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ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
COMPUTACIONAL SIMULATION OF NATURAL CONVECTION IN A SEMI-CIRCULAR CAVITY WITH A HEAT GENERATING FLUID
Submission Author:
Wallthynay Ferreira , RJ
Co-Authors:
Wallthynay Ferreira , Su Jian
Presenter: Wallthynay Ferreira
doi://10.26678/ABCM.ENCIT2018.CIT18-0117
Abstract
Based on the importance of natural convection for heat transfer analysis in a molten core, Computational Fluid Dynamics (CFD) simulations may provide a better understanding of the phenomena occuring within the corium oxide layer after a severe accident. This work presents two-dimensional numerical simulations of natural convection in a semi-circular cavity containing a fluid with a uniform internal heat generation, with the objective to investigate the heat transfer with internal heat generation in the cavity in order to guarantee the physical integrity of the reactor pressure vessel. The simulations were performed in laminar regime, using the commercial software ANSYS FLUENT v.18.2, for a fluid whose Prandtl number is 7.0 and five Rayleigh numbers were simulated ranging from 10^9 to 10^13. Two cases were simulated. In the first case, the Boussinesq approximation was applied to the Buoyancy term. In the second case, the Boussinesq approximation was not applied in order to make a comparison and analyze the importance of the model to the problem. The results showed that average Nusselt numbers on the top surface of the semiciruclar cavity were in agreement with the correlations of Mayinger et al (1976) and Kulacki and Emara (1975) with Ra = 10^10 in both cases (with and without Boussinesq) and the average Nusselt number on the bottom surface of the semicircular cavity was in excellent agreement with Mayinger et al. (1976) correlation with Ra = 10^10.
Keywords
heat trasnfer, severe accident, Natural Convection, rayleigh number, molten core
