LUPO, Temperature and Void Rate and Pressure Drop and Flow Rate in Pressure Loop

1 - Nature of physical problem solved: LUPO is a digital computer programme for predicting steady-state bulk fluid temperature, void fraction, pressure drops and mass flow rate in a closed pressurized water loop, operating at forced or natural circulation. The model treats the one-dimensional transfer of mass, momentum and energy throughout the whole liquid, subcooled boiling and bulk boiling regions of the coolant. 2 - Method of solution: Variations in heat transfer and hydraulic characteristics of the coolant due to changes in temperature and state are handled by continuously calculating local values of thermodynamic and physical properties. Semiempirical heat transfer and pressure drop correlations developed by other investigators are used. The representation of subcooled boiling is based upon the model of Bowring. 3 - Restrictions on the complexity of the problem: The programme allows the representation of a test-section, a riser, an heat-exchanger and a cold leg. Five localized pressure drop coefficients may be specified. The maximum number of lumps in the test-section is 250. The maximum number of lumps in the riser is 100