Multidisciplinary Optimization of the Working Process of Uncooled Axial Turbine According to Efficiency and Strength Criteria

Abstract

The results of multicriteria multidisciplinary optimization of three-stage low-pressure turbine are described in the paper. The aim of the optimization is to improve turbine operation process by three criteria: turbine outlet flow angle, value of residual swirl at the turbine outlet, and turbine efficiency. Moreover, the requirements of static and dynamic strength must be fulfilled for rotor blades. Full reprofiling of all blade rows is carried out while solving optimization problem. Reprofiling includes a change in both shape of flat blade sections (profiles) and threedimensional shape of the blades. The study is carried out with 3D numerical models of turbines both gas-dynamic and strength. The gas-dynamic improvement of turbine operation is performed as the first step. Then, strength improvement is carried out for the best variants in order to provide satisfactory margins of static and dynamic strength. Mutual strength and gas-dynamic optimization is done as the next step. The final variant of turbine that meets best the gas-dynamic and strength criteria is found as the result of this optimization.