JP2014095366A - Decompression device of axial flow compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of surge while suppressing influence on a normal operation of an axial flow compressor.SOLUTION: A decompression device is equipped to an axial flow compressor. The decompression device includes: a stationary blade (variable stationary blade 11) supported by a supporting shaft (rotary supporting shaft 12) penetrating through a casing 41 of the axial flow compressor, and formed with a hole 15 positioned on a face kept into contact with a gas flow channel 17 inside of the casing 41, of the stationary blade; and an internal passage 16 having a hollow structure penetrating through the inside of the stationary blade and the inside of the supporting shaft from the hole 15 to guide a gas in the gas flow channel 17 from the hole 15 to the external of the casing 41. Thus, generation of surge can be prevented while suppressing influence on a normal operation of the axial flow compressor.

Description

  The present invention relates to a pressure reducing device for an axial compressor.

  FIG. 6 schematically shows an example of the vicinity of the rotating shaft of an axial compressor having a variable vane. As can be seen from the drawing, the conventional axial compressor includes a moving blade 10, a variable stationary blade 11, a rotating support shaft 12, a gas flow path 17, a casing 41, and a rotating shaft 42. The variable stator blade provided on the most upstream side is referred to as IGV (inlet guide valve) 11a, and the variable stator blade provided on the most downstream side is referred to as OGV (outlet guide valve). Hereinafter, the simple description of “variable stationary blade 11” includes IGV 11a and OGV 11b.

  The above-described moving blade 10 is fixed to the rotating shaft 42. Further, the variable stator blade 11 is supported by the rotation support shaft 12 penetrating the casing 41 so as to be able to rotate and control with respect to the casing 41, thereby enabling the blade angle changing operation.

  However, although not specifically described in FIG. 6, not all the stationary blades are actually the variable stationary blades 11, and some stationary blades are fixed to the casing 41. The rotating support shaft 12 that supports the variable stationary blade 11 passes through the casing 41, whereas the fixed stationary blade support shaft does not penetrate the casing 41.

  Further, among the axial flow compressors, the difference between the compressor and the blower is that the variable stationary blade 11 occupies all or a part of the stationary blade.

  In general, the entire axial flow compressor including the multistage axial flow compressor and the blower is operated while controlling the air volume and the pressure near the outlet in a safe operating range. Incidentally, the reason for measuring the pressure in the vicinity of the outlet in the gas flow path 17 is that the pressure in the vicinity of the outlet is the highest.

  However, when operated without being inspected for a long period of time or when operated for a long time in an environment of corrosive atmosphere, accumulation of impurities on the rotor blade 10 disposed in the gas flow path 17 or thickness reduction due to corrosion, etc. Therefore, there is a case where the blade shape changes with time.

JP 2002-97970 A JP-A-2005-90300

  Under the circumstances as described above, a surge may occur even in an operation region that is conventionally assumed to be safe. Surge is transmitted at high speed from the outlet side to the inlet side.

  When a surge occurs, the energy of the high-pressure gas (including air; the same applies hereinafter) in the gas flow path acts on the blade, causing serious damage such as melting or breakage.

  If the wings are damaged, there will be a great disadvantage for the user due to loss of profits due to the suspension of operation or replacement work costs.

  In the above-mentioned Patent Document 1, a technique is described in which a bleed flow passage is provided in a compressor to bleed gas and the pressure of the gas flow passage is reduced. However, a specific configuration of the bleed flow passage is disclosed. Not.

  Accordingly, an object of the present invention is to prevent the occurrence of surge while suppressing the influence on the normal operation of the axial flow compressor.

A decompression device for an axial compressor according to the first invention for solving the above-mentioned problems is
A pressure reducing device for an axial flow compressor having a stationary blade supported by a support shaft passing through a casing of the axial flow compressor,
A hole located on a surface of the stationary blade in contact with the gas flow path inside the casing;
An internal passage that penetrates the inside of the stationary blade and the inside of the support shaft from the hole and guides the gas in the gas channel from the hole to the outside of the casing is provided.

