Article
Engineering, Environmental
Katie Cole, Pablo R. Brito-Parada, Kathryn Hadler, Diego Mesa, Stephen J. Neethling, Alexander M. Norori-McCormac, Jan J. Cilliers
Summary: This study measured the hydrodynamics of a stirred tank reactor containing multiphase flows using positron emission particle tracking (PEPT) technique. The probability density function (PDF) of particle velocity was estimated by averaging the location data from PEPT. The results showed bimodal vertical velocity distributions in the impeller radial jet. Comparisons of velocity distributions between hydrophilic and hydrophobic tracer particles revealed differences in various locations.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Chemical
Cihan Ates, Joel Arweiler, Habeb Hadad, Rainer Koch, Hans-Joerg Bauer
Summary: The objective of this study is to investigate the effect of secondary motion of particles in multiphase gas-solid flows and determine the relative impacts of particle shape and orientation information on particle distribution. The study finds that the shape and orientation information strongly affect the force balance for single particles, and the particle distribution in the chamber is significantly changed by the secondary motion of particles. The study also highlights the importance of particle orientation statistics in capturing the particle mixing and segregation patterns at dilute regime.
Article
Engineering, Environmental
Chuanpeng Zhang, Renshuai Zhu, Yanpei Chen, Wei Wang, Tomohiko Furuhata
Summary: The configuration-dependent dynamics of non-spherical particles were experimentally investigated in a quasi-two-dimensional gas-solid fluidized bed. It was found that the vertical velocity profiles were sensitive to the aspect ratio at low gas velocity but not at high gas velocity. The velocity distribution, particularly the rotational velocity distribution, deviated from the Maxwellian distribution. The joint probability density distribution of vertical and rotational velocity was asymmetric. Two high-probability particle configurations, two particles in a parallel or vertical arrangement, were identified by calculating various functions. The cause of this order appearance was explained through entropy theory. The drag force of the particle configurations at different angles and Re was compared, demonstrating the necessity of considering configuration-dependent drag force for non-spherical particle fluidization.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
Kimiaki Washino, Ei L. Chan, Yukiko Nishida, Takuya Tsuji
Summary: This study examines the validity of the Scaled-Up Particle (SUP) model as a novel coarse grain model for Discrete Element Method (DEM) in simulating a flow of non-spherical and poly-dispersed particles. The SUP model is based on the authors' previous work and the scaling law derived from the continuum assumption of an arbitrary particles flow. The study shows that the SUP model is applicable to both spherical and mono-dispersed particles as well as non-spherical and poly-dispersed particles, as long as the resolution is sufficiently high.
Article
Engineering, Chemical
M. Knoll, H. Gerhardter, P. Tomazic, C. Hochenauer
Summary: The study focused on predicting particle motion behavior in a fluid flow after injection, specifically the lateral distribution. Experimental and numerical analysis were conducted using a specially designed flow channel called the particle cross sifter. The results indicated that only combining LES approach with DPM could accurately predict the lateral particle distribution.
Article
Mechanics
Qiang He, Weifeng Huang, Yuan Yin, Yang Hu, Yanwen Li, Decai Li
Summary: In this paper, an improved lattice Boltzmann model for fluid-fluid-solid (FFS) flows with high viscosity ratio is presented. The model combines the bounce-back particle model with the Shan-Chen multicomponent model and extends the bounce-back scheme to moving particles within the multicomponent model framework. An improved virtual solid density model is employed for wetting boundary conditions. The model is able to simulate FFS flows with high viscosity ratio and preserve the total mass of the two fluids.
