WINGLET OF THE FLOW COMPRESSOR WHEEL

Abstract

 The invention relates to a winglet of the flow compressor wheel, designed for use in radial flow compressors and radial axial flow compressors, in particular in automotive turbochargers.
The subject invention relates to the curvature of the blade 2 and/or the supporting blade 3 at the outermost end in the section 6, which reduces the approach angle " β" of the blade and increases the angle "a". As a result, the leading edge 7 of the blade 2 and/or the supporting blade 3 is not a straight line, being curved at the external diameter of the compressor wheel. The section 6 is determined by the semi-axes H and L. This curvature reduces the pressure difference between the suction surface 4 and the compressing surface 5 of the blade 2 and/or the supporting blade 3 at the point where the pressure difference is greatest and turbulence occurs, i.e. in the section 6. Due to the fact that the pressure difference is reduced, turbulence at the end of the blade is also reduced, which increases the compressor's efficiency.

Description

[0001] The invention relates to a winglet of the flow compressor wheel, designed for use in radial compressors and radial-axial compressors, in particular in automotive turbochargers.

[0002] There are known radial flow compressors and radial-axial flow compressors which are composed of an impeller and an impeller housing (stators). After applying rotational speed to the impeller, the compressing process is initiated and the medium begins to flow. Compressors of this type are used e.g. in aircraft turbine engines, gas turbines, power generators, turbochargers used in combustion engines, electric compressors, industrial fans and many more.

[0003] Such compressors, including in particular those used in turbochargers for increasing the efficiency of reciprocating engines, the compressor's efficiency should be as high as possible. The greater the efficiency of a compressor, the greater the efficiency of the engine on which have been used such an compressor. The shape of the blades 2 and the supporting blades 3 of compressor wheel 1 - have significant impact on compressor's efficiency. Of importance is here the distribution of pressure at the blades 2 and the supporting blades 3 associated with the compressor wheel 1. The patents US7261513 B2 and EP1972795 A2 propose a solution aimed at increasing the efficiency of a compressor.

[0004] The wheel of the flow compressor 1 is composed of the blades 2 and additionally it can be provided with the supporting-leading blades 3. The blades have suction surfaces 4 and compressing surfaces 5. As an results of rotation of compressor wheel 1 there is generated pressure difference on the blades 2 and supporting blades 3. Negative pressure is produced at the suction surfaces 4 while positive pressure is produced at the compressing surfaces 5. The greatest pressure difference occurs at the external diameter of the blades 2 near the leading edge. This section is identified by number 6 in fig. 1. A pressure too low at the suction surface may cause the separation of a stream of the working medium, which reduces the efficiency and/or causes unstable operation of the compressor. A pressure difference between the suction side 4 and the compressing side 5 also causes turbulence in the section 6 presented in fig. 1. This turbulence reduces the compressor's efficiency. This effect is similar to that observable at the ends of aircraft wings. Winglets are used in aircraft wings to reduce the resistance induced by the said turbulence. The solution based on the use of a winglet is covered by the patents US8366056 B2 and US5348253 A, among others.

[0005] The blades 2 and the supporting blades 3 associated with the compressor wheel 1 most often are done as ruled surface. Such blades are relatively simple to design and fabricate. Solutions based on blades featuring a much more complicated surface are less common. In both cases, a solution for increasing the efficiency of the compressor wheel is a winglet of the flow compressor wheel, which reduces the pressure difference between the suction surface 4 and the compressing surface 5 at the point where the pressure difference is greatest and turbulence occurs, i.e. in the section 6, in that the end of the blade 2 is curved in the direction identified by the arrow 9 in the embodiment presented in fig. 3.

[0006] The subject of the invention is presented in its embodiment on the drawing where fig. 3 shows a diagram of how the end of the blade 2 is curved, where the angle α is the greatest difference in angles at the leading edge 7 of the blade 2.

[0007] The subject of the invention is presented in its embodiment on the drawing where fig. 4 shows a diagram of how the end of the blade 2 is curved, where the angle β is the approach angle of the blade.

[0008] The subject of invention is the curvature of the blade 2 and/or the supporting blade 3 at the outermost end in the section 6. This reduces the approach angle β and increases the angle α. As a result, the leading edge 7 is not a straight line, being curved at the external diameter of the compressor wheel towards the surface in the direction identified by the arrow 9 in fig. 3. The section 6 is determined by the semi-axes H and L presented in the embodiment in fig. 5.

Claims

1. Winglet of the flow compressor wheel,
characterized in that
it is the curvature in the edge of the compressor blade (2) and/or the supporting blade (3) in the section (6) in that it reduces the approach angle "β" of the compressor blade (2) and/or the supporting blade (3) in the section (6), thus reducing the pressure difference at the edge of the blade 2 and/or the supporting blade (3) and reducing the pressure difference at the surfaces in the section (6).

1. Winglet of flow radial compressor wheel according to claim 1, characterized in that the angle "α" is from 3° to 25°.

3. Winglet of the flow compressor wheel according to claim (1), characterized in that the angle "β" is from 0° to 15°.

4. Winglet of the flow compressor wheel according to claim 1, characterized in that it reduces the turbulence at the corner of the blade (2) and/or the supporting blade (3) in the section 6.

5. Winglet of the flow compressor wheel according to claim 1, characterized in that the length "H" with reduced approach angle of the blade (2) and/or the supporting blade (3) is up to 30% of the length of the leading edge (7).

6. Winglet of the flow compressor wheel according to claim 1, characterized in that the length "L" with reduced approach angle of the blade is equal up to 10% of the lateral length of the edge (8) of the blade (2) and/or the supporting blade (3).

Drawing