The Effect of Sinusoidally Changing Magnetic Field Strength on Flow Separation and Heat Transfer in Backward-Facing Step Geometry

Year 2020, Volume: 35 Issue: 2, 413 - 424, 30.06.2020

Harun Zontul , Beşir Şahin

https://doi.org/10.21605/cukurovaummfd.792432

Abstract

Flow separation is a physical phenomenon that greatly affects the performance in aerodynamic and heat transfer applications and cannot be neglected during design. Backward-facing step is the reference geometry, which is important in the studies carried out to examine the flow separation or to investigate the effectiveness of control methods aimed at manipulating the separated flow. In this study, the effect of the magnetic field, which is an active flow control method, on flow separation in backward-facing step geometry and heat transfer were investigated numerically. The intensity of the magnetic field was changed continuously, depending on a sinusoidal function over time. The investigation was limited to laminer flow conditions. Water based iron oxide (Fe3O4 – water) nanofluid was used as a working fluid and the nanofluid modeled as a single phase. As a result of numerical simulations, the method examined has been found to be successful in influencing the wake flow and the convective heat transfer caused by the flow in this zone.

Keywords

Backward-facing step, Flow control methods, Flow seperation, Heat transfer, Magnetohydrodynamics

Zamanla Sinüzoidal Olarak Değişen Manyetik Alan Şiddetinin Ters Basamak Geometrisinde Akış Ayrılması ve Isı Transferine Etkisi

Abstract

Akış ayrılması, aerodinamik ve ısı transferi uygulamalarında performansı büyük ölçüde etkileyen, tasarım sırasında göz ardı edilemeyecek fiziksel bir olgudur. Ters basamak geometrisi, akış ayrılmasını incelemek veya ayrılmış akışı manipüle etmeyi hedefleyen kontrol yöntemlerinin etkinliğini araştırmak amacıyla gerçekleştirilen çalışmalarda önemli bir yere sahip referans geometridir. Bu çalışmada bir aktif akış kontrol yöntemi olan manyetik alanın ters basamak geometrisinde akış ayrılması ve ısı transferine etkisi sayısal olarak incelenmiştir. Manyetik alanın şiddeti zamana göre sinüzoidal bir fonksiyona bağlı kalarak sürekli şekilde değiştirilmiştir. İnceleme laminer akış koşulları ile sınırlandırılmıştır. Çalışma sıvısı olarak su bazlı demir oksit (Fe3O4-su) nano akışkanı kullanılmış ve nano akışkan tek fazlı olarak modellenmiştir.
Sayısal simülasyonlar sonucunda incelenen yöntemin ölü akış bölgesine ve bu bölgedeki akışın sebep olduğu konveksiyon ile ısı transferine etki etmede başarılı olduğu görülmüştür.

Keywords

Akış kontrol yöntemleri, Akış ayrılması, Isı transferi, Manyetohidrodinamik, Ters basamak geometrisi

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