Numerical Modelling of Dry and Wet Steam Flows in Converging-Diverging Nozzles
Problem of water erosion in low pressure steam turbine stage is serious due to the formation of water droplets which travel at supersonic speed within the blade channel. The impact of these droplets could cause damage to turbine blade, and effort to understand the underlying mechanism of this type of flow has been devoted many years ago. This chapter describes the modelling of dry superheated and wet steam flows in two converging-diverging nozzles. The modelling is carried out using both in-house developed and commercial CFD code FLUENT. In this work, emphasis is given on understanding the capability of commercial CFD code to accurately predict the behaviour of dry and wet steam flow through the nozzles. The pressure and Mach number prediction using the commercial as well as in-house code show good agreement with one-dimensional analytical solution and experimental data. Quantitatively, further refinement to the geometrical mesh and mathematical model through user-defined function is desirable to increase the accuracy of the prediction using commercial CFD code.
KeywordsMach Number Steam Turbine Quadrilateral Mesh Mach Number Distribution Nozzle Distance
- 2.Bakhtar F, Webb RA (1983) Tabular method of estimating nucleating steam flows. Int J Heat Fluid Flow 217–228Google Scholar
- 5.Gyarmathy G (2005) Nucleation of steam in high pressure nozzle experiments. In: Proceedings of the 6th European conference on turbomachinery, Lille, France, 458–469Google Scholar
- 8.Hasini H, Yusoff MZ, Shuaib NH (2010) Preliminary theoretical study of the formation and growth of droplets in nucleating flows. In: AIP proceedings 10th Asian international conference of fluid machinery vol 1225. pp 751–757Google Scholar