Article
Engineering, Chemical
Hossein Fatahian, Esmaeel Fatahian, Rasool Erfani
Summary: The square cyclone separator is an efficient device for separating high-temperature gas in CFB boilers. This study analyzed gas flow in a square cyclone and investigated the effects of various parameters using CFD. The Taguchi method and ANOVA were used to optimize the cyclone performance. The results showed that particle mass flow rate had the least impact, while inlet velocity had the most contribution to the cyclone performance.
Article
Engineering, Chemical
Mehdi Modabberifar, Hadi Nazaripoor, Hamed Safikhani
Summary: This paper investigates the numerical simulation of flow field in three types of standard new design cyclone separators, revealing that cyclone 2D2Dn has the highest efficiency while cyclone 1D2Dn has the lowest. Additionally, the highest pressure drop occurs in cyclone 2D2Dn.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Engineering, Chemical
Anjun Li, Zhenbo Wang, Liyun Zhu, Ziyi Wang, Xiaogang Xu, Liang Fang
Summary: The study proposed a down-flow gas-solid cyclone reactor (GSCR) to tackle side reactions in fluidized catalytic cracking process. Three-dimensional numerical models were established to interpret the gas-solid flow features, showing that the four-way approach provided better prediction of the hydrodynamics in GSCR. Most catalysts accumulated on the wall during descent, forming a phase interface structure, where tangential velocity distribution was hump-shaped and tangential and axial kinetic energies dominated. In dilute condition, particle concentration exhibited more severe oscillatory behavior than gas velocities, with both having similar dominant frequency when particle loading increased tenfold.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Adrian Stuparu, Romeo Susan-Resiga, Alin Bosioc
Summary: This study aims to evaluate the feasibility of using an industrial stirred chemical reactor for liquid-solid suspensions, and found that the impeller design is not suitable for preparing a new chemical product due to insufficient suspension time of the solid phase.
APPLIED SCIENCES-BASEL
(2021)
Article
Agricultural Engineering
Mahmoud A. El-Emam, Ling Zhou, Abdelaziz I. Omara
Summary: The effects of using cyclone spiral inlets on the air flow pattern and the bioparticle separation process were investigated using computational fluid dynamics (CFD) and discrete element method (DEM). The study found that the design of the inlet plays a critical role in determining cyclone performance, affecting the pressure, velocity, and turbulence parameters of the airflow. Double axisymmetric spiral inlets demonstrated enhanced coordination and resulted in a 4%-14% increase in cyclone performance. The study concludes that the double axisymmetric spiral inlet cyclone design is the most optimized for achieving the highest performance in separating large particles.
BIOSYSTEMS ENGINEERING
(2023)
Article
Engineering, Chemical
Ehsan Dehdarinejad, Morteza Bayareh
Summary: This paper presents a study on improving the performance of a gas-solid cyclone by using twisted baffles. Numerical simulations demonstrate that the baffles have a significant effect on various parameters of the cyclone, such as velocities, turbulence intensity, pressure drop, and particle separation efficiency. Experimental results confirm the enhanced separation efficiency of solid particles with a diameter of less than 2 μm by using the baffles.
Article
Thermodynamics
Mohammad Naghashnejad, Hamidreza Shabgard, Theodore L. Bergman
Summary: A computational model is developed to investigate the dynamic response of an evaporating meniscus during capillary flow. The model accurately tracks the formation and evolution of the meniscus and reveals the critical effect of thermal diffusion on the evaporation rate.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Engineering, Chemical
Zachary Reinking, Kevin J. Whitty, JoAnn S. Lighty
Summary: This study proposes an alternative disengager gas-solid separator for circulating fluidized bed boilers, which allows for effective separation of ash and desirable bed material based on the entrainment velocity of particles. Compared to traditional cyclones, this disengager design can achieve higher ash removal efficiency while retaining sufficient desirable material.
Article
Engineering, Chemical
Ehsan Dehdarinejad, Morteza Bayareh
Summary: Cyclone separators play a dominant role in various fields and their performance criteria include separation mechanism, pressure drop, and collection efficiency. Numerical simulations help understand the impact of different parameters on cyclone performance and provide some suggestions based on previous simulations.
CHEMBIOENG REVIEWS
(2021)
Article
Engineering, Mechanical
Ebrahim Hosseini, Hossein Fatahian, Goodarz Ahmadi, Majid Eshagh Nimvari, Esmaeel Fatahian
Summary: The square cyclone's performance is affected by the inlet gas temperature, with the particle separation efficiency decreasing significantly as the temperature increases. With the increase in inlet temperature, the centrifugal force decreases, leading to a larger 50% cut size.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Adrian Stuparu, Romeo Susan-Resiga, Constantin Tanasa
Summary: Replacing a two-blade original impeller with a new three-blade design in a baffled stirred reactor has shown clear improvements in mixing liquid-solid suspensions, maintaining the shaft power at a similar level. Numerical investigations using a multiphase model and turbulence model demonstrate that the new design increases sedimentation time of the solid phase beyond specific chemical reaction times. Power required for the new impeller is slightly higher than for the original impeller, but can be sustained by the existing driving system.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Chemical
Hongjie Yan, Zhengzong Huang, Ming Hu, Jingwei Qi, Liu Liu
Summary: The plasma melting furnace is widely used in the harmless treatment of waste incineration due to its low leaching rate of heavy metals and high energy utilization. This paper numerically models the gas-solid flow in the furnace and studies the behavior of slag particles. The results show that pelletizing the raw fly ash is necessary for successful melting reaction and to prevent erosion with the graphite cathode. The velocity and temperature fields in the furnace are asymmetric due to the interaction between flue gas and slag particles. The study also analyzes the distribution of slag particles on the bath surface and discusses the collisional erosion effect on the graphite cathode.
