Development of Axial Turbine Blade Profile for sCO2 Power Block Using Streamline Curvature Method

Abstract The paper addresses the concerns in designing the firststage axial turbine stator blades for supercritical CO2 (sCO2) power blocks. Real gas behaviour of CO2 in the supercritical regime complicates blade profile generation, making it more complex than traditional methods. While extensive research relying on perfect gas assumptions for steam and gas turbine blade profiles are well documented in literature, unique properties of sCO2 mandate specific aerodynamic considerations. Current work employs a streamline curvature method to generate the blade profile of an axial turbine. Thermodynamic cycle parameters for the axial turbine are based on a simple recuperating sCO2 cycle producing a power output of 10MW. The cycle parameters serve as an input to a mean-line analysis to calculate the thermodynamic state and blade geometry at each station. The blade profile is generated using conventional approach via Pritchard’s method. The blade design framework is developed using Python and is coupled to the CoolProp fluid property database. Existing models for loss estimation, that are derived for air and steam flows, do not adequately capture the expansion behaviour of sCO2 flows. To address this issue, an inviscid through-flow solver is developed using the Streamline Curvature Method (SCM). A design space exploration study is performed by effectively integrating the blade design model with the SCM flow solver. The results obtained using the SCM model are validated with full-scale CFD simulations performed using ANSYS Fluent.