Thermomagnetic convection characteristics of paramagnetic gas in a square enclosure under non-uniform magnetic field

Significance 

Recently published studies have shown that thermomagnetic convection has great potential for better heat transfer than the overwhelmingly popular natural convection. This has therefore made it of considerable interest in many engineering applications such as in heat exchangers, crystal growth, electronic cooling devices and pure magnetic convection in space engineering. In most of these applications, the magnetic field is usually supplied by a uniform magnetic or superconducting magnet which provides a strong magnetic induction up to 10 T or more. Up to date, very few published studies have attempted to employ a permanent magnetic field. In addition, with regard to thermomagnetic convection, no reports have been published on the effect of permanent magnet position on thermomagnetic convection yet. Therefore, there is need for more studies with regard to this issue so as to better comprehend the thermomagnetic convection in non-uniform magnetic field supplied by permanent magnet, which is vital for both scientific research and practical application.

To this note, Dr. Ke Wei Song and Professor Toshio Tagawa from the Department of Aeronautics and Astronautics, Tokyo Metropolitan University in Japan assessed the effects of magnet position and magnet strength on the thermomagnetic convection of gaseous oxygen in a square enclosure under combined magnetic and gravity fields. They focused on utilizing a magnetic field provided by a Neodymium-Iron-Boron permanent magnet which has a high magnetic energy product. Their work is currently published in the research journal, International Journal of Thermal Sciences.

The research method employed commenced with the fabrication of a physical model in which natural convection in a square enclosure with two vertical walls at different temperatures and two adiabatic horizontal walls was considered due to its relative simplicity and practical importance. Next, the two scholars developed the governing mathematical equations where they computed the magnetic field intensity. The developed equations were then discretized using the finite volume method. Lastly, so as to validate the code utilized in their work, the researchers tested the same natural convection problem in a square enclosure filled with air. Overall, a very good agreement between present numerical results and the results reported in the available literature was achieved.

The authors observed that the thermomagnetic convection was considerably affected by the relative location of the permanent magnet. To be precise, it was seen that the total heat transfer increased with the increase of magnet strength when the magnet was placed near the hot wall, while the heat transfer increased first and then decreased with the increase of magnet strength when the magnet was placed near the cold wall.

In a nutshell, Ke Wei Song-Toshio Tagawa study presented an in-depth numerical assessment of the effects of permanent magnet position and magnet strength on thermomagnetic convection in a square enclosure under combined gravity field and magnetic field. Generally, they concluded that: first, the permanent magnet position has significant effect on the thermomagnetic convection in the enclosure. Second, the magnet strength also has an obvious effect on the thermomagnetic convection. Lastly, the optimal position of permanent magnet exists for best heat transfer performance. Altogether, the numerical results obtained here can provide more reliable information about thermomagnetic convection in a square enclosure under non-uniform magnetic field.

Thermomagnetic convection characteristics of paramagnetic gas in a square enclosure under non-uniform magnetic field - Advances in Engineering Thermomagnetic convection characteristics of paramagnetic gas in a square enclosure under non-uniform magnetic field - Advances in Engineering Thermomagnetic convection characteristics of paramagnetic gas in a square enclosure under non-uniform magnetic field - Advances in Engineering

 

About the author

Dr. Toshio Tagawa is currently working at Department of Aeronautics and Astronautics, Tokyo Metropolitan University, Japan since 2005. He received the Award for Scientific Contribution in 2003 from the Heat Transfer Society of Japan. Currently he has been engaged in the study of magneto-hydrodynamics, mathematical modeling of interfacial flows and heat transfer of natural convection in an enclosure. Convection in an enclosure.

Address: Department of Aeronautics and Astronautics, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo, 1910065, Japan
Email: [email protected].
Mobile: +81-42-585-8662

About the author

Dr. KeWei Song  is currently working in Lanzhou Jiaotong University as an academic tutor of Engineering Thermophysics since 2006. He has worked in Tokyo Metropolitan University as a Visiting Scholar under the guidance of professor Toshio Tagawa for one year since 2016. His research interests mainly lies in the fields of fluid dynamics and thermodynamics. He is doing researches in numerical method for fluid flow and heat transfer, heat transfer enhancement technology and thermomagnetic convection.
Address: School of Mechatronic Engineering, Lanzhou Jiaotong University, 88 West Anning Road, Lanzhou, Gansu, 730070, China.
Email: [email protected]
Mobile: +86-13919063664

Reference

Ke Wei Song, Toshio Tagawa. Thermomagnetic convection of oxygen in a square enclosure under non-uniform magnetic field. International Journal of Thermal Sciences, volume 125 (2018) page 52–65.

Go To International Journal of Thermal Sciences

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