CN213628157U - Circumferential groove type casing processing structure for axial flow compressor - Google Patents

Abstract

The utility model discloses a structure is handled to circumference groove class machine casket for axial compressor, this structure include by the circular arc of two sections smooth transitions

And

forming the cross-sectional shape of the circumferential groove, downstream roundingThe blade tip flow smoothly enters the treatment tank from the downstream, and the flow loss is low. The utility model discloses based on compressor back stage rotor apex leading edge position and apex clearance size, adopt the circumference slot type machine casket of efflux strenghthened type to handle, utilize the biarc molding to make the slick and sly transition of circumference groove profile molding to make the fluid flow in more smoothly, flow out the treatment trough, promote and expand steady ability, reduce the loss that flows.

Description

Circumferential groove type casing processing structure for axial flow compressor

Technical Field

The utility model belongs to impeller machinery, concretely relates to circumference groove class machine casket that is used for axial compressor handles structure.

Background

The flow process in the gap region of the gas turbine compressor is very complex, and the loss caused by the gap flow accounts for a large proportion of the total energy loss of the movable blades and the compressor stage. The performance of the compressor has higher sensitivity to the blade tip clearance, and the increase of the clearance in the operation process generally causes the decline of the performance of the compressor. During actual service, a temporary or permanent increase in tip clearance may occur, thereby affecting the economics and stability of gas turbine operation.

The end wall processing technology is a gas compressor clearance flow control method which is researched and successfully applied earlier, can effectively widen the stability margin of the gas compressor, and is widely applied to various practical engine models, such as American JT-9D engines, CFM-56 engines, Russian L-H-31 phi engines, national WP-14 and other aviation gas turbine engines. The basic circumferential groove and axial seam end wall processing schematic diagrams are shown in fig. 1 and 2.

Generally, the adverse effect of the circumferential groove type casing treatment on the efficiency of the compressor is smaller than that of the axial seam type casing treatment, but the stability expansion capability is weak, which is caused by the fact that the inner space of the circumferential groove is small and a jet with stronger energy cannot be formed. If the design characteristics of the axial seam type casing treatment are used for reference, the jet flow strength of the circumferential groove of the gas compressor is enhanced, and the effect of stability expanding capability can be enhanced under the condition of keeping efficiency loss as small as possible.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a structure is handled to circumference groove class machine casket for axial compressor, it adopts the circumference slot type machine casket of efflux strenghthened type to handle based on compressor back stage rotor apex leading edge position and apex clearance size, utilizes the biarc molding to make circumference groove section molding rounding off to make the fluid flow in more smoothly, flow out the treatment trough, promote and expand steady ability, reduce the loss that flows.

The utility model discloses a following technical scheme realizes:

a circumferential groove type casing processing structure for an axial flow compressor comprises two sections of arcs in smooth transition

And

the section shape of the circumferential groove is formed, and the downstream arc modeling enables the blade tip flow to smoothly enter the treatment groove from the downstream, so that the flow loss is low.

The utility model is further improved in that in the meridian plane view of the rotor basin, the front edge point in the range of 90% -98% of the blade height is used as the center of a circle O₁As a radius r₁Arc of (2)

The left end point of the arc is marked as A, and the intersection point of the right side and the casing is marked as B.

The utility model is further improved in that the arc

The included angle between the casing wall surface and the casing wall surface is alpha₁，α₁The value range of (1) is 30-60 degrees, and the radius r of the arc₁The value range is as follows: r is more than or equal to (tau + h)/cos30 DEG₁Not more than (tau + h)/cos60 degrees, wherein tau is the size of the rotor blade tip clearance, and h is the center O of the circle₁Distance from the tip of the blade.

The further improvement of the utility model lies in that the arc

Left end point A and circle center O₁The connecting line of the D-shaped connecting rod and the wall surface of the casing intersect at a point D, the included angle between AD and the radial direction is theta, and the value range of theta is 0-30 degrees.

The further improvement of the utility model lies in that the arc

Using the midpoint of connecting line AD as center O₂And taking AD as the diameter, and making an arc to intersect with the wall surface of the casing at a point C.

The further improvement of the utility model lies in that the arc

Radius r₂＝(r₁-DO₁)/2＝[r₁-(τ+h)/cos(θ+γ)]And/2, wherein gamma is the included angle between the wall surface of the casing and the axial direction.

The further improvement of the utility model lies in that the arc

C point's tangent line and the casing wall angle alpha₂＝θ+γ。

The further improvement of the utility model lies in that the arc

And

the sectional shape of the circumferential groove is formed, and the sectional shape forms the same groove in the circumferential direction, namely, the jet flow reinforced circumferential groove type casing processing structure is formed.

Compared with the prior art, the utility model discloses following profitable technological effect has at least:

the utility model provides a pair of a circumference groove class casket processing structure for axial compressor, this simple structure, the structure of easily utilizing compressor geometric characteristics to carry out circumference groove section. Two sections of smoothly connected arcs form two acute angles with the wall surface of the casing, so that airflow of the blade tip enters the groove from the rear part of the processing groove more easily, and returns to the blade tip in the direction pointing to the downstream direction at the front part of the processing groove, the purposes of reducing circulation loss in the groove and enhancing upstream jet flow are achieved, and the stability margin of the compressor is widened on the premise of having little influence on the efficiency.

