THE INFLUENCE OF LOAD DISTRIBUTION ON SECONDARY FLOW IN STRAIGHT TURBINE CASCADES

This paper describes an experimental study of the three-dimensional fl ow within two highly loaded turbine cascades subjected to the same ove rall load but different load distributions. Data were obtained using p neumatic probes, pressure tappings, and a surface flow visualization t echnique. It is found that the general nature of the flow is similar f or both cascades. In the exit plane the cascades show different spanwi se loss distributions. However, the averaged secondary loss is quite s imilar in this plane. Examining the measurements farther downstream an d also by comparing the calculated mixed-out values, if becomes clear that a higher magnitude of secondary loss is generated by the front-lo aded cascade.