CHAM Case Study - Natural Convection Flow in a Nuclear Reactor

Body Force (Buoyancy)Liquid Na convection zoneF βρg(T T )Air convection zoneF ρgResistance force in the porous medium zone:FKU2whereK: Pressure resistance coefficient. (This is different in each zone.)p: densityU: velocityRadiation

Energy source in the porous medium zoneCptefT (liqU iCpliqT )xixikefTxiSVliq liqCpliqT (liqU iCpliqT )txixikefTxiSVsolidsolidCptsolidTwherekVefCpsolefV1solidkVVsolidliqliqliqCpVliqsolidkVliqsolidsolidCpsolidPressure value in the air convection zone boundaryThe value of pressure in the air convection zone boundary is renewed while it is calculatedfrom the next experience equation.PoutoutghoutiPfi1,9i 1, 7PfiPinoutg(hhin)iPfi1,9i 1, 2PfiPfi0.5nkioutmA2iPfi0.5nkiinmA2i

ResultMaximum temperature [C˚]Experimental data:PHOENICS result:550 ˚C540.6699 ˚CTemperature distribution (steady)Pressure drop [MPa] in Na convectionzoneExperimental data: 2.5PHOENICS result: 2.51

tem trature[℃]mass flow rate[kg/ s]Pressure distribution (steady)Air flow rate in the air convection zone3.43.353.33.253.23.153.13.0532.952.90 10 20 30 40time[hour]mass flow rate[kg/ s]Maximum temperature in the liquid Na convection zone5405205004804604404204000 10 20 30 40tim e[h]

ConclusionSuch is the flexibility of PHOENICS that a model capturing the majorcomponents of the nuclear reactor system was able to be constructed frombuilt-in objects. Additional user-defined functionality was introduced viaGROUND coding. The final model performed well against experimental databoth for its normal steady-state operation and its transient predictions agreedwell with data gathered from a controlled and monitored cooling-systemfailure.______________________CHAM Ltd, Bakery House, 40 High Street, Wimbledon Village, London SW19 5AU, UKTel: +44 (0)20 8947 7651 Fax: +44 (0)20 8879 3497 Email: phoenics@cham.co.ukWeb: http://www.cham.co.uk