Aibing Yu

• UNSW Sydney

The design and optimization of blast furnace (BF) profiles generally rely on limited empirical knowledge and experience. Such exercise can now be improved by means of process modeling and optimization. In this work, the effect of furnace profile on BF performance is numerically investigated across a wide range of furnace volumes (500 to 6000 m3), f...

Coke and ore sizes are important to the efficiency and stability of blast furnace (BF) operation in practice. However, their selection is usually determined by experience and there is no systematic study on the effects of ore and coke sizes on BF operation. This paper presents a numerical study on the multiphase flow and thermochemical behaviors in...

Convective thermal drying is usually used in sludge dryers, and the air supply forms significantly affect the sludge drying efficiency. In this work, the drying process of multi-layered sludge is numerically simulated using a coupled computational fluid dynamics-discrete element method (CFD-DEM) approach. Better than our previous work, the current...

Oxygen blast furnace (OBF) has two well-recognized shortcomings, i.e., thermal shortage in the upper BF and overheating in the lower BF. Reducing gas injection is an effective method to overcome them. Based on an industrial 380 m3 OBF, the effect of hearth gas injection, and the effect of hearth and shaft co-injection on the global performance indi...

The stability of biofilms attached to support particles plays a crucial role in fluidized bed bioreactors (FBBRs) when treating non-Newtonian sewage. Biofilm instability is governed by particle-particle (P-P) and particle-wall (P-W) collisions. This paper presents a numerical study of particle behavior in a FBBR using a combined approach of computa...

Operation stability significantly impacts hydrocyclone separation performance during wastewater treatment, sludge processing, and microplastic removal from water. The air core inside a hydrocyclone is an important indicator of operation stability. This paper presents a machine learning model designed for fast prediction and control of air core prof...

The elaborate and appropriate design of blast furnace (BF) inner profile is indispensable. In practice, dumpiness, quantified by the ratio of belly diameter to effective height ( R D‐H ) in this work, primarily determines the inner profile and significantly affects the BF performance. However, the effects of R D‐H on BF operation have not been inve...

In recognition of Winning the FIRST Place of the IEOM Doctoral Dissertation 2023

Excavators have been used in construction for a century, and simulation-based performance prediction is cost effective for equipment design. In practice, particle size varies, and it is of interest to investigate how excavators perform differently when handling polydisperse bulk materials using different configurated buckets. This work simulates th...

Graphic Abstract from Thesis Defense at Industrial Academic Doctorate (DAI), and Energy Postgraduate Program, Federal University of ABC (UFABC), Brazil.

Sludge drying is a crucial part in the sludge treatment and disposal processes, while thermal drying has been a popular choice. In this work, the sludge thermal drying process is numerically simulated using coupled computational fluid dynamics-discrete element method (CFD-DEM) approach. The CFD-DEM model describes the flow and heat transfer in the...

Pneumatic conveying of powders is an engineering process used for conveying dry granulate or powder material where energy consumption is a significant cost factor and contributes to greenhouse gas emissions. In this RD&I project, work was conducted to model pneumatic conveying and bulk characteristics of the particulate product being conveyed. Beca...

Vortex elbows are generally used to mitigate erosive wear while conveying fine particles. This paper presents a modified vortex elbow designed to handle coarse particles. Gas‒solid flows and wall erosion of the modified vortex elbow are studied by the combined approach of discrete element model for particles and computational fluid dynamics for the...

This paper presents a numerical study on the hopper discharging of widely polydisperse particles. It focuses on the effects of particle size distributions (PSDs) in the form of the log-normal distribution of the number (nPSD) and volume (vPSD) of particle constituents. In doing so, a recent GPU-DEM model suitable for large-scale simulations is adop...

Oxygen blast furnace (OBF) is a promising ironmaking technology to realize low carbon emissions. It is featured in high oxygen-enriched operations and suffers from excessively high gas flame temperature. Aiming to overcome this problem, COREX off-gas (CROG) after CO2 and dust removal, which mainly consists of CO and H2, is proposed to be injected i...

