Non-axisymmetric flow field in an axial impulse turbine

摘要: Phenomena such as hard landings or geometric flaws can cause non-axisymmetric tip clearance in turbines. Such imperfections induce flow distortions which can, turn, self-excited vibration of the rotor, rotordynamic instability. Flow field perturbations a single-stage, unshrouded impulse turbine caused by have been investigated experimentally. Steady velocity and pressure data acquired at design point with without static casing offset. Perturbations tangential wall obtained, forces along perpendicular to axis offset inferred. Compared an 20% reaction turbine, due force asymmetry are much smaller, but comparable.