Numerical Simulation And Experimental Research Of Rotating Flow Of Air-cooled Turbo-generator

Due to the advantages of simple structure,convenient operation and maintenance,security and reliability and so on,air-cooled turbo-generator is still in an important position of the electric power market at present.Good design of ventilation cooling system is the essential condition to ensure long-term safe and reliable operation of air-cooled turbo-generator,which makes the disturbution of flow rate more accurate and reasonable and keeping local position from high temperature rise.Internal flow of the air gap as a link between stator and rotor is complex.Horizontal flow along the axial direction,rotating flow along circumferential direction and radial flow produced by air distribution of stator are included.Temperature field distribution is influenced by flow field distribution,so the research of flow field in the annular space of air gap is of great significance.In this paper,according to the ventilation cooling structure of 220MW air-cooled turbo-generator introduced by manufacturer,experiment table as the research object is designed and manufactured.The research method of numerical simulation and experiment is adopted respectively.Firstly,the optimum design scheme is selected,then size data of each structure of experiment table is designed and refined again,which provide basic data for the manufacture of the experiment table.Secondly,according to the design data,the structure of experiment table is reasonably simplified and the half of the three dimensional flow field model is established.Integration study of stator and rotor is done using different turbulence model and boundary conditions.Flow field information of pressure,velocity,flow rate and distribution law of rotating flow field in air gap is obtained under the three kinds of speed 500 r/min,1000 r/min and 1500 r/min.Then,experiment measurement plan of experiment table is designed and measuring points are decorated.The flow velocity of the inlet of experiment table and outlet of stator and radial ducts are measured with hot-wire anemometer.Experimental measurement data at speed of 500 r/min and 1000 r/min are got,and distribution law of external flow field under experiment conditions are analyzed and obtained.At last,accuracy of results,computation model and scheme adopted in numerical simulation through the comparison of simulation results and measure results.The results are closest to the measured value when using Rea/k—ε two-equation turbulent model at high speed.The results will provide powerful reference for ventilation system design of air-cooled turbo-generator.