Article
Thermodynamics
Mohammad Abbaszadeh, Mohammad Hossein Montazeri, Mojtaba Mirzaie
Summary: This study proposes a novel implementation of twisted tape in sinusoidal wavy-walled tubes to enhance heat transfer rate without compromising thermal efficiency. The study numerically investigates the effect of different geometrical configurations on heat transfer improvement and performance factor. The results suggest that implementing twisted tape in wavy tubes significantly increases heat transfer rate and performance factor.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Thermodynamics
Aziz Hakan Altun, Haluk Nacak, Eyub Canli
Summary: The trapezoidal and twisted trapezoidal tape elements used for heat transfer enhancement in tubes were experimentally investigated, analyzing their effects on heat transfer, pressure drop, and overall performance factor. The experimental results showed that the twisted trapezoidal tape elements had excellent heat transfer performance and overall performance factor.
APPLIED THERMAL ENGINEERING
(2022)
Article
Engineering, Chemical
Muhyaddin J. H. Rawa, Nidal H. Abu-Hamdeh, Osama K. Nusier, Bashar Shboul, Turki AlQemlas, Saleh Mahmoud
Summary: This paper presents a computational fluid dynamics simulation of a heat exchanger filled with a two-phase hybrid nanofluid. The results show that the Reynolds number and the volume fraction of nanoparticles have a significant impact on the average Nusselt number and pressure drop.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2023)
Article
Thermodynamics
Sumit Kumar Singh, Jahar Sarkar
Summary: This study investigates the hydrothermal behaviors of a double tube heat exchanger with various inserts, showing that different enhancers can affect the heat transfer performance and pressure drop. V-cut twisted tapes and tapered wire coils exhibit higher heat transfer performance, while D-type wire coil shows the minimum value of entropy generation.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Multidisciplinary Sciences
En Li, Jin-Xin Hu, Xuemeng Feng, Zishu Zhou, Liheng An, Kam Tuen Law, Ning Wang, Nian Lin
Summary: The authors demonstrate the emergence of multiple ultra-flat electronic bands in twisted bilayer WSe2 using scanning tunneling microscopy and spectroscopy, indicating the potential for further study of exotic correlated phases in TB-TMDs.
NATURE COMMUNICATIONS
(2021)
Article
Thermodynamics
M. E. Nakhchi, J. A. Esfahani
Summary: The turbulent characteristics and thermal enhancement of CuO-water nanofluids through heat exchangers with double V-cut twisted tapes were investigated numerically. The results showed that the modified twisted tapes with cuts led to strong turbulent kinetic energy and additional vortex flow, improving fluid mixing and heat transfer. A significant enhancement in heat transfer efficiency of about 14.5% was observed for the nanofluid with a volume fraction of phi=1.5%, reaching a maximum thermal performance of eta=1.99 at Re=5000.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Review
Green & Sustainable Science & Technology
Younus Hamoudi Assaf, Abdulrazzak Akroot, Hasanain A. Abdul Wahhab, Wadah Talal, Mothana Bdaiwi, Mohammed Y. Nawaf
Summary: Research focuses on improving the thermal conductivity of heat exchangers by using different strategies such as inserting tapes and rings of various shapes, as well as transforming fluids into nanoliquids with nanomaterials. Factors such as torsion tape ratio, ring spacing, and flow direction impact heat transfer efficiency.
Article
Thermodynamics
Mehran Ghasemian, M. Sheikholeslami, Maziar Dehghan
Summary: This study applies numerical techniques to assess the integration of twisted tapes in different cross-sectional tubes of Photovoltaic/Thermal (PV/T) collector units, and the impact on system performance. Computational fluid dynamics is used to evaluate PV/T systems with cylindrical, rectangular, and triangular cross-sectional tubes, with and without twisted tapes. Various pitch-to-width ratios (YD) of twisted tapes and total inlet mass flow rates are considered. The analysis of energy and exergy is carried out to evaluate system performance. The results show that the triangular cross-sectional tube is optimal without twisted tapes, but the cylindrical tube with twisted tapes outperforms other designs in terms of electrical and thermal aspects. The addition of a twisted tape in the cylindrical tube increases electrical efficiency by 7.2% and 9%, respectively. Furthermore, integrating twisted tapes with the lowest pitch-to-width ratio reduces surface temperature by 3.2℃ and 17.55℃ compared to systems with cylindrical tubes and PV alone.
