Heat Transfer in a High Turbulence Air Jet Impinging Over a Flat Circular Disk

Abstract

This study concerns the flow and heat transfer characteristics of a turbulent submerged circular air jet impinging on a horizontal flat surface when free stream turbulence exceeds 20 percent. The turbulent fluctuations of the free stream velocity are the primary aerodynamics influencing heat transfer. Two regions with distinct flow characteristics are observed: the stagnation region, and the wall-jet region. According to the linear form of the energy equation, the surface heat flux may be decomposed into laminar and turbulent components. An inverse methodology can determine the turbulent component of the heat transfer coefficient in the stagnation region and in the wall-jet region as a function of the root mean square value of the fluctuating component of velocity in the bulk flow direction.

An experimental investigation into impinging forced convection heat transfer from stationary isothermal circular disks

“…Some research has been performed with forced, natural and combined forced and natural (mixed) convection over stationary circular disks with the disk-axis perpendicular to the direction of the fluid flow [4] (crossflow). Research is also available in the archival literature involving a jet impinging locally on a stationary disk surface [5][6][7], as well as on one that is rotating [8,9]. However, no research exists, to the best knowledge of these authors, dealing with forced convection over a stationary threedimensional disk geometry with the disk-axis parallel to the direction of fluid flow (impinging flow).…”

Numerical study of transient conjugate heat transfer of a turbulent impinging jet

“…Different size meshes, 41 Â 126, 51 Â 136 and 61 Â 146 in r-, and z-directions, respectively, were employed in testing the numerical model. It has been validated using experimental data reported in Siba et al [26]. Certain discrepancies between calculations and the available data of Siba et al [26] may be caused by the roundoff and discretization or measurement errors.…”

“…These models were used to propose four transport equations for the turbulent kinetic energy of the carrier phase and its rate of dissipation, the turbulence kinetic energy of the dispersed phase, and the velocity covariance of the two phases. The flow and heat transfer characteristics of a turbulent submerged circular air jet impinging on a horizontal flat surface was presented by Siba et al [26]. An investigation into the predictive performance of linear and nonlinear eddy-viscosity turbulence models for a confined swirling coaxial jet was presented by Yang and Ma [27].…”

Development Of An Experiment For Measuring Flow Phenomena Occurring In A Lower Plenum For VHTR CFD Assessment

“…The literature on heat transfer and flow of impinging jets is vast and growing [Martin, 1977;Downs and James, 1987;Hrycak, 1981;Webb and Ma, 1995;Lee and Lee, 2000]. The primary application has been for enhancement of convective heat transfer parameters [Gardon and Akfirat, 1965] so much of the literature concentrated on integral heat transfer quantities, such as local or average heat transfer coefficients (e.g., Goldstein and Behbahani [1982], Hrycak [1983], Baughn and Shimizu [1989], Liu and Lienhard [1993], San, Huang and Shu [1997], , Siba et al [1998], Lee and Lee [2000] Behnia et al [1999] and others. To maintain effectiveness, often arrays of impinging jets are employed with small pitch-to-diameter spacings, so the non-dimensional radial extent is not large [Womac, Incropera and Ramadyani, 1994;Slayzak, Viskanta and Incropera, 1994;Lienhard et al, 1996].…”