Heat Transfer Analysis of a Buoyancy-Induced Flow of Nanofluids Along a Vertical Hot Plate: Effect of Nanoparticle Type and Diameter

2014 ◽  
Author(s):  
I. P. Koronaki ◽  
M. T. Nitsas
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Dynamic Models ◽  
Effective Means ◽  
Heat Transfer Analysis ◽  
Heated Plate ◽  
Induced Flow ◽  
Linear Differential ◽  
The Impact ◽  
Buoyancy Induced Flow

Nanofluids is a term to describe fluids engineered by dispersing nanometer-scale structures such as particles, tubes and fibers in base fluids. Nanofluids are viewed as effective means of enhancing heat and mass transfer and thus they can be implemented in many engineering applications. The present paper examines the two dimensional-steady state-natural convection during the buoyancy-induced flow of the incompressible Al2O3-water nanofluid along a vertical plate under two different scenarios: the uniform and non-uniform heated plate. Both dynamic and static models are proposed in the literature for the conductivity and viscosity of the nanofluids. Nevertheless, in this work, dynamic models for the nanofluids thermal conductivity and viscosity have been assumed so as the Brownian motion of the nanoparticles to be considered. The governing equations of continuity, momentum and energy are reduced to a system of two non-linear differential equations by means of introducing the Pohlhausen stream function, and are solved numerically with the Runge-Kutta method with the Prandtl number being the only parameter of the dimensionless differential equations. The results show that the convection heat transfer coefficient is enhanced due to the nanofluids and it increases further by augmenting the volume concentration of the nanoparticles. The results of the aforementioned analysis are validated with the Finite Difference Method (FDM) selecting the proper grid density for the field. In addition, the impact of the nanoparticle diameter and the type of the base fluid on maximizing heat transfer through free convection for the isothermal plate is investigated. Finally, the two ways of expressing the temperature of the plate are compared in terms of influencing the convection coefficient.

Effect of Porous Medium in Stagnation Point Flow of Ferrofluid Due to a Variable Convected Thicked Sheet

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Maria Imtiaz ◽  
Hira Nazar ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Differential Equations ◽  
Stagnation Point ◽  
Skin Friction Coefficient ◽  
Stagnation Point Flow ◽  
Heat Transfer Analysis ◽  
Series Solutions ◽  
The Impact

Abstract The focus of this paper is to study the effects of stagnation point flow and porous medium on ferrofluid flow over a variable thicked sheet. Heat transfer analysis is discussed by including thermal radiation. Suitable transformations are applied to convert partial differential equations to ordinary differential equations. Convergent results for series solutions are calculated. The impact of numerous parameters on velocity and temperature is displayed for series solutions. Graphical behavior for skin friction coefficient and Nusselt number is also analyzed. Numerical values of Nusselt number are tabulated depending upon various parameters

scholarly journals Heat Transfer Analysis of MHD Water Functionalized Carbon Nanotube Flow over a Static/Moving Wedge

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Waqar A. Khan ◽  
Richard Culham ◽  
Rizwan Ul Haq
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Differential Equations ◽  
Skin Friction ◽  
Volume Fraction ◽  
Heat Transfer Analysis ◽  
Published Data ◽  
Nusselt Numbers ◽  
Moving Wedge ◽  
The Impact

The MHD flow and heat transfer from water functionalized CNTs over a static/moving wedge are studied numerically. Thermal conductivity and viscosity of both single and multiple wall carbon nanotubes (CNTs) within a base fluid (water) of similar volume are investigated to determine the impact of these properties on thermofluid performance. The governing partial differential equations are converted into nonlinear, ordinary, and coupled differential equations and are solved using an implicit finite difference method with quasi-linearization techniques. The effects of volume fraction of CNTs and magnetic and wedge parameters are investigated and presented graphically. The numerical results are compared with the published data and are found to be in good agreement. It is shown that the magnetic field reduces boundary layer thickness and increases skin friction and Nusselt numbers. Due to higher density and thermal conductivity, SWCNTs offer higher skin friction and Nusselt numbers.

Two Dimensional-Steady State-Natural Convection During the Buoyancy-Induced Flow of CuO-Water Nanofluid Along a Vertical Channel

2014 ◽  
Author(s):  
I. P. Koronaki ◽  
M. T. Nitsas ◽  
Ch. Vallianos
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Base Fluid ◽  
Dynamic Models ◽  
Effective Conductivity ◽  
Vertical Channel ◽  
Two Dimensional ◽  
Induced Flow ◽  
Buoyancy Induced Flow

In many engineering applications, heat and mass transfer is of vital importance. Therefore a lot of research has been done trying to maximize the heat transfer rate. It is proved, mostly through experimental processes that nanofluids i.e., liquid suspensions of nanometer size particles, have the required capability to augment heat transfer since their efficacy is based on their improved properties compared to those of the base fluid. The present paper examines the two dimensional-steady state-natural convection during the buoyancy-induced flow of the incompressible CuO-water nanofluid along a vertical channel whose walls are uniformly heated. The available literature suggests static and dynamic models for calculating the effective conductivity and viscosity of nanofluids. In this work, both models are assumed so as the Brownian motion of nanoparticles to be considered. The governing equations of continuity, momentum and energy have been solved numerically with the Finite Difference Method (FDM) by using suitable dimensionless variables. The results of the aforementioned analysis prove that the convection coefficient is enhanced due to the presence of nanofluids and it increases further by changing the volume concentration of the nanoparticles. Finally, the effect of the nanoparticles size on heat transfer and the type of the base fluid is investigated.

