Session: 11-19-01: Methods in Computational Heat Transfer and Their Applications

Paper Number: 150980

150980 - Heat Transfer Enhancement by a Single Stage Corona Wind Generator 

Preceding studies have shown that electric fields in the form of corona wind can be used for gas pumping and heat transfer enhancement. In this study, a single stage corona wind generator in a rectangular channel has been evaluated by numerical simulations for its potential in the enhancement of heat transfer. The generation of corona wind is done by electrohydrodynamic (EHD) technique also known as EHD gas pump. Using the finite difference and finite volume method respectively, the three-dimensional governing equations for the electric, flow and temperature fields are solved. The EHD induced flow in a square channel is calculated first, and its results are compared with the collected experimental data to validate the computational code. The corona wind produced by the generator with three different sizes of the grounded electrode (in terms of its length): 0.5-inch, 1-inch, and 2-inch (1.27-cm, 2.54-cm, and 5.08-cm) with 12 emitting electrodes are examined to seek its effectiveness in the heat transfer enhancement and pumping power requirement. To achieve the maximum enhancement, the emitting electrodes of the EHD gas pump are flush mounted on the channel walls so that the fluid flow produced directly disturbs the boundary layer thickness and improves the heat transfer coefficient. 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. Both the current and fluid velocity inside the channel is obtained by positive polarity.

 

These three configurations are evaluated for a wide range of operating voltages starting from 20 kV up to 28 kV for further enhancement in its performance. According to the findings, the EHD gas pump can produce and sustain gas flows with a maximum velocity and its maximum performance is better than conventional cooling fan. The influence of electric field on the flow and temperature fields is also examined for a wide range of Reynolds numbers (Re). The Reynolds numbers considered in this study vary in a range between 100 and 2000. At Re = 100, a maximum increase of average Nusselt number is achieved with an applied voltage of 28 kV. The pumping power required for the heat transfer enhancement is also critically evaluated. The enhancement produced by the EHD gas pump is found to be higher than other techniques and with a smaller power penalty. 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.

Presenting Author: Akm Monayem Mazumder Saginaw Valley State University

Presenting Author Biography: A K M Monayem H. Mazumder received his Bachelor of Science from Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh, in 2006; Master of Science from the University of New Orleans (UNO), New Orleans, LA, in 2010 and PhD from the University of Oklahoma (OU), Norman, OK, in 2012, all are in Mechanical Engineering. During his PhD studies, he worked on various problems in electrohydrodynamics (EHD). He has been a Postdoctoral Fellow with Department of Mechanical Engineering at University of New Mexico, Albuquerque, NM. He developed a new method for flow simulation in internal combustion engines, particularly a 3D algorithm for the solution of the Navier-Stokes equations in domains containing moving parts and boundaries. He worked as a visiting assistant professor with department of Mechanical and Industrial Engineering at Texas A&M University-Kingsville, Kingsville, TX. He also worked as a visiting assistant professor in the department of Mechanical Engineering at Lamar University, Beaumont, TX. Presently, he is working as an associate professor in the department of Mechanical Engineering at Saginaw Valley State University, University Center, MI.

Authors:

Akm Monayem Mazumder Saginaw Valley State University