Design and computational fluid dynamics analysis of the last stage of innovative gas-steam turbine

Research regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency and strength of turbine blades. This paper relates to a new type turbine which is in the phase of theoretical analysis, because the working fluid is a mixture of steam and gas generated in a wet combustion chamber. The main aim of this paper is to design and analyze the flow characteristics of the last stage of gas-steam turbine. When creating the spatial model, the atlas of profiles of reaction turbine steps was used. Results of computational fluid dynamics simulations of twisting of the last stage are presented. Blades geometry and the computational mesh are also presented. Velocity vectors, for selected dividing sections that the velocity along the pitch diameter varies greatly. The blade has the shape of its cross-section similar to action type blades near the root and to reaction type blades near the tip. Velocity fields and pressure fields show the flow characteristics of the last stage of gas-steam turbine. The net efficiency of the cycle is equal to 52.61%.