Quasi-3D LDV measurements of unsteady flow field in a rim sealing of a turbine stage

Experimental flow data are urgently necessary to study interaction between the sealing flow and main flow in a turbine stage as well as the unsteady flow phenomena of hot ingestion in a disk cavity. There are many difficulties in measurements such as light path arrangements due to the narrow space in a rim sealing. Having worked out a lot of technique problems, the quasi-3D laser Doppler velocimeter (LDV) measurements of unsteady flow field in a rim sealing of a turbine stage was reported. The measurements were taken in two steps. First, radial and tangential velocities as well as turbulence intensities were measured by using two-dimensional LDV probes put on the casing, then the measurements were repeated by one LDV probe put in the hub. The axial velocity of the flow was calculated from two sets of data. With the help of a phase-locked technique, the periodically unsteady flow field in a rim sealing and a disk cavity can be disclosed at different rotor-stator relative positions. Some typical results of the unsteady flow field were presented.