Study of perforated plate effect in horizontal WWER1000 steam generator

Abstract

In this paper, the effect of perforated plate in horizontal steam generator (SG) has been studied. The injected feed water into the SG is cold and heavy, so it pulls down the fluid around the feed water injection pipeline. The perforated plate has been designed above tube bundles in the SG to relax this asymmetrically void generation. In this work, with consideration of the perforated plate and feed injection effects in tube side, it is illustrated that generated steam will be distributed in the top level of the SG homogeneously. Therefore, the steam collector contains high quality homogeneously distributed dry steam and the perforated plate prevents the water from ascending in the cold side containing cold collector and the steam from descending on the other side. In addition, it can be seen that without the perforated plate, the void fraction distribution becomes heterogeneous in the top level of the SG. In this analysis, the 3D numerical model of a large conventional WWER1000 steam generator in the nuclear industry has been presented. For the computational fluid dynamic (CFD) study of desired steam generator in ANSYS CFX, the SG geometry is prepared with details and interfacial relations of mass, momentum and heat transfer are defined by appropriate functions. In momentum source terms, the interfacial drag forces are defined with Ishii and Zuber model. An Euler–Euler approach is applied to modeling boiling heat transfer and condensation. Porosity model is applied to the primary side in which the tube bundles are not described in detail but they are modeled as sources of enthalpy and pressure loss. The primary side effect is modeled based on a 1D thermal heat source model. Finally, the importance of perforated plate is demonstrated and it shows that the results are in a good agreement with published and experimental data.