A decompression device for an axial-flow compressor according to a second invention for solving the above-described problems is
In the decompression device for an axial flow compressor according to the first invention,
Provided at the support shaft side outlet of the internal passage is a pressure control mechanism in which the pressure of the gas flow path is opened to the atmosphere above a predetermined pressure set in a range where no surge occurs and becomes airtight below the predetermined pressure. It is characterized by that.

A decompression device for an axial compressor according to a third aspect of the present invention for solving the above problem is as follows.
In the decompression device for an axial compressor according to the second aspect of the invention,
The pressure control mechanism includes:
A chamber that is divided into a first space and a second space by a film that is destroyed by the predetermined pressure, and the second space has an opening, and is in an open air state;
And a conduit that communicates the support shaft side outlet of the internal passage with the first space.

A decompression device for an axial compressor according to a fourth aspect of the invention for solving the above-described problem is
In the decompression device for an axial compressor according to the second aspect of the invention,
The pressure control mechanism includes:
A chamber that can be switched between an open state and an airtight state by opening and closing a valve;
A control unit that performs control to open the valve if the gas flow path is equal to or higher than the predetermined pressure, and to close the valve if the gas flow path is lower than the predetermined pressure;
And a conduit communicating with the support shaft side outlet of the internal passage and the chamber.

A decompression device for an axial-flow compressor according to a fifth aspect of the present invention that solves the above problem is as follows.
In the decompression device for an axial compressor according to the second aspect of the invention,
The predetermined pressure includes a first predetermined pressure and a second predetermined pressure that is higher than the first predetermined pressure.
The pressure control mechanism includes:
The film is broken into a first space and a second space by the film destroyed by the second predetermined pressure, and the first space can be switched between an open state and an airtight state by opening and closing a valve. The space has a chamber that is open to the atmosphere by having an opening, and
A control unit that performs control to open the valve if the gas flow path is equal to or higher than the first predetermined pressure, and to close the valve if the gas flow path is less than the first predetermined pressure;
And a conduit that communicates the support shaft side outlet of the internal passage with the first space.

  According to the decompression device for an axial compressor according to the first aspect of the present invention, it is possible to prevent the occurrence of surge while suppressing the influence on the normal operation of the axial compressor.

  According to the decompression device for an axial compressor according to the second aspect of the present invention, it is possible to prevent the occurrence of surge while further suppressing the influence on the normal operation of the axial compressor.

  According to the pressure reducing device for an axial compressor according to the third aspect of the present invention, the membrane is destroyed when the pressure exceeds a predetermined pressure, so that the atmosphere is released and surge can be prevented.

  According to the decompression device for an axial compressor according to the fourth aspect of the present invention, when the pressure becomes equal to or higher than a predetermined pressure, the valve is opened, so that the atmosphere is opened, and the occurrence of surge can be prevented.

  According to the pressure reducing device for an axial flow compressor according to the fifth aspect of the present invention, when the pressure exceeds the first predetermined pressure, the valve is opened to reduce the pressure, and when the pressure rapidly rises to the second predetermined pressure, the membrane is broken. By making it open to the atmosphere, surge can be prevented.

It is the schematic about the variable stator blade in Example 1 of this invention. It is a schematic enlarged view of the vicinity of the buttocks in Embodiment 1 of the present invention. It is the schematic about the decompression apparatus of the axial flow compressor which concerns on Example 1 of this invention. It is the schematic about the decompression apparatus of the axial flow compressor which concerns on Example 2 of this invention. It is the schematic about the decompression apparatus of the axial flow compressor which concerns on Example 3 of this invention. It is the schematic of the rotating shaft vicinity of the axial flow compressor which has a variable stationary blade.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a decompression device for an axial flow compressor according to the present invention will be described with reference to the drawings in an embodiment.

