Compressor impeller with variable-thickness blade roots and turbocharger

Abstract

The invention relates to a gas compressor impeller with variable-thickness blade roots and a turbocharger. A changing curve of the blade root thickness of a main blade of the compressor impeller is in a hump shape along a blade root length coordinate axis, linear interpolation extrapolation is carried out according to the blade root rear end thickness value of the changing curve at the 100% blade root length position and the blade root rear portion thickness value of the changing curve at the 70% blade root length position, and the reference thickness at the 30% blade root length position is obtained; and the thickness value of the front part of the blade root at 30% of the length of the blade root of the changing curve is at least 1.2 times of the reference thickness. The thickness of the blade root of the front section of the blade is gradually increased to the maximum value from the front vertical edge of the side face of the blade and is sharply thinned when approaching the rear section of the blade, and the thickness of the blade root of the rear section of the blade is slowly thinned to the rear vertical edge of the side face of the blade on the basis that the thickness of the blade root of the front section of the blade is sharply thinned. According to the blade root thickness distribution mode, the mass of the blades and the impeller can be reduced, the centrifugal load and the rotational inertia are reduced, and the high blade vibration inherent frequency can be guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the turbocharger technical field, especially to a variable thickness blade root compressor impeller and turbocharger. BACKGROUND

[0002] The turbocharger uses the high-temperature exhaust gas of the internal combustion engine to drive the turbine, and drives the compressor impeller to rotate at high speed, inhales and compresses fresh air, greatly improves the intake pressure, density and mass of the internal combustion engine, and thus improves the power and torque of the internal combustion engine, reduces fuel consumption and harmful pollutant emissions. The working speed of the compressor impeller is very high, up to hundreds of thousands of revolutions per minute, and the centrifugal load is very large; the shape of the impeller blade affects the intake flow and working efficiency; the front section of the blade is high and thin, which is easy to cause high-cycle fatigue damage due to excitation. It can be seen that the compressor impeller has a great influence on the performance and reliability of the turbocharger.

[0003] The existing conventional compressor impeller blade thickness distribution along the height direction has been optimized, which can be in the shape of a "bottle" to improve the blade stiffness and natural frequency, but in the direction along the length of the blade root, the thickness distribution of the blade root is generally in the shape of a "spindle", that is, from the front vertical edge of the blade side to the rear vertical edge of the blade side, the thickness of the blade root first increases to the maximum value, and then slowly thins, which is difficult to improve the blade natural frequency, reduce the blade mass and reduce the moment of inertia. SUMMARY

[0004] Therefore, the present application provides a variable thickness blade root compressor impeller and a turbocharger using the compressor impeller, the thickness distribution curve of the main blade of the compressor impeller along the length of the blade root is in the shape of a "hump", that is, from the front vertical edge of the blade side, the thickness of the blade root of the front section gradually increases to the maximum value, and near the rear section of the blade, the thickness of the blade root sharply thins, and the thickness of the blade root of the rear section of the blade is slowly thinned based on the sharp thinning of the thickness of the blade root of the front section until the rear vertical edge of the blade side. This blade root thickness distribution method can not only reduce the mass of the blade (rear section) and the impeller, reduce the centrifugal load and the moment of inertia, but also ensure a high blade vibration natural frequency.

