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Heat transfer enhancement of finned shell and tube heat exchanger using Fe_(2)O_(3)/water nanofluid

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Journal of Central South University 2021年第11期28卷 3297-3309页

作者： afshari faraz SÖZEN Adnan KHANLARI Ataollah TUNCER Azim Doğuş Department of Mechanical Engineering Erzurum Technical UniversityErzurumTurkey Department of Energy Systems Engineering Gazi UniversityAnkaraTurkey Department of Mechanical Engineering Faculty of EngineeringTarsus UniversityMersinTurkey Department of Energy Systems Engineering Burdur Mehmet Akif Ersoy UniversityBurdurTurkey Natural and Applied Science Institute Gazi UniversityAnkaraTurkey

Heat transfer mechanisms and their thermal performances need to be comprehensively studied in order to optimize efficiency and minimize energy *** nanoparticles in the base fluid are investigated to upgrade the thermal performance of heat *** this numerical study,a finned shell and tube heat exchanger has been designed and different volume concentrations of nanofluid were tested to determine the effect of utilizing nanofluid on heat ***_(2)O_(3)/water nanofluids with volume concentration of 1%,1.5% and 2% were utilized as heat transfer fluid in the heat exchanger and the obtained results were compared with pure *** Fluent software as a CFD method was employed in order to simulate the mentioned *** simulation results indicated the successful utilization of nanofluid in the heat ***,increasing the ratio of Fe_(2)O_(3) nanoparticles caused more increment in thermal energy without important pressure ***,it was revealed that the highest heat transfer rate enhancement of 19.1% can be obtained by using nanofluid Fe_(2)O_(3)/water with volume fraction of 2%.

关键词： heat transfer enhancement nanofluid shell and tube heat exchanger Fe_(2)O_(3)

Experimental investigation of effect of refrigerant gases,compressor lubricant and operating conditions on performance of a heat pump

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Journal of Central South University 2021年第11期28卷 3556-3568页

作者： afshari faraz SÖZEN Adnan KHANLARI Ataollah TUNCER Azim Doğuş ALI Hafiz Muhammad Department of Mechanical Engineering Erzurum Technical UniversityErzurumTurkey Department of Energy Systems Engineering Gazi UniversityAnkaraTurkey Department of Mechanical Engineering Faculty of EngineeringTarsus UniversityMersinTurkey Department of Energy Systems Engineering Burdur Mehmet Akif Ersoy UniversityBurdurTurkey Natural and Applied Science Institute Gazi UniversityAnkaraTurkey Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia Interdisciplinary Research Center for Renewable Energy and Power Systems(IRC-REPS) King Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia

In the field of heat pumps,there are a number of parameters that affect the performance and efficiency of the apparatus,which have been the subject of studies by individual researchers in the *** study describes an experimental method in order to investigate the effects of some significant parameters on heat pump *** this regard,a laboratory heat pump setup has been utilized to operate in different working conditions for achieving an appropriate estimation to find out effects of mentioned parameters such as refrigerant type and charge amount,compressor oil viscosity,compressor cooling fan,secondary fluids temperature and flow *** refrigerants have been selected and used as circulating fluid in the installed heat *** this work has been devoted to a detailed attempt to recognize the effects of various parameters on the coefficient of performance(COP) value,an appropriate method has been carried out to survey the obtained results by using economic *** was revealed that one of the main parameters is refrigerant charge amount which has a notable effect on *** temperature of the heat source was also tested and the performance of the system increased by more than 11% by employing mentioned modifications and various operating *** addition,by selecting a low viscosity compressor oil,the system performance increased by 18%.This improvement is more than 6% for the case that cooling fan is installed to cool the compressor element.

关键词： heat pump efficiency coefficient of performance(COP) performance compressor oil charge amount

Sustainable pathways to ammonia: a comprehensive review of green production approaches

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CLEAN ENERGY 2024年第2期8卷 60-72页

作者： Ahmed, Hafiz Sharjeel Yahya, Zaid Khan, Waqar Ali faraz, Ali Univ Engn & Technol UET Lahore Pakistan NFC Inst Engn & Fertilizer Res Chem Engn Dept Faislabad Pakistan Univ Punjab Chem Engn Dept Lahore Pakistan