  A decompression device for an axial compressor according to Embodiment 1 of the present invention will be described with reference to the schematic diagram of FIG. As shown in FIG. 3, the present apparatus includes a variable stationary blade 11, a rotation support shaft 12, an internal passage 16, a pressure conduit 20, and a diaphragm valve 21.

  As shown in the schematic diagram of FIG. 1, the above-described variable stationary blade 11 includes a flange portion 13, a blade surface 14, and a hole 15, and is controlled to rotate with respect to the casing 41 by a rotation support shaft 12 that penetrates the casing 41. Supported as possible.

  The above-described blade surface 14 is located in the gas flow path 17, and a part of the above-described collar part 13 is also in contact with the gas flow path 17.

  Although FIG. 1 shows a state in which the hole 15 is provided in the blade surface 14, when the hole 15 is provided in the blade surface 14, it is preferable to provide the hole 15 on the ventral side instead of the back side. More preferred.

  Furthermore, the position of the hole 15 is not limited to the blade surface 14, and may be a surface of the variable stationary blade 11 that is in contact with the gas flow path 17 inside the casing 41. For example, as shown in the enlarged view of the vicinity of the flange 13 shown in FIG. Thus, by providing the hole 15 in a portion other than the blade surface 14, it is possible to minimize the influence on the gas flow during the normal operation.

  However, even if the hole 15 is provided in the blade surface 14, the influence on the gas flow is slight due to the turbulence of the air around the hole 15, so that the performance deterioration of the entire axial flow compressor is small. Become.

  As shown in FIGS. 1 and 2, the internal passage 16 has a hollow structure that penetrates the inside of the variable stationary blade 11 and the inside of the rotary support shaft 12 from the hole 15 of the variable stationary blade 11. From the hole 15 to the outside of the casing 41.

  In this apparatus, all or some of the variable stationary blades 11 provided in the axial compressor have the above-described structure.

  Since the surge is generated from the downstream side of the gas flow path 17, the holes 15 and the internal passages 16 may be centrally arranged in the OGV 11b.

  The above-described diaphragm valve 21 is divided into two spaces a and b by a diaphragm film 22 that is broken at a predetermined pressure, and the chamber b has an opening 23 to open the atmosphere. is there. Moreover, although the diaphragm film | membrane 22 is used as a film | membrane here, the material of a film | membrane is not limited in fact.

  The pressure conduit 20 described above communicates the outlet of the internal passage 16 on the side of the rotation support shaft 12 and the chamber a of the diaphragm valve 21. As a result, the same pressure as that of the gas flow path 17 is applied to the a chamber.

  The predetermined pressure is set to a pressure value immediately before the occurrence of a surge. In this way, the diaphragm valve 21 prevents the gas in the gas passage 17 from leaking out of the system (atmospheric pressure) during normal operation of the axial compressor, and the pressure in the gas passage 17 is a predetermined pressure just before the occurrence of the surge. Then, the diaphragm film 22 is destroyed, and the air is released into the atmosphere as indicated by the white arrow in FIG.

  Therefore, in this apparatus, the gas in the gas flow path 17 in the axial flow compressor passes through the pressure conduits 20 communicating with the internal passages 16 of the plurality of variable stationary blades 11 and is concentrated in the a chamber of the diaphragm valve 21. When the chamber a becomes equal to or higher than the predetermined pressure due to the high pressure gas generated immediately before the occurrence of the surge, the diaphragm film 22 is destroyed so that the high pressure gas passes through the chamber b side and is released to the outside of the system. The flow path 17 is decompressed.

  In the axial flow compressor using this apparatus, the special processing is performed only inside the variable stationary blade 11 and the rotary support shaft 12, and the assembly of other parts is the same as before, so the manufacturing process is not complicated. In addition, there is an advantage that only a part of the design drawing is added, and a special additional operation is not necessary even in changing the angle of the variable stationary blade 11 during normal operation.

