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Experimental investigation into rheological property of copper oxide nanoparticles suspended in propylene glycol- water based fluids  [PDF]
M. T. Naik,G. Ranga Janardhana,K. Vijaya Kumar Reddy,B. Subba Reddy
Journal of Engineering and Applied Sciences , 2010,
Abstract: Nanofluids are a new generation heat transfer fluids and have opened a new horizon in the areas of heat transfer applications. Nanofluids are prepared by dispersing nano-sized metallic particles in conventional fluids of heat transfer. Heat transfer performance of nanofluid depends primarily on its thermo physical properties like viscosity, thermal conductivity, specific heat and desity. Viscosity assumes importance as it affects the pressure drop and hence the pumping power when nano fluids are circulated in a closed loop for transfer of heat in heat exchangers. In the present research, propylene glycol and water (60:40 by weight) is used as base fluid and viscosity of Cuo nanofluid with different particle volume concentration of 0.025, 0.1, 0.4, 0.8 and 1.2 percent is measured. Experimental results thus obtained revealed that temperature and nanoparticle concentration parameters influence the viscosity of nanofluids condiderably. The experimental results obtained in the present experiment found to be in closer agreement with those available in the literature.
Thermal physical properties and key influence factors of phase change emulsion
Hui Xu,Rui Yang,Yinping Zhang,Zhe Huang,Jia Lin,Xin Wang
Chinese Science Bulletin , 2005, DOI: 10.1360/04we0123
Abstract: Latent functionally thermal fluids (LFTF) are a novel kind of heat storage and heat transfer fluids that include phase change microcapsule slurry and phase change emulsion (PCE). They have much greater apparent specific heats and higher heat transfer abilities in the phase change temperature range than conventional single-phase heat transfer fluids such as water. Thus they are advantageous in the field of the convective heat transfer enhancement and energy transport. In this paper, some thermal physical properties such as viscosity, fusion heat and apparent specific heat (cp) are measured, and the influences of some factors (such as selection of surfactants, preparation method, temperature, mixing ratio of surfactants and mass concentration of phase change material) on them are discussed. The study shows that: 1) the viscosity of the PCE prepared in the present work is lower than that reported in the literature; 2) its apparent specific heat value for the phase change temperature region is high and proportionally increases with the concentration of phase change material.
Thermal physical properties and key influence factors of phase change emulsion
Hui Xu,Rui Yang,Yinping Zhang,Zhe Huang,Jia Lin,Xin Wang,
XUHui
,YANGRui,ZHANGYinping,HUANGZhe,LINJia,WANGXin

科学通报(英文版) , 2005,
Abstract: Latent functionally thermal fluids (LFTF) are a novel kind of heat storage and heat transfer fluids that in- clude phase change microcapsule slurry and phase change emulsion (PCE). They have much greater apparent specific heats and higher heat transfer abilities in the phase change temperature range than conventional single-phase heat transfer fluids such as water. Thus they are advantageous in the field of the convective heat transfer enhancement and energy transport. In this paper, some thermal physical prop- erties such as viscosity, fusion heat and apparent specific heat (cp) are measured, and the influences of some factors (such as selection of surfactants, preparation method, temperature, mixing ratio of surfactants and mass concentration of phase change material) on them are discussed. The study shows that: 1) the viscosity of the PCE prepared in the present work is lower than that reported in the literature; 2) its ap- parent specific heat value for the phase change temperature region is high and proportionally increases with the concentration of phase change material.
Development of the system of liquid consignment constant heating in tankers
Selivanov Nikolay Vasilevich,Golovchun Sergey Nikolayevich
Vestnik of Astrakhan State Technical University. Series: Marine Engineering and Technologies , 2010,
Abstract: The dynamics of the process of highly viscosity liquids heating by means of a heating element with the set temperature of the surface is studied. As a heater such linear source as stem warming up is used. On the basis of solutions of the self-similar equations describing heat mass transfer and hydrodynamics, the temperature and velocity fields are fixed. The mass expense and temperature of the liquid depending on height over a source are found. Solutions are received taking into account variable viscosity of the liquid for number of Prandtl from 10 to 10 000.
SISTEMA DE HOMOGENIZACIóN Y CONTROL DE VISCOSIDAD DEL COMBUSTóLEO
GROSSO V.,J. L; FORERO,J. E; CUADRADO,C. E; OTERO,F;
CT&F - Ciencia, Tecnología y Futuro , 1996,
Abstract: fuel oil is a refinery by-product with a big economical effect due to its high production volumen, diluent use and market specifications based on low viscosity and low sulfur content. when these specifications are not achieved or they are not steady during the process, additional costs are generated by reprocessing, recirculation, storage, laboratory analysis, pumping, etc.. an in-line viscosity automatic control, previously evaluated in a pilot plant, was installed in order to optimize the fuel oil preparation system. this type of control minimizes viscosity variation, maintains the product specifications and allows a proper dosage of diluent. the viscosity automatic control system has added several benefits as follows: decreases the diluent volumen per day, decreases length of final products preparation, fewer number of samples to analyze, a more steady operation of plant, less sedimentation in storage tanks and mass and heat transfer processes more efficient.
