80 research outputs found
Computational analysis of fluid flow and forced convective heat transfer of water-copper oxide nanofluid mixture
No full textA Complete Experimental Investigation on The Rheological Behavior of Silver Oil Based Nanofluid
No full textIn this study, thermo-physical properties including thermal conductivity, viscosity, density and specific heat capacity of an oil based nanofluid including silver as to be nanoparticles have been experimentally studied. The results indicate an enhancement in thermal conductivity which was depended on bulk temperature and volume fraction of utilized nanofluids. Viscosity data show a significant increment through volume fraction increasing. In addition, the specific heat capacity and density of nanofluids were studied experimentally and it was found that, all measured rheological properties of these nanofluids, were not in agreement to published correlations.No Full Tex
Experimental Study on Cu/Oil Nanofluids through Concentric Annular Tube: A Correlation
No full textThis study deals with an empirical investigation on the convective heat transfer of Cu/oil nanofluid flow inside a concentric annular tube with constant heat flux boundary condition and suggests a correlation to predict the Nusselt number. The average size of particles was 20 nm and the applied nanofluid was prepared by Electrical Explosion of Wire technique with no nanoparticle agglomeration during nanofluid preparation process and experiments. The nanofluid flowing between the tubes is heated by an electrical heating coil wrapped around it. The effects of different parameters such as the flow Reynolds number, tube diameter ratio, and nanofluid particle concentration on heat transfer coefficient are studied. Using the acquired experimental data, a correlation is developed for the estimation of the Nusselt number of nanofluid flow inside the annular tube. This correlation has been presented by using the exponential regression analysis and least-squares method. The correlation is valid for Cu/base oil nanofluid flow with weight concentrations of 0.12, 0.36, and 0.72 in the hydrodynamically full-developed laminar flow regime with Re <140, which is applicable in mini- and microchannel heat exchangers, and it is in good agreement with the experimental data.No Full Tex
Viscous Dissipation Effect in the Free Convection of Non-Newtonian Fluid with Heat Generation or Absorption Effect on the Vertical Wavy Surface
No full textThe present article analyzes the effect of viscous dissipations on natural convection heat transfer. The power law model for non-Newtonian fluid with heat generation or absorption effect along a sinusoidal wavy surface with isothermal boundary condition is investigated. A simple coordinate transform is employed to map the wavy surface into a flat surface, and also, the fully implicit finite difference method is incorporated for the numerical solution. The findings of this study can help better understand the effect of parameters such as the Brinkman number, heat generation/absorption, wave amplitude magnitude, and generalized Prandtl number on convective heat transfer in dilatant and pseudoplastic non-Newtonian. Results show that as the Brinkman number increases, the amount of heat transfer decreases. This is physically justifiable considering that the fluid becomes warmer due to the viscous dissipation, decreasing its temperature difference with the constant temperature surface. Also, the effect of the power law viscosity index is surveyed. It is demonstrated that the magnitude of the local Nusselt number in the plane leading edge has the smallest quantity for pseudoplastic fluids compared to dilatant Newtonian fluids. Additionally, as the distance from the plane leading edge increases, the heat transfer declines
Lattice Boltzmann Simulation of Nanofluid Mixed Convection in a Lid-Driven Trapezoidal Enclosure with Square Heat Source
No full textErratum: A survey of medical students\u27 attitudes and practices towards narcotics and psychotropic drugs
No full textThere was an error in the author list of the published article.Two authors (A Kohansal Vajargah, K Ghaderi) requested to add to the authors lists. After obtaining the agreement of the authors and the corresponding author, and describing author contributions, Editor-in-Chief accept the corrections as listed below.The correct author list is:Shahab Dastmardi, Alireza Kohansal Vajargah, Morteza Rahbar Taromsari, Hamid Mohammadi Kojidi, Ardalan Majidinia, Fariba Asgari Bozayeh, Kaveh Ghaderi, Kourosh Delpasand We apologize for any inconvenience this may have caused. Erratum for:A survey of medical students\u27 attitudes and practices towards narcotics and psychotropic drugsShahab Dastmardi, Morteza Rahbar Taromsari, Hamid Mohammadi Kojidi, Ardalan Majidinia, Fariba Asgari Bozayeh, Kourosh DelpasandJ Curr Biomed Rep. 2021; 2(3): 120-124
Experimental study on the rheological behavior of silver-heat transfer oil nanofluid and suggesting two empirical based correlations for thermal conductivity and viscosity of oil based nanofluids
No full textThermal conductivity and viscosity of nanofluids are the most important parameters that have to be determined specially, for industrial applications. Therefore, it is beneficial to precisely predict the thermal conductivity and viscosity of nanofluids. Because of the fact that experimental instruments are not possible in many situations, and present models are not applicable for any nanofluids, new correlations have been developed based on the data of oil based nanofluids in the literature. The proposed correlations are based on the bulk temperature, nanoparticle diameter and nanoparticle concentration as input variables. Since the published data studying rheological properties of oil based nanofluids were not found to be in a huge database, thermal conductivity and viscosity of heat transfer oil were investigated experimentally to be added to our database. The results showed that previous models for thermal conductivity of nanofluids predict thermal conductivity of oil based nanofluids in a decreasing way versus baulk temperature while, thermal conductivity of oil based nanofluids increases with rising temperature. So, this could be the motivation to develop an accurate correlation for thermal conductivity, specialized for oil based nanofluids. On the other hand, a new correlation for predicting viscosity of oil based nanofluids has been introduced. According to the results, the accuracy of the proposed correlation is in a better situation than other popular models.No Full Tex
Characterization and numerical evaluation of flow and blood damage in a pulsatile left ventricular assist device
No full textExergoeconomic and Exergoenvironmental Analysis and Optimization of the Cogeneration Cycle Under Dynamic Solar Radiation Model Using Two Renewable Sources
No full textTemperature Effect on Moving Water Droplets at the Channel of PEMFC by Multi-component Multiphase Lattice Boltzmann Method
No full textIn this paper, a multi-component multiphase pseudopotential Lattice Boltzmann method with multi relaxation time (MRT) collision operator is presented to examine the dynamic behavior of liquid droplets movement and coalescence process in the gas channel of PEMFC. In the numerical method, the forcing term is improved to achieve a high-density ratio and thermodynamic consistency. First, the density ratio, Laplace law, and contact angle are validated with previous studies. Then, different parameters, such as operating temperature, pressure difference, surface contact angle, the radius of droplets, and distance between two droplets on the droplet movement and coalescence process are studied. The results revealed by rising temperature from 30 to 80 degrees, the speed of drop increases around 6 percent. The simulation results indicated that the rising of pressure gradient increases the gas flow velocity on the channel and leads to increasing the shear force and eventually faster movement of the droplet on the gas channel. Also, investigation of various contact angles shows that a hydrophilic surface causes a resistance force between the droplet and the wall and delays the removal of droplets. Moreover, droplet coalescence is useful for droplet movement because of increasing the velocity gradient on top of the droplet; consequently, the shear force on the droplet is raised during coalescence
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