The Experts below are selected from a list of 10035 Experts worldwide ranked by ideXlab platform

Haisheng Chen - One of the best experts on this subject based on the ideXlab platform.

  • ENHANCED NATURAL CONVECTIVE HEAT TRANSFER OF CNT-ETHYLENE GLYCOL-WATER SUSPENSIONS
    2020
    Co-Authors: Sanjeeva Witharana, Haisheng Chen, Yulong Ding
    Abstract:

    ABSTRACT: This paper presents an experimental study on the rheology and steady state natural convective heat transfer of suspensions of Carbon nanotubes (CNT) in the WaterEthylene Glycol (WEG) base liquid, heated in a cylindrical cavity. Two series of experiment were performed in two orientations of the central axis of the cavity; vertical, and, horizontal. In vertical axis experiments, the heat was supplied from the bottom. The cylindrical cavity was made out of Aluminium, 10mm in height and 240mm in diameter. The heat input was 215W/m 2 . The CNTs used had an aspect ratio of~150. There were six suspensions investigated in either series of tests; CNT 0.1wt%, and EG 0, 10, 25, 50, 75 & 100wt%. It was found that the vertical axis orientation deteriorates heat transfer in all cases. However for horizontal orientation, there is a spectacular enhancement of up to 83% depending upon the EG concentration. The results also show that WEG-CNT suspension demonstrates non-Newtonian Behaviour, which augments with increasing EG concentration

  • rheological Behaviour of ethylene glycol based titania nanofluids
    Chemical Physics Letters, 2007
    Co-Authors: Yulong Ding, Haisheng Chen, Yurong He
    Abstract:

    Ethylene glycol based nanofluids containing titania nanoparticles up to 8 wt% show the Newtonian Behaviour over a shear rate range of 0.5-10(4) s(-1) at 293-333 K. The shear viscosity of the nanofluids (eta) depends strongly on temperature and particle concentration (phi). The normalized shear viscosity with respect to the based liquid viscosity (eta(0)) is found to be independent of temperature and can be given as eta/eta(0) - 1 = 10.6 phi + (10.6 phi)(2). Such theological Behaviour is explained by the aggregation mechanism. A combination of the aggregation mechanism with the Maxwell and Bruggeman models gives a good prediction of the effective thermal conductivity of the nanofluids. (C) 2007 Elsevier B.V. All rights reserved.

Manuel M Pineiro - One of the best experts on this subject based on the ideXlab platform.

  • rheological non Newtonian Behaviour of ethylene glycol based fe2o3 nanofluids
    Nanoscale Research Letters, 2011
    Co-Authors: Maria Jose Pastorizagallego, Luis Lugo, Jose Luis Legido, Manuel M Pineiro
    Abstract:

    The rheological Behaviour of ethylene glycol-based nanofluids containing hexagonal scalenohedral-shaped α-Fe2O3 (hematite) nanoparticles at 303.15 K and particle weight concentrations up to 25% has been carried out using a cone-plate Physica MCR rheometer. The tests performed show that the studied nanofluids present non-Newtonian shear-thinning Behaviour. In addition, the viscosity at a given shear rate is time dependent, i.e. the fluid is thixotropic. Finally, using strain sweep and frequency sweep tests, the storage modulus G', loss modulus G″ and damping factor were determined as a function of the frequency showing viscoelastic Behaviour for all samples.

David Kilpatrick - One of the best experts on this subject based on the ideXlab platform.

  • Non-Newtonian blood flow in human right coronary arteries: steady state simulations.
    Journal of biomechanics, 2004
    Co-Authors: Barbara Mary Johnston, Peter Rex Johnston, Stuart Corney, David Kilpatrick
    Abstract:

    This study looks at blood flow through four different right coronary arteries, which have been reconstructed from bi-plane angiograms. Five non-Newtonian blood models, as well as the usual Newtonian model of blood viscosity, are used to study the wall shear stress in each of these arteries at a particular point in the cardiac cycle. It was found that in the case of steady flow in a given artery, the pattern of wall shear stress is consistent across all models. The magnitude of wall shear stress, however, is influenced by the model used and correlates with graphs of shear stress versus strain for each model. For mid-range velocities of around 0.2 m s(-1) the models are virtually indistinguishable. Local and global non-Newtonian importance factors are introduced, in an attempt to quantify the types of flows where non-Newtonian Behaviour is significant. It is concluded that, while the Newtonian model of blood viscosity is a good approximation in regions of mid-range to high shear, it is advisable to use the Generalised Power Law model (which tends to the Newtonian model in those shear ranges in any case) in order to achieve better approximation of wall shear stress at low shear.