Ammonia production is vital in global industries but faces increasing environmental concerns, necessitating a shift towards sustainable methods. This review comprehensively explores diverse hydrogen production approaches and their potential impact on sustainable ammonia synthesis. The primary focus is investigating hydrogen production methods that enhance both efficiency and sustainability in ammonia synthesis, which is crucial for reducing its environmental footprint. Furthermore, the review highlights the pivotal role of catalysts in improving Faradaic efficiency in ammonia synthesis, emphasizing their significance in overall process efficiency. The study identifies innovative technologies that have the potential to revolutionize ammonia production while aligning with global sustainability goals. Through a thorough examination of hydrogen production methods and catalytic advances, this review provides valuable insight into greener and more efficient ammonia production practices. In conclusion, it emphasizes the importance of exploring hydrogen production methods and leveraging catalysts to improve ammonia production sustainability and efficiency. It addresses a critical research gap and paves the way for an environmentally responsible and globally aligned ammonia production industry. Hydrogen production methods that enhance both efficiency and sustainability in ammonia synthesis are reviewed, highlighting the pivotal role of catalysts in improving Faradaic efficiency in ammonia synthesis. It addresses a critical research gap and paves the way for an environmentally responsible and globally aligned ammonia production industry. Graphical Abstract

关键词： ammonia production green alternatives sustainability catalyst ELECTROCATALYTIC N-2 REDUCTION ELECTROCHEMICAL SYNTHESIS NITROGEN ELECTROSYNTHESIS CATALYSTS CARRIER WATER

Electronic and thermoelectric properties of YbMg_(2)X_(2)(X=P,As,Sb,Bi)zintl compounds by first-principles method

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Journal of Rare Earths 2024年第1期42卷 147-154,I0006页

作者： Sajid Khan Dil faraz Khan R.Neffati Tariq Usman Muhammad Waqar Ahsraf Shamim Khan Saeed Ullah Jan G.Murtaza Department of Physics University of Science&Technology BannuBannu28100Pakistan Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Laboratoire de Physique de La Matiere Condensee Departement de PhysiqueFaculte des Sciences de TunisUniversite Tunis El ManarCampus Universitaire1060TunisTunisia Department of Physics Shaoxing UniversityShaoxing312000China Department of Mathematics&Natural Sciences Prince Mohammad Bin Fahd UniversityAlkhobar31952Saudi Arabia Materials Modeling Lab Department of PhysicsIslamia College Peshawar25120KhyberPakhtunkhwaPakistan

In this work the structural,electronic and thermoelectric properties of YbMg_(2)X_(2)(X=P,As,Sb,Bi)zintl compounds were investigated comprehensively using first principles *** electronic properties were studied using PBE GGA,TB-mBJ and hybrid(YS-PBE0)*** the structural parameters of optimized structures are in harmonious agreement to the available *** band structure study illustrates that the titled materials manifest metallic and semi metallic nature using PBE and TB-mBJ potentials while they show wide band gap semiconducting behavior by following hybrid(YS-PBE0)*** density of states(TDOS)and partial density of states(PDOS)were also calculated to glimpse the contribution of orbitals of atoms in the formation of *** properties were studied by using BoltzTraP2 code employed to *** get enormous values of Seebeck coefficient(S),power factor(PF)and thermoelectric figure of merit(ZT)for all the samples YbMg_(2)X_(2)(X=P,As,Sb,Bi),Moreover,the overwhelming transport properties for the titled compounds indicate the optimum level of carriers’concentration which pinpoints these materials to be better thermoelectrics in the 1-2-2 zintl family.

关键词： Zintl compounds Hybrid functional Band structure Thermoelectrics Rare earths

Unveiling the cellular microstructure-property relations in martensitic stainless steel via laser powder bed fusion

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International Journal of Minerals,Metallurgy and Materials 2024年第11期31卷 2476-2487页

作者： Lingzhi Wu Cong Zhang Dil faraz Khan Ruijie Zhang Yongwei Wang Xue Jiang Haiqing Yin Xuanhui Qu Geng Liu Jie Su Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Department of Physics University of Science and Technology BannuBannu 28100Pakistan Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Institute for Special Steel Research Central Iron and Steel Research InstituteBeijing 100081China

Laser powder bed fusion(LPBF)is a widely recognized additive manufacturing technology that can fabricate complex components rapidly through layer-by-layer ***,there is a paucity of research on the effect of laser scanning speed on the cellular microstructure and mechanical properties of martensitic stainless *** study systematically investigated the influence of laser scanning speed on the cellular microstructure and mechanical properties of a developed Fe11Cr8Ni5Co3Mo martensitic stainless steel produced by *** results show that increasing the laser scanning speed from 400 to 1000 mm/s does not lead to a noticeable change in the phase fraction,but it reduces the average size of the cellular microstructure from 0.60 to 0.35μ*** scanning speeds of 400 and 1000 mm/s both had adverse effects on performances of sample,resulting in inadequate fusion and keyhole defects *** optimal scanning speed for fabricating samples was determined to be 800 mm/s,which obtained the highest room temperature tensile strength and elongation,with the ultimate tensile strength measured at(1088.3±2.0)MPa and the elongation of(16.76±0.10)%.Furthermore,the mechanism of the evolution of surface morphology,defects,and energy input were clarified,and the relationship between cellular microstructure size and mechanical properties was also established.

