JPH03260336A - Bleed device of centrifugal compressor - Google Patents

Abstract

PURPOSE:To recover the pressure of bleed and purify the bleed by providing a bleed cavity having an annular flow path, a slit for ejecting sand and dust and a divergent pipe having a divergent portion respectively contiguously to an annular bleed slit disposed in a shroud. CONSTITUTION:A centrifugal compressor is bled of air through an annular bleed slit 5 disposed between both front and rear shrouds 2, 3. A bleed cavity 6 having an annular flow path surrounding the outer periphery of the front shroud 2 is additionally provided adjacent to the bleed slit 5 while extending contiguously around the whole periphery thereof. An annular slit 7 for ejecting sand and dust is disposed contiguously to the outer periphery of the bleed cavity 6 between both front and rear shrouds 2, 3. A pair of divergent pipes 8 having their one-side ends opened to the central portion of a flow path in the bleed cavity 6 and the other-side ends led to the outside are disposed, so that only clean air having sufficiently recovered pressure is led to the outside.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a hydraulic system installed in a series compressor of a gas turbine engine for extracting air for pre-pressurizing an aircraft cabin. It is something.

[Conventional technology]

FIG. 4 is a partial cross-sectional view of a far-I compressor having a conventional air bleed device. In the figure, 0IFi compressor I/Bella, 0
2 is /Niraud, 03Vi is a 1-shaped bleed air slinn installed on Niraud), 04 is ff1 connected to the same slint.
The bleed cavity provided with K, 05#'i, bleed air take-off pipe, and the arrow indicate the flow of bleed air.

Conventionally, as shown in the figure, 817J was attached to the shroud and the differential user was replaced with a slint. Il construction in which air was extracted without using it was common.

[Problem H that the invention attempts to solve]

Conventional air extraction equipment does not use a diffuser, so
The velocity energy of the fluid cannot be recovered into pressure,
There were 1,200 disadvantages that were lost as the temperature of the bleed air increased. In order to compensate for this drawback, a method of installing a P7-type differential user has been considered, but since the flow rate of bleed air is generally not constant, separation occurs in the differential user, so it cannot be said to be effective. In addition, in the case of the bleed air structure shown in Figure 4, dust, etc. mixed in the intake air gathers on the outer wall due to centrifugal force and mixes with the bleed air, so it satisfies the cleanliness of the bleed air required for aircraft cabin preloading etc. I couldn't do it.

The present invention aims to provide an air bleed device that can sufficiently restore the velocity energy of the bleed air led from the shroud to pressure and that can separate and clean dust from the bleed air.

[Means to solve the problem]

The present invention has solved the above problem, and provides an air extraction device for a centrifugal compressor that extracts air from an annular slit provided in a shroud. a dust discharge slit provided on the outer periphery of the air bleed cavity, and a part that opens at one end facing the flow and continues to the opening at approximately the center of the cross section of the flow path of the air bleed cavity. The present invention relates to an air extraction device for a centrifugal pressure machine, characterized in that it is equipped with a divergent pipe whose other end is led to the outside.

[Effect]

In the apparatus having the above configuration, the air flowing into the bleed cavity from the bleed slit circulates around the annular flow path within the cavity. At this time, the solid matter of the sand (Ml) is pushed to the outside by the far lG force and is discharged to the outside from the dust discharge slit along with a small amount of air. The air circulating in the bleed cavity from which dust has been removed flows into the divergent pipe through its opening, and after its pressure is sufficiently restored at the divergent part, it is guided outside and used for cabin prepressurization, etc.

〔Example〕

FIG. 1 is a cross-sectional view of an aircraft turboshaft engine having a single-stage centrifugal compressor to which an embodiment of the present invention is applied, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG. It is an enlarged view of part B in the figure. In the figure, l is a compressor impeller, 2 is a front shroud, 3 is a rear shroud, 4 is a compressor diffuser, 5 is an annular bleed air slit provided between the front shroud 2 and the rear shroud 3, and 6 is a An air bleed cavity adjacent to the slit, connected to the slit over its entire circumference, and having an annular flow path surrounding the outer periphery of the front shroud 2; An annular dust discharge slit 8 provided so as to be connected to the annular bleed air cavity 6 has one end opening facing the flow of bleed air in the center of the flow path of the annular bleed air cavity 6, and has a widening part continuing to the opening. They are a pair of divergent pipes with the other end led to the outside. This is a successful diff user that recovers pressure at the widening end of the pipe. Arrow XFi is the direction of rotation of the compressor impeller, arrow yh is the direction of air flow in the bleed cavity.

In the device having the above configuration, the air flowing into the bleed cavity 6 from the bleed slit 5 circulates in the annular flow path within the cavity in the same direction as the rotation direction of the impeller. At this time, solid matter such as dust is pushed toward the outer periphery by centrifugal force and is discharged to the outside together with a small amount of air from the dust discharge slit.

One end of the divergent pipe 8 is connected to the bleed cavity 6
Since the central part of the annular flow path of the pipe is opened opposite to the air flow, the air flows in through the opening of the pipe, and after the pressure is sufficiently recovered by the divergent part of the divergent pipe, the air flows to the outside. It is used for cabin preloading, etc. The air introduced in this way has a temperature of about 3 atmospheres and 100°C, which is suitable for cabin prepressure. It is also clean because dust has been removed.

〔Effect of the invention〕

In the air bleed device for a centrifugal compressor of the present invention, there is provided an air bleed cavity having an annular flow passage extending over the entire circumference of the annular slit provided in the shroud and surrounding the outer periphery of the shroud; a dust discharge slit, and a divergent pipe having one end opening facing the flow at approximately the center of the flow path cross section of the air bleed cavity, a divergent pipe having a widening end continuing to the opening, and the other end leading to the outside. This allows clean air with sufficient pressure recovery to be guided to the outside.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a sectional view taken along line A-A of the first cause, Fig. 3 is an enlarged view of part B in Fig. 1, and Fig. 4 is a conventional bleed device. 1 is a partial cross-sectional view of a centrifugal compressor having a 1... Compressor impeller, 2... Front shroud, 3
... Rear shroud, 4 ... Compressor differential user 5
...Bleed air slit, 6...Bleed cavity, 7...
・Dust discharge slit, 8...Divergent pipe, 01...Compressor impeller, 02...Shroud 0
3...Bleed air slit, 04...Bleed air cavity, 0
5... Bleed air extraction pipe.

Claims (1)

[Claims] In an air bleed device for a centrifugal compressor that bleeds air from an annular slit provided in a shroud, an air bleed cavity has an annular flow path that extends around the entire circumference of the slit and surrounds the outer periphery of the shroud, and an outer periphery of the air bleed cavity. a dust discharge slit provided in the air bleed cavity, and a diver having one end opening facing the flow and a widening part continuing to the opening at approximately the center of the flow path cross section of the air bleed cavity, and the other end leading to the outside. A centrifugal compressor extraction device characterized by being equipped with a gent pipe.