Article
Engineering, Chemical
Farzin Darihaki, Jun Zhang, Ronald E. Vieira, Siamack A. Shirazi
Summary: Solid particle erosion is a complex process and CFD, combined with reliable correlations, has shown acceptable performance. However, errors may occur if particles are treated as point-masses without volume in the near-wall region. Proper consideration of particle size near the wall can help minimize errors.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Mechanics
Ramandeep Jain, Silvio Tschisgale, Jochen Froehlich
Summary: This study investigates the influence of different non-spherical particle shapes on sediment transport through direct numerical simulations. The results show that particle shape significantly affects both fluid and particle behavior, including parameters such as porosity and bed friction. The findings highlight the importance of considering particle shape in modeling natural sediment transport processes.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Marine
Ri Zhang, Kai Xu, Yong Liu, Haixiao Liu
Summary: A general numerical method is developed to analyze solid particle erosion in gas-liquid mixed pipeline. Particle trajectories are tracked as an important intermediate step. The method considers the random effects of gas and liquid phases on particle trajectories, as well as the influence of surface tension. The numerical procedure is verified by comparison with experimental data and the effects of phase volume fraction and surface tension are discussed.
Article
Engineering, Mechanical
Dongmei Wan, Haitao Xu
Summary: This experimental study investigates the motion of a spherical droplet in a plane traveling sound wave. The experimental data confirm the theoretical results and extend the parameter range for testing the theory on particle motion in unsteady fluid.
ACTA MECHANICA SINICA
(2022)
Article
Mechanics
Cheng Peng, Qichao Sun, Lian-Ping Wang
Summary: The controlling parameters of turbulence modulation by finite-size particles in homogeneous isotropic turbulence (HIT) are investigated through numerical and experimental studies. Four non-dimensional parameters, including Re, p(p)/p(f), d(p)/?, and f(v), are identified through dimensional analysis. Empirical models are developed to quantitatively predict the modulation of turbulent kinetic energy (TKE) and dissipation rate based on fully resolved direct numerical simulations.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Energy & Fuels
Shengyu Zhou, Zhongjie Shen, Jianliang Xu, Qinfeng Liang, Zhenghua Dai, Haifeng Liu
Summary: This study investigates the particle rotation induced by gas-solid phase reactions and analyzes the rotational frequency and forces acting on non-spherical particles through numerical simulations. The rotational frequency of particles is influenced by active area ratio, ambient gas temperature, and particle size.
Article
Energy & Fuels
Shengyu Zhou, Zhongjie Shen, Qinfeng Liang, Jianliang Xu, Zhenghua Dai, Haifeng Liu
Summary: Particle rotation induced by gas-solid phase reaction in gas-solid flow is investigated in this work. Numerical simulations of the combustion and rotation behavior of non-spherical particles are conducted, and the influences of active area ratio, ambient gas temperature, and particle size on the rotation frequency are analyzed.
Article
Engineering, Aerospace
Bo Zhang, Junyi Chen, Mohammad Shahsavari, Haocheng Wen, Bing Wang, Xiaotao Tian
Summary: This study utilizes numerical simulations to investigate the effects of inert dispersed particles on the propagation characteristics of the H-2/CO/air detonation wave. The results show that these particles reduce the temperature and velocity of both dispersed and continuous phases, while also altering the location of chemical equilibrium. Increasing the particle mass ratio decreases the detonation wave propagation velocity and hydrodynamic thickness, but increases velocity fluctuations at the detonation front. On the other hand, increasing the particle diameter augments the detonation wave propagation velocity and hydrodynamic thickness, and induces non-monotonic changes in velocity fluctuations at the detonation front. The effects of inert particles on the detonation wave are primarily determined by the relative scales of the particle relaxation time and the detonation propagation time.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Chemical
Ri Zhang, Guanhua Zhao
Summary: The numerical procedure involving the dense discrete phase model (DDPM) is used to calculate solid particle erosion. DDPM works in two mechanisms to evaluate the interaction among particles and reflect the blocking effect of high-concentration particles. The predicted erosion contours of DDPM are more uniform and smoother than the DEM-predicted contours.
ADVANCED POWDER TECHNOLOGY
(2022)
Article
Energy & Fuels
Saqib Sohail Toor, Ayaz Ali Shah, Kamaldeep Sharma, Tahir Hussain Seehar, Thomas Helmer Pedersen, Lasse Aistrup Rosendahl
Summary: The study showed that hydrothermal liquefaction of protein-extracted grass residue under subcritical conditions with a potassium carbonate catalyst at around 350 degrees Celsius can enhance bio-crude yield. Additionally, the supercritical conditions without catalyst improved the quality of bio-crude with reasonable heating values.
