JP2014114727A5

JP2014114727A5 -

Info

Publication number: JP2014114727A5
Application number: JP2012268402A
Authority: JP
Filing date: 2012-12-07
Publication date: 2015-03-12
Anticipated expiration: 2032-12-07

Description

上記課題を解決するために、本発明の遠心圧縮機は以下の手段を採用する。
すなわち、本発明は、ハブおよびその外周面に取り付けられた複数の遠心羽根を有する羽根車と、前記羽根車を回転可能に収容するケーシングと、を備え、前記ケーシングは、前記羽根車の回転によって外部から吸い込まれた流体を前記羽根車に向けて導く吸込流路と、前記羽根車の外周側に環状に形成され、前記羽根車の回転によって外周側に吐出される前記流体の流れを減速させるディフューザ部と、前記ディフューザ部の外周側に形成され、周方向に沿って断面積が漸次増大する渦巻き状のボリュート部と、前記ボリュート部の断面積が最大の部分から外周側に向けて延びる出口管と、前記ディフューザ部において前記流体が流れるディフューザ流路の側壁面に形成され、前記ボリュート部内と前記ディフューザ流路内とを連通する連通部と、を備え、前記連通部のディフューザ流路側の開口部が、前記ディフューザ流路の下流側に形成され、かつ、前記ボリュート部の最小面積部と前記出口管との間に形成された舌部を基準として、前記ディフューザ部の上流側３０度から下流側３０度までの領域にのみ形成されていることを特徴とする。
このような遠心圧縮機は、羽根車の回転により、外部から吸い込まれた流体が、吸込流路を経て、羽根車の外周側のディフューザ部に吐出されて減速され、ボリュート部へと流れ込む。ボリュート部においては、断面積が小さい側から大きい側へと流体が流れ、出口管から外部に高圧圧縮流体として吐出される。
このとき、ディフューザ部においては、連通部を通して、ボリュート部内の高圧圧縮流体が、ディフューザ流路内に吐出される。これによってディフューザ壁面から発生した剥離に伴う逆流領域がディフューザ部後縁に達する流量をより小さくしてサージングまでの流量範囲を拡大することができる。しかも、ディフューザ部を通過した高圧圧縮流体をボリュート部から循環させることで、ディフューザ部における効率を低下させることがない。
このような連通部は、前記ディフューザ部の周方向に沿って間隔を隔てて複数形成されているのが好ましい。連通部は、貫通孔としても良いし、ディフューザ部の周方向に連続するスリットとしても良い。 In order to solve the above problems, the centrifugal compressor of the present invention employs the following means.
That is, the present invention includes a hub and an impeller having a plurality of centrifugal blades attached to an outer peripheral surface thereof, and a casing that rotatably accommodates the impeller, and the casing is rotated by the rotation of the impeller. A suction flow path for guiding the fluid sucked from the outside toward the impeller, and an annular shape formed on the outer peripheral side of the impeller, and the flow of the fluid discharged to the outer peripheral side by the rotation of the impeller is decelerated. A diffuser part, a spiral volute part formed on the outer peripheral side of the diffuser part, the cross-sectional area of which gradually increases in the circumferential direction, and an outlet extending from the largest part to the outer peripheral side of the cross-sectional area of the volute part A pipe is formed on a side wall surface of a diffuser flow path through which the fluid flows in the diffuser section, and communicates with the inside of the volute section and the diffuser flow path. Comprising a part, the openings of the diffuser flow path side of the communicating portion is formed on the downstream side of the diffuser flow path, and which is formed between the outlet tube and the minimum area portion of the volute portion tongue It is characterized in that it is formed only in a region from 30 degrees upstream to 30 degrees downstream of the diffuser section with reference to the section .
In such a centrifugal compressor, the fluid sucked from the outside by the rotation of the impeller is discharged to the diffuser portion on the outer peripheral side of the impeller through the suction flow path, decelerated, and flows into the volute portion. In the volute part, the fluid flows from the side with the small cross-sectional area to the side with the large cross-sectional area and is discharged from the outlet pipe to the outside as a high-pressure compressed fluid.
At this time, in the diffuser part, the high-pressure compressed fluid in the volute part is discharged into the diffuser flow path through the communicating part. As a result, the flow rate of the reverse flow region accompanying the separation generated from the diffuser wall surface reaching the diffuser portion trailing edge can be further reduced, and the flow rate range up to surging can be expanded. In addition, the high-pressure compressed fluid that has passed through the diffuser part is circulated from the volute part, so that the efficiency in the diffuser part is not reduced.
It is preferable that a plurality of such communicating portions are formed at intervals along the circumferential direction of the diffuser portion. The communication part may be a through hole or a slit that is continuous in the circumferential direction of the diffuser part.

また、前記連通部は、少なくとも、前記側壁面側の端部が、前記遠心羽根の外周側端部と平行に形成されている構成としても良い。
さらに、前記連通部のディフューザ流路側の開口部が、前記舌部を基準として、前記舌部から前記ディフューザ部の上流側３０度までの範囲にのみ形成されている構成としても良い。 Moreover, the said communication part is good also as a structure by which the edge part by the side wall surface side is formed in parallel with the outer peripheral side edge part of the said centrifugal blade at least.
Furthermore, it is good also as a structure by which the opening part by the side of the diffuser flow path of the said communication part is formed only in the range from the said tongue part to 30 degree | times upstream of the said diffuser part on the basis of the said tongue part.

Claims

An impeller having a hub and a plurality of centrifugal blades attached to the outer peripheral surface thereof;
A casing for rotatably housing the impeller,
The casing, a suction flow path for guiding the fluid sucked from the outside by rotation of the impeller toward the impeller;
A diffuser portion that is annularly formed on the outer peripheral side of the impeller and decelerates the flow of the fluid discharged to the outer peripheral side by rotation of the impeller;
A spiral volute portion formed on the outer periphery side of the diffuser portion, the cross-sectional area gradually increasing along the circumferential direction;
An outlet pipe extending from the largest cross-sectional area of the volute part toward the outer peripheral side;
The diffuser part is formed on a side wall surface of a diffuser flow path through which the fluid flows, and includes a communication part that communicates the inside of the volute part and the diffuser flow path,
The opening on the diffuser flow channel side of the communication portion is formed on the downstream side of the diffuser flow channel , and the tongue formed between the minimum area portion of the volute portion and the outlet pipe is used as a reference. A centrifugal compressor characterized by being formed only in a region from 30 degrees upstream to 30 degrees downstream of the diffuser section .

2. The centrifugal compressor according to claim 1, wherein a plurality of the communication parts are formed at intervals along a circumferential direction of the diffuser part.

3. The centrifugal compressor according to claim 1, wherein the communication portion is formed at least on an inner peripheral side of a portion having a maximum cross-sectional area of the volute portion.

4. The communication portion according to claim 1, wherein at least an end portion on the side wall surface side is formed to be inclined from the inner peripheral side to the outer peripheral side of the diffuser portion. The centrifugal compressor according to item.

The centrifugal communication according to any one of claims 1 to 4, wherein at least the end portion on the side wall surface side of the communication portion is formed in parallel with the outer peripheral side end portion of the centrifugal blade. Compressor.

6. The opening on the diffuser flow path side of the communication portion is formed only in a range from the tongue portion to 30 degrees upstream of the diffuser portion with respect to the tongue portion. The centrifugal compressor according to any one of the above.