Investigation Of Aerodynamic Design And Effects Of Bowed Blade For Industrial Steam Turbine

The efficient use of energy to comply with the national energy policy for saving emission reduction and the development of renewable energy,clean energy is our goal.This is the goal of scientific researchers and engineering designers struggling for life.The industrial steam turbine,as an essential component for power generation is important in the national economy.The reliable performance of the industrial steam turbine is vital to the improvement of the overall performance of industrial production.So improvements in design are constantly expanding.With the structure,strength,manufacturing and other related technologies,Industrial steam turbine performance improvement potential is also expanding.Based on the scientific research and practical application,depth study and discussion of high-level and efficient industrial steam turbine design methods to optimize and improve the design system and design process,the influence of The optimization of design parameters on the internal flow field and the improvement of performance of the whole machine using pneumatic simulation technique have led to significant practical results,have a significant practical significance.The application of numerical simulation technology has led to the development of a mature industrial steam turbine design technology.It has gone from a three-dimensional design method for a single blade design to a full three-dimensional design method considering the actual structure of blade,had been deepened by the domestic and foreign scholars.However,there were many types of industrial steam turbines that covered saturated steam,superheated steam,and ultrahigh-pressure steam up to subsonic,transonic and supersonic flow,or even a mixture of two steam flows,two-phase wet steam flow(the main factors for the water erosion).In view of the complexity of steam flow,some problems still need to be further studied.In this paper,based on the practical application of industrial steam turbine,a study of the bowed blades in reducing the water erosion risk and improving the supersonic flow performance is carried out,and the design method of improving the convergence flow performance is explored.These studies are necessary not only to improve the level of design of the industrial steam turbine,but also to achieve the efficient use of energy.Based on the theory of multiphase flow and computational fluid dynamics methods,the following aspects were examined:Firstly,the water erosion problem of the moving blades in the condensing steam turbine was investigated by using the numerical method for the two-phase flow of water vapor;the experimental data of gas-liquid two-phase flow were used as control,and a method of two-phase flow was established accurately,taking into account the flow mechanics and the effect of curved blade on the movement characteristics of secondary water droplets.Considering that the flow field structure directly determines the influence of the secondary water droplets on the water erosion and the influence of the curved blade on the flow field,the empirical formula of the water erosion risk and the formula of metal erosion rate in the material mechanics are taken as the measurement standard.It can reduce the risk of water erosion and has a high aerodynamic performance of the curved blade design method.Secondly,for the supersonic flow problem,the research verified the accuracy by means of the experimental data of the planar cascade.The effect of the bowed blade on the shock wave structure and the design of the blade in the cross speed and supersonic flow of industrial steam turbine were studied.On the basis of this,in the condensed supersonic flow,the differences between the two methods of equilibrium and unbalanced coagulation were compared.The effect of the bowed blade on the non-equilibrium condensation of water vapor were demonstratedis studied emphatically,especially the influence of shock wave and condensed wave.A method to improve the flowability of water vapor condensable supersonic flow with curved blade design is proposed.Thirdly,the mixed flow problem of the steam supply structure in the steam turbine studied.Based on the research results of the "T"-type channel flow loss and the related conclusions,the research methods were validated and parametric research was carried out.Employing the research results of the convergence of the "T" channel flow and the relevant results,the total pressure loss of the steam confluence is known,and the structural parameters which have an important influence on the total pressure loss are analyzed.In order to improve the convergence flow performance,a hybrid structure with an elliptical cross section and tapering along the circumferential cross section is designed.The improved filling structure can effectively equalize the distribution of the steam in the circumference and the confluence.The results of the standard deviation calculation show the confluence of the vaporization after the distribution of a more uniform distribution.Improved design is beneficial to improve machine performance.Finally,this paper summarizes the application and design characteristics of industrial steam turbines,analyzes the characteristics of the loss model,and presents a pneumatic design system.Based on the design characteristics of industrial steam turbines,the design process and the composition of aerodynamic design concepts,as well as design criteria and database are given.The design system advanced a certain type of industrial steam turbine,while the results confirmed that the design system achieved a high level of efficiency to achieve the desired goal.