Numerical study of 3D blading in HP impulse turbines

One way to improve the performance of turbomachinery is to raise the efficiency of the flow system by means of 3D-shaped blading. The paper describes results of numerical (3D NS) study of straight Jean, compound Jean and compound twist, and their effect on flow characteristics of short-height HP cylindrical stages of impulse turbines. It is assumed that only stator blades are modified, leaving rotor blades cylindrical and endwalls unchanged. The overall effect of the tested designs is to redistribute blade load, reaction and loss span-wise. However, the predicted overall efficiency gains do not exceed 0.4%.