The circumferential uniformity of burden distribution is of critical importance in maintaining the stable and efficient operation of blast furnaces (BFs). It significantly affects the circumferential gas distribution and the reduction process of ferrous materials. However, during the burden charging process at the furnace top, circumferential non-u...

Shaft injection of reducing gas into ironmaking blast furnaces (BF) helps mitigate BF carbon footprint. However, its effectiveness relies on the interaction between shaft-injected gas (SIG) and other phases. This paper numerically studies shaft gas injection operations based on a 380-m3 industrial BF. A recently developed three-dimensional process...

Geometry designs are essential to reduce the influence of particles misplacement in a hydrocyclone. This paper proposes a hydrocyclone with a tapered inlet design. This tapered configuration essentially integrates the advantages of the spiral inlet (SI) and tangential inlet (TI). A two-fluid model, after validation, is used to study the new hydrocy...

Optimizing ironmaking blast furnaces (BFs) must consider bottom and top operations. This is done by a recently developed integrated BF model covering the BF below the burden surface. Key operating parameters are focused, viz. coal rate, oxygen enrichment, blast temperature, and burden central opening extent. Numerical orthogonal experiments are thu...

Solid-state lithium batteries (SSLBs) are promising energy-storage devices.

Modelling of machine-material interaction system is challenging. Many efforts have been made in the past to predict machine-material interactions through analytical and numerical models. However, few studies have focused on the dynamic response of machine to materials in automated machine operations. In this work, the co-simulation of multibody dyn...

Particle-resolved direct numerical simulations are carried out to investigate the distribution of drag coefficient (Cd) and average Nusselt number (Nu) of a porous spheroid in a fluid under different Reynolds number (20 ≤Re ≤200), particle shape (aspect ratio, 0.5 ≤Ar ≤2.5), incident angle (0 °≤θ ≤90 °) and porosity (0.57 ≤ε≤0.94). Through the anal...

Hydrogen is an environmentally friendly fuel that does not produce greenhouse gas (GHG) emissions. Its applications have attracted significant attention from many industries, especially the ironmaking industry, which consumes massive amounts of fossil energy. The injection of hydrogen into a blast furnace (BF) is one of the most promising low-carbo...

Hydrogen injection is a promising technology currently under development to reduce CO2 emissions in ironmaking blast furnaces (BFs). Therefore, hydrogen BF is studied by a recent process model based on computational fluid dynamics (CFD). It focuses on the effect of peripheral opening extent (POE), which represents the coke amount near the furnace w...

Multibody dynamics (MBD) simulation is a useful tool to analyse the kinematic function of multibody systems, while discrete element method (DEM) is widely used to simulate particle flows in various types of equipment at the individual particle scale and as an overall process. A combination of MBD and DEM methods, such as functional mock-up interfac...

This paper presents a numerical study of the sand retention process over premium square mesh screens, with special reference to the effect of fluid rheology. This is done by the combined approach of computational fluid dynamics (CFD) and discrete element method (DEM). The fluid viscosity μ_f is described by the power-law model (μ_f=Kγ ̇^(n-1)), and...

BaTiO3 powders was synthesized from cheap and readily available H2TiO3 and Ba(OH)2 by solid-state reaction at low temperature. The samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), Scanning electron microscope (SEM), Raman spectroscopy, Fourier-Transform Infrared Spectroscopy (FT...

High transparent CaF2 ceramics were prepared by a cold sintering process, and their microstructure and transmittance were studied. The results show that the sample with a relative density of 97.65% can be successfully sintered by the cold sintering process at 350 °C and 470 MPa. Micrographs show that the ceramics have high relative density and the...

