scholarly journals Darcy Brinkman Equations for Hybrid Dusty Nanofluid Flow with Heat Transfer and Mass Transpiration

Computation ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 118
Author(s):  
K. N. Sneha ◽  
U. S. Mahabaleshwar ◽  
Rachid Bennacer ◽  
Mohammed EL. Ganaoui
Keyword(s):  
Heat Transfer ◽  
Chemical Engineering ◽  
Exact Analytical Solution ◽  
Polymer Processing ◽  
Heat Transfer Process ◽  
Current Work ◽  
Physical Parameters ◽  
Processing Unit ◽  
Brinkman Equations ◽  
Non Linear

In the current work, we have investigated the flow past a semi-infinite porous solid media, after presenting a similarity transformation, governing equations mapped to a system of non-linear PDE. The flow of a dusty fluid and heat transfer through a porous medium have few applications, viz., the polymer processing unit of a geophysical, allied area, and chemical engineering plant. Further, we had the option to get an exact analytical solution for the velocity to the equation that is non-linear. The highlight of the current work is the flow of hybrid dusty nanofluid due to Darcy porous media through linear thermal radiation with the assistance of an analytical process. The hybrid dusty nanofluid has significant features improving the heat transfer process and is extensively developed in manufacturing industrial uses. It was found that the basic similarity equations admit two phases for both stretching/shrinking surfaces. The existence of computation on velocity and temperature profile is presented graphically for different estimations of various physical parameters.

scholarly journals A Computational Study on the Role of Parameters for Identification of Thyroid Nodules by Infrared Images (and Comparison with Real Data)

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4459
Author(s):  
José R. González ◽  
Charbel Damião ◽  
Maira Moran ◽  
Cristina A. Pantaleão ◽  
Rubens A. Cruz ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thyroid Nodules ◽  
Numerical Study ◽  
Computational Study ◽  
Internal Heat ◽  
Heat Transfer Process ◽  
The Body ◽  
Physical Parameters ◽  
Infrared Sensors ◽  
Wide Range

According to experts and medical literature, healthy thyroids and thyroids containing benign nodules tend to be less inflamed and less active than those with malignant nodules. It seems to be a consensus that malignant nodules have more blood veins and more blood circulation. This may be related to the maintenance of the nodule’s heat at a higher level compared with neighboring tissues. If the internal heat modifies the skin radiation, then it could be detected by infrared sensors. The goal of this work is the investigation of the factors that allow this detection, and the possible relation with any pattern referent to nodule malignancy. We aim to consider a wide range of factors, so a great number of numerical simulations of the heat transfer in the region under analysis, based on the Finite Element method, are performed to study the influence of each nodule and patient characteristics on the infrared sensor acquisition. To do so, the protocol for infrared thyroid examination used in our university’s hospital is simulated in the numerical study. This protocol presents two phases. In the first one, the body under observation is in steady state. In the second one, it is submitted to thermal stress (transient state). Both are simulated in order to verify if it is possible (by infrared sensors) to identify different behavior referent to malignant nodules. Moreover, when the simulation indicates possible important aspects, patients with and without similar characteristics are examined to confirm such influences. The results show that the tissues between skin and thyroid, as well as the nodule size, have an influence on superficial temperatures. Other thermal parameters of thyroid nodules show little influence on surface infrared emissions, for instance, those related to the vascularization of the nodule. All details of the physical parameters used in the simulations, characteristics of the real nodules and thermal examinations are publicly available, allowing these simulations to be compared with other types of heat transfer solutions and infrared examination protocols. Among the main contributions of this work, we highlight the simulation of the possible range of parameters, and definition of the simulation approach for mapping the used infrared protocol, promoting the investigation of a possible relation between the heat transfer process and the data obtained by infrared acquisitions.

scholarly journals Heat exchange between a bouncing drop and a superhydrophobic substrate

2017 ◽  
Vol 114 (27) ◽  
pp. 6930-6935 ◽  
Author(s):  
Samira Shiri ◽  
James C. Bird
Keyword(s):  
Heat Transfer ◽  
Water Drop ◽  
Heat Transfer Process ◽  
Physical Parameters ◽  
Short Contact Time ◽  
Bulk Substrate ◽  
Trapped Gas ◽  
Capillary Dynamics ◽  
Air Pockets

