Numerical Optimization Method for Turbine Blade Design Based on Condensation Theory

A method for controlling homogeneous nucleation and reducing degree of flow separation in high-speed transonic wet steam flow is presented. The spontaneous nucleation flow in a turbine cascade was numerically studied. The model was implemented within a full Navier-Stokes viscous flow solution procedure, and the process of condensation was calculated by the quadrature method of moments which show good accuracy with very broad size distributions in nucleating steam flow. Results shows in wet steam flow, degree of flow separation is greater than in superheated steam flow and the loss can´t be neglected. The suction side profile of turbine cascade impacts the nucleation rate distribution leading to different droplet distributions and affects the degree of flow separation. Flow separation and wake vortices can influent the unequilibrium state of flow. The numerical study provides a practical design method for turbine blade to reduce losses.