Determination of Separation Losses in the Rotor Wheels of Radial-Axial Turbines

The use of the basic hydrodynamics equations written for the portion of contracted flow at the inlet into the vane channel of the rotor wheel of the radial-axial turbines at considerable angles of attack and for the portion of subsequent expansion up to the reattachment of flow to the channel walls made it possible to obtain analytical dependences (characteristics) of losses on the angles of flow inlet into the channel. The circulation at the inlet into the channel exerts a noticeable influence on the actual angle of the flow that entered into the channel. The obtained method of calculation of losses also makes it possible to take into account the thickness of the blades, on which the region of insensitivity to the angle of attack depends, and to determine the corresponding angles of the flow entry that bound this region. The characteristics of the rotor wheels of radial-axial turbines obtained with the use of the developed method agree well with the known experimental data in a wide range of the angles of attack of flow.