Prediction of two-phase choked-flow through safety valves

31st UIT (Italian Union of Thermo-fluid-dynamics) Heat Transfer Conference 2013

Arnulfo, G.^1 ; Bertani, C.^1 ; De Salve, M.^1

Dipartimento Energia, Politecnico di Torino, corso Duca degli Abruzzi 24, 10129 Torino, Italy^1

关键词: Critical flow rate;    Direct integration;    Discharge coefficients;    Flashing flow;    Non equilibrium;    Subcooled liquid;    Thermal-hydraulic conditions;    Two phase fluid;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/501/1/012016/pdf
DOI  :  10.1088/1742-6596/501/1/012016

来源: IOP

【 摘 要 】

Different models of two-phase choked flow through safety valves are applied in order to evaluate their capabilities of prediction in different thermal-hydraulic conditions. Experimental data available in the literature for two-phase fluid and subcooled liquid upstream the safety valve have been compared with the models predictions. Both flashing flows and non-flashing flows of liquid and incondensable gases have been considered. The present paper shows that for flashing flows good predictions are obtained by using the two-phase valve discharge coefficient defined by Lenzing and multiplying it by the critical flow rate in an ideal nozzle evaluated by either Omega Method or the Homogeneous Non-equilibrium Direct Integration. In case of non-flashing flows of water and air, Leung/Darby formulation of the two-phase valve discharge coefficient together with the Omega Method is more suitable to the prediction of flow rate.