scholarly journals Heat transfer enhancement by sinusoidal-shaped disk rotating in a forced flow

2019 ◽  
pp. 283-283
Author(s):  
Ahmer Mehmood ◽  
Muhammad Usman ◽  
Bernhard Weigand
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Shear Stress ◽  
Heat Transfer Rate ◽  
Boundary Layer Flow ◽  
Transfer Rate ◽  
Forced Flow ◽  
Moment Coefficient ◽  
Flat Disk ◽  
Layer Flow

The geometric characteristics of the heat transferring surface and the outer flow conditions have a significant impact on heat transfer augmentation. Both, the surface roughness and the pressure gradient attribute to an enhanced heat transfer. These two effects are utilized in this study to enhance the convective heat transfer rate in a non-similar boundary-layer flow induced by the rotation of a sinusoidal-shaped disk in an external forced flow. The heat transfer coefficient is calculated numerically for the laminar boundary-layer flow with the help of the Keller-box method. The numerical solution of the governing system of equations is first validated by previous published (theoretical and experimental) results for a wavy rotating disk in the absence of an external flow field and also for a flat disk rotating in a forced flow. It is observed that the effect of surface waviness along with a relative fluid motion on heat transfer rate, shear stresses, and shaft torque is quite pronounced. Specifically, enhancement of moment coefficient due to waviness of the disk leads to increase the power of a wavy disk pump in comparison to a smooth one. Furthermore, 119%, 174%, 86%, and 86% enhancement in the heat transfer rate, the radial shear stress, the tangential shear stress, and the moment coefficient, respectively, is observed for a rotating wavy disk subjected to a forced flow (at fixed ?/? =? and ?0 / ? = 0.125) in comparison to a free rotating flat disk.

scholarly journals Boundary layer flow and heat transfer in a micropolar fluid past a permeable at plate

2013 ◽  
Vol 40 (3) ◽  
pp. 403-425 ◽  
Author(s):  
Mosharf Hossain ◽  
Nepal Roy ◽  
Anwar Hossain
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Shear Stress ◽  
Stream Function ◽  
Boundary Layer Flow ◽  
Micropolar Fluid ◽  
Couple Stress ◽  
Function Formulation ◽  
Layer Flow ◽  
Stream Function Formulation

An analysis is performed to study the shear stress, the couple-stress and heat transfer characteristics of a laminar mixed convection boundary layer flow of a micropolar fluid past an isothermal permeable plate. The governing nonsimilar boundary layer equations are analyzed using the (i) series solution for small ?, (ii) asymptotic solution for large ? and (iii) primitive-variable formulation and the stream function formulation are being used for all ?. The effects of the material parameters, such as, the vortex viscosity parameter, K, and the transpiration parameter, s, on the shear stress, the couple-stress and heat transfer have been investigated. The agreement between the solutions obtained from the stream-function formulation and the primitive-variable formulation is found to be excellent.

An Experimental Study of Surface Roughness Effects on Turbulent Boundary Layer Flow and Heat Transfer

1989 ◽  
Author(s):  
Hugh W. Coleman ◽  
Robert P. Taylor ◽  
M. H. Hosni ◽  
Glenn B. Brown ◽  
Philip H. Love
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Experimental Study ◽  
Surface Roughness ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Flow ◽  
Roughness Effects ◽  
Flow And Heat Transfer ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

scholarly journals Impact of Binary Chemical Reaction and Activation Energy on Heat and Mass Transfer of Marangoni Driven Boundary Layer Flow of a Non-Newtonian Nanofluid

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 702
Author(s):  
Ramanahalli Jayadevamurthy Punith Gowda ◽  
Rangaswamy Naveen Kumar ◽  
Anigere Marikempaiah Jyothi ◽  
Ballajja Chandrappa Prasannakumara ◽  
Ioannis E. Sarris
Keyword(s):  
Heat Transfer ◽  
Activation Energy ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Velocity Gradient ◽  
Boundary Layer Flow ◽  
Biological Fluids ◽  
Porosity Parameter ◽  
Layer Flow

The flow and heat transfer of non-Newtonian nanofluids has an extensive range of applications in oceanography, the cooling of metallic plates, melt-spinning, the movement of biological fluids, heat exchangers technology, coating and suspensions. In view of these applications, we studied the steady Marangoni driven boundary layer flow, heat and mass transfer characteristics of a nanofluid. A non-Newtonian second-grade liquid model is used to deliberate the effect of activation energy on the chemically reactive non-Newtonian nanofluid. By applying suitable similarity transformations, the system of governing equations is transformed into a set of ordinary differential equations. These reduced equations are tackled numerically using the Runge–Kutta–Fehlberg fourth-fifth order (RKF-45) method. The velocity, concentration, thermal fields and rate of heat transfer are explored for the embedded non-dimensional parameters graphically. Our results revealed that the escalating values of the Marangoni number improve the velocity gradient and reduce the heat transfer. As the values of the porosity parameter increase, the velocity gradient is reduced and the heat transfer is improved. Finally, the Nusselt number is found to decline as the porosity parameter increases.

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