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An Investigation into Forced Convection of a Nanofluid Flowing in a Rectangular microchannel under the Influence of a magnetic Field

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Fluid Dynamics & materials processing 2024年第2期20卷 311-323页

作者： muataz S.Alhassan Ameer A.Alameri Andrés Alexis Ramírez-Coronel I.B.Sapaev Azher m.Abed David-Juan Ramos-Huallpartupa Rahman S.Zabibah Division of Advanced Nanomaterial Technologies Scientific Research CenterAl-Ayen UniversityThi-QarIraq Department of Chemistry College of ScienceUniversity of BabylonBabylonIraq Research Group in Educational Statistics National University of EducatiosnAzoguesEcuador Department physics and Chemistry Tashkent Institute of Irrigation and Agricultural Mechanization EngineersNational Research UniversityTashkentUzbekistan Akfa University TashkentUzbekistan New Uzbekistan University TashkentUzbekistan Department of Airconditioning and Refrigeration Engineering Al-Mustaqbal University CollegeHilla51001Iraq Academic Department of Agro-Industrial Engineering and Technology Universidad Nacional JoséMaría ArguedasApurimacPerú The Islamic University NajafIraq

In line with recent studies,where it has been shown that nanoﬂuids containing graphene have a stronger capacity to boost the heat transfer coefﬁcient with respect to ordinary nanoﬂuids,experiments have been conducted using water with cobalt ferrite/graphene *** particular,a circular channel made of copper subjected to a constant heatﬂux has been *** nanoparticles are sensitive to the presence of a magneticﬁeld,different conditions have been examined,allowing both the strength and the frequency of such aﬁeld to span relatively wide ranges and assuming different concentrations of *** to theﬁndings,the addition of nanoparticles to theﬂuid causes its rotation speed to increase by a factor of two,whereas ultraviolet radiation plays a negligible *** amount of time required to attain the maximum rotation speed of the nanoﬂuid and the Nusselt number have been measured under both constant and alternating magneticﬁelds for a ferroﬂuid with a concentration of 0.5%and atﬂow reynolds number of 550 and 1750.

关键词： Nano fluid rectengular tube magnetic field

Aerodynamic Loading Distribution Effects on the Overall performance of Ultra-High-Lift Lp Turbine Cascades

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Journal of Thermal Science 2014年第1期23卷 1-12页

作者： m.Berrino F.Satta D.Simoni m.Ubaldi p.Zunino F.Bertini DImE Università degli Studi di Genova Via Montallegro 1I-16145 GenovaItaly Avio S.p.A. Professors I Maggio 56I-10040 Rivalta (TO) Italy

The present paper reports the results of an experimental investigation aimed at comparing aerodynamic perform- ance of three low-pressure turbine cascades for several reynolds numbers under steady and unsteady inflows. This study is focused on finding design criteria useful to reduce both profile and secondary losses in the aero-engine Lp turbine for the different flight conditions. The baseline blade cascade, characterized by a standard aerodynamic loading （Zw=1.03）, has been compared with two Ultra-High-Lift profiles with the same Zweifel number （Zw=1.3 for both cascades）, but different velocity peak positions, leading to front and mid-loaded blade cascade configurations. The aerodynamic flow fields downstream of the cascades have been experimentally in- vestigated for reynolds numbers in the range 70000〈Re〈300000, where lower and upper limits are typical of cruise and take-off/landing conditions, respectively. The effects induced by the incoming wakes at the reduced frequency ./＋=0.62 on both profile and secondary flow losses for the three different cascade designs have been studied. Total pressure and velocity distributions have been measured by means of a miniaturized 5-hole probe in a tangential plane downstream of the cascade for both inflow conditions. The analysis of the results allows the evaluation of the aerodynamic performance of the blade cascades in terms of profile and secondary losses and the understanding of the effects of loading distribution and Zweifel number on secondary flows. When operating un- der unsteady inflow, contrarily to the steady case, the mid-loaded cascade has been found to be characterized by the lowest profile and secondary losses, making it the most attractive solution for the design of blades working in real conditions where unsteady inflow effects are present.

关键词： Low-pressure Turbine Ultra-High-Lift prof'des profile Losses Secondary Losses mid-Loaded Blade Cascades Aft-Loaded Blade Cascades.

