In the frame of the SARnet Network of Excellence, the need was felt for assessing the status of condensation models adopted in CFD codes relevant for nuclear reactor containment applications. The motivation for this work was provided by the increasingly widespread use of CFD in the analysis of containment behavior consequent to postulated severe accidents, in which wall condensation can promote containment atmosphere mixing. Since standard models are seldom available in many CFD codes for dealing with condensation and in consideration of the different strategies envisaged for analyzing downscaled facilities or full scale containments, this aspect was considered worth of a specific attention. In this aim, after performing a review of the models available to the Participants in the network, appropriate Benchmark Problems were proposed to assess and compare their behavior. The University of Pisa took the charge of coordinating these efforts, proposing an initial step of the Benchmark (identified as the 0th Step) aimed at comparing code responses among each other and with applicable correlations in the application to a classical problem of condensation on a flat plate; the reference geometrical and operating conditions for this step were selected as an idealization of those typical in the CONAN experimental facility, operated at the University of Pisa. Then, the 1st Step of the activity involved addressing experimental data from the CONAN facility at different steam mass fractions and velocities and the comparison of the measured condensation rates and of local heat fluxes with code predictions. Both the steps in this activity were fruitful, since they constituted a gradual and relatively systematic approach to the actual experimental conditions, allowing for revising model details and discussing numerical and physical options. Though the comparison with experiments involved up to now only a limited number of data points, the activity is not considered to be completed and additional experimental data will be offered in the future to obtain a broader assessment of codes in conditions of interest for severe accidents in light water reactors.
Comparison and Analysis of the Condensation Benchmark Results
AMBROSINI, WALTER;FORGIONE, NICOLA;ORIOLO, FRANCESCO;PACI, SANDRO;
2008-01-01
Abstract
In the frame of the SARnet Network of Excellence, the need was felt for assessing the status of condensation models adopted in CFD codes relevant for nuclear reactor containment applications. The motivation for this work was provided by the increasingly widespread use of CFD in the analysis of containment behavior consequent to postulated severe accidents, in which wall condensation can promote containment atmosphere mixing. Since standard models are seldom available in many CFD codes for dealing with condensation and in consideration of the different strategies envisaged for analyzing downscaled facilities or full scale containments, this aspect was considered worth of a specific attention. In this aim, after performing a review of the models available to the Participants in the network, appropriate Benchmark Problems were proposed to assess and compare their behavior. The University of Pisa took the charge of coordinating these efforts, proposing an initial step of the Benchmark (identified as the 0th Step) aimed at comparing code responses among each other and with applicable correlations in the application to a classical problem of condensation on a flat plate; the reference geometrical and operating conditions for this step were selected as an idealization of those typical in the CONAN experimental facility, operated at the University of Pisa. Then, the 1st Step of the activity involved addressing experimental data from the CONAN facility at different steam mass fractions and velocities and the comparison of the measured condensation rates and of local heat fluxes with code predictions. Both the steps in this activity were fruitful, since they constituted a gradual and relatively systematic approach to the actual experimental conditions, allowing for revising model details and discussing numerical and physical options. Though the comparison with experiments involved up to now only a limited number of data points, the activity is not considered to be completed and additional experimental data will be offered in the future to obtain a broader assessment of codes in conditions of interest for severe accidents in light water reactors.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
