Semi-empirical model of a multi-diaphragm pump in an Organic Rankine Cycle (ORC) experimental unit

This paper presents a semi-empirical thermodynamic model of a displacement pump integrated into an ORC experimental unit. The pump behavior at design and off-design conditions is modeled as a set of thermodynamic processes the main geometrical parameters of which are calibrated using experimental data. Calibration is performed by setting an optimization procedure which minimizes the error between operation parameters calculated by the model and measured in the test rig. Maximum errors were in the range 0.06%-7%. Differently from the few papers on similar models in the literature, this model takes into account the trapped mass flow rate, and is used to calculate the pump characteristic curves and identify incipient cavitation. A good agreement with experimental data was found in both cases.