CN104100305A - Large meridional expansion variable-geometry turbine with orthogonal adjustable stator blades - Google Patents

Abstract

The object of the present invention is to provide a large meridian expansion variable geometry turbine with orthogonal adjustable vanes, including a large meridian expansion end wall casing and a hub, and the adjustable static blades are evenly installed between the casing and the hub along the circumferential direction. For blades and moving blades, the adjustable static blades are in the front and the moving blades are behind. The upper and lower end surfaces of the adjustable static blades are respectively equipped with upper and lower rotating shafts. The shaft is embedded in the casing, the lower rotating shaft is embedded in the hub, the moving blades are installed on the hub, the adjustable stationary vanes are orthogonal blades arranged orthogonally to the end wall of the blade itself, and the hub contains the adjustable stationary vanes Matching concave-convex joint segments. The invention can not only reorganize the flow in the end area of the gap, thereby reducing the loss of the end area of the gap, but also make the height of the gap in the end area change slowly with the change of working conditions, thereby improving the characteristics of variable working conditions.

Description

A Large Meridian Expansion Variable Geometry Turbine with Orthogonal Adjustable Vanes

technical field

The invention relates to a turbine of a gas turbine.

Background technique

Gas turbines often operate at off-design conditions, where turbine efficiency is significantly reduced. Variable geometry turbine technology can effectively improve the efficiency of gas turbines in variable working conditions, and adjusting the installation angle of turbine vanes is an effective variable geometry method. In the adjustable vane structure of the prior art, in order to ensure that the turbine vane can rotate, there must be a gap between the upper and lower end walls of the vane, which causes the leakage loss of the vane and seriously affects the turbine efficiency; and for large meridian expansion variable geometry turbine , the large meridional expansion angle tends to decelerate the flow near the end wall, thicken the boundary layer, weaken the ability of the fluid to resist the lateral pressure gradient, and make it easier to form secondary flow, which will further increase the flow loss in the end zone of the variable geometry turbine. In addition, when the turbine vane rotates, the gap height in the end zone will change, especially in the large meridian expansion variable geometry turbine, the change speed of the gap height is more obvious, which further affects the working performance of the variable geometry turbine.

In order to reduce the adverse effects of blade tip clearance leakage, modern gas turbines mainly adopt active and passive clearance control. The passive clearance control method mainly adopts blade top and casing processing, such as grooved blade top, casing end wall shape, etc. Although this method can improve the performance of the turbine design point, it cannot effectively feedback the change of the clearance height. The active gap control method mainly heats or cools the surface of the casing or the blade by drawing out the airflow of the compressor to make it expand or contract accordingly, so as to perform feedback control on the change of the gap height, but this method has problems such as thermal inertia and complicated structural arrangement. . In order to solve the flow problems caused by the large meridian expansion channel, most of the existing research focuses on the optimization of the end wall profile of the meridian channel. So far, for the unfavorable problems of large meridian expansion variable geometry turbines, the existing technology has not considered combining the control of blade tip clearance leakage with the reorganization of the flow at the end area of large meridian expansion, let alone improving the large meridian expansion. Variable working condition characteristics of expansion variable geometry turbine.

Contents of the invention

The purpose of the present invention is to provide a large meridian expansion variable geometry turbine with orthogonal adjustable stator blades which can not only recombine the flow in the end zone of the gap, but also make the height of the gap in the end zone change slowly with the change of working conditions.

The purpose of the present invention is achieved like this:

The present invention is a large meridional expansion variable geometry turbine with orthogonal adjustable stationary blades, which is characterized in that it includes a casing, a rotor hub and a rotor blade, the rotor hub is located in the casing, and the rotor hub is equipped with a hub The rotating shaft, the moving blade and the moving blade are evenly arranged along the circumferential direction of the hub and fixed on the moving blade hub. The front of each moving blade is equipped with an adjustable stationary vane, which is installed on the hub of the stationary vane, and a bearing is arranged in the hub of the stationary vane, and the end of the rotating shaft of the hub is matched with the bearing, and the upper end surface of the adjustable stationary vane is set to rotate upwards. shaft, the lower end surface of the adjustable vane is provided with a lower rotating shaft, the outer side of each adjustable vane is connected to the casing through its upper rotating shaft, the vane hub is provided with a vane groove, and the lower rotating shaft is set on the vane In the groove, an adjusting rod for adjusting the angle of the adjustable vane is installed on the upper rotating shaft. The adjusting rod protrudes out of the casing, and the angle between the rotational axis of the adjustable vane and the rotating shaft of the hub is between 5° and 20°. .