The ability to enhance or limit heat transfer between a surface and impacting drops is important in applications ranging from industrial spray cooling to the thermal regulation of animals in cold rain. When these surfaces are micro/nanotextured and hydrophobic, or superhydrophobic, an impacting drop can spread and recoil over trapped air pockets so quickly that it can completely bounce off the surface. It is expected that this short contact time limits heat transfer; however, the amount of heat exchanged and precise role of various parameters, such as the drop size, are unknown. Here, we demonstrate that the amount of heat exchanged between a millimeter-sized water drop and a superhydrophobic surface will be orders of magnitude less when the drop bounces than when it sticks. Through a combination of experiments and theory, we show that the heat transfer process on superhydrophobic surfaces is independent of the trapped gas. Instead, we find that, for a given spreading factor, the small fraction of heat transferred is controlled by two dimensionless groupings of physical parameters: one that relates the thermal properties of the drop and bulk substrate and the other that characterizes the relative thermal, inertial, and capillary dynamics of the drop.

scholarly journals A mathematical model on MHD slip flow and heat transfer over a nonlinear stretching sheet

2014 ◽  
Vol 18 (suppl.2) ◽  
pp. 475-488 ◽  
Author(s):  
Kalidas Das
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Slip Flow ◽  
Inverse Function ◽  
Partial Slip ◽  
Physical Parameters ◽  
Fluid Viscosity ◽  
Linear Ordinary Differential Equations ◽  
Flow And Heat Transfer ◽  
Non Linear

Some analyses have been carried out to study the influence of suction/blowing, thermal radiation and temperature dependent fluid properties on the hydro-magnetic incompressible electrically conducting fluid flow and heat transfer over a permeable stretching surface with partial slip boundary conditions. It is assumed that the fluid viscosity and the thermal conductivity vary as an inverse function and linear function of temperature respectively. Using the similarity transformation, the governing system of non-linear partial differential equations are transformed into non-linear ordinary differential equations and are solved numerically using symbolic software MATHEMATICA 7.0. The effects of various physical parameters on the flow and heat transfer characteristics as well as the skin friction coefficient and Nusselt number are illustrated graphically. The physical aspects of the problem are highlighted and discussed.

Flow and Heat Transfer of Powell–Eyring Fluid due to an Exponential Stretching Sheet with Heat Flux and Variable Thermal Conductivity

2015 ◽  
Vol 70 (3) ◽  
pp. 163-169 ◽  
Author(s):  
Ahmed M. Megahed
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Differential Equations ◽  
Variable Thermal Conductivity ◽  
Physical Parameters ◽  
Flow And Heat Transfer ◽  
Non Linear ◽  
Thermal Conductivity Parameter ◽  
Conductivity Parameter

AbstractAn analysis was carried out to describe the problem of flow and heat transfer of Powell–Eyring fluid in boundary layers on an exponentially stretching continuous permeable surface with an exponential temperature distribution in the presence of heat flux and variable thermal conductivity. The governing partial differential equations describing the problem were transformed into a set of coupled non-linear ordinary differential equations and then solved with a numerical technique using appropriate boundary conditions for various physical parameters. The numerical solution for the governing non-linear boundary value problem is based on applying the shooting method over the entire range of physical parameters. The effects of various parameters like the thermal conductivity parameter, suction parameter, dimensionless Powell–Eyring parameters and the Prandtl number on the flow and temperature profiles as well as on the local skin-friction coefficient and the local Nusselt number are presented and discussed. In this work, special attention was given to investigate the effect of the thermal conductivity parameter on the velocity and temperature fields above the sheet in the presence of heat flux. The numerical results were also validated with results from a previously published work on various special cases of the problem, and good agreements were seen.

scholarly journals An Unsteady Flow and Melting Heat Transfer of a Nanofluid Over a Stretching Sheet Embedded in a Porous Medium

2019 ◽  
Vol 24 (2) ◽  
pp. 245-258 ◽  
Author(s):  
K. Ganesh Kumar ◽  
B.J. Gireesha ◽  
N.G. Rudraswamy ◽  
M.R. Krishnamurthy
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Unsteady Flow ◽  
Stretching Sheet ◽  
Physical Parameters ◽  
Local Skin ◽  
Melting Heat ◽  
Linear Ordinary Differential Equations ◽  
Melting Heat Transfer ◽  
Non Linear

