每年出版 6 期
ISSN 打印: 1940-2503
ISSN 在线: 1940-2554
Indexed in
TRANSIENT CONJUGATED UPWARD AND DOWNWARD MIXED CONVECTION IN A PARTIALLY HEATED THICK PIPE
摘要
Transient conjugated downward and upward laminar mixed-convection heat transfer in a vertical pipe, partially submitted to a constant heat flux, has been investigated computationally. The governing Navier-Stokes and energy equations were solved by a code developed using the finite volume method and Boussinesq's assumptions. Solutions were obtained for (Pr, Re, Gr) = (5,100, 5 × 105), wall-to-fluid conductivity ratio K = 10, 50, and 100, and pipe thickness-to-diameter ratios Δ = 0.05 and 0.25. From a parametric study, transient distribution of the normalized interfacial heat flux and of the friction coefficient ratio as a function of the axial coordinates as well as transient evolution of the vector velocities were obtained and the effect of K and Δ investigated. It was found that the magnitude and the extent of upstream and downstream heating increase monotonically with an increase of Δ or K. In turn, this heat flux redistribution significantly affects the friction coefficient ratio and velocity field in the downstream and upstream adiabatic sections for the downward and upward mixed-convection cases.
-
Yang G., Wu J.Y., Conjugate mixed convection in the entrance region of a symmetrically heated vertical channel with thick walls, International Journal of Thermal Sciences, 98, 2015. Crossref