Operational conditions at inlets of outside vapor deposition (OVD) play an important role in production yields and quality of optical fiber preforms. This work aims to numerically investigate the inner states and SiO2 deposition performance of OVD under different inlet operational conditions. This is based on a recently developed Eulerian-Eulerian...

Wall erosion is a critical problem encountered in operation and maintenance of centrifugal slurry pumps. This paper presents a numerical study of the particle-fluid flow and wall erosion of industrial pumps. This is done by the dense discrete phase model. The model is validated by comparing the simulated results with the experimental measurements o...

Co-firing coal and biomass under pressurized oxy-fuel combustion (POFC) mode in fluidized beds is a novel and promising technology to capture CO2 at a low cost and with eco-friendly waste disposal. However, large knowledge gaps exist in combustion characteristics and pollutant generation owing to the tremendous lack of practices. Following our succ...

Wet particle fluidization is commonly applied in some industries such as catalytic cracking, pharmaceutical manufacturing, mineral processing, food drying, etc. Understanding the within fluidization characteristics is important for the scale-up, design and optimization of industrial process. This article reviews the recent studies on fluidization c...

Pressurized oxy-fuel combustion is a complex process consisting of free radical collisions and reactions. ReaxFF reactive Molecular Dynamics (MD) simulation method is a useful tool to investigate the chemical events in coal combustion at atomistic level. In this work, the impact of operating conditions on the distribution of main fragments and the...

The presentation shows our recent research efforts on hydrogen usage in blast furnace ironmaking process. The work first identifies the respective contribution of hearth-injected H2 , the shaft-injected H2 and hearth-generated CO on pre-reduction and pre-heating behaviors beside hydrogen blast furnace using a new developed gas tracking method. On t...

Particle-fluid flows are commonly encountered in industrial applications. It is of great importance to understand the fundamentals governing the behavior of such a flow system for better process design, control, and optimization. Generally, the particle-fluid flow behavior is strongly influenced by the interaction forces between fluid and particles...

Particle-scale modelling of the process physics involved in laser powder bed fusion (LPBF) is a recent research hotspot, and many efforts have been made in the literature. However, a comprehensive review of the physics in LPBF and the effects of key variables such as powder- and operation-related parameters, and the mechanisms of defects formation...

This paper presents a cost-effective method to optimize hydrocyclones used for particle separation. It integrates a mechanistic model for data generation with data-driven models for prediction and optimization. The mechanistic model is based on a validated two-fluid model (TFM), and the data-driven models are the artificial neural network (ANN) and...

Due to the effects of climate changing, the importance of outdoor thermal comfort has been recognized, and has gained more and more research attentions. Unlike indoor space where air conditioning can be easily implemented, outdoor thermal comfort can only be achieved by localized thermal management. Using textile is a simple but energy-saving way t...

In this work, the multi-physics of interactions between scanning tracks in laser powder bed fusion (LPBF) is investigated numerically by a CFD-based model. The results show that the flow at the head of the first track changes gradually which is driven by the intense centrifugal motion of the second track, and the combined tracks spread around. The...

Shaft gas injection is considered helpful for realizing an oxygen blast furnace (OBF) to mitigate CO2 emissions substantially. This paper presents a systematic study of the shaft injection for a 430-m3 industrial OBF using a process model. The OBF is operated at 35%, 50%, or 100% oxygen enrichment. It is combined with the reducing gas injection thr...

Selecting a suitable sand screen type and size has been a challenge. This paper presents a comprehensive evaluation of premium square mesh screens (SMS), wire-wrapped screens (WWS), and modified wire-wrapped screens with converging slots (CSS). This is done by the combined approach of computational fluid dynamics (CFD) and discrete element method (...

Pulverized coal injection (PCI) is generally used in modern blast furnace (BFs) ironmaking to reduce coke consumption by burning cheaper coal. This paper presents a numerical study on the effects of PCI on the inner states and overall performance of a 5000-m3 industrial BF. This is based on a recently developed integrated BF model that simulates an...

