Article
Thermodynamics
Mehdi Bahiraei, Mohammad Naseri, Ali Monavari
Summary: The study reveals that nanoparticle shape has an impact on the entropy generation rate in a heat exchanger, with platelet-shaped nanoparticles showing the highest entropy production in the hot fluid and Os-shaped particles exhibiting the highest thermal and frictional entropy production in the cold fluid.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Chemical
Mehdi Bahiraei, Ali Monavari
Summary: The study investigates the influence of varied nanoparticle shapes, Reynolds numbers, and inlet temperatures on the thermal-hydraulic efficacy of a boehmite nanofluid in a mini shell and tube heat exchanger. Results show that increasing Reynolds number leads to higher heat transfer rate, overall heat transfer coefficient, and effectiveness, while the performance index decreases.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Engineering, Chemical
Ali Monavari, Jafar Jamaati, Mehdi Bahiraei
Summary: The study investigates the effects of different particle shapes on the thermohydraulic performance of a boehmite nanofluid in a microchannel heat sink with various cross-sections. Results show that microchannels with triangular cross-sections exhibit the highest heat transfer coefficient and best temperature distribution, while nanofluids with platelet particles cause the highest pressure loss. Uniformity of temperature distribution and thermal resistance decrease with increasing Reynolds number, while heat transfer coefficient, pressure drop, and pumping power increase. Additionally, nanofluids with platelet particles demonstrate the highest heat transfer coefficient among all shapes tested.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2021)
Article
Engineering, Chemical
Mehdi Bahiraei, Mohammad Naseri, Ali Monavari
Summary: The irreversibility characteristics of a shell and tube heat exchanger fitted with the unilateral ladder type helical baffle were investigated in this study. It was found that the entropy production rates of both hot and cold fluids increased with the Reynolds number amplification, with the nanofluid containing platelet nanoparticles causing the maximum thermal entropy production. The minimum irreversibility for the whole STHE occurred for the nanofluid containing oblate spheroid particles, which is recommended for use in this STHE.
Article
Thermodynamics
Mehdi Bahiraei, Mohammad Naseri, Ali Monavari
Summary: The present study investigates the thermohydraulic characteristics and performance index for nanofluids with various particle shapes in a shell and tube heat exchanger, finding that nanofluids with platelet and OS additives demonstrate the best performance in terms of heat transfer rate, overall coefficient, effectiveness, NTU, and performance index. The study also highlights the significant impact of different particle shapes on heat transfer performance and flow patterns in the shell side of the heat exchanger.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Chemical
Mehdi Bahiraei, Ali Monavari
Summary: The thermal-hydraulic efficacy of boehmite nanofluids with different particle shapes was evaluated inside a microchannel heat sink, showing that nanofluids with platelet-shaped nanoparticles have the best heat transfer performance, while those with oblate spheroid particles have the lowest heat transfer performance and smallest pressure loss. Overall, the study found that heat transfer capabilities were influenced by particle shape, with platelet-shaped nanoparticles showing the most promising results.
CHINESE JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Engineering, Chemical
Mehdi Bahiraei, Ali Monavari
Summary: The second law of thermodynamics is evaluated for a water/Ethylene Glycol-boehmite nanofluid in a mini shell and tube heat exchanger. The results show that different particle shapes have different effects on entropy generation and Bejan number. Moreover, the fin structure of the heat exchanger also affects entropy generation and Bejan number.
Article
Metallurgy & Metallurgical Engineering
Faraz Afshari, Adnan Sozen, Ataollah Khanlari, Azim Dogus Tuncer
Summary: The study successfully utilized nanofluid in a shell and tube heat exchanger, increasing thermal energy without adding significant pressure drop. The highest heat transfer rate enhancement of 19.1% was achieved using Fe2O3/water nanofluid with a volume fraction of 2%.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2021)
Article
Thermodynamics
Aysan Shahsavar Goldanlou, Mohammad Sepehrirad, Mostafa Papi, Ahmed Kadhim Hussein, Masoud Afrand, Sara Rostami
Summary: The study investigated the forced convection heat transfer of Fe3O4/CNT/water hybrid nanofluid in a heat exchanger with blade-shape turbulators. The results showed that the highest performance features occurred under specific conditions, such as certain Reynolds number and volume concentrations of nanoparticles.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Engineering, Mechanical
Amin Shahsavar, Kasra Moradi, Cagatay Yildiz, Peyman Farhadi, Muslum Arici
Summary: This study investigates the effects of different nanoparticle shapes on flow and heat transfer characteristics in a microchannel helical heat sink. The study finds that the utilization of nanofluids significantly improves heat transfer while increasing pumping power. It also reveals that the nanoparticle shape strongly influences the parameters, with platelet shaped particles being the most advantageous.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Chemistry, Analytical
Maissa Bouselsal, Fateh Mebarek-Oudina, Nirmalendu Biswas, Abdel Aziz I. Ismail
Summary: The present study focuses on improving the tube/shell heat exchanger by altering the tube's geometrical shape and/or adding nanoparticles in its heat transfer fluid, aiming to maximize efficiency and energy savings. The results show that increasing the nanoparticle concentration and velocity of the heat transfer fluid can enhance the heat exchange rate, and diamond-shaped tubes exhibit superior heat transfer performance. This study is highly significant in solving many heat transfer problems in the industrial field.
Article
Energy & Fuels
Nima Mazaheri, Mehdi Bahiraei
Summary: The study investigated the energy, exergy, and hydrodynamic characteristics of using boehmite alumina nanofluid in a spiral heat exchanger with five different nanoparticle shapes. It was found that higher volume fractions of nanofluid enhanced heat exchange amount, overall heat transfer coefficient (U), and effectiveness. Different nanoparticle shapes had varying effects on thermal efficiency and energy efficiency, with platelet-shaped nanoparticles performing best at constant Re and oblate spheroid-shaped nanoparticles being recommended for energy efficiency perspective.
CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION
(2021)
Article
Engineering, Multidisciplinary
M. M. Alqarni, Muhammaad Ibrahim, Taghreed A. Assiri, Tareq Saeed, Abd Allah A. Mousa, Vakkar Ali
Summary: The purpose of this study is to design an efficient heat exchanger filled with hybrid nanofluid using numerical methods. The results show that using ribbed tubes and nanofluids can improve the efficiency of the heat exchanger. The study also discusses the method of choosing the optimal grid-mesh and identifies the model with the highest efficiency.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Article
Thermodynamics
Yuce Liu, Jian Wen, Simin Wang, Jiyuan Tu
Summary: A novel type of shell and tube heat exchanger with modified fold helical baffles and twisted oblate tubes (STHXsFBTB) is proposed and its thermal and hydraulic properties for water chiller systems are investigated in comparison with the traditional STHXsFB. The results show that STHXsFBTB has improved heat transfer performance, with factors such as screw pitch and tube diameter ratio, length width ratio, and cutting ratio influencing its performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Dan Zheng, Jianqiang Du, Wei Wang, Jiri Jaromir Klemes, Jin Wang, Bengt Sunden
Summary: This research investigates the convective heat transfer and hydraulic resistance of smooth and corrugated double-tube heat exchangers at different flow rates. The combination of a thread structure on the outer tube side and nanofluids on the inner tube side improves the overall heat transfer performance. The best combination is a 4 mm thread pitch with a 1.5 wt% SiC-water nanofluid, resulting in a 59% increment in the comprehensive performance index.
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.