Application of quadrature method of moments to the polydispersed droplet spectrum in transonic steam flows with primary and secondary nucleation

Abstract

This paper investigates the effectiveness of the Quadrature Method of Moments (QMOM) in representing droplet size distributions present in low-pressure steam turbine stages. In particular, distributions that result during transonic flow with sufficient supercooling and high expansion rate for primary and secondary nucleation to occur along the flow path. It is shown that the discretization of the droplet size distribution inherent in QMOM is robust for representing a polydispersed distribution with sizes several orders of magnitude apart, and originating from separate condensation phenomena. Inclusion of the QMOM method would thus provide a significant improvement in condensation models currently in use, which generally rely on a monodispersed representation of the droplet distribution.