Research on the stability enhancement mechanism of multi-parameter interaction of casing treatment in an axial compressor rotor

The research on geometric parameters of casing treatment (CT) has always been a hot topic, yet the multi-parameter interaction is rarely studied. In order to gain better knowledge of the interaction mechanism of geometric parameters of CT, the experimental and numerical study based on the response surface method has been carried out in an axial compressor rotor. First of all, the statistical analysis based on the database of experimental and numerical results is presented to summarize the influence law of varied parameters on the stability enhancement. It was found that axial overlap, open area ratio, and their interaction had the most significant influence on the stability enhancement of CT. Subsequently, the interaction between axial overlap and open area ratio was analyzed by visualization flow field in details, which provided a deeper insight into stability enhancement mechanism of CT. It indicated that the mass flow and momentum dominated by injection and the suction effect played a key role for extending stability. With smaller open area ratio, it was difficult for the slots to manipulate and control the tip leakage flow or secondary tip leakage flow, resulting in the weak effect of CT on compressor performance. Finally, the underlying flow physics in the tip region and dominant region of CT has also been discussed to penetrate the essential reason of multi-parameter interaction.