CN210422698U

CN210422698U - Low pressure turbine blade with wavy suction surface

Info

Publication number: CN210422698U
Application number: CN201920617225.XU
Authority: CN
Inventors: 崔佳欢; 刘俭; 王稳
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2019-04-30
Filing date: 2019-04-30
Publication date: 2020-04-28
Anticipated expiration: 2029-04-30

Abstract

The utility model discloses a wavy low pressure turbine blade of suction surface is applicable to and reduces aeroengine high load and super high load low pressure turbine blade profile loss, low pressure turbine blade includes blade leading edge, blade suction side, blade pressure side and blade trailing edge, the shape of blade suction side for the wave surface that extends along the blade height direction, the wave surface begins at the blade leading edge, and the blade trailing edge ends, the wave surface is formed by linking up in turn crest and trough, from blade leading edge to blade trailing edge, along the distance change of cascade apart from the direction between wavy crest and the trough for from 0 to 2A linear increase, again from 2A to 0 linear reduction, wherein A is the maximum amplitude of wave surface, maximum amplitude department is the fluid separation position. The blade structure can effectively reduce the separation of blade fluid, reduce loss and improve the performance of the low-pressure turbine.

Description

Low pressure turbine blade with wavy suction surface

Technical Field

The utility model relates to a civil aviation technical field especially relates to a wavy low pressure turbine blade of suction surface, is applicable to aeroengine high load and super high load low pressure turbine blade.

Background

The aero-engine is known as 'the flower of industry', which is the embodiment of comprehensive national strength of the country. The low pressure turbine is one of the important parts of an aircraft engine, and the weight of the low pressure turbine is about 25% of the weight of the whole engine, and the cost of the low pressure turbine is about 15% of the cost of the whole engine. If the low-pressure turbine efficiency is improved by 1 percent, the oil consumption of the whole machine is reduced by 0.5 to 1.0 percent.

Today, low pressure turbine efficiencies have exceeded 90%, and further improvements to them have been very difficult. The main way to improve the performance of the low-pressure turbine has been shifted from the aerodynamic performance of the individual blades to improving the overall performance of the low-pressure turbine, which mainly comprises: the load of a single blade is improved, the number of blades is reduced, the weight of the low-pressure turbine is reduced, and further the comprehensive cost (manufacturing cost and flight cost) is reduced. However, increasing the low pressure turbine blade loads increases the risk of boundary layer separation, and even open separation. If the design is slightly deviated, the ultrahigh load low pressure turbine can greatly increase the oil consumption rate and the comprehensive cost. Due to conservative design, to avoid boundary layer separation, the traditional low pressure turbine design load is relatively low. However, in recent years, companies such as roco/GE have tried to adopt the design concept of ultra-high load low pressure turbine, and the design of ultra-high load low pressure turbine will greatly reduce the number of blades and the weight of the turbine.

Although the number of blades and the weight of the low-pressure turbine can be greatly reduced by the ultra-high-load low-pressure turbine, researches show that compared with the traditional blades, the ultra-high-load low-pressure turbine is difficult to keep high-efficiency operation under all working conditions. Researchers have begun to use flow control methods to suppress low pressure turbine suction surface separation bubbles and secondary flow losses. Existing flow control schemes fall into two broad categories, active control and passive control. The active control comprises methods of flow direction momentum injection, boundary layer suction, flow direction vortex generation, instability excitation and the like. The vortex generator is passively controlled, the end wall intercepts (end wall inception), the joint of the front edge of the blade and the end wall surface is thickened, and the like.

SUMMERY OF THE UTILITY MODEL

The problem that fluids on a suction surface are easy to separate and the loss is aggravated when the aeroengine runs under the working condition of low Reynolds number under the high-load and ultrahigh-load low-pressure turbines is solved. The utility model provides a wavy low pressure turbine blade of suction surface increases the wave setting at the suction surface, can reduce the loss that the separation bubble brought to improve turbine efficiency.

In order to achieve the purpose, the method is realized by the following technical scheme: the low-pressure turbine blade with the wavy suction surface is suitable for reducing blade profile loss of high-load and ultrahigh-load low-pressure turbine blades of aircraft engines, and comprises a blade front edge, a blade suction side, a blade pressure side and a blade tail edge, wherein the shape of the blade suction side is a wavy surface extending in the blade height direction, the wavy surface starts from the blade front edge and ends at the blade tail edge, the wavy surface is formed by alternately connecting wave crests and wave troughs, the distance between the wave crests and the wave troughs of the wavy surface in the blade cascade pitch direction is changed from 0 to 2A in a linear increasing mode from 2A to 0A in a linear decreasing mode from the blade front edge to the blade tail edge, A is the maximum amplitude of the wave crest surface and the wave trough surface, and the maximum amplitude position is a fluid separation position.