Pressurized oxy-fuel combustion (POFC) is recognized to have the potential to effectively capture CO2 with low cost and high efficiency. To investigate the chemical mechanism of oxy-fuel combustion and the effects of different operating parameters on combustion characteristics, a gasification reaction model and the pressurized oxy-fuel combustion m...

The formation of pores can severely deteriorate the quality of parts fabricated by laser powder bed fusion (LPBF) technology. However, how the pores formation relates to melt pool and gas bubble dynamics is still not well understood. Here, through the modelling of the metal powder melting and the subsequent solidification under the conduction mode,...

Hydrogen use in the blast furnace (BF) ironmaking process promises to mitigate the carbon footprint substantially. This paper presents a numerical study on the effects of hydrogen enrichment on the inner states and overall performance of a 380-m3 industrial BF. This is done using a recently developed three-dimensional process BF model. The model is...

This study investigates the mixing of granular materials for rotating drums of different volumes which vary from 6.28 L to 402.12 L. Two groups of case studies are considered: Group I (constant particle diameter, d) and Group II (constant ratio of drum diameter to particle diameter, D/d). The results show that for Group I, the mixing performance de...

The keyhole dynamics in the laser powder bed fusion (LPBF) process and its relationship with driving forces of surface tension, Marangoni force and recoil pressure have not been well addressed and quantified. In this work, through the modelling of melt pool dynamics, the keyhole life cycle including formation and drilling, fluctuation, and disappea...

The packing of nanoparticles down to 20 nm is simulated by the discrete element method (DEM). The model is validated by good agreement between the simulated and measured porosity. It is found that the previous relationship between porosity and the force ratio of cohesion to gravity can also be applied to the packing of nanoparticles. However, diffe...

In this work, to reduce the “dead volume” due to the accumulation of synthesized products, the foam-structured NiCo2S4 (FSNCS) with a specific surface area of 25.4 m² g ⁻¹ was successfully synthesized by using well-dispersed SiO2 nanospheres as the framework. The FSNCS exhibited 559.3 C g ⁻¹ at a current density of 1 A g ⁻¹, which was 173.3 C g ⁻¹...

This work presents a numerical study of particle mixing and scale-up of ribbon mixers with four sizes (mixer A - 5.62 L, mixer B - 49.02 L, mixer C - 142.91 L, and mixer D - 482.32 L). The results show that the mixing performance becomes worse with the mixer size increasing. A correlation is proposed to predict the mixing rate as a function of the...

Non-uniform sand retention behavior often occurs to the serviced screen deteriorating erosion. However, this phenomenon is poorly understood. This paper presents a numerical study of the sand retention on wire-wrapped screens, with special reference to non-uniform behaviors. This is done by the combined approach of computational fluid dynamics (CFD...

Proppant placement inside hydraulic fractures is a key factor during gas production from unconventional gas reservoirs. Fracturing fluid somewhat leaks off through natural fractures when fracturing naturally fractured reservoirs, which affects proppant transportation and distribution. However, this phenomenon has often been neglected in existing ex...

This paper presents a numerical study of mixing of ellipsoidal particles in a bladed mixer by means of the discrete element method. A wide range of aspect ratios of ellipsoids and sliding friction coefficients are considered. The results show that oblate ellipsoids have worse mixing quality and a lower mixing rate compared with spheres and prolate...

The supercritical water fluidized bed reactor (SCWFBR) is a novel hydrogen production technique, so the understanding on its scale-up is limited. In this regard, the trial-and-error procedure is not an option for traditional experimental research because it is costly and high risk. To overcome these problems, numerical simulations were carried out...

Shaft injection of reducing gas into ironmaking blast furnace (BF) promises to mitigate the carbon footprint and improve the operation efficiency. However, its effectiveness relies on the interaction of shaft injected gas (SIG) with other phases inside a BF. A new tracking method is proposed to isolate the role of SIG and hearth generated gas (HGG)...

