Thermodynamic wetness loss calculation in nozzle and turbine cascade: nucleating steam flow

Rapid expansion of steam in turbines and nozzles cause condensation. The formation of liquid droplets due to condensation results in wetness losses, which include aerodynamic losses (due to friction between liquid droplets and the vapour), thermodynamic losses (due to irreversible latent heat addition), and braking losses (due to the impact of liquid droplets on the turbine blade). In this study, a numerical investigation of the thermodynamic loss in a nucleating steam flow is performed. The thermodynamic loss is calculated using the change in entropy due to condensation. The effect of different operating conditions on the thermodynamic loss is estimated for a nozzle and turbine cascade in a nucleating flow. The non-equilibrium condensation in high-speed steam flows is modelled using Eulerian-Eulerian approach.

[1]  Arthur Kantrowitz,et al.  Nucleation in Very Rapid Vapor Expansions , 1951 .

[2]  James E. McDonald,et al.  Homogeneous Nucleation of Vapor Condensation. I. Thermodynamic Aspects , 1962 .

[3]  M. J. Moore,et al.  Two-phase steam flow in turbines and separators : theory, instrumentation, engineering , 1976 .

[4]  G. Stein,et al.  On the Growth of Steam Droplets Formed in a Laval Nozzle Using both Static Pressure and Light Scattering Measurements , 1978 .

[5]  J. Young.  Spontaneous condensation of steam in supersonic nozzles , 1982 .

[6]  J. Young,et al.  An Equation of State for Steam for Turbomachinery and Other Flow Calculations , 1988 .

[7]  J. Young,et al.  Two-Dimensional, Nonequilibrium, Wet-Steam Calculations for Nozzles and Turbine Cascades , 1992 .

[8]  J. B. Young,et al.  Time-marching method for the prediction of two-dimensional, unsteady flows of condensing steam , 1993 .

[9]  F. Bakhtar,et al.  On the Performance of a Cascade of Turbine Rotor Tip Section Blading in Nucleating Steam: Part 2: Wake Traverses , 1995 .

[10]  F Bakhtar,et al.  On the Performance of a Cascade of Turbine Rotor Tip Section Blading in Nucleating Steam: Part 1: Surface Pressure Distributions , 1995 .

[11]  Mohammad Reza Mahpeykar,et al.  An Investigation of nucleating flows of steam in a cascade of turbine blading-theoretical treatment , 1995 .

[12]  F. Bakhtar.  On the performance of a cascade of turbine rotor tip section blading in nucleating steam. Part 1: surface pressure distributions , 1996 .

[13]  R. Hunt,et al.  The flow of wet steam in a one-dimensional nozzle , 1999 .

[14]  A. G. Gerber,et al.  A general formula for the evaluation of thermodynamic and aerodynamic losses in nucleating steam flow , 2003 .

[15]  M. Kermani,et al.  A pressure based Eulerian–Eulerian multi-phase model for non-equilibrium condensation in transonic steam flow , 2004 .