Hermetic expander detailed model


Model ExpanderHermeticDetailed simulates the expansion of fluid in an hermetic volumetric machine. The evolution of the fluid through the expander is decomposed into six thermodynamic processes, as shown in the figure:

  • Supply pressure drop (su –> su,1)
  • Supply cooling-down (su,1 –> su,2)
  • Isentropic expansion to the internal pressure imposed by the built-in volume ratio of the expander (su,2 –> in)
  • Expansion at a fixed volume to the exhaust pressure (in –> ex,2)
  • Mixing between suction flow and leakage flow (ex,2 –> ex,1)
  • Exhaust cooling-down or heating-up (ex,1 –> ex)


Lemort, V., Declaye, S., & Quoilin, S.. (2011). Experimental characterization of a hermetic scroll expander for use in a micro-scale Rankine cycle. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy.