PROGRESS AND PROSPECT OF AERODYNAMIC EXPERIMENTAL RESEARCH ON LINEAR CASCADE

The aerodynamic experiment on linear cascade, which can provide numerous and systematic experimental results, is traditionally the main methods to verify the elementary aerodynamic performance of compressor and turbine. In recent years, the overseas and domestic researchers have carried out a large number of flow measurement experiments to reveal the internal flow mechanism and then explore methods to decrease flow loss of linear cascade flow field. In this paper, the overseas and domestic aerodynamic experiment research progress for linear cascade, especially for supersonic and transonic linear cascade has been reviewed and discussed from the viewpoints of experimental equipment, measurement technologies and experimental research content. Firstly, the development of linear cascade equipment and the methods for improving flow quality are reviewed, which can increase the inlet flow uniformity and outlet flow periodicity of the test section. Meanwhile, various aerodynamic experimental measurement technologies for linear cascade are discussed in detail, including measurements for blade surface pressure field, blade surface temperature field, flow velocity field and flow visualization. The existing problems and improvement methods for current measurement technologies are analyzed, respectively. Furthermore, mainly based on the decrease of flow loss, several key scientific problems and research progress for the aerodynamic experiment of linear cascade are discussed herein, including the interaction between shock wave and turbulence boundary layer in transonic cascade, tip leakage clearance flow research, baseline profile modification, multi-scale secondary flow vortex structures, unsteady flow characteristics, the cascade flow field research in vibration environment, and so on. Finally, based on the previous research, the prospects of the direction and the trends of linear cascade aerodynamic experimental research are discussed briefly, which may provide reference for future related studies. By understanding the phenomenon and mechanism of complex flow in cascade, it provides technical support for further improving the aerodynamic performance of compressor and turbine.