Parametric Numerical Study of Turbulent Airflow in a Wavy Channel Under Pulsatile Conditions

Abstract

In the present work, a parametric numerical study is performed for a converging–diverging channel under pulsatile flow conditions. The sinusoidal velocity at the channel entrance provides the pulsatile flow condition. Simulations are performed for transient flow in the range of 0.001 − 0.5 for the Strouhal numbers, 3400 − 6500 for the Reynolds numbers, and 0.025 − 0.5 for the nondimensionalized amplitude values. The thermal–hydraulic performance is reported to compare pulsatile flow conditions with non-pulsatile conditions. The numerical results showed that the Nusselt number decreased as the Strouhal number and nondimensionalized amplitude values increased. In addition, an improvement in heat transfer is observed in pulsatile conditions for the Reynolds number range 3400–5200. It is understood that turbulent pulsatile airflow in a converging–diverging duct has a limited potential for heat transfer improvement in a specific range. The maximum thermal–hydraulic performance coefficient is found to be 1.17 for the Reynolds number of 3412 and for the Strouhal number of 0.001. It is concluded that pulsatile flow provides satisfactory improvement at lower Reynolds numbers than non-pulsatile flow. Moreover, pulsatile airflow in a converging–diverging duct has a limited potential for the heat transfer improvement in a specific range.

Additional information

Notes on contributors

Zekeriya Parlak

Zekeriya Parlak is an Associate Professor at the Mechanical Engineering Department of Sakarya University, Sakarya, Turkey. He graduated from Trakya University, Faculty of Engineering and Architecture, Department of Mechanical Engineering in 1998. He received the MSc and PhD degrees from Sakarya University in 2004 and 2010, respectively. He was a visiting researcher at Regensburg University of Applied Sciences, Germany, in 2005-2006. His research interests are on centrifugal pumps and fans, engineering optimization, thermal and fluid flow considerations, viscous and non-Newtonian fluid flows, devices with magnetorheological fluid, and computational fluid dynamics. https://orcid.org/0000-0002-2487-0065

Nezaket Parlak

Nezaket Parlak graduated from Trakya University, Faculty of Engineering and Architecture, Department of Mechanical Engineering in 2000. She earned her master's degree in 2003 and doctorate degree in 2010 from Sakarya University, Institute of Science and Technology, Department of Mechanical Engineering. In 2005 and 2006, she spent 12 months as a visiting researcher at Regensburg University of Applied Sciences in Germany, on the Stirling engine under the supervision of Prof. Dr.-Ing Michael Elsner. She is now working as an Associate Professor at Sakarya University. Her research interests are on flow and heat transfer in microchannels, drying techniques, Stirling engines, heat transfer enhancement techniques, and numerical methods. https://orcid.org/0000-0002-8469-2192

Yaşar Islamoğlu

Yaşar İslamoğlu graduated from ITU Sakarya Engineering Faculty Mechanical Engineering Department in 1994. He received the MSc in engineering fromt Istanbul Technical University in 1997 and Doctor of Science at Sakarya University in 2002. He worked as a Research Assistant between 1995 and 2002, Assistant Professor between 2002 and 2006, Associate Professor between 2006 and 2011 and he has been working as a Professor since 2011 in the Department of Thermodynamics and Heat Techniques in the Mechanical Engineering Department of Sakarya University. He works on heat transfer, enhancement of convection heat transfer, experimental and CFD methods in thermal systems and heat transfer in thermoelectric power generation and thermoelectric cooling systems. https://orcid.org/0000-0003-3856-7240

Ufuk Durmaz

Ufuk Durmaz graduated from Sakarya University both in Electrical Electronics and Mechanical Engineering in 2002 and 2003, respectively. After completing his master's and doctorate at the same university in 2006 and 2013, he did a post-doctorate for one year on computational fluid dynamics at the University of Duesseldorf, Germany, in 2013–2014. His areas of interest and study are renewable energy, heat exchangers, and computational fluid dynamics. https://orcid.org/0000-0001-5534-8117