RU2109990C1 - Centrifugal compressor - Google Patents

Abstract

FIELD: mechanical engineering; compressors. SUBSTANCE: turnable ring 6 with circular row of holes 7 is installed in chamber 3. Ring precludes flow of gas from chamber 3 into bladeless diffuser 2 in working zone of performance curve and connects spaces of chamber 3 and diffuser 2 at stable operation limit. Turning of ring 6 is carried out by signal of pickup recording the beginning of fluctuations at stables operation limit. EFFECT: provision of surgeless operation at different speeds and different delivery pressures. 4 dwg

Description

 The invention relates to mechanical engineering and can be used in centrifugal compressor machines.

 A known centrifugal compressor, in the inlet portion of the bladeless diffuser of which holes are made with deflecting visors for injection into the boundary layer of gas from an axisymmetric collection chamber [1].

 However, due to the insufficiently deep penetration of gas jets having an increased static pressure into the stream behind the impeller, it is not possible to completely suppress the occurrence of surge oscillations, which can lead to compressor breakdowns.

 A known centrifugal compressor, taken as a prototype, in which gas from the collection chamber is transferred to the area behind the impeller using valves installed in the lower part of the collection chamber. The normal position of the valves is closed. With a decrease in gas flow through the compressor and approaching the boundary of stable operation, the static pressure behind the wheel will increase. When the static pressure behind the wheel reaches the maximum pressure with the valves fully open, the latter open under the action of the increased pressure, and the gas, the static pressure of which increased even more when passing through the bladeless diffuser from the collection chamber, is transferred to the initial section of the diffuser, resulting in surge fluctuations completely absent. In the right branch of the characteristic in the zone of high efficiency, the efficiency and pressure do not fall, since the bypass valves are closed [2].

 However, since the valves are opened at a specific pressure drop, the design considered is advisable to be used only in compressors operating at a constant speed and at a constant discharge pressure, i.e., for example, in compressors driven by an electric motor.

 The objective of the invention is to enable the supply of gas from the collection chamber to the initial section of the bladeless diffuser at the beginning of surge oscillations when operating at different speeds and at different discharge pressures.

 The specified technical result is achieved by installing a ring in the collection chamber with a circular row of holes made in it, rotating it to match the holes in the ring with a circular row of holes made in the wall of the bladeless diffuser, and thus connecting the cavities of the collection chamber and the initial section of the bladeless diffuser. When working in the zone of high efficiency, the ring installed in the initial position prevents such a gas flow. The rotation of the ring is carried out using a drive that includes a drive mechanism, for example, a gear type and an electric motor. The start of operation of the drive is carried out by the signal of the sensor installed in the flow part of the compressor and registering the beginning of gas pulsations at the boundary of stable operation.

 In FIG. 1 shows a longitudinal section through a centrifugal compressor with a rotary ring in the closed position; in FIG. 2 is a section AA in FIG. one; in FIG. 3 is a longitudinal section of the compressor with the ring in the open position; in FIG. 4 is a section BB in FIG. 3.

 The proposed centrifugal compressor comprises an impeller 1, a bladeless diffuser 2, an axisymmetric collection chamber 3, a base of the collection chamber 4, a circular row of holes in the wall of the bladeless diffuser 5, a rotary ring 6 installed in the collection chamber 3 with a circular row of holes 7, preventing gas overflow from of the collection chamber into the bladeless diffuser in the working area of the characteristic and connecting the cavities of the collection chamber and the diffuser at the boundary of stable operation, drive 8, a sensor installed in the compressor striruyuschy top ripple (not shown).

 When the compressor is operating on the right branch of the characteristic in the high efficiency zone, there is no gas supply from the collection chamber to the initial section of the bladeless diffuser. The gas injected by the impeller 1, passing through the bezoplatochny diffuser 2, enters the collection chamber 3 and then into the pressure turbine. At the boundary of surging oscillations, according to the signal detecting the onset of pulsations at the boundary of stable operation, issued by the sensor, the drive mechanism 8 rotates the ring 6 until the holes in the ring 7 coincide with the wall of the bladeless diffuser 5, which results in the action of the annular row of gas jets from the collection chamber on flow behind the impeller and elimination of surge fluctuations.

Claims (1)

 A centrifugal compressor containing an impeller located in the housing along the gas, a bladeless diffuser and an axisymmetric collection chamber connected by a circular row of holes made in the diffuser wall to the inlet portion of the bladeless diffuser, characterized in that a sensor is installed in the compressor flow path that controls the beginning of pulsations stable operation at the border, a rotary ring with a circular row of holes is installed in the collection chamber, preventing gas from flowing from the collection chamber to the diffuserless the clearance in the working area of the characteristic and connecting the cavity of the collection chamber and the diffuser at the boundary of stable operation.

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