Research on the Periodicity of Flow Field in a Compressor Sector Cascade

Abstract

Sector cascade experiments can not only be convenient to measure various aerodynamic parameters but also reveal the real flow characteristics in turbomachinery. However, the sector cascade is only a part of the whole annular cascade. The circumferential angle, the structure of the side guide plate (SGP) and the suction mode on the SGP have a great effect on the periodicity of the flow field. Therefore, the effect of structure on periodicity must be taken into consideration in order to obtain accurate data of the sector cascade experiment. In this paper, a compressor sector cascade composed of a row of adjustable guide vanes (AGVs) and a row of stators is designed. The effect of the circumferential angle, SGP structure and suction position on the periodicity is studied by numerical simulation. An optimal cascade scheme is selected for experimental research. The results show that a larger circumferential angle can weaken the effect of low-energy fluid near the SGP on the middle passages. However, given the limited experimental conditions, the circumferential angle is set at 110° which consists of 15 AGVs and 14 stators. What’s more, the SGP with the same bowed angle of AGV on both sides of the cascade can reduce the influence of the SGP on the adjacent passages and obtain a regular periodicity. The low-energy fluids still accumulate near the SGP. The suction near the stator suction side of the SGP can alleviate the blockage in the flow passage and further improve the periodicity of the cascade. Serious analysis of the experiment results have further identified that the suction near the stator suction side of SGP can make the aerodynamic parameters of the flow field uniform and lead to a good periodicity. At the same time, the feasibility of this design method is verified.