A structure for suppressing the horseshoe vortex at the leading edge of a gas turbine blade

Abstract

The present invention discloses a structure for suppressing the horseshoe vortex at the leading edge of a gas turbine blade, comprising a plurality of micro-scale groove structures arranged on the end wall upstream of the leading edge of the turbine blade, wherein the shape, axial position and adjacent spacing of each micro-scale groove structure are the same. The present invention is based on the mechanism that the groove structure reduces flow resistance and absorbs the flow of the nearby wall surface, suppresses the separation of the leading edge flow, reduces the strength of the horseshoe vortex in the channel, reduces the secondary flow loss, and improves the overall performance of the turbine.

Description

Technical Field

[0001] The invention relates to the field of axial flow turbines of gas turbines, and in particular to a structure for suppressing horseshoe vortices at the leading edges of turbine blades of gas turbines. Background Art

[0002] A turbine is a device that converts the thermal energy of high-temperature combustion gas into mechanical energy and outputs mechanical work through rotation. It is one of the key components of a gas turbine. At the end of the turbine blade grid, secondary flow inconsistent with the mainstream direction will be generated due to the effects of circumferential, radial and axial pressure gradients. The existence of secondary flow causes a large secondary flow loss near the end wall, accounting for 30% to 50% of the total loss of the turbine channel. In order to achieve the design goal of improving the aerodynamic performance of gas turbines, current gas turbines generally adopt a design method of increasing blade loads. As the blade load continues to increase, the lateral pressure difference of the inter-blade channel also increases. This factor leads to the strengthening of the end zone lateral flow, the flow at the turbine end is more complicated, and the secondary flow loss at the end zone is further increased.

[0003] The secondary flow consists of a series of complex vortex structures, such as Figure 1 As shown in the figure, the leading edge stagnation zone is the location where the entire secondary flow is generated. The improvement of the flow state at this location can also suppress the secondary flow structure of the flow channel. The horseshoe vortex generated in the leading edge stagnation zone has the largest influence range and the strongest energy. Therefore, suppressing the development of the leading edge horseshoe vortex is particularly important for reducing secondary flow losses. According to existing research, methods to suppress the horseshoe vortex include changing the leading edge shape, changing the leading edge end wall shape, and increasing the jet. Summary of the invention

[0004] The object of the present invention is to provide a structure for suppressing the horseshoe vortex at the leading edge of a gas turbine blade. The structure is based on the mechanism that the groove structure reduces the flow resistance and absorbs the flow on the nearby wall. By suppressing the leading edge flow separation, the strength of the horseshoe vortex in the channel is reduced, the secondary flow loss is reduced, and the overall performance of the turbine is improved.

[0005] The present invention is implemented by the following technical solutions:

[0006] A structure for suppressing the horseshoe vortex at the leading edge of a gas turbine blade comprises a plurality of micro-scale groove structures arranged on the end wall upstream of the leading edge of the turbine blade, wherein the shape, axial position and adjacent spacing of each micro-scale groove structure are the same.

[0007] A further improvement of the present invention is that the cross section of the micro-scale groove structure is rectangular, triangular or semicircular, and its symmetry axis is consistent with the streamline direction.

[0008] A further improvement of the present invention is that the starting point of the microscale groove structure is at a distance S from the leading edge of the turbine blade, and the ending point is at a distance T from the leading edge of the turbine blade, wherein the value range of S is 20%C to 60%C, the value range of T is 2%C to 20%C, and C represents the axial chord length of the blade.

[0009] A further improvement of the present invention is that the distance between the micro-scale groove structure close to the pressure surface side and the leading edge of the blade is L, and the value range of L is 5%C to 20%C.

[0010] A further improvement of the present invention is that the width of the micro-scale groove structure is W, and the range of W is 0.1%C to 1.5%C.

[0011] A further improvement of the present invention is that the depth of the micro-scale groove structure is H, and the range of H is 0.1%C to 1.8%C.

[0012] A further improvement of the present invention is that the spacing between each micro-scale groove structure is G, and the range of G is 0.1%C to 1%C.

