Modification of the condensation heat transfer model of RELAP/MOD3.1 for the simulation of secondary condensers
- KAIST, Taejon (Korea, Republic of)
This paper deals with the improvement of RELAP5/MOD3.1 code predictive capability for steam condensation on an inclined surface. In modeling the Secondary Condensers (SC) with RELAP5 we encountered two problems with respect to condensation in vertically stacked tube walls, capability for turbulent film condensation and the wall node size effect on the prediction of condensation heat transfer coefficients (HTCs). The code original model based on the Nusselt model for laminar film condensation is extended to the turbulent film condensation by introducing two previously-developed models into the code. The code is further improved to properly take the condensation length over many nodings into account. To eliminate the dependence on the node size in predicting the condensation HTC of the code, film Reynolds numbers at each node are calculated recursively to track the growing condensate film thickness along the condensation length. The modified version is tested in the idealized boundary conditions and the simulation of SC, compared with an analytical solution and the original code. It turns out that the simulation results by this modified version are independent of the node size and are better agreement with the analytical solution than those by the original one. 11 refs., 7 figs.
- Research Organization:
- American Nuclear Society, La Grange Park, IL (United States)
- OSTI ID:
- 552131
- Report Number(s):
- CONF-970607--Vol.2
- Country of Publication:
- United States
- Language:
- English
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