Simulation of a Two-Stage Rotary Vane Steam Expander

The purpose of this work was to develop a tool for evaluating the performance of different positive-displacement steam expanders. The model reported here allows for two stages of expansion, friction, and heat transfer. The equations developed include also the transient charging and exhaust processes, but do not include the inertia effects in the fluid. These equations are in dimensionless form and the solutions are applicable to all expanders of this type. If expanders of different geometry are to be considered, only the volume equations must be changed to obtain a simulation. The performance (work output and adiabatic expansion efficiency) is shown as a function of breathing number and arcs of admission and exhaust.