Article
Thermodynamics
S. Mahmoudinezhad, D. T. Cotfas, P. A. Cotfas, Enok J. H. Skjolstrup, K. Pedersen, L. Rosendahl, A. Rezania
Summary: The study demonstrates significant impact of spectrum splitting technique on a hybrid PV-TEG system, enhancing power generation of PV cell and overall power generation.
Article
Chemistry, Physical
Siavash Zargari, Alireza Rezania, Ziaddin Daie Koozehkanani, Hadi Veladi, Jafar Sobhi, Lasse Rosendahl
Summary: Triboelectric nanogenerator (TENG) is an efficient technology for energy harvesting applications by converting low-frequency mechanical motions into electrical energy. Optimal series capacitors can stabilize the variations in inherent capacitance of TENG and improve power generation performance. Incorporating this optimization method and modifying the power management circuit can significantly boost the harvested power and increase the stored energy in a capacitor.
Review
Engineering, Chemical
Ayaz Ali Shah, Kamaldeep Sharma, Muhammad Salman Haider, Saqib Sohail Toor, Lasse Aistrup Rosendahl, Thomas Helmer Pedersen, Daniele Castello
Summary: Hydrothermal liquefaction (HTL) is a leading technology for converting various types of biomass into drop-in biofuels and renewable materials. Catalysis plays a crucial role in increasing product yields and improving product properties. This review provides an updated overview of catalysis strategies applied in HTL, comparing different catalysts and their effects on product yields and properties. The advantages and disadvantages of each catalysis approach are critically discussed, along with future research directions.
Article
Chemistry, Multidisciplinary
Havva Hashemi, Hasan Behnejad, Lasse Rosendahl, Ahmad Tavasoli
Summary: This study systematically investigates the sol-gel process and examines the influence of key operating parameters on the properties of the final product. By using response surface methodology, optimal conditions for the synthesis of Engineering SBA-15 (E-SBA-15) were determined. The E-SBA-15 exhibits large mesoporous structure and unique surface chemistry, making it promising for various industrial applications, particularly as support material in heterogeneous catalysis.
Article
Chemistry, Analytical
Majid Khazaee, Lasse Aistrup Rosendahl, Alireza Rezania
Summary: This paper investigates the self-powering online condition monitoring for rotating machines using a piezoelectric transducer as an energy harvester and sensor. The method is designed for real-time working motors and relies on self-powered wireless data transfer. The study shows that energy harvesting by piezoceramic can generate enough power for autonomous wireless data transfer, and the piezoelectric transducer is highly sensitive to faults, making it suitable for monitoring rotating machines using a self-powered system.
Article
Environmental Sciences
Yan Li, Dongliang Hua, Haipeng Xu, Fuqiang Jin, Yuxiao Zhao, Lei Chen, Baofeng Zhao, Lasse A. Rosendahl, Zhe Zhu
Summary: This study investigated the disposal and reutilization of hydrothermal liquefaction wastewater (HTLWW) and found that anaerobic digestion (AD) is an alternative method for treating organic wastewater. Results showed that the highest bio-crude yield was obtained at 350 degrees C. The presence of toxic substances in HTLWW decreased methane yield at high organic loading. The microbial community and diversity were influenced by the complex compounds in the wastewater.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Environmental
Fatma Marrakchi, Saqib Sohail Toor, Asbjorn Haaning Nielsen, Thomas Helmer Pedersen, Lasse Aistrup Rosendahl
Summary: The effects of different catalysts on the production of crude bio-oils from wheat stem through hydrothermal liquefaction (HTL) were studied. It was found that Na2CO3 catalyst resulted in a yield of 30.85 wt% crude bio-oil with the highest higher heating value (HHV) of 34.36 MJ/kg and the lowest hydrochar content of 22.03 wt%. Additionally, HTL-AP treatment with various catalysts showed significant removal efficiencies for pollutants, such as COD, TOC, phenols, total N, P, and dissolved K.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Yeyun Cai, Ning Ding, A. Rezania, Fang Deng, L. Rosendahl, Jie Chen
Summary: For designing thermoelectric generation systems in practice, it is important to maximize output power, system efficiency, and minimize system investment. Existing studies often make ideal assumptions about the input heat and coefficients, and focus more on optimizing the geometry of the thermoelectric generator (TEG) rather than the system parameters. This study proposes a transient model that considers three system parameters and explores their effects on output power, conversion efficiency, and system investment, leading to a more comprehensive and efficient system design.