The present invention may also include:

1. The axes of the upper and lower rotating shafts and the rotating axes of the adjustable vanes are located on the same straight line, and the shaft diameter of the upper rotating shaft is larger than that of the lower rotating shaft.

2. The shape between the upper end surface of the adjustable vane and the inner wall of the casing facing it is the same, and there is a rotation gap between the two, and the length of each part of the rotation gap is equal.

3. The profile line on the outside of the hub of the stator includes the connected straight section of the inlet and the concave-convex joint section, and the section line on the outside of the rotor hub includes the connected tapered section and the straight section of the outlet, where the concave-convex joint section corresponds to the lower The position of the end surface, the taper section corresponds to the position of the root of the moving blade, the shape between the lower end surface of the adjustable stationary blade and the concave-convex joint section is the same, and there is a rotation gap between the two, and the length of each part of the rotation gap is equal.

4. The angle between the extension line of the leading edge profile of the adjustable stationary vane and the tangent line of the casing intersection and the leading edge profile line of the adjustable stationary vane is 75°～105°, the extension line of the trailing edge profile of the adjustable stationary vane and the The angle between the tangent line of the box intersection and the trailing edge profile line of the adjustable stationary blade is 75°～105°; The angle is 75°～105°, and the angle between the extension line of the trailing edge profile line of the adjustable stationary vane and the intersection point of the hub of the stationary vane and the profile line of the adjustable stationary vane trailing edge is 75°～105°.

The advantages of the present invention are: the present invention by adopting orthogonal blades (similar to "swept forward blades" from a structural point of view), one is to reduce the reverse pressure gradient along the flow direction of the blade end region, although the reverse pressure gradient in the middle of the blade span has However, because the flow is in the mainstream area, the influence is not significant; second, a "C"-shaped pressure distribution with large ends and small middle is formed along the blade height, which can "suck" the boundary layer in the end area into the mainstream, reducing the The accumulation of low-energy fluid in the end area improves the flow performance of the end area; moreover, the axis of the rotating shaft of the adjustable orthogonal stator blade designed by the present invention is nearly orthogonal to the casing and the end wall profile of the hub, so that the large meridian expands When the variable geometry turbine vane rotates, the change speed of the end zone clearance height slows down, and the change of the end zone clearance height with the working conditions is similar to that of the conventional non-expansion variable geometry turbine, thus improving the variable working condition characteristics of the large meridian expansion variable geometry turbine ; In addition, the structure of the present invention is relatively simple, easy to engineering.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2a is a structural schematic diagram of the cooperation between the adjustable stationary blade and the casing of the present invention, and Fig. 2b is a structural schematic diagram of the cooperation between the adjustable stationary vane and the hub of the present invention;

Fig. 3 is a schematic diagram of the hub structure of the present invention.

Detailed ways

The present invention is described in more detail below in conjunction with accompanying drawing example:

1-3, the present invention is composed of hub 1, adjustable stationary vanes 4, moving vanes 5 and large meridian expansion end wall casing 10, and adjustable stationary vanes are uniformly installed along the circumferential direction between hub 1 and casing 10 4 and moving blade 5, the adjustable stationary blade 4 is in the front, and the moving blade 5 is in the rear. The upper end surface 8 and the lower end surface 3 of the adjustable stationary blade are respectively provided with an upper rotating shaft 9 and a lower rotating shaft 2, and their axes rotate at the same On the axis to facilitate the rotation of the adjustable vane, and the shaft diameter of the upper rotating shaft is larger than that of the lower rotating shaft, and the lower rotating shaft only plays a positioning role. The upper rotating shaft 9 is embedded in the casing 10 , the lower rotating shaft 2 is embedded in the hub 1 , and the moving blade 5 is installed on the hub 1 . Gaps are respectively formed between the casing 10 and the blade upper end surface 8 and between the hub 1 and the blade lower end surface 3 .