Three-dimensional Numerical Study of Laminar Confined Slot Jet Impingement Cooling using Slurry of Nano—encapsulated phase Change material

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Journal of Thermal Science 2016年第5期25卷 431-439页

作者： m.mohib Ur Rehman Z.G Qu R.p.Fu Key Laboratory of Thermal Fluid Science and Engineering Ministry of EductionSchool of Energy and Power EngineeringXi'an Jiaotong University

This Article presents a three dimensional numerical model investigating thermal performance and hydrodynamics features of the confined slot jet impingement using slurry of Nano Encapsulated phase Change material(NEpCm)as a *** slurry is composed of water as a base fluid and n-octadecane NEpCm particles with mean diameter of 100 nm suspended in it.A single phase fluid approach is employed to model the NEpCm *** thermo physical properties of the NEpCm slurry are computed using modern approaches being proposed recently and governing equations are solved with a commercial Finite Volume based *** effects of jet reynolds number varying from 100 to 600 and particle volume fraction ranging from 0% to 28% are *** computed results are validated by comparing Nusselt number values at stagnation point with the previously published results with water as working *** was found that adding NEpCm to the base fluid results with considerable amount of heat transfer *** highest values of heat transfer coefficients are observed at H/W=4 and C_m=***,due to the higher viscosity of slurry compared with the base fluid,the slurry can produce drastic increase in pressure drop of the system that increases with NEpCm particle loading and jet reynolds number.

关键词： Nano-encapsulated phase change material heat transfer enhancement confined slot jet impingement

Stokes flow of micro-polar fluids by peristaltic pumping through tube with slip boundary condition

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Applied mathematics and mechanics(English Edition) 2011年第12期32卷 1587-1598页

作者： D.TRIpATHI m.K.CHAUBE p.K.GUpTA Department of mathematics Indian Institute of Technology Ropar Punjab 140001 India Department of mathematics Raj Kumar Goel Institute of Technology Ghaziabad 201001 India Department of Applied mathematics Institute of Technology Banaras Hindu University Varanasi 221005 India

This paper studies the Stokes flow of micro-polar fluids by peristaltic pumping through the cylindrical tube under the effect of the slip boundary condition. The motion of the wall is governed by the sinusoidal wave equation. The analytical and numerical solutions for the axial velocity, the micro-polar vector, the stream function, the pressure gradient, the friction force, and the mechanical efficiency are obtained by using the lu- brication theory under the low reynolds number and long wavelength approximations. The impacts of the emerging parameters, such as the coupling number, the micro-polar parameter, the slip parameter on pumping characteristics, the friction force, the velocity profile, the mechanical efficiency, and the trapping phenomenon are depicted graphically. The numerical results infer that large pressure is required for peristaltic pumping when the coupling number is large, while opposite behaviors are found for the micro-polar parameter and the slip parameter. The size of the trapped bolus reduces with the increase in the coupling number and the micro-polar parameter, whereas it blows up with the increase in the slip parameter.

关键词： Stokes flow slip boundary condition mechanical efficiency micro-polarfluid peristaltic pumping trapping

Analysis for stress environment in the alveolar sac model

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Journal of Biomedical Science and Engineering 2013年第9期6卷 901-907页

作者： Ramana m. pidaparti matthew Burnette Rebecca L. Heise Angela reynolds Department of Applied mathematics Virginia Commonwealth University Richmond USA Department of Biomedical Engineering Virginia Commonwealth University Richmond USA Department of mechanical and Nuclear Engineering Virginia Commonwealth University Richmond USA

Better understanding of alveolar mechanics is very important in order to avoid lung injuries for patients undergoing mechanical ventilation for treatment of respiratory problems. The objective of this study was to investigate the alveolar mechanics for two different alveolar sac models, one based on actual geometry and the other an idealized spherical geometry using coupled fluid-solid computational analysis. Both the models were analyzed through coupled fluid-solid analysis to estimate the parameters such as pressures/ velocities and displacements/stresses under mechanical ventilation conditions. The results obtained from the fluid analysis indicate that both the alveolar geometries give similar results for pressures and velocities. However, the results obtained from coupled fluid-solid analysis indicate that the actual alveolar geometry results in smaller displacements in comparison to a spherical alveolar model. This trend is also true for stress/strain between the two models. The results presented indicate that alveolar geometry greatly affects the pressure/velocities as well as displacements and stresses/strains.

关键词： Alveolar Sac Stress Analysis modeling

pIV measurements of turbulent jets issuing from triangular and circular orifice plates

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Science China(physics,mechanics & Astronomy) 2013年第6期56卷 1176-1186页

作者： XU minYi ZHANG Jianpeng mI JianChun NATHAN G J KALT p A m marine Engineering College Dalian Maritime University State Key Laboratory of Turbulence & Complex Systems College of EngineeringPeking University Centre for Energy Technology and School of mechanical Engineering University of AdelaideSA 5005Australia

The present study experimentally investigated the near-field flow mixing characteristics of two turbulent jets issuing from equilateral triangular and circular orifice plates into effectively unbounded surroundings,*** particle image velocimetry(pIV) was applied to measure the velocity field at the same reynolds number of Re=50,000,where Re = UeDe /with Ue being the exit bulk velocity and the kinematic viscosity of fluid,D e the equivalent *** instantaneous velocity,mean velocity,reynolds stresses were *** the mean velocity field,the centreline velocity decay rate and half-velocity width were *** the mixing characteristics of the two jets,it is found that the triangular jet has a faster mixing rate than the circular *** triangular jet entrainments with the ambient fluid at a higher rate in the near *** is evidenced by a shorter unmixed core,faster reynolds stress and centreline turbulence intensity *** primary coherent structures in the near field are found to break down more rapidly in the triangular jet as compared to the circular *** the entire measurement region,the triangular jet maintained a higher rate of decay and ***,all components of reynolds stress of the triangular jet appear to reach their peaks earlier,and then decay more rapidly than those of the circular *** addition,the axis-switching phenomenon is observed in the triangular jet.