关键词： laser powder bed fusion martensitic stainless steel cellular microstructure mechanical properties strengthening mechanism

High Velocity Compaction of Aluminum Powders

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稀有金属材料与工程 2011年第S3期40卷 86-89页

作者： Khan Dil faraz University of Science and Technology Beijing

High velocity compaction process of atomized Al powders was studied. The green density, the maximal force and the withdraw force of specimen were investigated. The green density of atomized aluminum powder was obtained to be 2.68 g/cm3 and its relative density is about 99%. The maximal force increased proximately linearly with the compaction energy. The withdraw force was observed ranging between 30 and 70 kN. The radial spring back was less than 0.1%.

关键词： high velocity compaction powder metallurgy aluminum powder

Lattice parameters of Ti–4Al–2V alloy with thermal oxidation

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Rare Metals 2016年第2期35卷 149-153页

作者： faraz Omidbakhsh Ali Reza Ebrahimi Department of Mechanical Engineering Tabriz Branch Islamic Azad University Mining and Metallurgical Engineering Department Amirkabir University of Technology

In this study, the effect of thermal oxidation on the lattice parameters of Ti-4Al-2V alloy was *** were oxidized at 450, 600 and 650 °C for 1-7 h in electric furnace under air atmosphere. The lattice parameters were determined using the Cohen method as a function of oxidation time at each temperature. The lattice parameters of as-received alloy are calculated as a = 0.29289 nm and c = 0.46652 nm. The thermal oxidation at 450 °C results in a gradual increase in a-parameter, whereas it goes through a maximum at higher temperatures（600 and 700 °C）. The results show that these maximums are reduced to an approximately constant value after a long-time oxidation. The c-parameter generally increases over the whole treatment condition. It is believed that these variations could be due to the dissolution of oxygen atoms in octahedral sites of hcp lattice of titanium.

关键词： Lattice parameter Ti-4Al-2V X-ray diffraction Cohen method Octahedral sites

Thin Film Flow of a Second Grade Fluid over a Stretching/Shrinking Sheet with Variable Temperature-Dependent Viscosity

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Chinese Physics Letters 2010年第3期27卷 212-215页

作者： S. Nadeem Naeem faraz Department of Mathematics Quaid-i-Azam University 45320 Islamabad Pakistan

Effects of variable viscosity on the flow and heat transfer in a thin film on a horizontal porous stretching sheet are analyzed. The steady boundary layer equations for momentum and thermal energy are simplified by using similarity transformations. The resulted and coupled nonlinear differential equations are solved by Homotopy analysis method. The results are presented graphically to interpret various physical parameters appearing in the problem.

关键词： Soft matter liquids and polymers Fluid dynamics Mathematical physics

A multi-layered policy generation and management engine for semantic policy mapping in clouds

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Digital Communications and Networks 2020年第1期6卷 38-50页

作者： faraz Fatemi Moghaddam Philipp Wieder Ramin Yahyapour Gesellschaft für wissenschaftliche Datenverarbeitung mbH Gottingen(GWDG) Germany Institute of Informatics Georg-August-UniversitatGottingenGermany

The long awaited cloud computing concept is a reality now due to the transformation of computer ***,security challenges have become the biggest obstacles for the advancement of this emerging technology.A well-established policy framework is defined in this paper to generate security policies which are compliant to requirements and ***,a federated policy management schema is introduced based on the policy definition framework and a multi-level policy application to create and manage virtual clusters with identical or common security *** proposed model consists in the design of a well-established ontology according to security mechanisms,a procedure which classifies nodes with common policies into virtual clusters,a policy engine to enhance the process of mapping requests to a specific node as well as an associated cluster and matchmaker engine to eliminate inessential mapping *** suggested model has been evaluated according to performance and security parameters to prove the efficiency and reliability of this multilayered engine in cloud computing environments during policy definition,application and mapping procedures.

关键词： Cloud computing Security Security management Policy management Access control Policy mapping