The effects of end wall profiling on secondary loss is a turbine nozzle row

Abstract

This thesis presents detailed investigations of the effect of end wall profiling on the secondary loss in a turbine nozzle row. The purpose of this project was to obtain a detailed view of the flow structure downstream of the blade passage, especially of the area adjacent to the end wall, and the influence of the shaped end wall on both flow and loss. The cascade was designed and manufactured by Yan [1999] based on nozzle blades by ALSTOM Energy Ltd. The low speed wind tunnel used by Yan was also used for the experimental work of this thesis, which were carried out in Durham thermodynamic laboratories. Two finer probes were used for the experiments allowing closer to the end wall measurements.».The flow field was investigated at exit from the blade row through two traverse slots. The secondary flow structure was understood and the effect of the profiled end wall was demonstrated by a reduction in the secondary loss and boundary layer thickness. The data collected along with the previous work by Yan could be regarded as an indication of the possible advantages of end wall profiling in a real turbine. The next step would be to carry out similar work on real turbomachinery.