Structural Analysis And Optimization Of A Large Power Station Condenser

The condenser is one of the important auxiliary equipment of condensate gas turbine,it is widely used in thermal power stations and nuclear power plants.As the main condensing equipment of steam turbine,condenser plays a very important role in ensuring the normal working efficiency of the steam turbine and ensuring safe operation of the steam turbine unit,whether the condenser can normal operation is not only related to economic benefit of the whole plant,but also has a great impact on safe and stable operation of the plant.The large power station condenser is mainly consist of water chamber,tube sheets,neck,support plates and tens of thousands of condensing tubes.The condenser design size is constantly growing with the capacity increase of power station steam turbine,which carries the loads of the condenser rise greatly and leads to the stress of its key components such as the tube sheet become more complicated,the structure strength of condenser just faces enormous challenges.Therefore,it is particularly significant for the security performance assessment and the further optimization design of the condenser whole structure to research the stiffness and strength requirement of the condenser components,and to grasp the size and distribution of stress and deformation of condenser components in the running process.This thesis combines the project of “Research on the calculation method of stiffness and strength of condenser tube sheet” commissioned by Dongfang Steam Turbine Co.,LTD,Dongfang Electric Group to research the stiffness and strength of the condenser whole structure,mainly finished the following research:1.According to the grasp of the condenser running performance and the research of calculation analysis program,determining the simplified solution to construct condenser model,that is construct the perforated area of the tube sheet as a solid plate,and construct the condensing tubes as a solid model under the rule of constant volume but the elastic modulus is calculated equivalently,and others components with no simplified.Then constructing the full three-dimensional modeling of the two different common types of condenser,and getting the accurate integral structure calculation model of condenser.2.The overall structure statistic calculation analysis of the two different common types of condenser had been done,and the size and distribution trend of the stress and deformation under the same pressure test of the two different types condenser components had been obtained.3.The intensity check of the two kinds of condenser had been done,at the same time,the dangerous position of its main components had been determined.4.The strength requirement in the actual operation process of condenser components were analyzed,and by comparing the results of the same components of the two different condensers,this thesis had got some significant conclusions which can guide the condenser design.5.According to the stress and deformation distribution trend,adopting the U-shaped flange on the center position left and right sides of the tube sheet which the equivalent stress and deformation is concentrated on to optimize the tube sheet under the premise that does not affect the condenser cooling effect,the result is the existence of U-shaped flange cannot reduce the equivalent stress left and right sides of tube sheet,but it can reduce the deformation,within the distance of 250 mm to the edge of tube sheet,the deformation on the left side of tube sheet reduced 17.25%,and the right side reduced 12.8%,which enhanced the security performance of the tube sheet greatly.Through statics calculation analysis for the whole structure of two different types condenser,this thesis has a more fully grasped the strength requirement of the condenser components during normal operation.By comparing the results of the same components of the two different common types of condenser,some useful guidance and gist for determining important parameters of the main components of condenser had been got,finally,the area of the left and right sides of tube sheet where the equivalent stress and deformation concentrated is optimized,and the deformation of tube sheet had been reduced,the research of this paper provides a necessary theoretical support for the improvement of condenser design.