Preferably, the shape of one interface of the wavy surface along the blade height direction is a sine wave.

The utility model has the advantages that: the utility model provides a low pressure turbine blade surface wave shape forms near the trailing edge and to the vortex, with the part that the energy is low through substituting the vortex into the mainstream, effectively strengthen the kinetic energy exchange between mainstream and the boundary layer, increase boundary layer kinetic energy, restrain the separation bubble and generate, will originally separate the loss and turn into the lower to the vortex loss of losing, owing to the existence to the vortex, the average air current off-angle of trailing edge department and loss coefficient are less than original turbine blade simultaneously, realize the promotion of low pressure turbine performance.

Drawings

Fig. 1 is a schematic view of an original blade profile, a peak blade profile and a trough blade profile of a low-pressure turbine blade provided by the present invention;

FIG. 2 is a three-dimensional schematic view of a low pressure turbine blade provided by the present invention;

fig. 3 is a front view of a low-pressure turbine blade according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the low pressure turbine blade of the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

The utility model provides a wavy low pressure turbine blade of suction surface is applicable to and reduces aeroengine high load and super high load low pressure turbine blade profile loss, low pressure turbine blade includes blade leading edge 1, blade suction side 2, blade pressure side 3 and blade trailing edge 4, the wave surface of shape for extending along the blade height direction of blade suction side 2, the wave surface begins at blade leading edge 1, and final blade trailing edge 4, the crest and the trough of wave surface link up in turn and form, from blade leading edge to blade trailing edge trough, the distance variation along the cascade apart from the direction between the crest of wave surface and the trough is from 0 to 2A linear increase, again from 2A to 0 linear reduction, wherein A is the maximum amplitude of crest surface and trough surface, maximum amplitude department is the fluid separation position.

The design concept of the low-pressure turbine blade with the wavy suction surface provided by the present invention is not limited to the following description; as shown in fig. 1-3, the blade profile provided by the present invention in this embodiment is obtained by using the original two-dimensional blade profile 5 as a reference, i.e. the peak blade profile 6 and the valley blade profile 7. First, the fluid separation position is determined (0.6)C _x，C _xAxial chord length) determined by cascade experiments or numerical simulation of the original blade profile, then obtaining a point P (figure 1) from the position to the outer side A of the blade along the cascade direction, drawing a curve respectively passing through a leading edge and a trailing edge by the point, linearly increasing the distance between the curve and the suction side of the original two-dimensional blade profile 5 from the leading edge to a separation position, and linearly decreasing from the separation position to the trailing edge, wherein a closed curve formed by connecting the curve and a pressure side curve is called a peak blade profile 6. On the basis of the obtained peak profile 6, the distance in the blade height direction is half a wavelength (λAnd/2) a position where a point T (FIG. 1) is obtained at a distance A from the inner side of the blade in the cascade direction at the separation position with reference to the original two-dimensional blade profile 5, and the blade profile obtained by the point T is called a trough blade profile 7. The wave crest blade profiles 6 and the wave trough blade profiles 7 are alternately arranged along the blade height direction, and finally the low-pressure turbine blade with the suction surface provided with the wave type and the loss reduction function is obtained.

Will now the utility model provides an improve low pressure turbine performance blade structure's theory of operation as follows: the incoming flow passes through the low-pressure turbine blade with the structure, and a plurality of groups of counter-rotating vortexes are generated in the fluid through the wave protrusions, so that the energy exchange between the main flow and the boundary layer is increased, and the effect of restraining the separation bubbles is achieved. At the trailing edge of the blade, the loss is converted from the original boundary separation loss into the counter-vortex loss, and the local position loss is larger than the loss of the original blade at the position. The wavy vanes do not reduce endwall secondary flow losses and only act in a two-dimensional flow area.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings, or directly or indirectly applied to other related technical fields, are included in the same way in the protection scope of the present invention.

Claims

1. The utility model provides a low pressure turbine blade of suction surface wave is applicable to and reduces aeroengine high load and super high load low pressure turbine blade profile loss, low pressure turbine blade includes blade leading edge, blade suction side, blade pressure side and blade trailing edge, characterized by: the shape of the suction side of the blade is a wave surface extending along the blade height direction, the wave surface starts from the front edge of the blade and ends at the tail edge of the blade, wave crests and wave troughs of the wave surface are alternately connected, the distance between the wave crests and the wave troughs of the wave surface along the cascade pitch direction is changed from 0 to 2A in a linear increasing mode and then from 2A to 0 in a linear decreasing mode, A is the maximum amplitude of the wave surface, and the position of the maximum amplitude is the fluid separation position.

2. A suction surface undulating low pressure turbine blade as set forth in claim 1 wherein a cross-section of said undulating surface in the direction of the blade height is sinusoidal or cosine in shape.