A COMPUTATIONAL STUDY OF HEAT AND MASS TRANSFER FROM A CIRCULAR CYLINDER IN OSCILLATORY FLOW


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ÇUHADAROĞLU B. , Yiğit S.

HEAT TRANSFER RESEARCH, vol.48, no.17, pp.1581-1598, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 48 Issue: 17
  • Publication Date: 2017
  • Doi Number: 10.1615/heattransres.2017015493
  • Title of Journal : HEAT TRANSFER RESEARCH
  • Page Numbers: pp.1581-1598

Abstract

In the present study, heat and mass transfer in oscillating fl ow around a wet circular cylinder has been analyzed numerically. The oscillating fl ow is modeled by defi ning the vertical velocity component as v(t) = A sin (ωt) at the inlet, and, hence, the oncoming fl ow is controlled by the amplitude and frequency of oscillation. The infl uence of nondimensional oscillating frequency on heat and mass transfer has been analyzed regarding the Nusselt and Sherwood numbers. The low-Re number k–ε turbulence model equations in conjunction with unsteady Reynolds-averaged Navier–Stokes equations have been used in the computations. All the numerical simulations have been carried out by the ANSYS-Fluent code using the fi nite volume method with nonuniform grid arrangement. Certain values of the dimensionless frequency of the oscillating fl ow, which is a measure of frequency of the oncoming fl ow to the vortex shedding frequency, provide a higher heat and mass transfer compared to nonoscillating fl ow. The position of the separation point on the circular cylinders has a dominant eff ect on heat and mass transfer as well as unsteady fl ow structure downstream. In practical applications, such as drying in the food industry, using the oscillating fl ow technique requires lower energy compared to oscillating solid bodies.

In the present study, heat and mass transfer in oscillating flow around a wet circular cylinder has been analyzed numerically. The oscillating flow is modeled by defining the vertical velocity component as v(t) = A sin (omega t) at the inlet, and, hence, the oncoming flow is controlled by the amplitude and frequency of oscillation. The influence of nondimensional oscillating frequency on heat and mass transfer has been analyzed regarding the Nusselt and Sherwood numbers. The low-Re number k-epsilon turbulence model equations in conjunction with unsteady Reynolds-averaged Navier-Stokes equations have been used in the computations. All the numerical simulations have been carried out by the ANSYS-Fluent code using the finite volume method with nonuniform grid arrangement. Certain values of the dimensionless frequency of the oscillating flow, which is a measure of frequency of the oncoming flow to the vortex shedding frequency, provide a higher heat and mass transfer compared to nonoscillating flow. The position of the separation point on the circular cylinders has a dominant effect on heat and mass transfer as well as unsteady flow structure downstream. In practical applications, such as drying in the food industry, using the oscillating flow technique requires lower energy compared to oscillating solid bodies.