Drawings

Fig. 1 is a schematic diagram of a conventional circumferential groove type casing processing structure, in which fig. 1(a) is a front view and fig. 1(b) is a sectional view.

Fig. 2 is a schematic diagram of a conventional axial slot casing processing structure, wherein fig. 2(a) is a front view, and fig. 2(b) is a sectional view.

Fig. 3 is a schematic view of the meridian plane structure of the present invention.

Fig. 4 is a schematic top view of the present invention.

FIG. 5 is a jet enhanced circumferential slot casing process for a certain compressor rotor design.

Detailed Description

The specific embodiment of the present invention will be described by taking the first-stage rotor of the high-pressure compressor of a certain gas turbine as an example.

Some of the design parameters of the compressor rotor are shown in table 1.

Table 1 design parameters of the first stage rotor part of the high pressure compressor of a gas turbine.

As shown in fig. 3 to 5, the utility model provides a circumferential groove type casing processing structure for axial compressor, its design method includes:

1) in the meridian plane view of the rotor basin, the leading edge point with the blade height of 95 percent is taken as the center O₁If H is 5% H is 6.75 mm;

2) selecting alpha₁The value is 45 DEG, then r₁＝(τ+h)/cosα₁10.54mm in terms of O₁As a circle centerRadius r₁The arc of (a) intersects the casing wall at point B;

3) if theta is selected to be 15 deg., the position of the end point A on the left side of the circular arc is determined. End point A and circle center O₁The connecting line of (D) is crossed with the connecting line of (D);

4) using AD midpoint as circle center O₂And taking AD as the diameter, and making an arc to intersect with the wall surface of the casing at a point C. Circular arc

Radius r of₂Comprises the following steps:

r₂＝(r₁-DO₁)/2＝[r₁-(τ+h)/cos(θ+γ)]/2＝1.2mm

5) according to the arc determined in step 4)

The included angle between the tangent line at the point C and the wall surface of the casing is:

α₂＝θ+γ＝23.6°

6) two smoothly connected arcs determined according to the design steps

And

the sectional shape of the circumferential groove is formed, and the sectional shape forms the same groove in the circumferential direction, namely, the jet flow reinforced circumferential groove casing treatment is formed.

According to the jet flow reinforced circumferential groove type casing treatment with the structure, two sections of arcs which are smoothly connected are utilized, so that the blade tip fluid can smoothly flow into the treatment groove from the rear part of the treatment groove and can be injected into the upstream of the front edge from the front part of the treatment groove, and the purposes of reducing flow loss and improving margin widening capacity are achieved.

Claims (8)

1. A circumferential groove type casing processing structure for an axial flow compressor is characterized by comprising two sections of arcs in smooth transition

And

the section shape of the circumferential groove is formed, and the downstream arc modeling enables the blade tip flow to smoothly enter the treatment groove from the downstream, so that the flow loss is low.

2. The circumferential groove type casing processing structure for the axial flow compressor as claimed in claim 1, wherein in a meridian plane view of a rotor basin, a front edge point in a range of 90% -98% of a blade height is taken as a center O₁As a radius r₁Arc of (2)

The left end point of the arc is marked as A, and the intersection point of the right side and the casing is marked as B.

3. The structure for treating a casing of a circumferential groove type for an axial compressor according to claim 2, wherein the arc is circular

The included angle between the casing wall surface and the casing wall surface is alpha₁，α₁The value range of (1) is 30-60 degrees, and the radius r of the arc₁The value range is as follows: r is more than or equal to (tau + h)/cos30 DEG₁Not more than (tau + h)/cos60 degrees, wherein tau is the size of the rotor blade tip clearance, and h is the center O of the circle₁Distance from the tip of the blade.

4. The circumferential groove type casing processing structure for the axial flow compressor as claimed in claim 2, wherein the arc is circular

Left end point A and circle center O₁The connecting line of the D-shaped connecting rod and the wall surface of the casing intersect at a point D, the included angle between AD and the radial direction is theta, and the value range of theta is 0-30 degrees.

5. The circumferential groove type casing processing structure for the axial flow compressor as claimed in claim 2, wherein the arc is circular

Using the midpoint of connecting line AD as center O₂And taking AD as the diameter, and making an arc to intersect with the wall surface of the casing at a point C.

6. The circumferential groove type casing processing structure for the axial flow compressor as claimed in claim 5, wherein the arc is circular

Radius r₂＝(r₁-DO₁)/2＝[r₁-(τ+h)/cos(θ+γ)]And/2, wherein gamma is the included angle between the wall surface of the casing and the axial direction.

7. The circumferential groove type casing processing structure for the axial flow compressor as claimed in claim 5, wherein the arc is circular

C point's tangent line and the casing wall angle alpha₂＝θ+γ。

8. The circumferential groove type casing processing structure for the axial flow compressor as claimed in claim 7, wherein the arc is circular

And

the sectional shape of the circumferential groove is formed, and the sectional shape forms the same groove in the circumferential direction, namely, the jet flow reinforced circumferential groove type casing processing structure is formed.

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