Article
Acoustics
Majid Khazaee, John E. Huber, Lasse Rosendahl, Alireza Rezania
Summary: This paper presents a four-point bending piezoelectric energy harvester with extensive investigation and modeling to identify influential parameters for improving energy conversion efficiency. The electromechanical analytical model is verified by experimental data. The study compares the four-point bending harvester with standard cantilever harvesters in terms of voltage generation, mechanical strain, and figure of merit. Optimal operating conditions for the four-point bending harvester are investigated using dimensionless parameters.
JOURNAL OF SOUND AND VIBRATION
(2023)
Review
Green & Sustainable Science & Technology
Hamid Reza Rahbari, Matthias Mando, Ahmad Arabkoohsar
Summary: Multigeneration high-temperature systems utilize high-temperature heat sources to simultaneously produce multiple forms of energy. They offer various advantages including higher energy efficiency, reduced greenhouse gas emissions, and lower operating costs. This study reviews multigeneration high-temperature systems with focus on cycles operating above 550 degrees C, using fossil fuels, solar heat, and molten salts as heat storage mediums. The supercritical CO2 cycle is found to be the most efficient for multigeneration systems, while the ultrasupercritical steam cycle is still more efficient than the gas turbine cycle. Supercritical steam cycles in multigeneration systems have been under-researched, presenting a gap in the literature. Supercritical CO2 cycles have a huge potential for multi-vector supply.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2023)
Article
Energy & Fuels
Milad Hasani, Majid Khazaee, John E. Huber, Lasse Rosendahl, Alireza Rezania
Summary: In this study, the prominent features and characteristics of four-point bending energy harvesters (FPB-EH) were investigated to improve energy conversion in piezoelectric energy harvesters. The innovative FPB configuration extends energy harvesting capabilities compared to conventional cantilever beams. A comprehensive analytical electromechanical model, which includes multi-beam sections and multi-mode-shape functions, was developed and validated against experimental results and finite element analysis. The parametric study showed that the FPB configuration can enhance energy conversion efficiency and normalized output energy by factors of over 3 and 6, respectively. Guidance is provided for selecting between cantilever and four-point bending configurations.
Article
Thermodynamics
Hengfeng Yuan, Shaowei Qing, Shangkun Ren, Alireza Rezania, Lasse Rosendahl, Xiankui Wen, Jingliang Zhong, Xiaolong Gou, Shengli Tang, E. Peng
Summary: In this study, a novel hollow PDMS-filler design is proposed to improve the performance of the thermoelectric generator (TEG). The effects of longitudinal and transverse hollow structures on the TEG's output power and optimal fill factor are evaluated using a validated thermal and electrical coupled model, and the impact of key geometrical and physical parameters on TEG design optimization is revealed. Results show that the transverse-hollow structure combined with both-sides high-thermal-conductivity layers can significantly increase the TEG's output power up to 137.34 μWcm<sup>2</sup>, presenting a potential solution for the next generation of efficient and low-cost flexible TEGs.
Article
Green & Sustainable Science & Technology
Sajjad Mahmoudinezhad, Matthias Mando, Ahmad Arabkoohsar
Summary: Storing off-peak cheap electricity for high-temperature heat supply in different mediums shows promise, but designing an appropriate heat exchanger system is crucial for minimizing risks and maximizing economic benefits. This study focuses on designing an optimal energy conversion unit and conducting a techno-economic analysis to demonstrate its proficiency in a case study in Denmark.