[0005] To solve the above technical problems, the application provides a compressor impeller with variable blade root thickness, which comprises a hub and main blades arranged on the hub, the hub has a hub small diameter end and a hub large diameter end along a rotation center of the hub, the main blades have suction side surfaces and pressure side surfaces for guiding fluid flow, the suction side surfaces and the pressure side surfaces have front vertical edges close to the hub small diameter end and rear vertical edges close to the hub large diameter end, the length of the front vertical edges is greater than the length of the rear vertical edges, the main blades further have leading edge surfaces sandwiched between the front vertical edges of the suction side surfaces and the front vertical edges of the pressure side surfaces and facing fluid entry, and trailing edge surfaces sandwiched between the rear vertical edges of the suction side surfaces and the rear vertical edges of the pressure side surfaces and facing fluid exit, the suction side surfaces and the pressure side surfaces are connected to each other through the leading edge surfaces and the trailing edge surfaces, the roots of the suction side surfaces, the pressure side surfaces, the leading edge surfaces and the trailing edge surfaces are connected to the hub, the thickness of the main blades between the roots of the suction side surfaces and the roots of the pressure side surfaces is variable along a length direction of the blade root, the distribution position along the length direction of the blade root is indicated by a blade root length coordinate axis, and the value of the blade root thickness is indicated by a blade root thickness coordinate axis, and the application is characterized in that: wherein the change curve of the blade root thickness along the blade root length coordinate axis is in the shape of a hump, the blade root thickness at the rear end of the blade root at 100% of the blade root length, i.e. the rear vertical edge, and the blade root thickness at the rear part of the blade root at 70% of the blade root length are used for linear interpolation and extrapolation to obtain a reference thickness at 30% of the blade root length, and the blade root thickness at the front part of the blade root at 30% of the blade root length is at least 1.2 times the reference thickness.

[0006] In an embodiment of the application, the hub is further provided with splitter blades shorter than the main blades.

[0007] In an embodiment of the application, the roots of the suction side surfaces and the pressure side surfaces of the main blades further have blade root fillet surfaces between the roots and the hub, the suction side surfaces and the pressure side surfaces are naturally extended until intersecting with the hub, and the blade root thickness of the main blades is sandwiched between the two intersection lines.

[0008] The application further provides a turbocharger comprising the compressor impeller with variable blade root thickness.

[0009] The above technical solution of the application has the following advantages compared with the prior art: The compressor impeller with variable blade root thickness and the turbocharger provided by the application have the following advantages: The root thinning of the blade rear section can reduce its mass, and since the blade rear section is farther from the rotation center, reducing the blade rear section is more beneficial to reduce the centrifugal load and rotational inertia of the impeller, the height of the blade rear section is small, and the root thinning has no obvious effect on the natural frequency of the blade; The height of the blade front section is large, that is, the blade overhang is longer, which is prone to vibration, increasing the blade root thickness of the blade front section helps to improve the structural stiffness and natural frequency of the blade, and avoid high-cycle fatigue damage of the blade, and since the place is closer to the rotation center, the centrifugal load and rotational inertia caused by the mass increase is not obvious. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the accompanying drawings.

[0011] Figure 1 It is a schematic diagram of the compressor impeller of the turbocharger of the present application.

[0012] Figure 2 It is a schematic diagram of the pressure side of a single main blade of the compressor impeller of the present application.

[0013] Figure 3 It is a schematic diagram of the suction side of a single main blade of the compressor impeller of the present application.

[0014] Figure 4 It is a blade root thickness distribution diagram of the compressor impeller of the present application.

[0015] Figure 5 It is a blade root thickness distribution diagram of the conventional compressor impeller for comparison of the present application.

[0016] Figure 6 It is a cross-sectional view of the blade rear section of the present application and the conventional compressor impeller.

[0017] Figure 7 It is a mesh diagram for CAE analysis of the compressor impeller.

[0018] Figure 8 It is a result diagram for CAE analysis of the compressor impeller.

[0019] Explanation of the drawing marks in the specification: 1. main blade; 2. splitter blade; 3. hub large diameter end; 4. root fillet; 5. hub; 6. hub small diameter end; 7. rear vertical edge; 8. pressure side; 9. root thickness; 10. front vertical edge; 11. leading edge face; 12. trailing edge face; 13. suction side; 14. root forward thickness value; 15. change curve; 16. root rear thickness value; 17. root rear end thickness value; 18. 100% root length; 19. root length coordinate axis; 20. 70% root length; 21. 30% root length; 22. 0% root length; 23. reference thickness; 24. root thickness coordinate axis; 25. blade rear section root thinning zone. DETAILED DESCRIPTION

[0020] The present application will be further described below with reference to the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it. The embodiments are not intended to limit the present application.

