Abstract:

 Large scale compressed air energy storage systems have the potential for a wide range of applications including peak load shifting, distributed energy systems, and renewable energy utilization. However, such a technology requires the compression system to have a high efficiency and a wide operating range. The use of adjustable vane diffusers provides a compact solution to enlarge the operating regime of the compressor with a high efficiency. In this paper, a centrifugal compressor with a vane diffuser for large scale compressed air energy storage is analyzed. A multi-objective optimization method is applied to the initial diffuser vane. Through numerical modelling, the regulation relationship and the perform curve are obtained The results show that the optimized three dimensional twisted vane can reduce the impact of the non-uniform impeller outlet flow on the diffuser and improve the performance of the compressor. The adjustable range of the vane diffuser is between 8°and +5°at the design speed. The use of the adjustable vane diffuser could improve the operating regime of centrifugal compressors by 117%. Significant improvement could also occur on the compressor performance at off-design conditions.

Key words: compressed air energy storage, centrifugal compressor, adjustable vane diffuser; , optimization design, regulation rules