Article
Chemistry, Physical
Komeil Kohansal, Kamaldeep Sharma, Muhammad Salman Haider, Saqib Sohail Toor, Daniele Castello, Lasse Aistrup Rosendahl, Joscha Zimmermann, Thomas Helmer Pedersen
Summary: Aqueous phase recirculation (APR) is used to enhance hydrothermal liquefaction (HTL) performance, but the resulting bio-crude has a high heteroatom content. This study investigates the influence of APR on hydrotreated bio-crude. APR improves bio-crude yield and energy recovery, but increases heteroatom content and nitrogen distribution. More hydrogen and severe hydrotreating conditions are required for obtaining drop-in quality biofuel.
SUSTAINABLE ENERGY & FUELS
(2022)
Article
Engineering, Chemical
Ri Zhang, Shasha Zhang, Mengyan Ding
Summary: A thin liquid film method is proposed to evaluate sand erosion in annular flow. This method considers the direct interaction between the liquid film and gas core, as well as the entrainment and deposition of droplets. The erosion rate is calculated by considering the effects of liquid entrainment and particle velocity decay. The method is fully verified by comparing with experimental data.
Article
Engineering, Chemical
Yu Suo, Xianheng Su, Wenyuan He, Xiaofei Fu, Zhejun Pan
Summary: This research investigates the mechanical properties of sandstone-shale composite through orthogonal experimental method and discrete element simulation. The results show that different lithologies and thickness ratios can affect the strength and fracture mode of the composite rock samples.
Article
Engineering, Chemical
Maurizio Troiano, Andrea El Hassanin, Roberto Solimene, Alessia Teresa Silvestri, Fabrizio Scala, Antonino Squillace, Piero Salatino
Summary: This study investigates the potential of Fluidized Bed Finishing (FBF) for square flat AlSi10Mg specimens manufactured via Laser-Powder Bed Fusion (L-PBF) additive manufacturing technology. The results show that good finishing can be achieved using rotation-assisted tests, with a maximum reduction of surface roughness by 67%. Steel particles are found to be the most effective bed material.
Review
Engineering, Chemical
Ningbo Song, Wanzhong Yin, Jin Yao
Summary: Seawater's dissolved salts and minerals have various effects on the flotation process, including influencing the characteristics and behavior of flotation factors, as well as affecting the surface of sulfide minerals. In most cases, seawater has adverse effects on the flotation of sulfide minerals, but these effects can be mitigated by adjusting the reagents.
Article
Engineering, Chemical
Kaiqiao Wu, Shuxian Jiang, Victor Francia, Marc-Olivier Coppens
Summary: In rectangular and cylindrical annular fluidized beds, pulsating gas flow can create regular bubble patterns, overcoming challenges seen in conventional units. This study provides new opportunities for modularization of fluidized bed operations.
Article
Engineering, Chemical
Shuo Li, Huili Zhang, Jan Baeyens, Miao Yang, Zehao Li, Yimin Deng
Summary: The paper assesses the behavior of cohesive Geldart C-type particles when fluidized by air with the aid of vibration. It determines that mechanical vibration is a simple and effective method to improve the fluidity of cohesive particles during fluidization.
Article
Engineering, Chemical
Zhenfei Feng, Qingyuan Zhang, Shanpan Liang, Zhenzhou Li, Fangwen Guo, Jinxin Zhang, Ding Yuan
Summary: A new micro/mini-channel heat sink (MCHS) with a combined structure of longitudinal and transverse vortex generators is designed, using Al2O3 nanofluid as the working medium. The study explores the effects of transverse vortex generator shape and longitudinal vortex generator angle on the hydraulic and thermal characteristics, comprehensive performance, entropy generation, and exergy efficiency. The results show that the triangular transverse vortex generator improves the comprehensive performance and exergy efficiency. Combined with the longitudinal vortex generator, the MCHS achieves the best comprehensive performance, entropy generation, and exergy efficiency when the Reynolds number is 742.
