Convection heat transfer in a Maxwell fluid at a non-isothermal surface

Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Kuppalapalle Vajravelu ◽  
Kerehalli Prasad ◽  
Ashwatha Sujatha
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Variable Temperature ◽  
Nonlinear Partial Differential Equations ◽  
Convection Heat Transfer ◽  
Maxwell Fluid ◽  
Convection Heat ◽  
Stretching Surface ◽  
Coupled Equations ◽  
Wide Range

AbstractAnalysis is carried out to study the convection heat transfer in an upper convected Maxwell fluid at a non-isothermal stretching surface. This is a generalization of the paper by Sadeghy et al. [21] to study the effects of free convection currents, variable thermal conductivity and the variable temperature at the stretching surface. Unlike in Sadeghy et al., here the governing nonlinear partial differential equations are coupled. These coupled equations are transformed in to a system of nonlinear ordinary differential equations and are solved numerically by a finite difference scheme (known as the Keller-Box method) and the numerical results are presented through graphs and tables for a wide range of governing parameters. The results obtained for the flow and heat transfer characteristics reveal many interesting behaviors that warrant further study of nonlinear convection heat transfer.

Numerical exploration of mixed convection heat transfer features within a copper-water nanofluidic medium occupied a square geometrical cavity

2021 ◽  
Vol 8 (4) ◽  
pp. 807-820
Author(s):  
M. Zaydan ◽  
◽  
A. Wakif ◽  
E. Essaghir ◽  
R. Sehaqui ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Mixed Convection ◽  
Nonlinear Differential Equations ◽  
Convection Heat Transfer ◽  
Local Heat Transfer ◽  
Physical Parameters ◽  
Convection Heat ◽  
Linear Temperature ◽  
Mixed Convection Heat Transfer

The phenomenon of mixed convection heat transfer in a homogeneous mixture is deliberated thoroughly in this study for cooper-water nanofluids flowing inside a lid-driven square cavity. By adopting the Oberbeck-Boussinesq approximation and using the single-phase nanofluid model, the governing partial differential equations modeling the present flow are stated mathematically based on the Navier--Stokes and thermal balance formulations, where the important features of the scrutinized medium are presumed to remain constant at the cold temperature. Note here that the density quantity in the buoyancy body force is a linear temperature-dependent function. The characteristic quantities are computed realistically via the commonly used phenomenological laws and the more accurate experimental correlations. A feasible non-dimensionalization procedure has been employed to derive the dimensionless conservation equations. The resulting nonlinear differential equations are solved numerically for realistic boundary conditions by employing the fourth-order compact finite-difference method (FOCFDM). After performing extensive validations with the previously published findings, the dynamical and thermal features of the studied convective nanofluid flow are revealed to be in good agreement for sundry values of the involved physical parameters. Besides, the present numerical outcomes are discussed graphically and tabularly with the help of streamlines, isotherms, velocity fields, temperature distributions, and local heat transfer rate profiles.

Existence of Dual Solutions and Melting Phenomenon in Unsteady Nanofluid Flow and Heat Transfer over a Stretching Surface

2019 ◽  
Vol 35 (5) ◽  
pp. 705-717
Author(s):  
S. Ghosh ◽  
S. Mukhopadhyay ◽  
K. Vajravelu
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Nonlinear Partial Differential Equations ◽  
Lewis Number ◽  
Skin Friction Coefficient ◽  
Dual Solutions ◽  
Stretching Surface ◽  
Melting Phenomenon ◽  
Runge Kutta Method ◽  
Layer Flow

ABSTRACTThe problem of unsteady boundary layer flow of a nanofluid over a stretching surface is studied. Heat transfer due to melting is analyzed. Using a similarity transformation the governing coupled nonlinear partial differential equations of the model are reduced to a system of nonlinear ordinary differential equations, and then solved numerically by a Runge-Kutta method with a shooting technique. Dual solutions are observed numerically and their characteristics are analyzed. The effects of the pertinent parameters such as the acceleration parameter, the Brownian motion parameter, the thermophoresis parameter, the Prandtl number and the Lewis number on the velocity, temperature and concentration fields are discussed. Also the effects of these parameters on the skin friction coefficient, the Nusselt number and the Sherwood number are analyzed through graphs. It is observed that the melting phenomenon has a significant effect on the flow, heat and mass transfer characteristics.

Heat transfer over an unsteady stretching surface with prescribed heat flux

2008 ◽  
Vol 86 (6) ◽  
pp. 853-855 ◽  
Author(s):  
A Ishak ◽  
R Nazar ◽  
I Pop
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Differential Equations ◽  
Nonlinear Partial Differential Equations ◽  
Method Comparison ◽  
Temperature Fields ◽  
Stretching Surface ◽  
Keller Box Method ◽  
Unsteady Stretching Surface ◽  
Layer Flow

The unsteady laminar boundary-layer flow over a continuously stretching surface in a viscous and incompressible quiescent fluid is studied. The unsteadiness in the flow and temperature fields is caused by the time dependence of the stretching velocity and the surface heat flux. The nonlinear partial differential equations of continuity, momentum, and energy, with three independent variables, are reduced to nonlinear ordinary differential equations, before they are solved numerically by the Keller-box method. Comparison with available data from the open literature as well as the exact solution for the steady-state case of the present problem is made, and found to be in good agreement. Effects of the unsteadiness parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined.PACS No.: 47.15.Cb

Experimental Study of Forced Convection From Isothermal Circular and Square Cylinders and Toroids

