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1 – 4 of 4Chinedu Chinakwe, Adekunle Adelaja, Michael Akinseloyin and Olabode Thomas Olakoyejo
Inclination angle has been reported to have an enhancing effect on the thermal-hydraulic characteristics and entropy of some thermal systems. Therefore, this paper aims to…
Abstract
Purpose
Inclination angle has been reported to have an enhancing effect on the thermal-hydraulic characteristics and entropy of some thermal systems. Therefore, this paper aims to numerically investigate the effects of inclination angle, volume concentration and Reynolds number on the thermal and hydraulic characteristics and entropy generation rates of water-based Al2O3 nanofluids through a smooth circular aluminum pipe in a turbulent flow.
Design/methodology/approach
A constant heat flux of 2,000 Watts is applied to the circular surface of the tube. Reynolds number is varied between 4,000 and 20,000 for different volume concentrations of alumina nanoparticles of 0.5%, 1.0% and 2.0% for tube inclination angles of ±90o, ±60o, ±45o, ±30o and 0o, respectively. The simulation is performed in an ANSYS Fluent environment using the realizable kinetic energy–epsilon turbulent model.
Findings
Results show that +45o tube orientation possesses the largest thermal deviations of 0.006% for 0.5% and 1.0% vol. concentrations for Reynolds numbers 4,000 and 12,000. −45o gives a maximum pressure deviation of −0.06% for the same condition. The heat transfer coefficient and pressure drop give maximum deviations of −0.35% and −0.39%, respectively, for 2.0% vol. concentration for Reynolds number of 20,000 and angle ±90o. A 95%–99.8% and 95%–98% increase in the heat transfer and total entropy generation rates, respectively, is observed for 2.0% volume concentration as tube orientation changes from the horizontal position upward or downward.
Originality/value
Research investigating the effect of inclination angle on thermal-hydraulic performance and entropy generation rates in-tube turbulent flow of nanofluid is very scarce in the literature.
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Han Zhao, Qingmiao Ding, Yaozhi Li, Yanyu Cui and Junjie Luo
This paper aims to study the influence of microparticles on the surface cavitation behavior of 2Cr3WMoV steel; microparticle suspensions of different concentration, particle size…
Abstract
Purpose
This paper aims to study the influence of microparticles on the surface cavitation behavior of 2Cr3WMoV steel; microparticle suspensions of different concentration, particle size, material and shape were prepared based on ultrasonic vibration cavitation experimental device.
Design/methodology/approach
2Cr3WMoV steel was taken as the research object for ultrasonic cavitation experiment. The morphology, quantity and distribution of cavitation pits were observed and analyzed by metallographic microscope and scanning electron microscope.
Findings
The study findings showed that the surface cavitation process produced pinhole cavitation pits on the surface of 2Cr3WMoV steel. High temperature in the process led to oxidation and carbon precipitation on the material surface, resulting in the “rainbow ring” cavitation morphology. Both the concentration and size of microparticles affected the number of pits on the material surface. When the concentration of microparticles was 1 g/L, the number of pits reached the maximum, and when the size of microparticles was 20 µm, the number of pits reached the minimum. The microparticles of Fe3O4, Al2O3, SiC and SiO2 all increased the number of pits on the surface of 2Cr3WMoV steel. In addition, the distribution of pits of spherical microparticles was more concentrated than that of irregularly shaped microparticles in turbidity.
Originality/value
Most of the current studies have not systematically focused on the effect of each factor of microparticles on the cavitation behavior when they act separately, and the results of the studies are more scattered and varied. At the same time, it has not been found to carry out the study of microparticle cavitation with 2Cr3WMoV steel as the research material, and there is a lack of relevant cavitation morphology and experimental data.
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Florence Dami Ayegbusi, Emile Franc Doungmo Goufo and Patrick Tchepmo
The purpose of this study is to explore numerical scrutinization of micropolar and Walters-B non-Newtonian fluids motion under the influence of thermal radiation and chemical…
Abstract
Purpose
The purpose of this study is to explore numerical scrutinization of micropolar and Walters-B non-Newtonian fluids motion under the influence of thermal radiation and chemical reaction.
Design/methodology/approach
The two fluids micropolar and Walters-B liquid are considered to start flowing from the slot to the stretching sheet. A magnetic field of constant strength is imposed on their flow transversely. The problems on heat and mass transport are set up with thermal, chemical reaction, heat generation, etc. to form partial differential equations. These equations were simplified into a dimensionless form and solved using spectral homotopy analysis method (SHAM). SHAM uses the basic concept of both Chebyshev pseudospectral method and homotopy analysis method to obtain numerical computations of the problem.
Findings
The outcomes for encountered flow parameters for temperature, velocity and concentration are presented with the aid of figures. It is observed that both the velocity and angular velocity of micropolar and Walters-B and thermal boundary layers increase with increase in the thermal radiation parameter. The decrease in velocity and decrease in angular velocity occurred are a result of increase in chemical reaction. It is hoped that the present study will enhance the understanding of boundary layer flow of micropolar and Walters-B non-Newtonian fluid under the influences of thermal radiation, thermal conductivity and chemical reaction as applied in various engineering processes.
Originality/value
All results are presented graphically and all physical quantities are computed and tabulated.
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The construction industry shows an increased interest in how to manage logistics within construction projects. Often construction logistics is outsourced to a logistics service…
Abstract
Purpose
The construction industry shows an increased interest in how to manage logistics within construction projects. Often construction logistics is outsourced to a logistics service provider (LSP). However, construction logistics is normally approached either as a strategic decision or as an operational issue and rarely as a tactical concern. The purpose of this study is to explore how to organize the logistics outsourcing decision at strategic, tactical and operational levels.
Design/methodology/approach
This study is performed as a single-case study within a construction corporation, containing (amongst others) a building contractor (BC) and a construction equipment rental company (CERC) offering logistics services.
Findings
The study shows that to procure construction logistics service successfully, BCs need logistics capabilities at strategic and tactical levels to maintain an alignment between the use of logistics services and operational characteristics. Simultaneously, CERC’s need to design their service offerings to correspond to the needs of the BC.
Research limitations/implications
This study builds on a single-case study of a Swedish construction corporation. Further research is needed to better understand current logistics outsourcing and development practices and how these can be improved to foster better logistics management at the project level.
Practical implications
BCs find suggestions of different logistics organization structures and suitable outsourcing arrangements. CERCs and LSPs can use the findings to understand their customers’ needs and adapt service offerings.
Originality/value
To the best of the authors’ knowledge, this study is one of the first studies of how two companies within a corporation can work together to develop construction logistics service offerings.
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