Thermodynamics And Aerodynamic Optimization Design Of The Multistage Low Pressure Long Blade In Extraction Condensing Steam Turbine

Steam turbine is one of the three big equipments in coal-fired power plants, the working medium of steam turbine is steam, the efficiency of the steam turbine is an important performance index of thermal power equipment. Cogeneration steam turbine can meet the needs of process steam and district heating, also improve the thermal cycle efficiency. The cogeneration of medium and large sized thermal power plant is a trend in the development of the future.The main content of this paper is blade optimization design for the low-pressure stage of extraction condensation type steam turbine, the blade optimization design can be widely used as low-pressure cascades of a single flow LP casing of high temperature and high pressure, sub-high pressure, intermediate temperature and intermediate pressure50/60MW steam turbine, also in double LP casing of high temperature and high pressure100MW and ultrahigh pressure135/150MW, etc. According to the change of the one-dimensional thermodynamic parameters, complete blade profile optimization using the full-three dimensional aerodynamic design method based on one dimensional and quasi-three dimensional calculated examples, in order to improve the low pressure flow path cascades operation ability which is in the small volume flow condition. Complete the multidisciplinary optimization design of the blade root type, blade shroud structure, meridian plane streamline, blade materials and water erosion prevention measures of blade, stress and strength of blade, coupling vibration, and so on.The purpose of this topic is the low pressure long blade optimization design research, achieve the goal of the following aspects:(1) optimization design of the stationary, rotational blade height and matching area;(2) increase the reaction degree of the blade root and reduce the reaction degree of blade, keep a uniform change of reaction degree along the radial direction of blade;(3) Mach number is controlled for a uniform change of the stationary blade outlet along the radial direction;(4) The outlet steam angle of stationary blade along the radial direction is optimization designed, improve the rotating blade angle of attack;(5) analysis the full dimensional aerodynamic numerical simulation example and the meridian plane flow path in small volume flow condition, in order to reduce the rotating stall area;(6) high damping LP rotating blade, without brace structure.The theoretical calculation and engineering design are closely integrated in this topic, using multidisciplinary theory to analyze problems with engineering problems as the starting point, and the results of analysis are applied to the engineering design. The actual operation parameters are collected and analyzed, inspection the results of optimization design. In theoretical analysis and engineering optimization design process, this topic has achieved some breakthrough research results in the associated influence factors of long blade thermodynamics calculation, pneumatic numerical analysis, strength and vibration check, and successfully applied to the analysis of engineering problems.