Begell House Inc.
Heat Transfer Research
HTR
1064-2285
45
5
2014
SIMULATION OF THE SECOND-GRADE FLUID MODEL AND HEATING SCHEME OF THE BLOOD FLOW THROUGH A TAPERED ARTERY WITH MASS TRANSFER
391-408
10.1615/HeatTransRes.2014007003
Noreen Sher
Akbar
DBS&H, CEME, National University of Sciences and Technology, Islamabad, Pakistan
Sohail
Nadeem
Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000, Pakistan
second-grade fluid
blood flow
tapered artery
stenosis
analytical solution
heat and mass transfer
In the present work, we have studied the heat and mass transfer effects on the second-grade fluid model for blood flow through a tapered artery with a stenosis. The resulting nonlinear implicit system of partial differential equations is solved analytically with the help of the perturbation method. The expressions for shear stress, velocity, temperature, concentration, flow rate, wall shear stress, and longitudinal impedance are obtained. The physical behavior of different parameters have also been presented graphically. Trapping phenomena have been discussed at the end of the article.
EFFECT OF NANOFLUID VARIABLE PROPERTIES ON MIXED CONVECTION FLOW AND HEAT TRANSFER IN AN INCLINED TWO-SIDED LID-DRIVEN CAVITY WITH SINUSOIDAL HEATING ON SIDEWALLS
409-432
10.1615/HeatTransRes.2013007127
Mohammad
Hemmat Esfe
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
Mohammad
Akbari
Department of Mechanical Engineering, Semnan University, Semnan, Iran
Davood Semiromi
Toghraie
Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University,
Khomeinishahr, Iran
Arash
Karimipour
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Isfahan, Iran
Masoud
Afrand
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
nanofluid
variable properties
mixed convection
inclined cavity
In this study, mixed convection fluid flow and heat transfer in an inclined two-sided lid-driven cavity subjected to Al2O3âˆ’water nanofluid (with different particle diameters from 15 to 99 nm) has been investigated numerically. The geometry is a double lid-driven square cavity with sinusoidal temperature distribution on the left sidewall, while the right wall is kept at Tc. The top and bottom walls of the cavity, which move in opposite directions, are assumed to be insulated. The effects of inclination angle, Richardson number, nanoparticle volume fraction, temperature, and nanoparticle diameter based on recent variable property formulations are studied. The effects of an increase in Richardson number while the solid volume fraction is constant and effects of an increase in solid volume fraction when the Richardson number is kept constant are investigated. Also, the obtained results show that an increase in nanoparticle diameter influences the flow pattern and isotherm contours inside the cavity relatively when the Richardson number is kept constant and the diameter is varied from 15 to 99 nm. As the mean nanoparticle diameter increases, the corresponding flow velocity decreases, and hence the heat transfer enhancement is reduced. The results indicate that as Richardson number increases, the average Nusselt number rapidly increases for different values of dp. Moreover, the results have clearly indicated that the addition of Al2O3 nanoparticles has produced a remarkable enhancement on heat transfer with respect to that of the pure fluid.
DESIGN, DEVELOPMENT, AND TESTING OF A MODIFIED GREENHOUSE DRYER UNDER CONDITIONS OF NATURAL CONVECTION
433-451
10.1615/HeatTransRes.2014006993
Om
Prakash
Department of Mechanical Engineering, Birla Institute of Technology, Mesra Ranchi-835215, India
Anil
Kumar
Energy Technology Research Center, Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand; Department of Energy (Energy Center), Maulana Azad National Institute of Technology, Bhopal-462003, India
modified greenhouse dryer
black sheet
convective heat transfer coefficient
heat loss
coefficient of diffusion
instantaneous thermal loss efficiency factor
In this paper, the designing, development, and testing of a modified greenhouse dryer under conditions of natural convection have been performed to study the effect of convective heat transfer coefficients, heat loss, coefficient of diffusion, and of the instantaneous thermal loss efficiency factor. In order to minimize the losses, the north wall is made opaque with the help of a mirror. Two sets of experiments were performed. First, a modified greenhouse was kept on the ground and another one was kept on the floor covered with a black plastic sheet. The experimental constant C and exponent n are calculated from the experimental data by regression analysis.
MIXED CONVECTION FLOW AND HEAT TRANSFER IN A LID-DRIVEN CAVITY SUBJECTED TO NANOFLUID: EFFECT OF TEMPERATURE, CONCENTRATION AND CAVITY INCLINATION ANGLES
453-470
10.1615/HeatTransRes.2014007211
Mohammad
Hemmat Esfe
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
Seyed Sadegh Mirtalebi
Esforjani
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Isfahan, Iran
Mohammad
Akbari
Department of Mechanical Engineering, Semnan University, Semnan, Iran
nano scale particles
heat transfer
mixed convection
lid-driven cavity
In this work, mixed convection in a lid-driven cavity with an inside heated obstacle at various cavity inclination angles with new formulation of variable properties was studied numerically. The bottom and vertical walls are kept insulated, whereas the top moving wall is maintained at a low temperature Tc. An obstacle of a relatively higher temperature Th is located on the bottom wall of the cavity. The governing equations are discretized using the finite volume method and SIMPLER algorithm. Using a developed code, we accomplished a parametric study and analyzed the influence of important parameters, such as the Richardson number, solid volume fraction of Al2O3 nanoparticles, cavity inclination angles, height of a hot obstacle, and the nanofluid temperature on the thermal behavior and flow characteristics.
STRUCTURAL IDENTIFICATION OF A THERMAL PROCESS USING THE VOLTERRA MODEL
471-484
10.1615/HeatTransRes.2014006034
Safa
Chouchane
Research Unit ATSI, National School of Engineers of Monastir, University of Monastir, Rue Ibn El Jazzar, 5019 Monastir, Tunisia
Kais
Bouzrara
Research Unit ATSI, National School of Engineers of Monastir, University of Monastir, Rue Ibn El Jazzar, 5019 Monastir, Tunisia
Hassani
Messaoud
Research Unit ATSI, National School of Engineers of Monastir, University of Monastir, Rue Ibn El Jazzar, 5019 Monastir, Tunisia
PT326 Trainer
Volterra model
structure estimation
determinant ratio
This paper proposes a new method to estimate, from input/output measurements, the structural parameters (order and memory) of the Volterra models used for describing a nonlinear thermal process, the Trainer PT326. The proposed estimation method is an extension of the recent work in which a new algorithm for estimating the memory of the Volterra model was proposed. The structure parameters identification method, proposed in this paper, is based on the definition of a specific matrix whose components are lagged inputs and lagged outputs. We prove that this matrix becomes singular once the parameter value exceeds its exact value. The estimated values of the order and the memory are used to provide a suitable Volterra model for the Process Trainer PT326. The performance of the model and the identification method that uses experimental data are evaluated.