The flow over cylinders attracted researchers throughout the years and considerable studies were conducted in the past decades. Understanding the fundamentals of such flows for different configurations and boundary conditions can facilitate more efficient applications in the industry.&nbsp; Some of the applications of flow over circular cylinders &nbsp;are heat exchangers, offshore oil structures, power lines, adjacent skyscrapers&nbsp;etc.The flow over bluff bodies results in periodic forces on the system which can be detrimental in some applications e.g., nuclear power plant heat exchangers. The flow over cylinders occurs naturally along with heat transfer in numerous applications. This heat transfer causes the fluid properties to vary with space and time, which in turn changes the flow features. Several researchers studied the flow over cylinders in tandem with heat transfer [1-3]. In this research, two-dimensional numerical simulations for heated and unheated flows over two circular cylinders of different diameters in tandem are conducted. The study is conducted for laminar flow, Re=150 and temperature ratio, where &nbsp;and &nbsp;are the cylinder surface and air temperatures, respectively. The study is limited to spacing ratios in the range &nbsp;and diameter ratios , where L is the center-to-center distance between the cylinders, &nbsp;and &nbsp;are the diameters of the upstream and downstream cylinders, respectively. The effect of heating on the flow is captured by modelling the thermophysical properties of the fluid following polynomial functions of temperature. The flow features around the cylinders for each configuration are visualized by plotting the streamlines, temperature fields, and velocity magnitude contours to analyze and understand the flow dynamics and heat transfer characteristics. These flow patterns are also compared to the classification of Zdravkovich [4] which are, extended-body, reattachment, and co-shedding regimes. The effect of varying geometrical parameters on the flow in terms of change of regime is discussed. Also, the drag coefficient on both upstream and downstream cylinders is presented as a function of spacing and diameter ratios. In addition, the average surface heat transfer coefficient of cylinders is also focused in this study.References:[1] Dhiman, S. K., Arbind Kumar, and J. K. Prasad. 2017. “Unsteady Computation of Flow Field and Convective Heat Transfer over Tandem Cylinders at Subcritical Reynolds Numbers.” Journal of Mechanical Science and Technology 31 (3): 1241–57.[2] Harimi, Iman, and Mohsen Saghafian. 2012. “Numerical Simulation of Fluid Flow and Forced Convection Heat Transfer from Tandem Circular Cylinders Using Overset Grid Method.” Journal of Fluids and Structures 28: 309–27.[3] Mahir, Necati, and Zekeriya Altaç. 2017. “Numerical Investigation of Flow and Heat Transfer Characteristics of Two Tandem Circular Cylinders of Different Diameters.” Heat Transfer Engineering 38 (16): 1367–81.[4] Zdravkovich, M. M. 1987. “The Effects of Interference between Circular Cylinders in Cross Flow††An Earlier Version as Originally Presented as an Invited Paper, Entitled ‘Forces on Pipe Clusters’, at the International Sympo&nbsp;on Separated Flow around Marine Structures, Norwegian .” J of Fluids and Structures 1 (2): 239–61.

Dynamics of Flow and Heat Transfer Around Two Circular Cylinders of Different Diameters in Tandem Subjected to Forced Convection

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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