Boiling heat transfer characteristics of binary magnetic fluid flow in a vertical circular pipe with a partly heated region

2004 ◽  
Vol 218 (2) ◽  
pp. 223-232 ◽  
Author(s):  
S Shuchi ◽  
K Sakatani ◽  
H Yamaguchi
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Boiling Heat Transfer ◽  
Transfer Rate ◽  
Heated Region ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
The Magnetic Field

An investigation was conducted for heat transfer characteristics of binary magnetic fluid flow in a partly heated circular pipe experimentally. The boiling heat transfer characteristics on the effects of the relative position of the magnetic field to the heated region were particularly considered in the present study. From the experimental verification, the Nusselt number, representing boiling heat transfer characteristics, was obtained for various flow and magnetic conditions which were represented by the non-dimensional parameters of the Reynolds number and the magnetic pressure number. Additionally, the rate of change of the Nusselt number found by applying the magnetic field was also estimated and the optimal position of the field to the partly heated region was discussed. The results indicated that the effect of the magnetic field to the heat transfer rate from the heated wall was mainly subjected to the effect of the vortices induced in the magnetic field region and the possibility of controlling the heat transfer rate by applying an outer magnetic field to utilize the effect.

Analytical Investigation of Nusselt Number and Skin Friction of Fluid Flow Over a Stretching Sheet Using Optimal Homotopy Asymptotic Method

2020 ◽  
Vol 12 (5) ◽  
pp. 657-661
Author(s):  
Zohreh Aliannejadi
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Differential Equations ◽  
Skin Friction ◽  
Flow And Heat Transfer ◽  
Optimal Homotopy Asymptotic Method ◽  
The Magnetic Field

In many cases such as production of metal sheets, the behavior of fluid flow and heat transfer in the neighborhood of a hot plate is very important. The CFD simulation of fluid flow is a widespread study that reveals detail information about the fluid flow in the calculated domain. In this study, the flow and heat transfer of a specific fluid in the above area of a stretching plate is examined analytically to find the variation of skin friction and Nusselt number. For this purpose, the similarity transformations can be employed to achieve the ordinary differential equations from the governing partial differential equations. The optimal homotopy asymptotic method (OHAM) is used to solve the ordinary differential equations which is applicable in solving of nonlinear equations. The effects of magnetic field on the analytical results from solving the equations are evaluated in detail. It is found that the thickness of the flow boundary layer decreases and the thickness of the thermal boundary layer increases by increasing in the magnetic field. Moreover, the Nusselt number is lower and skin friction is higher for the higher values of the magnetic field.

Numerical investigation of fluid flow and heat transfer characteristics in novel circular wavy microchannel

2018 ◽  
Vol 233 (5) ◽  
pp. 954-966 ◽  
Author(s):  
Valaparla Ranjith Kumar ◽  
Karthik Balasubramanian ◽  
K Kiran Kumar ◽  
Nikhil Tiwari ◽  
Kanishk Bhatia
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Constant Heat Flux ◽  
Heat Transfer Characteristics ◽  
Number Range ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Centrifugal Instability ◽  
Transfer Behavior

In this study, the fluid flow and heat transfer behavior in a novel circular wavy microchannel design is numerically examined and compared with a sinusoidal wavy microchannel. The numerical studies were carried out in the Reynolds number range of 100–300 under a constant heat flux wall boundary condition. The sinusoidal profile has a continuously varying curvature, which peaks at the crests and troughs, and diminishes to naught at each section at the middle of adjacent crests and troughs. On the other hand, the circular profile has a curvature constant in magnitude (and alternating in direction). Heat transfer in wavy microchannels is enhanced by vortex flow induced by centrifugal instability, which in turn depends on the curvature of fluid channel profile. The sinusoidal wavy microchannel has a curvature continuously varying in a large range results in large fluctuations of Nusselt number, while the Nusselt number in the circular channel has smaller fluctuations. Hence, heat transfer performance of the circular wavy microchannel is higher than that of the sinusoidal wavy microchannel. Velocity vectors, velocity contours, and temperature contours are presented to aid the explanation of hydrodynamic and heat transfer characteristics of fluid flow in the novel circular wavy microchannels. The Nusselt number and pressure drop along the channel are also compared with the sinusoidal wavy microchannel using a performance factor.

Numerical Investigation of Fully Developed Fluid Flow and Heat Transfer in Double-Trapezoidal Microchannels

2013 ◽  
Author(s):  
Mostafa Shojaeian ◽  
Ali Koşar
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Aspect Ratio ◽  
Heat Transfer Characteristics ◽  
Constant Wall Temperature ◽  
Base Angle ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Poiseuille Number

Fully developed fluid flow and heat transfer characteristics of double-trapezoidal microchannels with constant wall temperature are numerically investigated in the slip flow regime. The governing equations are solved together with the appropriate boundary conditions using finite volume method. The effect of rarefaction on Poiseuille number, Po, and Nusselt number, Nu, is studied for Knudsen numbers, Kn, varying from 0 to 0.1. The effects of base angle, B, and aspect ratio, A, on the fluid flow and the heat transfer characteristics are also examined. The results reveal that the rarefaction and the cross-section shapes have prominent effects on these characteristics of double-trapezoidal microchannels. According to the results, the Poiseuille number decreases with increasing Kn, while the values of the Nusselt number completely depend on the impacts of the rarefaction and the fluid-surface interaction. Po and Nu decrease with aspect ratio for A<1, while the effect of aspect ratio on Po and Nu becomes unclear for A>1. Moreover, an increase in the base angle has a positive effect on Po and Nu, however this increasing trend is less pronounced for B > 60 ° and A < 1.67.

Sign in / Sign up

Export Citation Format

Share Document