Work

Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO2 Centrifugal Compressors

Year: 2025

Type: article

Abstract: The windage loss in impeller back gap and labyrinth seal cavities significantly impacts the aerodynamic performances of supercritical carbon dioxide (sCO2) compressors. To accurately calculate windage loss, essential factors affecting the skin friction coefficients Cf,d (disk-type gap) and Cf,s (shaft-type gap), including Reynolds number Re, pressure ratio π, and radius ratio η, are investigated in this paper. The flow characteristics of the gap are analyzed and prediction models are proposed. The results indicate that both Cf,d and Cf,s decrease with increasing Re and grow with π and η, attributable to expanded high-vorticity regions caused by enhanced flow instability and larger vortices. The leakage flow rate m is unchanged for Re < 106 since the fluid can flow into the impeller back gap, and slightly decreases for Re ≥ 106 due to the centrifugal force and the inhibition effect of the vortices filling inlet regions. Moreover, the m grows with π and η due to a larger pressure difference and through-flow area. Maximal relative deviations of 6.23% and 6.83% can satisfy the requirements for calculating accurate windage loss in the impeller back gap and labyrinth seal cavities, which help the primary design of sCO2 compressors.

Source: Applied Sciences

DOI: 10.3390/app15073678

Authors: Bing Tang, Jianxin Liao, Zhuobin Zhao, Qinghua Deng, Jun Li, Zhenping Feng

Institutions: Aviation Industry Corporation of China (China), AviChina Industry & Technology (China), Dongfang Electric Corporation (China), Xi'an Jiaotong University

Language: English

Topic: Turbomachinery Performance and Optimization

Subfield: Aerospace Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $2,896