Partial regularity for the Navier-Stokes-Fourier system  [PDF]
Luisa Consiglieri
Mathematics , 2009, DOI: 10.1016/S0252-9602(11)60351-2
Abstract: This paper addresses a nonstationary flow of heat-conductive incompressible Newtonian fluid with temperature-dependent viscosity coupled with linear heat transfer with advection and a viscous heat source term, under Navier/Dirichlet boundary conditions. The partial regularity for the velocity of the fluid is proved to each proper weak solution, that is, for such weak solutions which satisfy some local energy estimates in a similar way to the suitable weak solutions of the Navier-Stokes system. Finally, we study the nature of the set of points in space and time upon which proper weak solutions could be singular.
Linear response relations in fluctuational electrodynamics  [PDF]
Vladyslav A. Golyk,Matthias Krüger,Mehran Kardar
Physics , 2013, DOI: 10.1103/PhysRevB.88.155117
Abstract: Near field radiative heat transfer and dynamic Casimir forces are just two instances of topics of technological and fundamental interest studied via the formalism of fluctuational electrodynamics. From the perspective of experiment and simulations, it is hard to precisely control and probe such non-equilibrium situations. Fluctuations in equilibrium are easier to measure, and can typically be related to non-equilibrium response functions by Green-Kubo relations. We consider a collection of arbitrary objects in vacuum, perturbed by changing the temperature or velocity of one object. Developing a method for computation of higher order correlation functions in fluctuational electrodynamics, we explicitly compare linear response and equilibrium fluctuations. We obtain a Green-Kubo relation for the radiative heat transfer, as well as a closed formula for the vacuum friction in arbitrary geometries in the framework of scattering theory. We comment on the signature of the radiative heat conductivity in equilibrium fluctuations.
Field Synergy Principle for Energy Conservation Analysis and Application  [PDF]
Qun Chen,Moran Wang,Zeng-Yuan Guo
Advances in Mechanical Engineering , 2010, DOI: 10.1155/2010/129313
Abstract: Optimization of mass and energy transfer process is critical to improve energy efficiency. In this contribution we introduce the field synergy principle as a unified principle for analyzing and improving the performance of the transfer process. Three field synergy numbers are introduced for heat, mass, and momentum transfer, respectively, and three cases are demonstrated for validation. The results indicate that the field synergy numbers will increase when reducing the angle between the velocity vector and the temperature gradient or the species concentration gradient fields in the convective heat or mass transfer, and the overall heat or mass transfer capability is therefore enhanced. In fluid flows, it will reduce the fluid flow drag to decrease the synergy number between the velocity and the velocity gradient fields over the entire domain and to decrease the product between the fluid viscosity and the velocity gradient at the boundary simultaneously. 1. Introduction Energy conservation is not only a scientific or engineering problem but also a social one that most people on this planet are facing [1–3]. Solutions of this problem include both developments of new substitutable energy products [4–6] and optimizations of current energy utilizations [7–9]. The energy efficiency is always expected maximized by enhancing the energy output for a given cost, or by minimizing the input energy loss for a given output [10]. In recent years, the multiphysical transport process in energy systems, involving mass and energy transfer, has been a hot but challenging topic [6]. The difficulties come mainly from the coupling of the multiphysical transport processes. In this work, we focus on the fluid flow coupled with species or heat transfer, which is one of the most popular transport phenomena in energy systems. In such a multiphysical process, three kinds of transports are involved: the fluid flow (momentum transport), heat transfer (energy transport), and species transfer (mass transport) [11–13]. During the past several decades, a great number of heat, mass transfer enhancement, and fluid flow drag reduction technologies have been developed including using extended surfaces, spoiler elements, and external electric or magnetic field [14–17] for heat and mass transfer, riblet surfaces, guide plates, and drag-reduction additives of low viscosity for fluid flow [18–20]. All these methods have successfully cut down not only the energy consumption but also the cost of equipment itself. In the meanwhile, in the interest of revealing the essence of these methods from the
From Laurent Series to Exact Meromorphic Solutions: the Kawahara equation  [PDF]
Maria V. Demina,Nikolay A. Kudryashov
Physics , 2011, DOI: 10.1016/j.physleta.2010.08.013
Abstract: Nonlinear waves are studied in a mixture of liquid and gas bubbles. Influence of viscosity and heat transfer is taken into consideration on propagation of the pressure waves. Nonlinear evolution equations of the second and the third order for describing nonlinear waves in gas-liquid mixtures are derived. Exact solutions of these nonlinear evolution equations are found. Properties of nonlinear waves in a liquid with gas bubbles are discussed.
Numerical Simulation of Temperature and Mixing Performances of Tri-screw Extruders with Non-isothermal Modeling  [cached]
X.Z. Zhu,G. Wang,Y.D. He
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: Tri-screw extruders are new extrusion equipments for food and polymer processing. Especially, there is one special circumfluence exists in center region only at cross section. In this study, the 2D transient and non-isothermal modeling of a tri-screw extruder is established by using Finite Element Method (FEM) with particle tracking technology to reduce the axial effects. The transient temperature and flow fields are calculated with a commercial code, Polyflow. Moreover, the effect of temperature rise due to viscous heating on the flow and mixing characteristics such as mixing index, segregation scale, mean and instantaneous time-averaged efficiency of mixing for the tri-screw extruder are carried out. The results show that in the special center region, the velocity and mixing index is small and viscosity and temperature are relatively big, indicating the poor mixing efficiency. When the heat transfers due to self-heating is considered, the dispersive mixing of the tri-screw extruder decreases, but the distributive mixing and stretching mixing efficiency all increase for the tri-screw extruder. In particular, the stretching effect of the fluid particles in the tri-screw extruder decreases due to the decrease of viscous dissipation when the non-isothermal model is employed.
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