Numerical Simulation Of The Flow In The Turbine And Redesign Of The Blade

Industrial steam turbine is widely used in power plant, chemical industry and many other important fields. To improve the efficiency of the industrial steam turbine may have a great influence on the national economy. Steam turbine driving furnace feed water pump of 600MW power plant is one of the key products in the industrial steam turbine market and there is a great demanding in the current market. The improvement of the design of the steam turbine may bring a great profit, economically, environmentally, or socially.To improve the performance of the steam turbine, it is crucial to understand the flow structure in the machine. Based on the computational fluid dynamics software, NUMECA, a numerical analytic platform was developed in this paper, after a detailed discussion of the flow controlling equation, turbulence modeling, discretization of the governing equation, geometry modeling of the steam turbine, mesh generation, boundary condition, etc.. The numerical simulations of the flow in the high pressure section and lower pressure section of the steam turbine were presented. For lower pressure section, as the steam may not be overheated anymore, it is crucial to add the condensable model in the computational system to justify the numerical results.Based on the careful examination of the flow field, the key factors affecting the performance of the machine were discussed and various measures were proposed to improve the design of the steam turbine. It is found that the design of the high pressure section is generally satisfactory, except that the meridian flow path changed very sharply at some places and this may contribute a great part to the flow losses. However, the performance of the lower pressure section is not very high and there is still great potential for further improvement.For lower pressure section, research works were concentrated to stage 8, with straight stator blade and twisted rotor blade. Intensive researches were carried out on the blade profile modification, after-loading and positively curved blading techniques in an attempt to reduce the aerodynamic losses in the stator blades and rotor blades as well. Results indicate that after-loading and positively curved blading techniques can effectively reduce the flow losses in the stator blade, and rotor blade can be effectively modified by a redesign of the blade profile at different radial sections. An overall efficiency increase of 2.51 percent was achieved with intensive numerical experiment.