Centrifugal compressor with surge control, and associated method

  • US 7,775,759 B2
  • Filed: 04/04/2007
  • Issued: 08/17/2010
  • Est. Priority Date: 12/24/2003
  • Status: Active Grant
First Claim
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1. A centrifugal compressor for compressing a fluid, comprising:

  • a centrifugal compressor wheel having a hub defining a rotational axis and having a plurality of circumferentially spaced blades each having a root joined to the hub and extending generally radially outwardly to a tip of the blade, each of the blades having a leading edge and a trailing edge spaced downstream from the leading edge along a flow direction;

    a compressor housing in which the compressor wheel is mounted so as to be rotatable about the rotational axis of the compressor wheel, the compressor housing including an inlet duct through which the fluid enters in a direction generally parallel to the rotational axis of the compressor wheel and is led by the inlet duct into the compressor wheel, the fluid flowing along a main flowpath defined by the compressor wheel and compressor housing and exiting the compressor wheel in a generally radially outward direction, the inlet duct comprising a duct wall that encircles the rotational axis, the compressor housing further including a wheel shroud located radially adjacent the tips of the blades;

    a bleed port defined in the wheel shroud at a location intermediate the leading and trailing edges of the blades for bleeding off a bleed portion of the fluid being compressed by the compressor wheel, the bleed port being sized in flow area, in relation to a flow area of the main flowpath, such that at a predetermined operating condition the bleed portion constitutes from about 15% to about 25% of the total mass flow entering the compressor; and

    a converging injection nozzle defined in the duct wall upstream of the leading edges of the blades for injecting the bleed portion of the fluid back into the main fluid flow stream approaching the compressor wheel, the injection nozzle being configured to inject the bleed portion in a direction that makes an angle of from 0°

    to 90°

    with respect to the rotational axis, and wherein a flow area of the injection nozzle decreases in the flow direction such that the bleed portion is accelerated before being injected into the main fluid flow stream.

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