A flow guidance device for leakage flow in the shroud cavity of compressors and its numerical research

The shrouded impeller centrifugal compressor serves as a core component of the Compressed Air Energy Storage system, and its performance directly affects the overall system performance. The leakage flow from the shroud cavity restricts efficiency improvements, particularly under low-flow conditions, where it significantly degrades the compressor’s performance. This paper proposes a flow guidance device and conducts an in-depth numerical study and analysis on it. The guidance device effectively reduces the circumferential swirl angle at the impeller inlet by directing the leakage flow to a position away from the impeller inlet and reintroducing it into the main flow passage. This approach improves the flow separation conditions within the impeller, resulting in a substantial performance enhancement of the compressor under low-flow conditions.