Abstract: Various embodiments of ported-shroud centrifugal compressors are described. In some embodiments a wall of a compressor housing defines a pair of bulb-shaped hollow spaces or “bulbs”, one located proximate the compressor wheel and the other spaced upstream from the wheel, and having a connection therebetween. The downstream bulb is connected to the main flow path of the compressor by a port slot through the wall. The upstream bulb is connected to the inlet area of the main flow path by a passage through the wall. The bulbs can provide acoustic wave cancellation through multiple internal reflections in various directions. In one embodiment, the upstream bulb has a second passage connected to it, facing axially upstream, for receiving a portion of the total flow in a choked-flow operating regime, and conducting that portion through the upstream bulb, through the connection to the downstream bulb, and through the port slot into the main flow path.

Abstract: Various embodiments of ported-shroud centrifugal compressors are described. In some embodiments a wall of a compressor housing defines a pair of bulb-shaped hollow spaces or “bulbs”, one located proximate the compressor wheel and the other spaced upstream from the wheel, and having a connection therebetween. The downstream bulb is connected to the main flow path of the compressor by a port slot through the wall. The upstream bulb is connected to the inlet area of the main flow path by a passage through the wall. The bulbs can provide acoustic wave cancellation through multiple internal reflections in various directions. In one embodiment, the upstream bulb has a second passage connected to it, facing axially upstream, for receiving a portion of the total flow in a choked-flow operating regime, and conducting that portion through the upstream bulb, through the connection to the downstream bulb, and through the port slot into the main flow path.