Single-phase different temperature counterflows mixing process modeling in a Y-junction at NPU operational thermal parameters
A.E. Sobornov, R.R. Ryazapov, S.M. Dmitriev, A.V. Kotin, N.V. Matsin, S.S. Borodin
Nizhny Novgorod State Technical University named after R.E. Alekseev, Nizhny Novgorod, Russia
Keywords: temperature pulsations, numerical simulation, Y-junction, CFD, WALE
Abstract
The results of experimental and computational studies for the coolant flows mixing at different temperatures for standard operational parameters of a nuclear power unit (NPU) are presented in this paper. Experiments were performed using an upgraded version of measurement model. This study defines a temperature filed in the mixing zone and offers the optimal set of operation parameters calculated from the condition of maximum temperature pulsation within the mixing zone. Simulation was performed using a software kit Ansys Fluent. The grid model is based on the block structure in Ansys ICEM code. Numerical simulation was performed for unsteady problem statement based on the LES WALE turbulence model. Analysis of simulation and experimental fields for flow velocity and temperature confirmed the validity of the developed numerical method. A qualitative compliance for the probability density distribution and the spectral-correlation characteristics for temperature signals in the mixing zone was observed. The spectral power density for calculated temperature and velocity distributions fits the case of 1D energy spectrum of developed isotropic turbulence.
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