scholarly journals Convective Hydromagentic Slip Flow with Variable Properties Due to a Porous Rotating Disk

2010 ◽  
Vol 15 ◽  
pp. 55 ◽  
Author(s):  
Mohammad M. Rahman
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Slip Flow ◽  
Rotating Disk ◽  
Heat Transfer Characteristics ◽  
Temperature Dependent ◽  
Transfer Characteristics ◽  
Similarity Transformations ◽  
Flow And Heat Transfer ◽  
Highly Nonlinear

In this paper we investigate convective heat transfer characteristics of steady hydromagnetic slip flow over a porous rotating disk taken into account the temperature dependent density, viscosity and thermal conductivity  in the presence of  Hall current, viscous dissipation and Joule heating. Using von-Karman similarity transformations we reduce the governing equations for flow and heat transfer into a system of ordinary differential equations which are highly nonlinear and coupled. The resulting nondimensional equations are solved numerically by applying Nachtsheim-Swigert iteration technique. The results show that when modeling a thermal boundary layer, with temperature dependent fluid properties, consideration of Prandtl number as constant within the boundary layer, produces unrealistic results.   therefore  Therefore it must be treated as variable throughout the boundary layer. Results also show that the slip factor significantly controls the flow and heat transfer characteristics.  

Variable Property Effects in Simultaneously Developing Gaseous Slip-Flow in Rectangular Microchannels With Prescribed Wall Heat Flux

2010 ◽  
Author(s):  
Azad Qazi Zade ◽  
Metin Renksizbulut ◽  
Jacob Friedman
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Knudsen Number ◽  
Thermophysical Properties ◽  
Slip Flow ◽  
Wall Heat Flux ◽  
Heat Transfer Characteristics ◽  
Rectangular Microchannels ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer

The effects of variable physical properties on the flow and heat transfer characteristics of simultaneously developing slip-flow in rectangular microchannels with constant wall heat flux are numerically investigated. A co-located finite-volume method is used in order to solve the mass, momentum and energy equations in their most general form. Thermophysical properties of the flowing gas are functions of temperature, while density and Knudsen number are allowed to change with both pressure and temperature. Different Knudsen numbers are considered in order to study the effects of slip-flow. Simulations indicate that the constant physical property assumption can result in under/over-prediction of the local friction and heat transfer coefficients depending on the problem configuration. Density and thermophysical property variations have significant effects on predicting flow and heat transfer characteristics since the gas temperature constantly changes as a result of the applied wall heat flux. Heat transfer coefficient is affected both due to the change in the velocity field and change in thermophysical properties. Also temperature dependence of the local Knudsen number can significantly alter the friction coefficients due to its strong dependence on slip conditions. The degree of discrepancy varies for different cases depending on the Knudsen number, and the applied heat flux strength and direction (cooling versus heating).

scholarly journals A Stability Analysis of Boundary Layer Stagnation-Point Slip Flow and Heat Transfer towards a Shrinking/Stretching Cylinder over a Permeable Surface

CFD letters ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 97-105
Author(s):  
Ahmad Nazri Mohamad Som ◽  
Nurul Shahirah Mohd Adnan ◽  
Norihan Md. Arifin ◽  
Norfifah Bachok ◽  
Fadzilah Md Ali ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Stability Analysis ◽  
Stagnation Point ◽  
Slip Flow ◽  
Dual Solution ◽  
Stretching Cylinder ◽  
Governing Equations ◽  
Similarity Transformations ◽  
Flow And Heat Transfer

A stability analysis of dual solution for the problem of stagnation-point slip flow over a stretching or shrinking cylinder is studied. The partial differential equations governing will be transformed to a set of coupled nonlinear nonsimilar equations via similarity transformations. The transformed governing equations are solved numerically using the bvp4c function in MATLAB software. Numerical calculations exhibit the existence of dual solution and the implementation of stability analysis proved that the first solution is stable and physically realizable.

scholarly journals Hydromagnetic Boundary Layer Flow and Heat Transfer Characteristics of a Nanofluid over an Inclined Stretching Surface in the Presence of a Convective Surface: A Comprehensive Study

2015 ◽  
Vol 19 (2) ◽  
pp. 53 ◽  
Author(s):  
Mohammad M. Rahman ◽  
Mohammed M. Al-Hatmi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Differential Equations ◽  
Boundary Layer Flow ◽  
Base Fluid ◽  
Stretching Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Layer Flow

In this paper we investigate numerically the hydromagnetic boundary layer flow and heat transfer characteristics of a nanofluid using three types of nanoparticles (copper, aluminium oxide and titanium dioxide) having various shapes (spherical, cylindrical, arbitrary, etc) by considering three kinds of base fluids (water, ethylene glycol and engine oil) over a nonlinear inclined stretching surface, taking into account the effect of convective surface condition. Using similarity transformations, the governing nonlinear partial differential equations of the physical model are transformed into non-dimensional ordinary differential equations which are solved for local similar solutions using the very robust computer algebra software, Maple 13. The numerical simulation is carried out to investigate the role of the pertinent parameters on the flow and temperature fields as well as on the rate of heat transfer and on the rate of shear stress. The results show that the addition of nanoparticles to the base fluid may not always increase the rate of heat transfer. It depends significantly on the surface convection, type of base fluid and nanoparticles.  The finding of this study will open a gate for better understanding of nanofluid characteristics.  

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