MATHEMATICAL MODELLING OF A STEAM GENERATOR

Abstract A detailed nonlinear model of a once-through steam generator of BENSON® type is presented with special emphasis placed on accurate modelling of two-phase heat transfer. The nonlinear coupled partial differential equations were derived from first principles and thus permit predictions of the dynamic response of the unit already in the planning stage. The model equations, comprising a stiff two-point boundary value problem, are solved by means of an implicit Runge-Kutta-method featuring step-size control with prespecified numerical error. Using an optimized solution algorithm, computational requirements are kept modest. Comparison of simulation results to actual data shows good agreement and demonstrates the validity of the model. In addition, new insight into the physical phenomena occuring in the two-phase region is gained.