  The reason for using the variable stator blade 11 among the stator blades in this apparatus is that the rotary support shaft 12 that supports the variable stator blade 11 penetrates the casing 41, unlike the support shaft of the fixed stator blade. Therefore, the internal passage 16 that guides the gas in the gas flow path 17 from the hole 15 to the outside of the casing 41 can be easily processed, and the fact that the blade angle changing operation is possible is not an essential component.

  As mentioned above, although the decompression apparatus of the axial flow compressor which concerns on Example 1 of this invention was demonstrated, in the said patent document 2, the valve is provided in the inlet of a compressor, for example, and the gas flow rate which enters a compressor is reduced. On the other hand, this device is, in other words, a pressure reducing device for an axial flow compressor having a stationary blade (variable stationary blade 11) supported by a support shaft (rotating support shaft 12) that penetrates the casing 41 of the axial flow compressor. And a hole 15 located on a surface of the stationary blade that is in contact with the gas flow path 17 inside the casing 41, and a hollow structure that penetrates the inside of the stationary blade and the support shaft from the hole 15. And an internal passage 16 that guides the air from the hole 15 to the outside of the casing 41.

  Thereby, the occurrence of surge can be prevented while suppressing the influence on the normal operation of the axial compressor.

  Further, the present apparatus has a pressure at the outlet of the support shaft side of the internal passage 16 where the pressure of the gas flow path 17 is open to the atmosphere when the pressure is not less than a predetermined pressure set in a range where no surge occurs and becomes airtight when the pressure is less than the predetermined pressure. A control mechanism is provided.

  Thereby, it is possible to prevent the occurrence of surge while further suppressing the influence on the normal operation of the axial compressor.

  The pressure control mechanism is divided into a first space (a chamber) and a second space (b chamber) by a film (diaphragm film 22) that is broken at a predetermined pressure, and the second space has an opening 23. And a chamber (diaphragm valve 21) that is open to the atmosphere, and a conduit (pressure conduit 20) that communicates the support shaft side outlet of the internal passage 16 and the first space.

  Thereby, when the pressure exceeds a predetermined pressure, the film is destroyed, so that the atmosphere is opened and surge can be prevented.

  The decompression device for an axial compressor according to the second embodiment of the present invention is obtained by changing the pressure control mechanism in the decompression device for an axial compressor according to the first embodiment.

  A decompression device for an axial compressor according to Embodiment 2 of the present invention will be described with reference to FIG. As shown in FIG. 4, the apparatus includes a variable stationary blade 11, a rotation support shaft 12, an internal passage 16, a pressure conduit 20, a chamber 31, a motor drive valve 32, a pressure sensor 33, and a control unit 34. Since the variable stationary blade 11, the rotation support shaft 12, the internal passage 16, and the pressure conduit 20 are the same as those in the pressure reducing device for an axial compressor according to the first embodiment, the description thereof is omitted.

  The chamber 31 is communicated with the rotary support shaft 12 side outlet of the internal passage 16 by each pressure conduit 20, and the gas in the gas flow path 17 guided from each pressure conduit 20 is collected.

  The motor-driven valve 32 described above is a valve that switches the chamber 31 to an open state or an airtight state by opening and closing being controlled by the control unit 34.

  The pressure sensor 33 described above is a sensor that detects the pressure in the gas flow path 17.

  The above-described control unit 34 controls the opening and closing of the motor drive valve 32 based on the pressure detected by the pressure sensor 33. For example, a PC or the like may be used as the control unit 34.

  That is, if the pressure of the gas flow path 17 detected by the pressure sensor 33 is less than a predetermined pressure (during normal operation), the control unit 34 closes the motor drive valve 32 to bring the chamber 31 into an airtight state. If the pressure is equal to or higher than the predetermined pressure, the motor drive valve 32 is opened to open the atmosphere as indicated by the white arrow in FIG. After decompression, the motor drive valve 32 is closed and normal operation is resumed. The predetermined pressure is set to a pressure value immediately before the occurrence of a surge. For opening / closing control of the motor driven valve 32, for example, a relay circuit using an electric signal may be used.

