FLOW DISTURBANCES IN A SINGLE-STAGE COLD-AIR TURBINE

摘要

The paper deals with an experimental analysis of turbulence and unsteadiness levels of velocity field in the axial-flow turbine stage. Hot-wire probes mounted in a stationary frame of reference were used during the experiment. All the measurements were performed at the stator inlet, stator-rotor axial gap and rotor outlet, respectively. The phase-averaging technique applied to velocity-time records confirmed that the perturbations about the mean flow velocity were composed of both random fluctuations of a small scale turbulent motion and periodic fluctuations caused by the rotor-stator interaction. It was also found that for ail considered stage loadings the most important contribution to the overall flow disturbances was made by the random velocity fluctuations. Contribution by the periodic flow unsteadiness was much smaller with the tendency to decrease with the downstream distance from the rotor blades.