Abstract
The impeller backside cavity (IBC) is a unique structure of centrifugal compressor in compressed air energy storage (CAES) systems, which affects the aerodynamic performance of centrifugal compressor, and the angle change of the downstream coupled adjustable vaned diffusers (AVDs) will affect the flow field inside the cavity and compressor performance. This paper relies on the closed test facility of the high-power intercooling compressor to measure static pressure and static temperature at different radii on the static wall of the IBC. The coupling relationship between the IBC and compressor under variable operating conditions is analyzed, and the influence of AVDs on the internal flow in IBC is studied. The results show that static pressure and static temperature rise along the direction of increasing radius, but static temperature drops near the coupling between the impeller outlet and the cavity inlet. Under AVDs’ design angle, static pressure and static temperature at each point, static pressure loss and static temperature loss in the direction of decreasing radius all increase as the flow decreases. Under variable AVDs’ angles, static pressure and static temperature will change differently, and respective loss will also be different.
Highlights
Published: 28 September 2021In the field of distributed energy applications with fluctuant and intermittent renewable energy and the construction of smart grids and microgrids, compressed air energy storage (CAES) system is considered a key technology to improve penetration of renewable energy and provide important support for peak power regulation [5,6]
(1) The static pressure on the static wall of the impeller backside cavity (IBC) gradually decreases along the direction of decreasing radius, and the loss along the way of centripetal motion mainly includes friction loss and the resistance loss of Coriolis force and centrifugal force
The static temperature on the static wall of the IBC gradually rises along the direction of increasing radius but drops near the coupling between the impeller outlet and the cavity inlet, because the air-cooling effect is stronger than the effect of wind resistance and temperature rise in there
Summary
Published: 28 September 2021In the field of distributed energy applications with fluctuant and intermittent renewable energy (photovoltaics [1,2], wind power [3,4]) and the construction of smart grids and microgrids, compressed air energy storage (CAES) system is considered a key technology to improve penetration of renewable energy and provide important support for peak power regulation [5,6]. There is an impeller backside cavity (IBC) structure in the centrifugal compressor, which has an important influence on the flow field details, pressure ratio, efficiency, torque, shaft power, and axial thrust of the centrifugal compressor [8,9,10,11]. Its outer edge junction surface is connected with the mainstream of compressor, and the inner edge junction surface is connected with an air seal. It is mainly affected by the movement of the impeller, the heat transfer efficiency of both side walls, the different types of boundary layers on both side walls, the existence and type of the rotating core between the boundary
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