Natural convection heat transfer from upward-Facing horizontal heated surface with heated cylindrical pipe (effects of flow characteristic around heated cylinder)

Natural convection heat transfer from upward-facing horizontal heated surface which a heated cylindrical pipe is placed above is estimated experimentally. The purpose of this study is to determine the relationships of the heat transfer from the horizontal heater to the flow characteristics around the heated cylinder. The parameters considered were the distance of between the heaters, the heat flux and the aspect ratio of the heated cylinder. The results showed that flow characteristics had three distinctive patterns: non flow reversal, flow reversal occurred only in the heated cylinder and reached the horizontal heater. The necessary conditions determined the flow field were discussed. Heat transfer from the horizontal heater was enhanced by placing the heated cylinder above. In the case of no flow reversal and flow reversal occurred in the heated cylinder, Nusselt number increased with increasing the modified Rayleigh number. On the other hand, in flow reversal to the horizontal heater, they decreased generally with increasing that.