Abstract
Steam condensation induced water hammer (CIWH) phenomena are investigated and new theoretical results are presented. We use the WAHA3 model based on two-phase flow six first-order partial differential equations that present one dimensional, surface averaged mass, momentum and energy balances. A second order accurate high-resolution shock-capturing numerical scheme was applied with different kind of limiters in the numerical calculations. The applied two-fluid model shows some similarities to RELAP5 which is widely used in the nuclear industry to simulate nuclear power plant accidents. This model was validated with different CIWH experiments which were performed in the PMK-2 facility, which is a full-pressure thermohydraulic model of the nuclear power plant of VVER-440/312 type in the Energy Research Center of the Hungarian Academy of Sciences and in the Rosa facility of the Japan Atomic Energy Agency. In our present study we show the first part of a planned large database which will give us the upper and lower flooding mass flow rates for various pipe geometries where CIWH can happen. Such a reliable database would be a great help for future reactor constructions and scheming.
Kurzfassung
Neue Ergebnisse aktueller analytischer Untersuchungen zu durch Dampfkondensation verursachten Kondensationsschlägen werden vorgestellt. Dabei wurden die Rechnungen mit dem Programm WAHA durchgeführt, bei dem die sechs partiellen Differentialgleichungen erster Ordnung zur Beschreibung der Zweiphasenströmung durch eindimensionale oberflächengemittelten Massen-, Impuls und Energiebilanzen angenähert werden. Zusätzlich wurde in diesen Analysen ein hochauflösender und Druckschläge erkennender Algorithmus zweiter Ordnung mit verschiedenen Limitern angewendet. Dieser Algorithmus wurde anhand der Nachrechnung ausgewählter Experimente in der ungarischen Versuchsanlage PMK-2 (Volldruckmodell eines WWER-440/312) und in der japanischen Versuchsanlage ROSA validiert. In diesem Beitrag wird der erste Teil einer geplanten großen Datenbank vorgestellt, in dem unteren und oberen Massenstromgrenzen für verschiedene Rohrgeometrien zusammengestellt werden, innerhalb deren Kondensationsschläge infolge Dampfkondensation auftreten können.
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