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The present work is focused on the computational analysis of the condensation phenomena in the presence of the noncondensable gases by means of CFD codes and on the validation of experimental data obtained by the CONAN Facility, an experimental device installed at the Scalbatraio Laboratory of the DIMNP of Pisa University.
After the description of the CONAN apparatus, which is a separate effects test facility, the computational domains, the mathematical models and the matrix of the performed simulations are definite. In the first part of the current work, the calculations are executed by the Fluent code, using a mechanistic approach and employing a two-dimensional geometry. Special attention has been paid to the study of the effects on the condensation rate and the heat flux, due to the different air concentration in the mixture and to the variation of the thermo-fluid-dynamics properties (velocity and temperature of the mixture and secondary coolant temperature), which characterized each test. The data predicted by the code are compared with the experimental and the calculated values, available from a previous work, in order to verify the agreement. Moreover six particular tests are repeated, making use of a different geometry, a three-dimensional model is implemented in the Fluent code with the aim to validate the results obtained by the CFD code, with the 2D computational domain. Both configurations are investigated with the same conditions of turbulence.
In the second part, one hundred and twenty-nine tests are carried out by Castem, a research fluid dynamics code; in this case two different turbulent models are applied and the results are discussed and compared with the Fluent data.