A Hernandezmachado - One of the best experts on this subject based on the ideXlab platform.

  • front microrheology of the non Newtonian Behaviour of blood scaling theory of erythrocyte aggregation by aging
    Soft Matter, 2017
    Co-Authors: C Trejosoto, E Costamiracle, Ivon Rodriguezvillarreal, Joan Cid, Mario Castro, Tomas Alarcon, A Hernandezmachado
    Abstract:

    We introduce a new framework to study the non-Newtonian Behaviour of fluids at the microscale based on the analysis of front advancement. We apply this methodology to study the non-linear rheology of blood in microchannels. We carry out experiments in which the non-linear viscosity of blood samples is quantified at different haematocrits and ages. Under these conditions, blood exhibits a power-law dependence on the shear rate. In order to analyse our experimental data, we put forward a scaling theory which allows us to define an adhesion scaling number. This theory yields a scaling Behaviour of the viscosity expressed as a function of the adhesion capillary number. By applying this scaling theory to samples of different ages, we are able to quantify how the characteristic adhesion energy varies as time progresses. This connection between microscopic and mesoscopic properties allows us to estimate quantitatively the change in the cell-cell adhesion energies as the sample ages.

  • rheology of red blood cells under flow in highly confined microchannels i effect of elasticity
    Soft Matter, 2014
    Co-Authors: Guillermo R Lazaro, A Hernandezmachado, Ignacio Pagonabarraga
    Abstract:

    We analyze the rheology of dilute red blood cell suspensions in pressure driven flows at low Reynolds number, in terms of the morphologies and elasticity of the cells. We focus on narrow channels of width similar to the cell diameter, when the interactions with the walls dominate the cell dynamics. The suspension presents a shear-thinning Behaviour, with a Newtonian-Behaviour at low shear rates, an intermediate region of strong decay of the suspension viscosity, and an asymptotic regime at high shear rates in which the effective viscosity converges to that of the solvent. We identify the relevant aspects of cell elasticity that contribute to the rheological response of blood at high confinement. In a second paper, we will explore the focusing of red blood cells while flowing at high shear rates and how this effect is controlled by the geometry of the channel.

Sara L. Moya - One of the best experts on this subject based on the ideXlab platform.

  • rheological property measurement of drilling fluids used in geothermal wells
    Applied Thermal Engineering, 2001
    Co-Authors: E Santoyo, G. Espinosa, S Santoyogutierrez, A. García, Sara L. Moya
    Abstract:

    Abstract With the goal of increasing understanding of drilling fluid temperature Behaviour during geothermal well drilling operations, and for providing a database for a better development of numerical wellbore simulators, an experimental work based on a rheological evaluation of drilling fluids was carried out. High-temperature drilling fluid systems (HTDFS) which are most commonly used in the Mexican geothermal well drilling industry were selected and evaluated. Eleven water-based drilling fluids were formulated and chemically characterised in order to carry out the rheological evaluation. Dynamic experimental tests considering the non-Newtonian Behaviour of such HTDFS were performed using a coaxial cylinder-type viscometer (Fann 50C). Drilling fluid viscosities in a programmed temperature range of 25–180°C (at a constant reservoir pressure and a shear rate of 3448.2 kPa and 170 s −1 , respectively) were measured. These dynamic viscosity measurements were then fitted to derive correlating equations for determining the drilling fluid viscosity as a function of temperature. Details of the experimental rheological tests including a complete description of the equipment and all the HTDFS used as well as the derived viscosity–temperature equations are presented.