  Thus, the gas in the gas flow path 17 in the axial compressor passes through the pressure conduits 20 communicating with the internal passages 16 of the plurality of variable stationary blades 11 and is collected in the chamber 31 and simultaneously the pressure in the gas flow path 17. Is constantly monitored by the pressure sensor 33. When the chamber 31 reaches a predetermined pressure or higher due to the high-pressure gas generated immediately before the occurrence of the surge, the high-pressure gas is released out of the system by opening the motor drive valve 32, and the gas flow path 17 is decompressed. After decompression, the motor drive valve 32 is closed and normal operation is resumed.

  Further, since the surge is generated from the downstream side of the gas flow path 17, the pressure sensor 33 may be installed in the vicinity of the OGV 11b, and the detection value in the vicinity of the OGV 11b may be used for control.

  As described above, the decompression device for the axial flow compressor according to the second embodiment of the present invention has been described. In other words, this device has a pressure control mechanism different from that of the decompression device for the axial flow compressor according to the first embodiment. The pressure control mechanism of the apparatus opens and closes the chamber 31 that can be switched between an open state and an airtight state by opening and closing a valve (motor-driven valve 32) and the gas flow path 17 is a predetermined pressure or higher. If the flow path 17 is less than a predetermined pressure, the control part 34 which performs control which closes a valve, and the conduit | pipe (pressure conduit | pipe 20) which connects the support shaft (rotary support shaft 12) side exit of the internal channel 16 and the chamber 31 are communicated. It is to be prepared.

  Thus, when the pressure exceeds a predetermined pressure, the valve is opened to open the atmosphere, and surge can be prevented.

  The decompression device for an axial compressor according to the third embodiment of the present invention includes a pressure control mechanism in the decompression device for the axial compressor according to the first embodiment and a compression control mechanism in the decompression device for the axial compressor according to the second embodiment. The first predetermined pressure and the second predetermined pressure that is higher than the first predetermined pressure are set as the predetermined pressure. The second predetermined pressure is the pressure immediately before the occurrence of the surge.

  A decompression device for an axial compressor according to a third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 5, the apparatus includes a variable stationary blade 11, a rotation support shaft 12, an internal passage 16, a pressure conduit 20, a diaphragm valve 21, a motor drive valve 32, a pressure sensor 33, and a control unit 34. Since the variable stationary blade 11, the rotation support shaft 12, the internal passage 16, the pressure conduit 20, and the pressure sensor 33 are the same as those of the decompression device of the axial flow compressor according to the first and second embodiments, the description thereof is omitted.

  The above-described diaphragm valve 21 is divided into two spaces a and b by a diaphragm film 22 that is broken at a second predetermined pressure, and the chamber b is open to the atmosphere by having an opening 23. Chamber.

  A motor drive valve 32 is provided in the a chamber of the diaphragm valve 21 described above, and can be switched between an open state and an airtight state by opening and closing the motor drive valve 32.

  If the pressure of the gas flow path 17 detected by the pressure sensor 33 is less than the first predetermined pressure, the control unit 34 closes the motor drive valve 32 to bring the chamber a of the diaphragm valve 21 into an airtight state. Gas leakage in the passage 17 is prevented, and if the pressure is equal to or higher than the first predetermined pressure, the motor drive valve 32 is opened to open the atmosphere, and the gas passage 17 is decompressed. After decompression, the motor drive valve 32 is closed and normal operation is resumed.

  In this manner, during normal operation of the axial compressor, the motor drive valve 32 is closed to be in an airtight state, and when the pressure exceeds the first predetermined pressure, the motor drive valve 32 is opened to reduce the pressure, and the second immediately before the occurrence of the surge. When the pressure suddenly rises to a predetermined pressure, the diaphragm film 22 is broken so as to release the atmosphere, and the gas flow path 17 is decompressed.

