Pressurized Thermal Shock (PTS) modelling has been identified as one of the most important industrial needs related to nuclear reactor safety. A severe PTS scenario limiting the Reactor Pressure Vessel (RPV) lifetime is the cold water Emergency Core Cooling (ECC) injection into the cold leg during a Loss of Coolant Accident (LOCA). Since it represents a big challenge for numerical simulations, this scenario was selected within the NURESIM (European Platform for Nuclear Reactor Simulations) Integrated Project as a reference two- phase problem for CFD code validation. This paper presents a CFD analysis of a stratified air-water flow experimental investigation performed at the Institut de Mécanique des Fluides de Toulouse in 1985 [1], which shares some common physical features with the ECC injection in PWR cold leg. Numerical simulations have been carried out with two commercial codes (Fluent and Ansys CFX), and a research code NEPTUNE_CFD (developed by EDF and CEA). The aim of this work, carried out at the University of Pisa within the NURESIM IP, is to validate the free surface flow model implemented in the codes against the available experimental data, and to perform code to code benchmarking. Obtained results suggest the relevance of three-dimensional effects and stress the importance of a suitable interface drag coefficient modelling. A relevant improvement of results has been achieved with 3D simulations, even if the air velocity profile was still significantly underestimated.
CFD Code Validation against Stratified Air-Water Flow Experimental Data
D'AURIA, FRANCESCO SAVERIO
2007-01-01
Abstract
Pressurized Thermal Shock (PTS) modelling has been identified as one of the most important industrial needs related to nuclear reactor safety. A severe PTS scenario limiting the Reactor Pressure Vessel (RPV) lifetime is the cold water Emergency Core Cooling (ECC) injection into the cold leg during a Loss of Coolant Accident (LOCA). Since it represents a big challenge for numerical simulations, this scenario was selected within the NURESIM (European Platform for Nuclear Reactor Simulations) Integrated Project as a reference two- phase problem for CFD code validation. This paper presents a CFD analysis of a stratified air-water flow experimental investigation performed at the Institut de Mécanique des Fluides de Toulouse in 1985 [1], which shares some common physical features with the ECC injection in PWR cold leg. Numerical simulations have been carried out with two commercial codes (Fluent and Ansys CFX), and a research code NEPTUNE_CFD (developed by EDF and CEA). The aim of this work, carried out at the University of Pisa within the NURESIM IP, is to validate the free surface flow model implemented in the codes against the available experimental data, and to perform code to code benchmarking. Obtained results suggest the relevance of three-dimensional effects and stress the importance of a suitable interface drag coefficient modelling. A relevant improvement of results has been achieved with 3D simulations, even if the air velocity profile was still significantly underestimated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