Article
Engineering, Chemical
Kostas Giannis, Christoph Thon, Guoqing Yang, Arno Kwade, Carsten Schilde
Summary: This study presents a 3D convolutional neural network (3D-CNN) methodology for generating realistic 3D models of particles. The method trains on 2D projections of particle images to predict their 3D shapes, and evaluates the accuracy of the predictions using Fourier shape descriptors (FSDs). This methodology has wide applications in particle shape analysis.
Article
Engineering, Chemical
Zheng-qing Zhou, Lu-jia Chai, Yu-long Zhang, Ya-bin Wang, Ze-chen Du, Tian-yi Wang, Yu-zhe Liu
Summary: The dynamic oxidation and shell-breaking processes of aluminum nanoparticles (ANPs) during heating were studied using in situ transmission electron microscopy. The results revealed that the changes in shell thickness can be divided into three stages, and the active aluminum content of ANP decreased before shell-breaking.
Article
Engineering, Chemical
Fulei Chen, Huaqing Ma, Zihan Liu, Lianyong Zhou, Yongzhi Zhao
Summary: A particle breakage model based on the particle replacement scheme, using the polyhedral model to describe particles, is proposed in this work to accurately describe the breakage of a large number of particles. Additionally, a fast-cutting algorithm is proposed to reproduce the size distribution of progeny particles determined by the breakage model. The validation and simulation results show satisfactory accuracy, efficiency, and stability of the algorithm.
Review
Engineering, Chemical
Matteo Errigo, Christopher Windows-Yule, Massimiliano Materazzi, Dominik Werner, Paola Lettieri
Summary: Gas-solid fluidized-bed systems have advantages in terms of chemical reaction efficiency and temperature control, making them widely used in industrial applications. However, the design, scale-up, and optimization of these complex units are limited by the lack of deep physical understanding. Non-invasive and non-intrusive diagnostic techniques provide a way for researchers to study these systems without affecting the flow field or directly contacting the medium under study.
Article
Engineering, Chemical
Saeed Fateh, Mohammad Behshad Shafii, Mohammad Najafi, Cyrus Aghanajafi
Summary: Applying a magnetic field to ferrofluids alters their flow characteristics and enhances heat transfer. Through visualization and quantitative investigation, it is found that the magnetic field influences the flow patterns and velocity profiles, improving fluid mixing and vorticity magnitude.
Article
Engineering, Chemical
Lei Gao, Bingbing Wei, Xiaochuan Hu, Zaifeng Yao, Yiwen Fang, Xuejian Gao
Summary: In this study, a numerical model of sand triaxial test was established using discrete element software PFC3D, and an indoor triaxial test was conducted to calibrate the numerical model. The influence of microscopic parameters on the macroscopic mechanical response of sand was analyzed. The results showed that the friction coefficient had the greatest impact on the peak strength and residual strength of the sand's stress-strain curve, and it was positively correlated. The normal tangential stiffness ratio was negatively correlated, while the porosity and boundary flexibility stiffness had minimal influence on it.
Article
Engineering, Chemical
Xuan Liu, Jie Gong, Kai Jiang, Xiaojuan Lai, Yu Tian, Kang Zhang
Summary: This study aimed to improve the performance of lignite coal water slurries (CWSs) by synthesizing a series of three-arm amphiphilic block copolymers. By controlling the relative molecular weight, hydrophilic/hydrophobic ratio, and ionic group content, the apparent viscosity of CWSs was significantly reduced and the static stability was improved. Thermogravimetric testing and XPS analysis were conducted to reveal the mechanism behind the improved performance.
Article
Engineering, Chemical
Lanka Dinushke Weerasiri, Daniel Fabijanic, Subrat Das
Summary: Fluidization at low pressure offers significant benefits for the fine chemical industry. This study investigates the behavior of bubbles and bed expansion under low pressure conditions. It is found that lower pressure leads to larger bubbles, increased bubble quantity, and higher aspect ratio. The predictability is affected by the inhomogeneous fluidization, but low pressure fluidization can generate similar bubble sizes with lower fluidizing mass compared to atmospheric pressure.