1997 ◽  
Vol 119 (1) ◽  
pp. 70-79 ◽  
Author(s):  
G. Refai Ahmed ◽  
M. M. Yovanovich
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Reynolds Numbers ◽  
Empirical Models ◽  
Experimental Program ◽  
Convection Heat ◽  
Forced Convection Heat Transfer ◽  
Wide Range

Experimental studies of forced convection heat transfer from different body shapes were conducted to determine the effects of Reynolds number and different characteristic body lengths on the area-averaged Nusselt number. Although the bodies differed significantly in their shapes, they had approximately the same total surface area, A = 11,304 mm2 ± 5%. This ensured that for a given free stream velocity and total heat transfer rate all bodies had similar trends for the relationship of Nusselt and Reynolds numbers. The experimental program range was conducted in the Reynolds number range 104≤ReA≤105 and Prandtl number 0.71. Finally, the empirical models for forced convection heat transfer were developed. These empirical models were valid for a wide range of Reynolds numbers 0≤ReA≤105. The present experimental correlations were compared with available correlation equations and experimental data. These comparisons show very good agreement.

Magnetohydrodynamics Thermocapillary Marangoni Convection Heat Transfer of Power-Law Fluids Driven by Temperature Gradient

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Yanhai Lin ◽  
Liancun Zheng ◽  
Xinxin Zhang
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Differential Equations ◽  
Power Law ◽  
Numerical Solutions ◽  
Marangoni Convection ◽  
Convection Heat Transfer ◽  
Temperature Fields ◽  
Convection Heat ◽  
Power Law Fluids

This paper presents an investigation for magnetohydrodynamics (MHD) thermocapillary Marangoni convection heat transfer of an electrically conducting power-law fluid driven by temperature gradient. The surface tension is assumed to vary linearly with temperature and the effects of power-law viscosity on temperature fields are taken into account by modified Fourier law for power-law fluids (proposed by Pop). The governing partial differential equations are converted into ordinary differential equations and numerical solutions are presented. The effects of the Hartmann number, the power-law index and the Marangoni number on the velocity and temperature fields are discussed and analyzed in detail.

scholarly journals Unsteady Marangoni convection heat transfer of fractional Maxwell fluid with Cattaneo heat flux

2017 ◽  
Vol 44 ◽  
pp. 497-507 ◽  
Author(s):  
Jinhu Zhao ◽  
Liancun Zheng ◽  
Xuehui Chen ◽  
Xinxin Zhang ◽  
Fawang Liu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Marangoni Convection ◽  
Convection Heat Transfer ◽  
Maxwell Fluid ◽  
Convection Heat ◽  
Cattaneo Heat Flux

scholarly journals PREDIKSI KARAKTERISTIK TERMOFLUIDA PROSES PERPINDAHAN PANAS DI DALAM RUANG BAKAR INCINERATOR

2015 ◽  
Vol 16 (1) ◽  
pp. 43
Author(s):  
Veronica Indriati Sri Wardhani
Keyword(s):  
Heat Transfer ◽  
Process Simulation ◽  
Negative Impact ◽  
Variable Temperature ◽  
Outer Space ◽  
Combustion Process ◽  
Convection Heat Transfer ◽  
Axial Direction ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient

ABSTRAK PREDIKSI KARAKTERISTIK TERMOFLUIDA PROSES PERPINDAHAN PANAS DI DALAM RUANG BAKAR INCINERATOR. Penanganan limbah padat dengan proses pembakaran merupakan salah satu cara yang efektif sampai saat ini, instalasi incinerator masih menjadi perlatan pilihan yang dipergunakan untuk proses pembakaran. Namun penggunaan incinerator sebagai alat pembakaran sampah harus direncanakan dengan baik, karena efek yang dihasilkan adalah produk-produk destruktif yang justru bernilai negatif terhadap lingkungan. Mengingat proses pembakaran yang sangat kompleks di dalam incinerator, maka dilakukan simulasi dengan membuat suatu pemodelan menggunakan perangkat lunak compu-tational fluid dinamics (Fluent). Simulasi ini bertujuan untuk melihat karakteristik termo fluida yang terjadi di dalam ruang bakar incinerator meliputi variabel-variabel antara lain distribusi temperatur, sifat-sifat fisik fluida dan jenis aliran ( laminer atau turbulen ). Variabel-variabel tersebut akan mempengaruhi harga koefisien perpindahan panas konveksi (h). Perhitungan karakteristik termofluida yang meliputi panas yang mengalir (Q) dan koefisien perpindahan panas (h) pada tiga (3) titik pengukuran arah aksial diperoleh hasil koefisien perpindahan panas konveksi di ruang bagian dalam lebih besar 10 kali dari koefisien perpindahan panas konveksi di ruang bagian luar antara bata dalam dan bata luar. ABSTRACT THERMOFLUID characteristic prediction oF heat transfeR in the combustion chamber of incinerator. Handling of solid waste with the combustion process by installing the incinerator, is one effective way at present. However, the use of incinerators as a means of burning waste should be well planned, because of the resulted destructive products that have a negative impact to the environment. Considering the complexity process of combustion in the incinerator, the process simulation is done by using Computational fluid Dynamics software (Fluent). This simulation is proposed to obtain thermofluid characteristics such as variable temperature distribution, physical properties of the fluid and flow pattern (laminer or turbulent). These variables will affect the convection heat transfer coefficient (h). The Calculation characteristics of termofluida such as heat  flow (Q) and coefficient heat transfer (h) on three (3) points in axial direction obtained the coefficient heat transfer convection inner space is greater 10 times  than the coefficient heat transfer convection outer space  between the inner brick  and the outer brick.

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