Two-phase chamber modeling of a twin-screw expander for Trilateral Flash Cycle applications

In the current research work, a twin-screw expander has been modeled in the commercial software GT-SUITE™. The modeling activity resulted in a two-phase chamber model based on the coupling of the conservation equations and the REFPROP library to calculate the thermophysical properties of the liquid-vapor mixture of the R245fa working fluid at each time step. Using pre-processed geometrical data, the model includes a detailed breakdown of the leakage paths and allows to retrieve key information for a future optimization of the machine such as the indicator diagram and the quality-angle diagram. Parametric analyses were eventually carried out to assess the expander behavior at different operating conditions, namely manometric expansion ratio, revolution speed and inlet quality.