Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
658672 | International Journal of Heat and Mass Transfer | 2012 | 11 Pages |
Abstract
The thermally developing turbulent lead bismuth (Pb45Bi55) flow within a vertical annulus with the inner surface uniformly heated is experimentally investigated. The ratio between internal and external diameter is 0.136. The investigated Reynolds numbers vary between 1.48Â ÃÂ 104 and 2.37Â ÃÂ 105 and the applied heat flux from 135Â kW/m2 to 905Â kW/m2, covering both the forced and mixed convection regime. For forced convection, the local heat transfer convective coefficient is evaluated and compared with literature correlations for low Prandtl number fluids. Additionally, a new empirical relation for the local Nusselt number in the thermal entry region is proposed. The applicability of criteria addressing the forced to mixed convection transition in medium to high Prandtl number fluids is reviewed and extended to account also for low Prandtl number fluids such as heavy liquid metals. Here, the transition from turbulent-diffusion to molecular-diffusion dominated mixed convection is clearly shown.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Luca Marocco, André Loges, Thomas Wetzel, Robert Stieglitz,