关键词： triangular jet turbulent mixing coherent structures axis-switching

Calcium phosphate cements for bone engineering and their biological properties

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Bone Research 2017年第4期5卷 286-304页

作者： Hockin HK Xu ping Wang Lin Wang Chongyun Bao Qianming Chen michael D Weir Laurence C Chow Liang Zhao Xuedong Zhou mark A reynolds Department of Endodontics Periodontics and ProsthodonticsUniversity of Maryland School of DentistryBaltimoreMD 21201USA Center for Stem Cell Biology and Regenerative medicine University of Maryland School of MedicineBaltimoreMD 21201USA University of maryland mariene and Stewart Greenebaum Cancer Center University of Maryland School of MedicineBaltimoreMD 21201USA mechanical Engineering Department University of Maryland Baltimore CountyBaltimoreMD 21250USA State Key Laboratory of Oral Diseases National Clinical Research Center for Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengduSichuan 610041China VIp Integrated Department Stomatological Hospital of Jilin UniversityChangchunJilin 130011China Volpe Research Center American Dental Association FoundationNational Institute of Standards&TechnologyGaithersburgMD 20899USA Department of Orthopaedic Surgery Nanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China

Calcium phosphate cements （CpCs） are frequently used to repair bone defects. Since their discovery in the 1980s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. much effort has been made to enhance the biological performance of CpCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability, bioactivity, and interactions with cells. This review article focuses on the major recent developments in CpCs, including 3D printing, injectability, stem cell delivery, growth factor and drug delivery, and pre- vascularization of CpC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.

关键词： CpC BmSCs Calcium phosphate cements for bone engineering and their biological properties

Turbine Blade Boundary Layer Separation Suppression via Synthetic Jet: an Experimental and Numerical Study

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Journal of Thermal Science 2012年第5期21卷 404-412页

作者： Bernardini C. Carnevale m. manna m. martelli F. Simoni D. Zunino p. Università degli Studi di Firenze Firenze Italy Università degli Studi di Napoli Federico Ⅱ Napoli Italy Università degli Studi di Firenze FirenzeItaly Università degli Studi di Genova Genova Italy

The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging test section specifically designed to attain a local velocity distribution typical of a high-lift LpT blade. Both experimental and numerical investigations have been carried out. Unsteady RANS results have been compared with experiments in terms of time-averaged velocity and turbulence intensity distributions. Two different reynolds number cases have been investigated, namely Re = 200,000 and Re = 70,000, which characterize low-pressure turbine operating conditions during take-off/landing and cruise. A range of synthetic jet aerodynamic parameters (Strouhal number and blowing ratio) has been tested in order to analyze the features of control-separated boundary layer interaction for the aforementioned reynolds numbers.

关键词： Synthetic Jet Separated Flow Active Flow Control Unsteady Flow Ultra High Lift LpT.

profile and Secondary Flow Losses in a High-Lift LpT Blade Cascade at Different reynolds Numbers under Steady and Unsteady Inflow Conditions

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Journal of Thermal Science 2012年第6期21卷 483-491页

作者： Satta F. Simoni D. Ubaldi m. Zunino p. Bertini F. DImSET-Università di Genova Via Montallegro 1I-16145 GenovaItaly Avio S.p.A. Viale I Maggio 56I-10040 Rivalta(TO)-Italy

The aerodynamic flow field downstream of a Low-pressure High-Lift(HL)turbine cascade has been experimentally investigated for different reynolds numbers under both steady and unsteady inflows,in order to analyse the cascade performance under real engine operating *** reynolds number has been varied in the range 100000pper limits are typical of cruise and take-off/landing conditions,*** effects induced by the incoming wakes at the reduced frequency f+=0.62 on both profile and secondary flow losses have been *** pressure,velocity and secondary kinetic energy distributions at the downstream tangential plane have been measured by means of a miniaturized 5-hole *** quantities provide information on both blade wake and secondary flow structures(passage and horse-shoe vortices).The analysis of the results allows the evaluation of the aerodynamic performance of the HL front-loaded blade in terms of both profile and secondary losses.

关键词： profile losses secondary flow losses high-lift profdes unsteady inflow LpT blade.