ISSN Online: 2377-424X
International Heat Transfer Conference 4
NATURAL CONVECTION INSIDE INCLINED TUBES
Аннотация
Natural convection will occur in inclined cylinders if the interior fluid has density variations. For stably stratified fluids at large Rayleigh numbers, the flow will consist of thin boundary layers; the theoretical upper limit for the Nusselt number along a cylinder of any cross-sectional shape is shown to be: Nu = sin-2ϑ when ϑ < O. (The angle from horizontal, ϑ , is defined to be negative when the heavy fluid is at the lower end.) Experimental data for heat and for salt convection in water show Nusselt
numbers ranging from Nu = 1.5 at ϑ = − 36° to Nu = 107 at ϑ = + 45°.