Article
Computer Science, Interdisciplinary Applications
Achyut Panchal, Suresh Menon
Summary: A hybrid EE-EL formulation is developed in this work for accurate and efficient computational modeling involving a transition between dense and dilute dispersed phase regimes. A smooth and dynamic transition criterion and conversion algorithm enable smooth transition between the two representations of the dispersed phase. The method's ability to dynamically transition from EE to EL and vice versa is evaluated in numerical tests and simulations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Review
Mathematics
Aleksey Yu. Varaksin, Sergei V. Ryzhkov
Summary: This article focuses on the importance of mathematical modeling in studying gas-solid two-phase flows and analyzes the main problems and characteristics in dealing with solid particles as the dispersed phase. The main features of gas flows with solid particles are discussed, leading to the development of a classification of two-phase flows. The article describes the Lagrangian and Euler approaches for modeling the motion of dispersed phase, and pays attention to the consideration of different numerical simulation methods at various hierarchical levels, interphase interactions, and interface resolutions. Examples of studies based on the identified approaches are excluded, and the latest research on mathematical modeling of various classes of gas-solid two-phase flows is also excluded.
Article
Engineering, Chemical
Ying Cui, Ye Zou, Xinwang Wang, Wenqi Zhong
Summary: The supercritical CO2 (S-CO2) power cycle has become a highly efficient and low-pollution method used worldwide to improve thermal power generation efficiency and reduce energy consumption. By comparing it with a conventional water steam CFB boiler, the S-CO2 CFB boiler demonstrates a smooth and stable gas-solid flow pattern with uniform particle concentration and velocity distribution, indicating its good combustion uniformity. Compared to smaller S-CO2 CFB boilers, the 1000 MW one exhibits higher carbon conversion rate but lower desulphurization and nitrogen removal performance with specific outlet concentrations of CO, NO, and SO2.(c) 2023 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.
ADVANCED POWDER TECHNOLOGY
(2023)
Article
Construction & Building Technology
Asgar Minaei, Hamed Safikhani
Summary: A simple yet accurate transient model was developed to evaluate the thermal performance of earth to air heat exchangers (EAHEs) in this study. The analytical model was validated using experimental data and compared with numerical simulations, showing good correlation. Results also revealed thermal saturation of the soil with continuous operation, highlighting the importance of considering this factor in system performance evaluation.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Thermodynamics
Alireza Aminmahalati, Alireza Fazlali, Hamed Safikhani
Summary: In this study, the combustion chamber of a CO steam boiler is multi-objectively optimized using computational fluid dynamics and NSGA II algorithm, with the main goals of maximizing outlet gas temperature and minimizing chamber wall temperature. A step-wise increase of the mesh was used to ensure an adequate number of nodes, and simplifications were made to deal with the complexity of the steam boiler system.
Article
Green & Sustainable Science & Technology
Asgar Minaei, Zahra Talee, Hamed Safikhani, Hadi Ghaebi
Summary: A new hybrid model for transient heat transfer in Earth-Air Heat Exchangers (EAHE) based on thermal resistance capacity circuit is developed in this study, taking into account the thermal capacity of the soil around the pipe in the simulation. The results of the model show acceptable agreement with experimental and numerical ones, indicating the reliability of the model.
Article
Engineering, Chemical
Hamed Safikhani, Mohammad Rafiee, Dariush Ashtiani
Summary: This paper investigates the flow field in new design cyclones with different wall temperature profiles and finds that heating the bottom zone can improve efficiency and reduce pressure drop. Among the five temperature profiles tested, types C and E showed the most significant improvement in efficiency.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Engineering, Civil
Mostafa Yousefi, Morteza Yousefi, Hamed Safikhani, Kiao Inthavong, Keivan Bamdad
Summary: Fire safety is a major design concern for tunnel engineers, with longitudinal ventilation being a common method for dealing with smoke and hot gases. The critical velocity, key to designing the longitudinal exhaust system, was determined using an analytical solution in this study. By comparing analytical results with experimental and numerical data, the study showed that a modified Froude number can improve the accuracy of the analytical solution and save time compared to iterative methods.