Pressurized oxy-fuel combustion (POFC) of solid fuels in fluidized beds possess the potential for CO2 capture at low cost. However, the practical experience of oxy-coal combustion in pressurized fluidized beds (PFB) is still very limited, and there is a lack of attempts on the co-firing of coal and other fuels. In this study, the co-firing of coal...

The raceway is a zone of considerable significance in a blast furnace (BF) because it supplies energy and reducing agents that ensure successful and stable BF operation. Recently, experimental and numerical studies of BF have been widely conducted to examine the inner multiphase flow transport phenomena; however, the study of reacting flows at the...

Selective laser melting is an advanced additive manufacturing technology to use laser beams to melt metal powder and fabricate parts layer by layer. To understand the involved multi-physics, a validated mathematical model is employed in this work to assess effect of material properties such as powder melting and solidification coefficients and mush...

Discrete element method is used in this work to examine the mechanisms determining powder deposition efficiency during powder spreading in powder bed fusion additive manufacturing. The results reveal that powder flow in the powder pile is critical for the formation and break of transient jamming. The forces on the underlying part increase first wit...

The oxy-fuel co-firing of solid fuels (such as coal, biomass, and solid waste) in fluidized beds is one of the most promising technologies for the industrial application of CO2 capture and waste disposal. However, both the practical experimentation and numerical simulations for elucidating co-firing in an oxy-fuel fluidized bed are still limited. I...

This study focuses on the combined effect of particle shape and porosity on the momentum and heat transfer of granular matter under laminar flow. Particle-resolved direct numerical simulations (PR-DNS) are carried out at different working conditions. Numerical results show that both the particle shape (via the aspect ratio, Ar, of the spheroid) and...

Vanadium oxides (VOx) and their related compounds have been received extensive attentions because of their special chemical and physical properties, which make them have a wide range of practical applications. VOx can offer high pseudocapacitance for energy storage due to its high electrochemical activity. Herein, 0D (nanoparticles), 1D (nanowires)...

Bends are potentially most problematic in a hydraulic conveying pipeline system. This paper presents a numerical study of hydraulic bends, with special reference to the interaction between pipe orientation and flow regime. This is done by the combined approach of computational fluid dynamics and discrete element method facilitated with a wear model...

Non-uniform blast injection often occurs in blast furnace (BFs) ironmaking process, but the consequences in the inner state remain unclear under industrial operating conditions. This paper presents a numerical study of three-dimensional (3D) flow and thermochemical behaviors inside a 5000-m3 commercial BF under non-uniform blast injection. This is...

The minimum fluidization velocity of a supercritical water fluidization bed reactor (SCWFBR) is numerically investigated based on coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) simulations. The accuracy of the CFD-DEM model is firstly validated via previously published experimental data. Then, the model is adopted to study t...

With increasing social concern towards industrial wastewater treatment, desulfurization wastewater evaporation technology is attracting attention in theoretical investigation and showing competitive capability in practical applications by virtue of its low cost and high efficiency. In engineering practice, the selection of nozzle model, evaporation...

This paper aims to establish the relationships between microscopic and macroscopic properties for uniform sphere packings under gravity. The packings are generated by the discrete element method under different conditions with the packing density ranging from about 0.2 to 0.74. The microscopic properties are the structural properties commonly used,...

Oxygen blast furnace (OBF) ironmaking promises to realize “zero carbon footprint” production via high oxygen enrichment in the blast. This paper presents a comprehensive study of the inner states and overall performance of the BF under such an operation. This is done by means of our recently developed multi-fluid process model, covering the oxygen...

Packing properties are determined by the dynamic deposition history and affected by many variables. In this work, DEM is used to study the effects of dropping height, deposition intensity and friction coefficient on the dynamic response and stable-state packing properties of ellipsoidal particles. The results demonstrate that with dropping height i...