Measurement of Buoyancy-Induced Flow Using a Self-Heated Thermistor Flowmeter

1987 ◽  
Vol 109 (1) ◽  
pp. 34-39 ◽  
Author(s):  
A. H. Fanney ◽  
B. P. Dougherty
Keyword(s):  
Heat Transfer ◽  
Water System ◽  
Hot Water ◽  
Heat Transfer Analysis ◽  
Fluid Temperature ◽  
Measured Flow ◽  
Induced Flow ◽  
Dimensionless Heat ◽  
Buoyancy Induced Flow ◽  
Good Agreement

The development and calibration of a self-heated thermistor anemometer is described. The variation in thermistor power dissipation as a function of fluid temperature and velocity is presented. The thermistor flowmeter, which evolves from this investigation, is used to measure the buoyancy-induced flow in a thermosyphon solar hot water system. Measured flow rates for a representative day are presented. A dimensionless heat transfer analysis, applied to the thermistor probe, yielded results in good agreement with classical heat transfer correlations for spheres.

scholarly journals Entropy Generation and Heat Transfer Analysis in MHD Unsteady Rotating Flow for Aqueous Suspensions of Carbon Nanotubes with Nonlinear Thermal Radiation and Viscous Dissipation Effect

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 492 ◽  
Author(s):  
Muhammad Jawad ◽  
Zahir Shah ◽  
Aurungzeb Khan ◽  
Waris Khan ◽  
Poom Kumam ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Differential Equations ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Heat Transfer Analysis ◽  
Shrinking Sheet ◽  
Bejan Number ◽  
Nanofluid Flow ◽  
The Impact

The impact of nonlinear thermal radiations rotating with the augmentation of heat transfer flow of time-dependent single-walled carbon nanotubes is investigated. Nanofluid flow is induced by a shrinking sheet within the rotating system. The impact of viscous dissipation is taken into account. Nanofluid flow is assumed to be electrically conducting. Similarity transformations are applied to transform PDEs (partial differential equations) into ODEs (ordinary differential equations). Transformed equations are solved by the homotopy analysis method (HAM). The radiative source term is involved in the energy equation. For entropy generation, the second law of thermodynamics is applied. The Bejan number represents the current investigation of non-dimensional entropy generation due to heat transfer and fluid friction. The results obtained indicate that the thickness of the boundary layer decreases for greater values of the rotation parameter. Moreover, the unsteadiness parameter decreases the temperature profile and increases the velocity field. Skin friction and the Nusselt number are also physically and numerically analyzed.

scholarly journals Impact of Maxwell velocity slip and Smoluchowski temperature slip on CNTs with modified Fourier theory: Reiner-Philippoff model

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258367
Author(s):  
Tanveer Sajid ◽  
Wasim Jamshed ◽  
Faisal Shahzad ◽  
M. A. Aiyashi ◽  
Mohamed R. Eid ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Thermal Radiation ◽  
Velocity Slip ◽  
Heat Transfer Analysis ◽  
Brownian Diffusion ◽  
Slip Boundary Conditions ◽  
Slip Boundary ◽  
The Impact

The present article presents a novel idea regarding the implementation of Tiwari and Das model on Reiner-Philippoff fluid (RPF) model by considering blood as a base fluid. The Cattaneo-Christov model and thermal radiative flow have been employed to study heat transfer analysis. Tiwari and Das model consider nanoparticles volume fraction for heat transfer enhancement instead of the Buongiorno model which heavily relies on thermophoresis and Brownian diffusion effects for heat transfer analysis. Maxwell velocity and Temperature slip boundary conditions have been employed at the surface of the sheet. By utilizing the suitable transformations, the modeled PDEs (partial-differential equations) are renewed in ODEs (ordinary-differential equations) and treated these equations numerically with the aid of bvp4c technique in MATLAB software. To check the reliability of the proposed scheme a comparison with available literature has been made. Other than Buongiorno nanofluid model no attempt has been made in literature to study the impact of nanoparticles on Reiner-Philippoff fluid model past a stretchable surface. This article fills this gap available in the existing literature by considering novel ideas like the implementation of carbon nanotubes, CCHF, and thermal radiation effects on Reiner-Philippoff fluid past a slippery expandable sheet. Momentum, as well as temperature slip boundary conditions, are never studied and considered before for the case of Reiner-Philippoff fluid past a slippery expandable sheet. In the light of physical effects used in this model, it is observed that heat transfer rate escalates as a result of magnification in thermal radiation parameter which is 18.5% and skin friction coefficient diminishes by the virtue of amplification in the velocity slip parameter and maximum decrement is 67.9%.