Article
Chemistry, Physical
Jiao An, Jun Kang
Summary: This study demonstrates the creation of multiple flat bands in carbon allotropes using twisted bilayer gamma-graphyne (TBGY) without the need for a specified magic angle. It also proposes a method to tune the width and extent of localization of flat bands through an energy mismatch between the layers of TBGY. This could allow for the study of correlation physics and quantum phase transitions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Green & Sustainable Science & Technology
Awatef Abidi, A. S. El-Shafay, Mohamed Degani, Kamel Guedri, S. Mohammad Sajadi, Mohsen Sharifpur
Summary: This study investigates the thermal and hydraulic efficiency of a parabolic trough solar collector using water-copper oxide nanofluid with different nanoparticles volume fractions. The results show that inserting twisted tape with circular holes can increase the pressure drop and heat transfer rate, and the best performance is achieved when using nanofluids with a nanoparticles volume fraction of 4%.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Physics, Multidisciplinary
M. Sheikholeslami, Seyyed Ali Farshad, M. Barzegar Gerdroodbary, Amir H. Alavi
Summary: This study investigates the influence of helical tapes on nanofluid turbulent flow in solar flat plate collectors and evaluates the impact of twisted tap (TT) and inlet velocity on the thermal efficiency and Darcy factor of the nanofluid flow. The results suggest that using twisted tapes significantly improves heat transfer efficiency.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Thermodynamics
Anwer B. Al-Aasam, Adnan Ibrahim, Kamaruzzaman Sopian, M. Bassam Abdulsahib, Mojtaba Dayer
Summary: The thermal performance of a photovoltaic thermal (PVT) collector with a twisted absorber tube and nanoparticle-enhanced phase change material (Nano-PCM) was evaluated. The photovoltaic, thermal, and combined photovoltaic thermal efficiencies were assessed using an indoor solar simulator. Circular and twisted absorber tubes with Nano-PCM were tested in two designs. Water with different volume fractions of SiC nanofluids was used as the working fluid. The highest efficiencies were achieved by the PVT-PCM with twisted tube and 0.6% nanofluids, with photovoltaic, thermal, and combined photovoltaic thermal efficiencies of 9.57, 84.74, and 94.31, respectively.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Sashank Thapa, Raj Kumar, Khusmeet Kumar, Sushant Samir, Daeho Lee, Tej Singh
Summary: Exergy analysis is a crucial method for studying the actual output of a system, taking into account all losses. This study uses MATLAB R2018a simulation software to calculate the thermal and exergetic efficiencies of a parabolic trough receiver. The results show that analyzing the design parameters of the receiver can improve energy and exergy performance, and reduce the need for extensive experimentation.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Abdullah Dawar, Abderrahim Wakif, Anwar Saeed, Zahir Shah, Taseer Muhammad, Poom Kumam
Summary: Motivated by the temporal relaxation feature of the Jeffrey model and its practical uses in the Theological modeling of several vital liquids, this study presents a theoretical analysis of three-dimensional MHD Jeffrey nanofluid flows over a dual stretching surface with velocity slip conditions. The results show that the magnetic and viscoelastic parameters have a declining effect on the velocity distributions, while the Deborah number generally has an escalating influence. Additionally, the presence of slip effects leads to greater variations in the velocity profiles. Moreover, the velocity stretching factor has a dominant impact on the velocity distribution along the y-direction compared to the x-direction. Thermally, a higher Biot number increases the temperature distribution, while a higher Schmidt number reduces the concentration distribution.
JOURNAL OF COMPUTATIONAL DESIGN AND ENGINEERING
(2022)
Article
Thermodynamics
Kim Leong Liaw, Jundika C. Kurnia, Zulfan A. Putra, Muhammad Aziz, Agus P. Sasmito
Summary: This study evaluates the heat transfer performance in a helical twisted Multilobe tube and proposes an enhancement method by combining twisting and Multilobe strategies. The results from experiments and numerical simulations reveal that this combination improves convective heat transfer performance. Furthermore, the variation of Multilobe geometries has a negligible effect on the heat transfer performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Hamid Reza Bahrami, Hamed Safikhani
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2020)
Article
Energy & Fuels
Hamed Bagheri-Esfeh, Hamed Safikhani, Sadegh Motahar
JOURNAL OF ENERGY STORAGE
(2020)
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
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)