Abstract An unsteady flow and melting heat transfer of a nanofluid over a stretching sheet was numerically studied by considering the effect of chemical reaction and thermal radiation. The governing non-linear partial differential equations describing the flow problem are reduced to a system of non-linear ordinary differential equations using the similarity transformations and solved numerically using the Runge–Kutta–Fehlberg fourth–fifth order method. Numerical results for concentration, temperature and velocity profiles are shown graphically and discussed for different physical parameters. Effect of pertinent parameters on momentum, temperature and concentration profiles along with local Sherwood number, local skin-friction coefficient and local Nusselt number are well tabulated and discussed.

scholarly journals DTM-BF TECHNIQUE FOR FLOW AND HEAT TRANSFER OF A NANOFLUID OVER A NON-LINEARLY STRETCHING/SHRINKING SHEET IN PRESENCE OF THERMAL RADIATION AND PARTIAL SLIP

2020 ◽  
Vol 50 (3) ◽  
pp. 185-195
Author(s):  
Nasreen Bano Muslim Shaikh ◽  
Brijbhan Singh ◽  
Oluwole Makinde ◽  
Shoeb Rashid Sayyed
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Transformation Method ◽  
Analytic Solutions ◽  
Partial Slip ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
Base Function ◽  
Flow And Heat Transfer ◽  
Non Linear

The present paper investigates the problem of flow and heat transfer in a two dimensional boundary layer flow of a nanofluid over a non-linear, permeable stretching/shrinking sheet by considering the effects of suction/blowing, momentum slip, thermal slips and thermal radiation. Three different types of spherical nanoparticles such as ,  and  are considered by taking water as the base fluid. With the aid of suitable similarity transformations, the governing non-linear partial differential equations are transformed to ordinary ones. A new analytical method namely DTM-BF, based on the differential transformation method (DTM) and base function (BF), has been applied to get approximate analytic solutions of these equations in an unbounded domain. Comparison of the present numerical results has been done with the corresponding results available in the literature and they have been found to be in good agreement. The effects of different physical parameters on the flow and temperature profiles have been presented graphically.

Expanding/contracting fin of rectangular profile

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Turkyilmazoglu M.
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Transfer Problem ◽  
Rectangular Cross Section ◽  
Heat Transfer Process ◽  
Heat Transfer Analysis ◽  
Physical Parameters ◽  
Specific Rate ◽  
Content Type ◽  
Fin Efficiency

Purpose The purpose of this paper is to study an expandable or contractible metallic fin and heat transfer process. The fin is assumed to be thin having a rectangular cross section. It is attached to a hot surface with a time-dependent temperature, and its tip extends to a medium (fluid) of an ambient temperature. With the insulated wall constraint at the tip, the tip of the metallic fin has the property of expanding or contracting in time at a specific rate. Design/methodology/approach The corresponding physical problem is so formulated that the unsteady heat transfer problem is governed by means of a similarity variable represented by a second-order ordinary differential equation. The system can be reduced to the traditional well-documented steady state fin problem often studied in the literature, if the unsteadiness is turned off from the formulated system. Findings The system is then solved analytically for the temperature distribution through the fin. The fin tip temperatures are calculated, and the heat transfer analysis is made with varying physical parameters. And finally, observations are discussed leading to better fin efficiency and heat transfer enhancement. Originality/value An expandable or contractible metallic fin and heat transfer process are analyzed for the first time in the literature. Full solutions are presented, whose numerical correspondence is discussed through graphical and tabular forms.

scholarly journals Heat transfer enhancement in rotating disk boundary layer

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2467-2482
Author(s):  
Ahmer Mehmood ◽  
Muhammad Usman
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Enhancement ◽  
Rotating Disk ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Bench Mark ◽  
Physical Parameters ◽  
Transfer Enhancement ◽  
Severe Condition

A generally admitted fact about the nanofluids is the expedition of heat transfer process in comparison to pure fluids. The calculation of enhanced rate of heat transfer depends strongly upon the nanofluid modeling. Following the experimental evidence most of the researchers assume the nanofluid to be a homogeneous mixture. However, this is a severe condition that results in under-prediction of heat transfer rates. Due to the ongoing convection phenomena the nanoparticle concentration is actually non-homogeneous within the boundary-layer because of the presence of concentration gradients. The objective of this study is to calculate the heat transfer enhancement in 3-D boundary-layer when the working fluid is a nanofluid. The rotating disk geometry, which perhaps serves as the bench mark for the 3-D boundary-layers, have been chosen for the purpose here. The non-homogeneous nanofluid modeling has been utilized and a percent increase in Nusselt number has been calculated. Detailed analyses of flow and heat transfer phenomena for nanofluids have been conducted under the influence of several physical parameters.

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