10th ISAIF Meeting VKI Belgium

30 June 2011

The 10th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, ISAIF10 will take place at the conference center of the Vrije Universiteit Brussel (VUB), Brussels, Belgium on July 4-7, 2011. More details can be found on https://www.vki.ac.be/isaif10/


Dr Jason Wu from PCA will present a paper on leaning of intermediate pressure (IP) steam turbine blades, reporting a piece of work carried out with Skoda Power, a Doosan company located in the Czech Republic.


ISAIF10-013 A comparison study on blade lean in an IP steam turbine

X Wu, GD Cox and Z Simka


This paper presents an extensive investigation of the influence of the radial stack on the performance of an intermediate pressure (IP) steam turbine stage. The range of stacking options including compound lean, end bend and asymmetric lean were studied using the spanwise variation in performance parameters to assess the benefit and penalty predicted by steady-state CFD. The radial stacking has a strong effect on reducing the loading and the loss in the endwall flows at the expense of increasing the loading at the mid-span, hence the loss, which is likely due to the increased wetted area (profile loss). It is observed that there is no obvious contribution from radial stacking to the overall loss reduction.

A further comparison between the steady-state prediction and time-averaged transient solution including the rotor tip shroud leakage, suggests that the tip shroud flow is likely to remove the low momentum secondary flow from the upstream, though a jet flow is produced at the outlet slot of the cavity, which may result in a strong interaction between the jet and the mainstream flow, and most significantly secondary flow. It is of interest to notice that although the time-averaged overall efficiency is significantly lower than the steady-state value due to tip leakage, the spanwise profile shows the time-averaged efficiency to be higher than that in the steady-state prediction near the hub endwall, implying that the mixing plane treatment in the steady-state solution may overestimate the secondary loss.