[0021] In the present application, if the direction (up, down, left, right, front and back) is described, it is only for the convenience of describing the technical solutions of the present application, and is not intended to indicate or imply that the indicated technical features must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0022] In the present application, the meaning of "several" is one or more, and the meaning of "multiple" is two or more; "greater than", "less than", "exceeding" and the like are understood as not including the number, and "above", "below", "within" and the like are understood as including the number. In the description of the present application, if "first", "second" and the like are described, they are only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0023] In the present application, unless otherwise explicitly limited, the words "set", "install", "connect" and the like should be broadly understood, for example, they can be directly connected, or indirectly connected through an intermediate medium; can be fixedly connected, or can be detachably connected, or can be integrally formed; can be mechanically connected, or can be electrically connected or capable of communicating with each other; can be the communication or interaction relationship between two parts inside an element or between two elements. Those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solutions.

[0024] Reference Figure 1 , Figure 2 , Figure 3As shown, the embodiment provides a variable-thickness blade root compressor impeller, which is similar to the conventional compressor impeller and includes a hub 5 having a hub small-diameter end 6 and a hub large-diameter end 3 along the rotation center thereof, and a main blade 1 arranged on the hub 5, the main blade 1 having a suction side 13 and a pressure side 8 for guiding fluid flow, the suction side 13 and the pressure side 8 having a front vertical edge 10 close to the hub small-diameter end 6 and a rear vertical edge 7 close to the hub large-diameter end 3, respectively, the length of the front vertical edge 10 being greater than that of the rear vertical edge 7, the main blade 1 further having a leading edge surface 11 sandwiched between the front vertical edge 10 of the suction side 13 and the front vertical edge 10 of the pressure side 8 and facing the fluid inlet, and a trailing edge surface 12 sandwiched between the rear vertical edge 7 of the suction side 13 and the rear vertical edge 7 of the pressure side 8 and facing the fluid outlet, the suction side 13 and the pressure side 8 being connected to each other through the leading edge surface 11 and the trailing edge surface 12, the roots of the suction side 13 and the pressure side 8 being connected to the hub 5, the thickness of the blade root 9 being sandwiched between the root of the suction side 13 and the root of the pressure side 8, and varying along the blade root length direction from the root of the front vertical edge 10 to the root of the rear vertical edge 7.

[0025] Referring to Figure 4 As shown, the distribution position of the blade root thickness 9 along the blade root length direction is indicated by a blade root length coordinate axis 19, the value of the blade root thickness 9 is indicated by a blade root thickness coordinate axis 24, the 0% blade root length 22 indicates the front end of the blade root, i.e., the root of the blade side front vertical edge 10, and the 100% blade root length 18 indicates the rear end of the blade root, i.e., the root of the blade side rear vertical edge 7, and the value distribution of the blade root thickness 9 along the blade root length direction is plotted as a variation curve 15.

[0026] Different from the conventional compressor impeller, the variation curve 15 of the embodiment is in the shape of a “hump”, the reference thickness 23 at the 30% blade root length 21 is calculated by linear extrapolation according to the blade root rear thickness value 16 at the 70% blade root length 20 and the blade root rear end thickness value 17 at the 100% blade root length 18 of the variation curve 15, the blade root front thickness value 14 at the 30% blade root length 21 of the variation curve 15 has reached about 1.5 times of the reference thickness 23, far exceeding 1.2 times of the reference thickness 23.

[0027] Specifically, the hub 5 is further provided with a splitter blade 2 shorter than the main blade 1.

[0028] Specifically, the root of the suction side 13 and the pressure side 8 of the main blade 1 has a blade root fillet surface 4 between the hub 5, the suction side 13 and the pressure side 8 extend naturally to intersect with the hub 5, and the intersection between the two lines is the blade root thickness 9 of the main blade 1.

[0029] Figure 5 The blade root thickness 9 of a conventional compressor wheel blade along the blade root length direction is shown as an example of a variation curve 15, which is in a "spindle" shape, and the blade root front thickness value 14 at 30% of the blade root length 21 is only about 0.95 times the reference thickness 23 at 30% of the blade root length 21.

