Characterization of limacon gas expanders with consideration to the dynamics of apex seals and inlet control valve

Abstract

Limacon machine, of which the relative motion between the rotor and housing follows the limacon curve, belongs to a class of rotary positive displacement machines. The profiles of rotors and housings of those machines can be constructed of either limacon or circular curves, hence the names: limacon-to-limacon, circolimacon, and limacon-to-circular machines. This paper presents the investigation into the thermodynamic performance of the limacon-to-circular machines with the presence of apex seals and inlet valve. This paper sets out by briefly introducing the limacon technology and the construction of the limacon-to-circular machine working volume. The mathematical descriptions of ports positions and areas have also been introduced. The paper then discusses the flow and phase composition of working fluid through the working chambers as well as how the fluid velocity is modeled and calculated. Then the seal dynamic model and response of inlet valve are presented followed by the machine thermodynamic model. A case study has also been presented to show the responses of seals and inlet valve during the machine operation.