Effects of non-equilibrium condensation on deviation angle and efficiency in a steam turbine stage

Abstract

In this paper, the AUSM-van Leer hybrid scheme is extended to solve the governing equations of two-phase transonic flow in a steam turbine stage. The dominant solver of the computational domain is the non-diffusive AUSM scheme (1993), while a smooth transition from AUSM in regions with large gradients to the diffusive scheme by van Leer (1979) guarantees a robust hybrid scheme throughout the domain. The steam is assumed to obey non-equilibrium thermodynamic model. The effects of condensation on different specifications of the flow field are studied at subsonic/supersonic flow regimes. It is observed that as a result of condensation, the aerothermodymics of the flow field changes. For example in supersonic wet case (Pb = 14.55 kPa), pressure loss coefficient of rotor and total entropy generation are, respectively, 77% and 29% more than those in dry conditions. Also the value of rotor deviation angle reaches 6.27° in wet case and Pb = 14.55 kPa. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.