Barannik V. The three-dimensional aerodynamic optimization of axial turbine nozzle cascade

Research object is the aerodynamic processes in the nozzle cascades of turbomachines.The purpose of research is development of design technique of the aerodynamically perfect axial turbine nozzle cascades using optimization of the profile and the variation of its shape along the height of the cascade and the followed by design of the meridional shape.Research methods: Computational and theoretical methods of research in the turbine cascades are based on the fundamental positions of the theory of fluid dynamics. Optimal design of turbine cascade was determined using design of experiment theory with a formal metamodel of high accuracy and BS - sequence. The flow structure in the turbine cascades, and its characteristics were determined using methods of computational fluid dynamics (CFD). Models for CFD simulations are obtained using a solid-state three-dimensional computer modeling.Theoretical and practical results: the technique of design of the aerodynamically perfect axial turbine nozzle cascade using optimization of the profile shape along the height of the blade and the peripheral meridional contour of the flow path is developed.Novelty: it was further developed the method of the analytical design and optimization of turbine blades profiles using Bezier curves, cubic interpolation splines and exponential polynoms, which provides a perfect aerodynamic turbine profiles. It was further developed the construction of the formal meta models (FMM) on the basis of complete quadratic polynomial, which allows to accurately describe multimodal function to approximate the quality of performance and functional limitations of turbomachines. For the first time the method of the optimization of the peripheral meridional contours of turbine stage nozzle cascades using CFD simulations, providing integrated reduction of the aerodynamic losses is developed. For the first time the effect of the working fluid to the form of optimal profiles is shown.Degree of implementation: Department of turbine NTU "KPI", PJSC "Turboatom", Kharkov. Scope of use: turbine construction.