JPH0544557Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a multi-stage axial flow compressor for gas turbines or industrial use.

(Prior Art) An example of a conventional multistage axial flow compressor is shown in FIG. 3, in which 1 is a rotor, 2 is a rotor blade, 3 is a stationary blade, and 4 is a casing. The rotor blades 2 are installed on the rotor 1 and rotate as one. The stationary blade 3 is installed in the casing 4. A multistage compressor is constructed by arranging a large number of stages each consisting of a pair of rotor blades 2 and a stator blade 3. Reference numeral 5 designates an air bleed hole formed in the casing 4 to bleed or discharge the air flow within the casing 4 from between the intermediate stages, and 6 represents an air bleed chamber formed outside the air bleed hole 5.

However, when this type of multi-stage axial flow compressor is operated at a low rotation speed such as when starting up, as shown in FIG. 4, rotational stall may occur, which may impair the safety of the multi-stage axial flow compressor. Therefore, during low rotational speed operation where mismatch between the front stage and the rear stage occurs, the airflow inside the casing 4 is extracted or discharged from the bleed hole 5 into the bleed chamber 6 to control rotational stall. Note that in a multistage axial flow compressor for a gas turbine, air is extracted or blown out not only at the time of startup but also for air cooling of the blades of the gas turbine.

(Problems to be Solved by the Invention) In the conventional multistage axial flow compressor described above, the bleed hole 5 is constituted by an annular slit that penetrates the casing 4 in the radial direction and extends along the circumferential direction. The airflow inside 4 is swirling while flowing through the bleed hole 5.
Even after passing through and entering the bleed chamber 6, the rotational momentum is still conserved, and the rotational speed becomes a large value of about half the circumferential speed of the rotor blade 2.

Therefore, it is necessary to match the mounting position and installation direction of the duct for collecting this bleed air and sending it to a required location with the swirling direction of the bleed air in the bleed air chamber 6.
If they did not match, there was a problem that the pressure loss would increase in the opening area of the duct, making it impossible to bleed the required amount of air.

(Means for Solving the Problems) The present invention was proposed to solve the above problems, and its gist consists of a casing and a rotor rotatably disposed inside the casing. , a large number of rows of rotor blades are installed at intervals in the axial direction on the outer peripheral surface of the rotor, and rows of rotor blades are installed at intervals in the axial direction on the inner surface of the casing so as to be located on the wake side of each row of rotor blades. A large number of stator blade rows planted in
A slit is formed in the casing and extends radially through the casing so as to be located on the outer circumferential side between the stages in the intermediate body of a large number of stages constituted by the rotor blade row and the stator blade row. It includes an annular bleed hole, an annular bleed chamber formed outside the casing so as to surround the bleed hole, and a duct connected to the bleed chamber to direct swirling airflow between the stages to the bleed hole and the duct. In a multi-stage axial flow compressor that bleeds air through a bleed chamber and a duct, the inner radial leading edge is oriented in the opposite direction to the moving direction of the rotor blade inside or on the downstream side of the bleed hole, and the outer radial trailing edge is approximately A multi-stage axial flow compressor is provided with a turning vane array which is made up of a large number of vanes oriented in a radial direction and gradually turns the swirling airflow extracted through the bleed holes in a radial direction.

(Function) In the present invention, the airflow extracted through the bleed hole is deflected in the radial direction by the deflection vane row disposed inside the bleed hole or immediately after the bleed hole. I am forced to do it.

(Embodiment) An embodiment of the present invention is shown in FIGS. 1 and 2. 1 is a rotor, 2 is a rotor blade installed in the rotor 1, 3 is a stationary blade installed in a casing 4, and 5 is a perforation in the casing 4, which directs the swirling airflow inside the casing 4 between intermediate stages. An air bleed hole 6 is an air bleed chamber for extracting or discharging air from the air, and the above is the same as the conventional one shown in FIG.

Reference numeral 7 denotes a vane arranged inside the bleed hole 5, whose inner diameter side leading edge 7a is oriented in the direction opposite to the traveling direction of the rotor blade 3 shown by the solid line arrow in FIG. 2, and its outer diameter side trailing edge 7b
is oriented approximately in the radial direction. Therefore, the airflow bleed through the bleed hole 5 is smoothly scooped out by the inner diameter side leading edge 7a of each vane 7 and flows along the vane 7, as shown by the broken line arrow in FIG. In the process of flowing, the air is turned in the radial direction and decelerated, and then flows into the bleed chamber 6. And bleed chamber 6
From there, it is sent to the required location by a duct (not shown) connected to this. In the above embodiment, the row of vanes 7 is arranged inside the bleed hole 5, but it may be arranged immediately after the bleed hole 5.

(Effect of the invention) In the present invention, a large number of radially inner leading edges are oriented in the opposite direction to the moving direction of the rotor blades, and outer radially trailing edges are oriented substantially in the radial direction, inside or on the downstream side of the bleed hole. Since a turning vane row is provided that gradually turns the swirling airflow extracted through the bleed hole in the radial direction, the swirling airflow extracted through the bleed hole passes through this turning vane row. It is gradually turned in the radial direction. As a result, no swirl remains in the bleed chamber, which increases the degree of freedom in the position and direction of the duct connection port, making handling easier.

In addition, the casing of this type of multi-stage axial flow compressor is usually divided into two along a plane that includes the axis, and there is a flange inside the bleed chamber to connect these divided casings together. By preventing swirling in the chamber, it is possible to prevent uneven pressure distribution inside the bleed chamber, and therefore, based on this uneven pressure distribution, the flow may become uneven in the circumferential direction within the main flow path. You can prevent it from getting messy.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention,
Figure 1 is a partial sectional view, Figure 2 is a - of Figure 1.
FIG. 3 is a partial cross-sectional view taken along a line. FIG. 3 is a partial sectional view of a conventional multi-stage axial compressor, and FIG. 4 is a characteristic diagram of the multi-stage axial compressor. Rotor...1, moving blade...2, stationary blade...3, casing...4, bleed hole...5, vane...7.

Claims (1)

[Scope of utility model registration request] A casing, a rotor rotatably arranged inside the casing, a number of rows of rotor blades installed on the outer peripheral surface of the rotor at intervals in the axial direction, and a row of rotor blades located on the wake side of each row of rotor blades. A stage in an intermediate stage of a large number of stages constituted by a large number of rows of stator blades installed at intervals in the axial direction on the inner surface of the casing, and a row of rotor blades and a row of stator blades. an annular bleed hole consisting of a slit bored in the casing and extending radially through the casing, and an annular bleed chamber formed outside the casing to surround the bleed hole; and a duct connected to the bleed chamber, and bleeds the swirling airflow between the stages through the bleed hole, the bleed chamber, and the duct. It consists of a large number of vanes whose inner radial leading edge is oriented in the opposite direction to the moving direction of the rotor blades, and whose outer radial trailing edge is oriented almost in the radial direction. A multi-stage axial flow compressor characterized by having a row of turning vanes that turn the air in a radial direction.