Effects of wall heating on laminar mixed convection in a cylindrical enclosure with a rotating end wall

Abstract

Steady-state laminar mixed convection in a cylindrical enclosure has been numerically analysed for different values of Reynolds, Richardson and Prandtl numbers given by 500 <= Re <= 3000, 0 <= Ri <= 1 and 10 <= Pr <= 500 respectively. The aspect ratio (i.e. height: radius = AR = H/R) of the cylindrical container is considered to be unity (ie. AR = H/R = 1). The bottom and top covers of the cylindrical enclosure are kept at different temperatures (T-C < T-H), while the cylindrical surface is taken to be adiabatic. The simulations for rotating top and bottom cover configurations yield the same numerical values of the mean Nusselt number (Nu) over bar when the thermal boundary conditions are kept unaltered. For this reason, only rotating top hot wall (ie. C1 configuration) and rotating top cold wall (ie. C2 configuration) have been considered for this analysis. The mean Nusselt number (Nu) over bar has been found to assume higher values in the C2 configuration than in the Cl configuration. Moreover, it has been found that the variation of the mean Nusselt number with Richardson number in the C2 configuration is qualitatively different from that in the C1 configuration. The simulation data has been used to propose a correlation for (Nu) over bar for the range of Re, Ri and Pr considered here for both Cl and C2 configurations. In addition to this, a regime diagram has been proposed for the C2 configuration in order to demarcate different flow regimes.