  As described above, the decompression device for the axial flow compressor according to the third embodiment of the present invention has been described. In other words, this device has a different pressure control mechanism from the decompression device for the axial flow compressor according to the first and second embodiments. In the present apparatus, first, the predetermined pressure includes a first predetermined pressure and a second predetermined pressure that is higher than the first predetermined pressure, and the pressure control mechanism detects a film (diaphragm) that is destroyed at the second predetermined pressure. The membrane 22) is divided into a first space (a chamber) and a second space (b chamber), and the first space can be switched between an open state and an airtight state by opening and closing a valve (motor-driven valve 32). The second space has an opening 23 to open the atmosphere (diaphragm valve 21), and if the gas flow path 17 is equal to or higher than the first predetermined pressure, the valve is opened and the gas flow path 17 Control to close the valve if the pressure is less than the first predetermined pressure 34, in which and a conduit (pressure line 20) which communicates the support shaft (rotation shaft 12) side outlet and the first space of the internal passage 16.

  As a result, when the pressure exceeds the first predetermined pressure, the valve is opened to reduce the pressure, and when the pressure rapidly rises to the second predetermined pressure, the film is destroyed, so that the air is released and surge can be prevented. .

  The decompression device for an axial flow compressor according to Embodiments 1 to 3 of the present invention is applicable to an axial flow compressor. However, the axial compressor here includes a multistage axial compressor and a blower.

  The present invention is suitable as a pressure reducing device for an axial compressor.

10 Moving blade 11 Variable stator blade 11a IGV
11b OGV
12 Rotating Support Shaft 13 (Variable Stator Blade) 13 Ridge 14 Blade Surface 15 Hole 16 Internal Passage 17 Gas Flow Path 20 Pressure Conduit 21 Diaphragm Valve 22 Diaphragm Film 23 Opening 31 Chamber 32 Motor Drive Valve 33 Pressure Sensor 34 Control Unit 41 Casing 42 Rotating shaft (for axial compressor)

Claims (5)

A pressure reducing device for an axial flow compressor having a stationary blade supported by a support shaft passing through a casing of the axial flow compressor,
A hole located on a surface of the stationary blade in contact with the gas flow path inside the casing;
A pressure reducing device for an axial flow compressor, comprising: an internal passage that penetrates the inside of the stationary blade and the inside of the support shaft from the hole and guides the gas in the gas passage from the hole to the outside of the casing.   Provided at the support shaft side outlet of the internal passage is a pressure control mechanism in which the pressure of the gas flow path is opened to the atmosphere above a predetermined pressure set in a range where no surge occurs and becomes airtight below the predetermined pressure. The decompression device for an axial compressor according to claim 1. The pressure control mechanism includes:
A chamber that is divided into a first space and a second space by a film that is destroyed by the predetermined pressure, and the second space has an opening, and is in an open air state;
The decompression device for an axial-flow compressor according to claim 2, further comprising a conduit that communicates the support shaft side outlet of the internal passage with the first space. The pressure control mechanism includes:
A chamber that can be switched between an open state and an airtight state by opening and closing a valve;
A control unit that performs control to open the valve if the gas flow path is equal to or higher than the predetermined pressure, and to close the valve if the gas flow path is lower than the predetermined pressure;
The decompression device for an axial-flow compressor according to claim 2, further comprising a conduit that communicates the support shaft side outlet of the internal passage and the chamber. The predetermined pressure includes a first predetermined pressure and a second predetermined pressure that is higher than the first predetermined pressure.
The pressure control mechanism includes:
The film is broken into a first space and a second space by the film destroyed by the second predetermined pressure, and the first space can be switched between an open state and an airtight state by opening and closing a valve. The space has a chamber that is open to the atmosphere by having an opening, and
A control unit that performs control to open the valve if the gas flow path is equal to or higher than the first predetermined pressure, and to close the valve if the gas flow path is less than the first predetermined pressure;
The decompression device for an axial-flow compressor according to claim 2, further comprising a conduit that communicates the support shaft side outlet of the internal passage with the first space.

Images