the CCDM, the motion of discrete particles phase is obtained by Discrete Element Method (DEM) which applies Newton's laws of motion to every particle and the flow of continuum fluid is...

This paper presents a numerical study of the gas-powder-liquid flow in a standard hydrocyclone. In the approach, the turbulent fluid flow is described by the Reynolds stress model, the interface between the liquid and air core is modeled using the volume of fluid multiphase model, and the results of fluid flow are used in the simulation of particle...

This paper presents a numerical study of the gas-solid flow in a three-dimensional Circulating Fluidized Bed (CFB) by means of Combined Continuum and Discrete Method (CCDM) in which the motion of discrete particles is described by Discrete Particle Method (DPM) on the basis of Newton’s laws of motion applied to individual particles and the flow of...

This paper presents a numerical study of the gas–powder flow in a typical Lapple cyclone. The turbulence of gas flow is obtained by the use of the Reynolds stress model. The resulting pressure and flow fields are verified by comparing with those measured and then used in the determination of powder flow that is simulated by the use of a stochastic...