Authors: W. Fuls
Industry: Fossil Fuel Power Generation
Keywords: Use FSE
ABSTRACT
This paper presents a methodology to model a turbine on a stage-by-stage basis using nozzle flow analogy, requiring minimal detail information of the geometry of the individual blade passages. The classical nozzle theory is slightly expanded such that a turbine stage can be represented as a series of two nozzles with appropriate inlet conditions and loss factors. Conservation equations and component characteristics are presented which can be programmed into a simultaneous solver.
The thermo-hydraulic network solver Flownex was used to model the nozzles in such a manner. This enabled the definition of a custom turbine stage component, which was then used to model a 4-stage air turbine, as well as two steam turbines of an arbitrary power plant. The model predicted the turbines’ off-design (low load) conditions very well, considering the limited information used to set up the models.
The approach can be used for accurate prediction of a turbine’s off-design and abnormal operation, provided the physical geometry of the turbine remains unchanged. Plant operators can use this method to obtain better information regarding the inter-stage process conditions of a turbine, without requiring detail design information or complex CFD software.