[0013] A further improvement of the present invention is that the number of the micro-scale groove structures is N, and the range of N is 5-20.

[0014] The present invention has at least the following beneficial technical effects:

[0015] The present invention provides a structure for suppressing the horseshoe vortex at the leading edge of a gas turbine blade. After the end wall of the turbine channel is treated with the groove as described above, the lateral pressure gradient of the end wall of the turbine channel is reduced, the flow separation phenomenon at the leading edge of the blade is suppressed, the development of the horseshoe vortex is weakened, and the secondary flow loss is reduced. Therefore, the present invention is different from other methods in the past. The structure adopted by this method is simple, the effect is obvious, and the implementation is convenient. At the same time, due to the small scale, the additional aerodynamic loss is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional schematic diagram of the groove structure of the turbine channel end wall of the present invention.

[0017] Figure 2 A top view of the present invention

[0018] Figure 3 It is a cross-sectional view of the present invention. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] like Figures 1 to 3 As shown, the present invention provides a structure for suppressing the leading edge horseshoe vortex of a gas turbine blade, including arranging a plurality of micro-scale groove structures on the end wall upstream of the leading edge of the turbine blade, reducing the lateral pressure gradient of the end wall of the turbine channel, reducing the leading edge horseshoe vortex intensity, and reducing secondary flow losses. The cross section of the micro-scale groove structure is a symmetrical figure, the symmetry axis of which is consistent with the streamline direction, and the axial position and adjacent spacing of each micro-scale groove are the same.

[0021] The axial chord length of the turbine blade is C. In this embodiment, the value of C is 100 mm.

[0022] In this embodiment, the cross section of the added micro-scale groove structure is rectangular.

[0023] The distance S between the starting point of the micro-scale groove structure and the leading edge of the turbine blade ranges from 20%C to 60%C. In this embodiment, S is preferably 30%C, i.e. 30 mm.

[0024] The distance T between the end point of the micro-scale groove structure and the leading edge of the turbine blade ranges from 2%C to 20%C. In this embodiment, T is preferably 8%C, ie 8 mm.

[0025] The distance L between the rightmost side of the micro-scale groove structure and the leading edge of the blade ranges from 5%C to 20%C. In this embodiment, L is preferably 10%C, ie, 10 mm.

[0026] The width W of the micro-scale groove structure ranges from 0.1%C to 1.5%C. In this embodiment, W is preferably 1%C, ie, 1 mm.

[0027] The depth H of the micro-scale groove structure ranges from 0.1%C to 1.8%C. In this embodiment, H is preferably 1.5%C, ie, 1.5 mm.

[0028] The spacing G between each micro-scale groove ranges from 0.1%C to 1%C. In this embodiment, preferably G is 0.8%C, ie, 0.8 mm.

[0029] The number N of micro-scale grooves ranges from 5 to 20. In this embodiment, N is preferably 12.

[0030] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A structure for suppressing the horseshoe vortex at the leading edge of a gas turbine blade, characterized in that: The invention comprises a plurality of micro-scale groove structures arranged on the end wall upstream of the leading edge of the turbine blade, wherein the shape, axial position and adjacent spacing of each micro-scale groove structure are the same; The cross-section of the microscale groove structure is rectangular, triangular or semicircular, and its symmetry axis is consistent with the streamline direction; The starting point of the micro-scale groove structure is at a distance S from the leading edge of the turbine blade, and the ending point is at a distance T from the leading edge of the turbine blade, wherein the value range of S is 20%C to 60%C, the value range of T is 2%C to 20%C, and C represents the axial chord length of the blade; The distance between the micro-scale groove structure near the pressure surface and the leading edge of the blade is L, and the value range of L is 5%C to 20%C; The width of the micro-scale groove structure is W, and the range of W is 0.1%C to 1.5%C; The depth of the micro-scale groove structure is H, and the range of H is 0.1%C to 1.8%C; The spacing between each micro-scale groove structure is G, and the range of G is 0.1%C to 1%C.

2. The structure for suppressing the leading edge horseshoe vortex of a gas turbine blade according to claim 1, characterized in that: The number of the micro-scale groove structures is N, and the range of N is 5-20.

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