Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
THERMAL HYDRAULIC ANALYSIS OF SUPERCRITICAL CARBON DIOXIDE NATURAL CIRCULATION LOOPS
Submission Author:
Gabriel Caetano Gomes Ribeiro da Silva , RJ
Co-Authors:
Gabriel Caetano Gomes Ribeiro da Silva, Su Jian
Presenter: Gabriel Caetano Gomes Ribeiro da Silva
doi://10.26678/ABCM.COBEM2019.COB2019-1700
Abstract
Passive safety systems for core residual heat removal are indispensable for the future of nuclear energy and natural circulation loops have shown to be an effective model for this purpose, also owning applicability in other engineering areas, such as solar energy and waste management. Supercritical carbon dioxide is considered one of the best coolants for this type of system due to its high rates of heat transfer and high buoyancy. In this paper, one of the main intrinsic limitations of this system was studied, the phenomenon of heat transfer deterioration (HTD). The four most common configurations of a rectangular natural circulation loop (NCL) were analyzed, differed by the orientation of the heater and the cooler. The simulations were performed in steady state, using a three-dimensional model. The turbulence model chosen was RNG -. The software used was ANSYS Fluent v. 18.2. The natural circulation mass flowrate was analyzed as a function of the heating power and the operating pressure for all the four loop configurations. It was observed that the NCL with horizontal heater and cooler (HHHC) presented the highest flow rate among all four configuration, whilst the NCL with vertical heater and cooler (VHVC) presented the lowest flow rate. In order to investigate the heat transfer, the Nusselt number was analyzed as a function of the modified Grashof number and good agreement was observed between the literature and the results obtained.
Keywords
CFD, natural circulation, Supercritical CO2
