Optimal Design Study Of High Pressure Turbine

For the modern high power steam turbine,the initial pressure of the high pressure stage is higher and higher,and the blade height is very small.One is that the change of aerodynamic parameters along the blade height is smaller,and the two is to save manufacturing cost,therefore,it is generally designed as straight blade.In the engineering design,straight blade design often use S1 stream surfaces two-dimensional design,through preferred to design the profile and the meridi an,the profile loss and secondary flow loss dropped to lower levels.With the continuous improvement and development of computer,the commercial software is increasingly used in engineering design.It is still an important way of rapid development steam turbine industry that using modern design techniques to a retrofit design of a production model of the steam turbine have been carry out,in order to meet the user requirements.Using the artificial neural network and genetic algorithm in commercial software NUMECA,the high pressure turbine with three stages(the eighth,ninth,tenth stage)of a certain type of steam turbine carred out modified design optimization,and analysed the dynamic performance in comparison with the original turbine.The numerical simulation for the original turbine show that,the transverse secondary flow losses of upper and lower endwall in total losses are accounted for the major proportion.In addition,the vortex losses produced by the meridional mutation part yet is one reason which led to the increasing of the turbine stage flow efficiency.On the basis of the numerical simulation results that show the factors generating the high flow losses,under the condition of the maintainting the original design of the rotors of the three-stage turbine,the stator profiles had been optimized,and the meridian smoothed.The original stator blades are aft-loaded blades,with the help of the optimization design the loaded peaks of the blades had been moved further towards the trailing edges,which weakened the the transverse pressure gradients on the front and middle parts of the upper and lower endwalls,thereby the endwall transverse secondary flow losses had been reduced.The matching of the meridian smooth treatment with the profile optimal design,that canceled the local separations and the vortices by the Meridian passage mutations,the fluid efficiency of the three-stage turbine was increased more greatly.