CFD modelling of the condensation inside a cascade of steam turbine blades: comparison with an experimental test case

Non-equilibrium condensation of steam occurs in many jet and turbomachinery devices, such as supersonic nozzles, ejectors and across the last stages of steam turbines. Wet steam models are available in many commercial CFD codes and can represent the metastable behaviour of the flow with reasonable accuracy. Unfortunately, the use of built-in models does not allow freedom in the choice of parameters and settings. In the present paper, a numerical model for the simulation of wet steam flow has been developed and implemented within a commercial CFD code (ANSYS Fluent) via user-defined functions. The scheme is based on a Mixture-model approach. The model is compared with literature data for a 2D stationary cascade of a steam turbine blade.