Combining with Fig. 2(a)-2(b), to manufacture the large meridian expansion variable geometry turbine with orthogonal adjustable vanes of the present invention, the conventional twisted blades are firstly designed by using the traditional design method, and then for the given turbine overall parameters and the range of operating conditions, etc., the blade should be properly orthogonally operated to ensure that the tangent at the intersection of the blade leading edge, trailing edge profile and the end wall of the casing is respectively clamped with the leading edge and trailing edge profile line. The angles α1 and α2 are between 75° and 105°. Then, in order to ensure that the angles α4 and α5 between the tangent at the intersection of the leading edge, trailing edge profile and the hub end wall and the leading edge and trailing edge profile are between 75° and 105°, the hub end wall should Satisfy the structural form shown in Figure 2 or 3, specifically, the hub is sequentially composed of an inlet straight section 11, a concave-convex joint section 13 matched with the root of the adjustable stationary blade, a tapered section 15 connected with the root of the moving blade, and an outlet The straight section 17 is composed of the inlet straight section 11 and the concave-convex joint section 13 matched with the root of the adjustable stationary blade connected at the inflection point 12, the concave-convex joint section 13 matched with the root of the adjustable stationary blade and the concave-convex joint section 13 matched with the root of the moving blade. The tapered section 15 is connected at an inflection point 14 , and finally the tapered section 15 connected with the root of the moving blade is connected with an outlet straight section 17 at an inflection point 16 . In addition, in order to ensure that the vane rotation mechanism can be realized and can work reliably, the included angle between the rotational axis of the adjustable vane and the radial direction should not be too large, and generally the included angle is between 5° and 20°.

The present invention is a large meridian expansion variable geometry turbine with orthogonal adjustable stator blades, comprising a large meridian expansion end wall casing and a hub, and adjustable stator blades and moving blades are uniformly installed along the circumferential direction between the casing and the hub , the adjustable static blade is in the front, and the moving blade is in the rear. The upper and lower end surfaces of the adjustable static blade are respectively provided with upper and lower rotating shafts. In the box, the lower rotating shaft is embedded in the hub, and the moving blades are installed on the hub. The adjustable stationary vanes are orthogonal blades arranged perpendicular to the blade itself and the end wall, and the hub contains concave and convex matching with the adjustable stationary vanes. combined segment.

The included angle between the tangent at the intersection positions of the leading edge molding lines of the adjustable stationary blades and the casing and the hub end wall and the leading edge molding line is 75°-105°.

The included angle between the tangent at the intersection positions of the trailing edge molding lines of the adjustable stationary blades and the casing and the hub end wall and the trailing edge molding lines is 75°-105°.

The included angle between the axis of the rotating shaft of the adjustable stationary vane and the radial direction is 5°-20°.

Claims (9)