scholarly journals Approximate Analytical Analysis of Unsteady MHD Mixed Flow of Non-Newtonian Hybrid Nanofluid over a Stretching Surface

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 138
Author(s):  
Ali Rehman ◽  
Zabidin Salleh
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Base Fluid ◽  
Research Work ◽  
Hybrid Nanofluid ◽  
Stretching Surface ◽  
Optimal Homotopy Analysis Method ◽  
Analytical Analysis ◽  
Transfer Ratio ◽  
The Impact

This paper analyses the two-dimensional unsteady and incompressible flow of a non-Newtonian hybrid nanofluid over a stretching surface. The nanofluid formulated in the present study is TiO2 + Ag + blood, and TiO2 + blood, where in this combination TiO2 + blood is the base fluid and TiO2 + Ag + blood represents the hybrid nanofluid. The aim of the present research work is to improve the heat transfer ratio because the heat transfer ratio of the hybrid nanofluid is higher than that of the base fluid. The novelty of the recent work is the approximate analytical analysis of the magnetohydrodynamics mixed non-Newtonian hybrid nanofluid over a stretching surface. This type of combination, where TiO2+blood is the base fluid and TiO2 + Ag + blood is the hybrid nanofluid, is studied for the first time in the literature. The fundamental partial differential equations are transformed to a set of nonlinear ordinary differential equations with the guide of some appropriate similarity transformations. The analytical approximate method, namely the optimal homotopy analysis method (OHAM), is used for the approximate analytical solution. The convergence of the OHAM for particular problems is also discussed. The impact of the magnetic parameter, dynamic viscosity parameter, stretching surface parameter and Prandtl number is interpreted through graphs. The skin friction coefficient and Nusselt number are explained in table form. The present work is found to be in very good agreement with those published earlier.

Entropy generation and heat transfer analysis for ferrofluid flow between two rotating disks with variable conductivity

2021 ◽  
pp. 095440622199118
Author(s):  
Anupam Bhandari
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Differential Equations ◽  
Entropy Generation ◽  
Heat Transfer Analysis ◽  
Entropy Generation Rate ◽  
Geometrical Parameters ◽  
Rotating Disks ◽  
Coupled Differential Equations ◽  
Lower Disk

Present model analyze the flow and heat transfer of water-based carbon nanotubes (CNTs) [Formula: see text] ferrofluid flow between two radially stretchable rotating disks in the presence of a uniform magnetic field. A study for entropy generation analysis is carried out to measure the irreversibility of the system. Using similarity transformation, the governing equations in the model are transformed into a set of nonlinear coupled differential equations in non-dimensional form. The nonlinear coupled differential equations are solved numerically through the finite element method. Variable viscosity, variable thermal conductivity, thermal radiation, and volume concentration have a crucial role in heat transfer enhancement. The results for the entropy generation rate, velocity distributions, and temperature distribution are graphically presented in the presence of physical and geometrical parameters of the flow. Increasing the values of ferromagnetic interaction number, Reynolds number, and temperature-dependent viscosity enhances the skin friction coefficients on the surface and wall of the lower disk. The local heat transfer rate near the lower disk is reduced in the presence of Harman number, Reynolds number, and Prandtl number. The ferrohydrodynamic flow between two rotating disks might be useful to optimize the use of hybrid nanofluid for liquid seals in rotating machinery.

Heat Transfer Analysis of Jet Impingement Cooling on a Simulated Ceramic Matrix Composite Surface

2017 ◽  
Author(s):  
Karthik Krishna ◽  
Mark Ricklick
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Matrix Composite ◽  
Ceramic Matrix Composite ◽  
Jet Impingement ◽  
Ceramic Matrix ◽  
Heat Transfer Analysis ◽  
Test Surface ◽  
Composite Surface ◽  
The Impact

Ceramic Matrix Composite is a woven material characterized by a significant level of surface waviness of 35–60μm and surface roughness of 5–6μm. To be implemented in a future gas turbine engine they will be cooled traditionally to increase power and efficiency. To analyze the CMC surface effects on heat transfer rate, an impinging circular jet on a simulated CMC surface is studied experimentally and the CMC surface is represented by a high resolution CNC machined surface. The test parameters are jet to plate distance of 7 jet diameters, oblique impingement angles of 45° and 90° and Reynolds numbers of 11,000 to 35,000. The test surface is broken down into constant temperature segments, and individual segment Nusselt number is determined and plotted for the various impingement cases studied. Area-Averaged results show negligible changes in average Nusselt number as compared to the hydrodynamically smooth surface. The impact of the CMC surface feature is negligible compared to the uncertainty in heat transfer coefficient, and therefore traditional design tools can be utilized.

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