Three-Dimensional Unsteady Flow in a Single Stage Axial-Flow Turbine and Compressor

Abstract

In this paper the importance of unsteady flow effects is demonstrated for the accelerated turbine and decelerated compressor flow. For the understanding of the entire core flow in turbomachines, it is necessary to investigate the unsteady three-dimensional flow field inside the blade passages. Here the flow is mainly disturbed by periodic unsteadiness due to rotor-stator interaction. In order to determine the unsteady flow quantities by means of the experiment, two problems have to be solved. First it is necessary to investigate the unsteady flow field downstream of a rotating cascade. In a second step the influence of the periodically disturbed inlet flow on the passage flow inside a downstream located blade row has to be resolved. In this paper experimental methods are presented to attack the above described problems. It is demonstrated how different experimental methods and techniques of measurements are employed and supplement each other. The combination of the obtained results lead to a very close description of the flow structures. The importance of the unsteady flow effects will be discussed while presenting the results of tested configurations.