FIRE SAFETY JOURNAL
(2021)
Article
Engineering, Chemical
Mehdi Modabberifar, Hadi Nazaripoor, Hamed Safikhani
Summary: This paper investigates the numerical simulation of flow field in three types of standard new design cyclone separators, revealing that cyclone 2D2Dn has the highest efficiency while cyclone 1D2Dn has the lowest. Additionally, the highest pressure drop occurs in cyclone 2D2Dn.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Thermodynamics
Alireza Aminmahalati, Alireza Fazlali, Hamed Safikhani
Summary: This study evaluated the combustion chamber performance of the CO boiler at an oil refinery using computational fluid dynamics, showing a 96% accuracy in simulation compared to experimental results. Analysis included velocity profiles, flame thermal profiles, and reaction rates of combustible compounds. The study used non-dominated sorting genetic algorithm II to determine optimal operating conditions and presented the impact of different fluid intensities on various parameters.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
C. Thianpong, K. Wongcharee, H. Safikhani, S. Chokphoemphun, A. Saysroy, S. Skullong, S. Eiamsa-ard
Summary: This study utilized a hybrid technique involving TiO2/water nanofluid and loose-fit delta-wing twisted tape to enhance heat transfer efficiency. Experimental results showed that the combined enhancement technique significantly improved heat transfer rates, mainly due to the swirling flow effect and higher thermal conductivity. Furthermore, reducing the loose-fit ratio and increasing the nanofluid concentration can also enhance heat transfer rates and thermohydraulic performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Environmental Sciences
S. A. Mostafavi, A. Dadsetan, H. Safikhani
Summary: This paper models the impact of using urban buses with outdated or modern environmental technologies on the air pollution in Arak city. The results show that the presence of EURO3 and EURO4 urban buses leads to PM2.5 pollutants concentration exceeding the standard level. The use of EURO4 urban buses can effectively reduce the number of polluted days.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Aerospace
S. Eiamsa-ard, V Chuwattanakul, H. Safikhani, P. Promthaisong
Summary: In this paper, multi-objective optimization of geometric parameters of spirally-cross-corrugated (SCC) tubes is carried out using numerical methods, genetic algorithms, and artificial neural networks. The analysis reveals several important optimal design principles for heat transfer in such tubes.
THERMOPHYSICS AND AEROMECHANICS
(2022)
Article
Engineering, Multidisciplinary
A. Aminmahalati, A. Fazlali, H. Safikhani
Summary: This study re-examined the design of the combustion chamber in Imam Khomeini Oil Refinery Company using CFD and simplified the 3D simulation by applying the symmetry principle. The results showed that the temperature and velocity in the combustion chamber were within an appropriate range without thermal damage.
INTERNATIONAL JOURNAL OF ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
M. Yousefi, H. Safikhani, E. Jabbari, V. Tahmasbi
Summary: This paper utilizes CFD and RSM for optimization of drug delivery efficiency for emergency respiratory patients. Through DOE and RSM, the output efficiency and regression equation model are derived to investigate the impact of each input parameter on efficiency, and the best combination of input parameters yielding the highest efficiency is found through optimization algorithm.
INTERNATIONAL JOURNAL OF ENGINEERING
(2021)
Article
Energy & Fuels
Seyed Alireza Mostafavi, Hamed Safikhani, Siavash Salehfard
Summary: This paper develops a comprehensive model for studying air pollution in Arak city, Iran, and validates the model by comparing it with data from ambient air monitoring. The study finds that the levels of NOx, CO, and SO2 pollutants in Arak city exceed standard values, with a significant contribution from industrial sources, particularly IRALCO.
INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENTAL ENGINEERING
(2021)
Article
Engineering, Chemical
Hamed Safikhani, Sadegh Allahdadi
ADVANCED POWDER TECHNOLOGY
(2020)
Article
Engineering, Multidisciplinary
H. Safikhani, F. Esmaeili, S. Salehfard
INTERNATIONAL JOURNAL OF ENGINEERING
(2020)
Article
Engineering, Chemical
Yongxiang Wu, Nguyen Thi Hong Nhung, Deqian Zeng, Nengneng Luo, Akira Otsuki, Gjergj Dodbiba, Toyohisa Fujita
Summary: This study proposed a novel method for synthesizing flower-like vaterite calcium carbonate using nanobubble-containing ethanol and water mixed solution as the solvent and discussed the formation mechanism of vaterite with different shapes. The synthesized vaterite has significant practical interest in the integrated treatment of wastewater contaminated by heavy metals with effective Cd(II) removal, providing a promising field for studying heavy metal and pollutant adsorption in the liquid phase.
ADVANCED POWDER TECHNOLOGY
(2024)
Article
Engineering, Chemical
Jian Gong, Lipo Cheng, Ming Liu, Jie Jiang, Xiaoduo Ou
Summary: This study investigates the effects of particle shape on the collapse of granular columns using the discrete element method. The results show that particle shape has a significant impact on deposition morphology, energy evolution, and mechanical coordination number. Sphericity and angularity are identified as the most important macroscale factors, while roughness has a weaker microscale influence.
ADVANCED POWDER TECHNOLOGY
(2024)
