Enhanced Forced Convection in a Square Channel With Two-Stage Corona Wind Generator

2012 ◽  
Author(s):  
A. K. M. Monayem H. Mazumder ◽  
F. C. Lai
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Thermal Management ◽  
Forced Convection ◽  
Two Stage ◽  
Maximum Enhancement ◽  
Square Channel ◽  
Wind Generator ◽  
Wide Range ◽  
Corona Wind

In this study, enhancement in forced convection inside a square channel by a two-stage electrohydrodynamic (EHD) gas pump has been examined by numerical simulations. The EHD gas pump with 28 emitting electrodes in each stage has been evaluated for a wide range of operating voltages starting from the corona threshold voltage up to 28 kV for further improvement in its performance over that of a single-stage. To achieve the maximum enhancement in heat transfer, the emitting electrodes of the corona wind generator are flush mounted on the channel walls so that the corona wind produced directly perturbs the boundary layer. The results show that EHD technique has a great potential for applications in thermal management.

Heat Transfer Enhancement for Flows in a Channel With Corona Wind Generator

2010 ◽  
Author(s):  
J. Zhang ◽  
F. C. Lai
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Transfer Enhancement ◽  
Power Requirement ◽  
Maximum Enhancement ◽  
Wind Generator ◽  
Wind Generators ◽  
Corona Wind

Heat transfer enhancement using corona wind generators in a square channel has been numerically examined in this study. Three configurations of the corona wind generators (separately with 4, 12, and 28 pins) are investigated for their effectiveness in the enhancement of heat transfer as well as the pumping power requirement. To achieve the maximum enhancement in heat transfer, the emitting electrodes of the corona wind generator are flush mounted on the channel walls so that the corona wind produced directly perturbs the boundary layer. The Reynolds number considered varies in a range between 200 and 2000. The influence of electric field on the flow and temperature fields is examined for a wind range of operating conditions. The results show that EHD technique has a great potential for many engineering applications.

Enhancement in Forced Convection by a Two Stage Corona Wind Generator

2020 ◽  
Author(s):  
A. K. M. Monayem H. Mazumder
Keyword(s):  
Forced Convection ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Temperature Fields ◽  
Two Stage ◽  
Power Requirement ◽  
Maximum Increase ◽  
Square Channel ◽  
Wide Range ◽  
Volume Method

Abstract In this study, forced convection enhancement in a square channel by a two stage electrohydrodynamic (EHD) gas pump is numerically analyzed. This study is implemented for a two stage EHD gas pump with three emitting electrode configurations: 8, 24, and 56 respectively to seek their effectiveness in the enhancement of forced convection and pumping power requirement. The EHD gas pump is evaluated for a wide range of operating voltages starting from 20 kV up to 28 kV. The influence of electric field on the flow and temperature fields is also examined for a wide range of Reynolds numbers. The three-dimensional governing equations for the flow and temperature fields are solved using the finite volume method. The Reynolds numbers (Re) considered in this study varies in a range between 100 and 2000. At Re = 100, a maximum increase of 42% in the average Nusselt number is achieved with an applied voltage of 28 kV. The overall effectiveness of the EHD gas pump in heat transfer enhancement is evaluated by the thermal hydraulic performance parameter, (Nu/Nu0)/(f/f0), which is always greater than unity. These results disclose that EHD technique has a great potential for many engineering applications, particularly for thermal management.

Flow Characteristics in a Channel With Corona Wind Generator

2010 ◽  
Author(s):  
J. Zhang ◽  
F. C. Lai
Keyword(s):  
Volume Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Square Channel ◽  
Wind Generator ◽  
Numerical Predictions ◽  
Wide Range ◽  
Flow Transport ◽  
Corona Wind

Electrohydrodynamically induced flows have shown great potential for many engineering applications. Previous studies have revealed that a corona wind generator can be used to enhance flow transport in a channel. In this study, a corona wind generator with emitting wire electrodes flush mounted on the channel walls is considered for a wide range of operating conditions. Specifically, three configurations of the generator (with 4, 12, and 28 pins of emitting electrodes) are evaluated for their effectiveness in delivering the air flow. To investigate the flow characteristics inside a square channel, three-dimensional governing equations for electric and flow fields are numerically solved. The corona current is first measured experimentally and used in the numerical calculations. Numerical predictions on the velocity profile of corona-induced air flows as well as the volume flow rate delivered have been successfully verified by experimental results.

Flow Induced by a Two Stage Electrohydrodynamic Gas Pump in a Square Channel

2020 ◽  
Author(s):  
A. K. M. Monayem H. Mazumder ◽  
Grace S. Trombley ◽  
Brendon G. Cusinio
Keyword(s):  
Velocity Profile ◽  
Cross Sections ◽  
Volume Flow Rate ◽  
Forced Flow ◽  
Tube Length ◽  
Two Stage ◽  
Maximum Enhancement ◽  
Square Channel ◽  
Parabolic Velocity Profile ◽  
Wide Range

Abstract In this study, fluid flow induced by a two stage electrohydrodynamic (EHD) gas pump in a square channel has been evaluated by experimental measurement and numerical simulations. This study is implemented for a two stage EHD gas pump with three emitting electrode configurations: 8, 24, and 56 respectively to seek the relation between the number of stages and emitting electrodes. The EHD pump is evaluated for a wide range of operating voltages starting from 20 kV up to 28 kV for further improvement in its performance over a single stage. To achieve the maximum enhancement, the emitting electrodes of the EHD gas pump are flush mounted on the channel walls so that the corona wind produced directly disturbs the boundary layer thickness and improves the heat transfer. This is leading to a higher velocity near the channel walls and resulting in an inverted parabolic velocity profile at the center of the channel, which is opposite to the fully developed velocity profile of a forced flow. Velocities are measured at three cross-sections along the tube length and then integrated to obtain the volume flow rate. The results show that EHD technique has a great potential for many engineering applications.

Heat and Mass Transfer in an Incompressible Turbulent Boundary Layer

1972 ◽  
Vol 94 (1) ◽  
pp. 23-28 ◽  
Author(s):  
E. Brundrett ◽  
W. B. Nicoll ◽  
A. B. Strong
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Porous Plate ◽  
Mixing Length ◽  
Two Dimensional ◽  
Transfer Data ◽  
Incompressible Turbulent Boundary Layer ◽  
Wide Range ◽  
Incompressible Boundary

The van Driest damped mixing length has been extended to account for the effects of mass transfer through a porous plate into a turbulent, two-dimensional incompressible boundary layer. The present mixing length is continuous from the wall through to the inner-law region of the flow, and although empirical, has been shown to predict wall shear stress and heat transfer data for a wide range of blowing rates.

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