1. A large meridional expansion variable geometry turbine with orthogonal adjustable stationary blades, characterized in that it comprises a casing, a moving blade hub, and moving blades, the moving blade hub is located in the casing, and the moving blade hub is equipped with a hub The rotating shaft, the moving blade and the moving blade are evenly arranged along the circumferential direction of the hub and fixed on the moving blade hub. The front of each moving blade is equipped with an adjustable stationary vane, which is installed on the hub of the stationary vane, and a bearing is arranged in the hub of the stationary vane, and the end of the rotating shaft of the hub is matched with the bearing, and the upper end surface of the adjustable stationary vane is set to rotate upwards. shaft, the lower end surface of the adjustable vane is provided with a lower rotating shaft, the outer side of each adjustable vane is connected to the casing through its upper rotating shaft, the vane hub is provided with a vane groove, and the lower rotating shaft is set on the vane In the groove, an adjusting rod for adjusting the angle of the adjustable vane is installed on the upper rotating shaft. The adjusting rod protrudes out of the casing, and the angle between the rotational axis of the adjustable vane and the rotating shaft of the hub is between 5° and 20°. . 2. A large meridional expansion variable geometry turbine with orthogonal adjustable vanes according to claim 1, characterized in that: the axes of the upper and lower rotating shafts and the rotational axes of the adjustable vanes are located at On the same straight line, the shaft diameter of the upper rotating shaft is larger than that of the lower rotating shaft. 3. A large meridional expansion variable geometry turbine with orthogonal adjustable vanes according to claim 1 or 2, characterized in that: the shape between the upper end surface of the adjustable vanes and the inner wall of the casing facing them is the same , and there is a rotation gap between the two, and the length of each part of the rotation gap is equal. 4. A large meridional expansion variable geometry turbine with orthogonal adjustable stator blades according to claim 1 or 2, characterized in that: the section line on the outside of the hub of the stator blades includes a connected straight section of the inlet, a combination of concave and convex section, the section line on the outer side of the rotor hub includes the connected tapered section and the straight outlet section, in which the concave-convex joint section corresponds to the position of the lower end surface of the adjustable stationary blade, the tapered section corresponds to the position of the root of the movable blade, and the bottom of the adjustable stationary blade The shape between the end surface and the concave-convex joint section is the same, and there is a rotation gap between the two, and the lengths of the rotation gaps are equal. 5. A large meridional expansion variable geometry turbine with orthogonal adjustable stator blades according to claim 3, characterized in that: the section line outside the hub of the stator blades includes a connected straight inlet section and a concave-convex joint section, The section line on the outer side of the rotor hub includes the connected tapered section and the straight section of the outlet. The shapes of the concavo-convex combined segments are the same, and there is a rotation gap between the two, and the lengths of the rotation gaps are equal. 6. A large meridional expansion variable geometry turbine with orthogonal adjustable stator blades according to claim 1 or 2, characterized in that: the extension line of the leading edge profile of the adjustable stator blades and the tangent of the casing intersection The included angle with the profile line of the leading edge of the adjustable stationary vane is 75°～105°, and the angle between the extension line of the profile line of the trailing edge of the adjustable stationary vane and the intersection point of the casing and the profile line of the trailing edge of the adjustable stationary vane is 75°～ 105°; the angle between the extension line of the leading edge profile of the adjustable stationary vane and the intersection point of the hub of the stationary vane and the profile line of the leading edge of the adjustable stationary vane is 75°～105°; the extension line of the trailing edge profile of the adjustable stationary vane The included angle between the tangent line of the intersection with the hub of the stator blade and the profile line of the trailing edge of the adjustable stator blade is 75°-105°. 7. A large meridional expansion variable geometry turbine with orthogonal adjustable stator blades according to claim 3, characterized in that: the extension line of the leading edge profile of the adjustable stator blades and the tangent line of the intersection of the casing and the adjustable The angle between the profile line of the leading edge of the adjustable vane is 75°～105°, and the angle between the extension line of the profile line of the trailing edge of the adjustable vane and the intersection point of the case and the profile line of the trailing edge of the adjustable vane is 75°～105° ; The angle between the extension line of the leading edge profile of the adjustable stationary vane and the intersection point of the hub of the stationary vane and the profile line of the leading edge of the adjustable stationary vane is 75°～105°; the extension line of the trailing edge profile of the adjustable stationary vane and the static The angle between the tangent line of the impeller hub intersection and the profile line of the trailing edge of the adjustable stationary blade is 75°-105°. 8. A large meridional expansion variable geometry turbine with orthogonal adjustable stator blades according to claim 4, characterized in that: the extension line of the leading edge profile of the adjustable stator blades and the tangent line of the intersection of the casing and the adjustable The angle between the profile line of the leading edge of the adjustable vane is 75°～105°, and the angle between the extension line of the profile line of the trailing edge of the adjustable vane and the intersection point of the case and the profile line of the trailing edge of the adjustable vane is 75°～105° ; The angle between the extension line of the leading edge profile of the adjustable stationary vane and the intersection point of the hub of the stationary vane and the profile line of the leading edge of the adjustable stationary vane is 75°～105°; the extension line of the trailing edge profile of the adjustable stationary vane and the static The angle between the tangent line of the impeller hub intersection and the profile line of the trailing edge of the adjustable stationary blade is 75°-105°. 9. A large meridional expansion variable geometry turbine with orthogonal adjustable stator blades according to claim 5, characterized in that: the extension line of the leading edge profile of the adjustable stator blades and the tangent line of the intersection of the casing and the adjustable The angle between the profile line of the leading edge of the adjustable vane is 75°～105°, and the angle between the extension line of the profile line of the trailing edge of the adjustable vane and the intersection point of the case and the profile line of the trailing edge of the adjustable vane is 75°～105° ; The angle between the extension line of the leading edge profile of the adjustable stationary vane and the intersection point of the hub of the stationary vane and the profile line of the leading edge of the adjustable stationary vane is 75°～105°; the extension line of the trailing edge profile of the adjustable stationary vane and the static The angle between the tangent line of the impeller hub intersection and the profile line of the trailing edge of the adjustable stationary blade is 75°-105°.