[0030] Figure 6 The rear section of the blade of the compressor wheel of the embodiment of the present application is shown in a cross-sectional view stacked with the conventional compressor wheel, and the hub 5, the pressure side 8 of the main blade 1, the splitter blade 2 and the number of blades of the two wheels are completely the same. Due to the "hump" shape of the variation curve 15 of the blade root thickness 9 of the main blade 1 of the compressor wheel of the embodiment of the present application, the blade root thickness 9 of the rear section of the blade is reduced to form a blade root thinning area 25, and at the root of the front section of the blade, the blade root thickness 9 of the main blade 1 of the compressor wheel of the embodiment is slightly thicker than that of the conventional compressor wheel to improve the rigidity of the front section of the blade.

[0031] Figure 7 Figure 8 The grid and result diagrams of the CAE analysis of the compressor wheel are shown respectively, and the calculation shows that: under the premise that the shapes of other parts of the wheel remain the same, compared with the conventional wheel, the embodiment of the present application realizes: the blade mass is reduced by 1.75%, the moment of inertia of the blade relative to the center of rotation of the wheel is reduced by 3.08%, the total mass of the wheel is reduced by 0.44%, the moment of inertia of the wheel is reduced by 1.01%, the blade natural frequency remains the same, and the equivalent stress at the same position of the root of the front and rear sections of the blade is reduced by about 7%.

[0032] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.​

Claims

1. A compressor impeller with variable blade root thickness, comprising a hub (5) having a hub small diameter end (6) and a hub large diameter end (3) along its rotation center, and a main blade (1) arranged on the hub (5), the main blade (1) having a suction side (13) and a pressure side (8) for guiding fluid flow, the suction side (13) and the pressure side (8) having a front vertical edge (10) near the hub small diameter end (6) and a rear vertical edge (7) near the hub large diameter end (3), the length of the front vertical edge (10) being greater than the length of the rear vertical edge (7), the main blade (1) further having a leading edge surface (11) sandwiched between the front vertical edge (10) of the suction side (13) and the front vertical edge (10) of the pressure side (8) and facing fluid entry, and a trailing edge surface (12) sandwiched between the rear vertical edge (7) of the suction side (13) and the rear vertical edge (7) of the pressure side (8) and facing fluid exit, the suction side (13) and the pressure side (8) being connected to each other through the leading edge surface (11) and the trailing edge surface (12), the roots of the suction side (13) and the pressure side (8) and the leading edge surface (11) and the trailing edge surface (12) being connected to the hub (5), the blade root thickness (9) being sandwiched between the root of the suction side (13) and the root of the pressure side (8), the blade root thickness (9) varying along the blade root length direction from the root of the front vertical edge (10) to the root of the rear vertical edge (7), the distribution position along the blade root length direction being indicated by a blade root length coordinate axis (19), and the value of the blade root thickness (9) being indicated by a blade root thickness coordinate axis (24), characterized in that: the variation curve (15) of the blade root thickness (9) along the blade root length coordinate axis (19) is in the shape of a hump, the reference thickness (23) at 30% blade root length (21) is calculated by linear extrapolation from the blade root rear thickness value (17) at 100% blade root length (18), i.e. the rear vertical edge (7), and the blade root rear thickness value (16) at 70% blade root length (20) according to the variation curve (15), the blade root front thickness value (14) at 30% blade root length (21) of the variation curve (15) being at least 1.2 times the reference thickness (23). wherein The hub (5) is further provided with a splitter blade (2) shorter than the main blade (1).

2. An inducer impeller of variable blade thickness at blade root according to claim 1, characterized in that, The hub (5) is further provided with a blade root fillet surface (4) between the roots of the suction side (13) and the pressure side (8) and the hub (5), the suction side (13) and the pressure side (8) being naturally extended until intersecting with the hub (5), the blade root thickness (9) of the main blade (1) being sandwiched between the two intersection lines.

3. An inducer impeller of variable blade thickness at blade root according to claim 1, characterized in that, The compressor impeller with variable blade root thickness according to any one of claims 1-3.

4. A turbocharger characterized by, ​

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