Moving blade of centripetal turbine

Abstract

The invention discloses a centripetal turbine moving blade, which is formed by stacking a plurality of two-dimensional blade-shaped sections along the height direction of an inlet blade by taking the center point of the front edge of the blade as the center point, and the connecting line of the front edge positions of the stacked three-dimensional blade is a straight line parallel to the height of the inlet blade. The inlet geometric angle of the two-dimensional blade-shaped section and the blade height percentage are in a quadratic function relationship, the outlet geometric angle of the two-dimensional blade-shaped section and the blade height percentage are in a quadratic function relationship, and the blade turning angle and the blade height percentage are in a linear relationship. The mean camber line shape of two-dimensional blade profiles with different blade height sections can be quickly determined through the function relation, and the moving blade determined according to the function relation can effectively reduce secondary flow loss and blade profile loss in a turbine flow channel, can also reduce axial thrust of an impeller and obviously improves the flow separation phenomenon in the flow channel.

Description

Technical Field

[0001] The present invention belongs to the technical field of turbine blades, and particularly relates to a centripetal turbine rotor blade. Background Art

[0002] The movable small modular reactor (SMR) is a strategic development focus in the United States, Russia and other countries, and is also a hot research field at home and abroad. For China, with its long land and sea borders, improving border control and security capabilities is one of the major demands. The Brayton cycle is safe, efficient and compact, meeting the goals of miniaturization, intelligentization and high efficiency of movable SMRs, and is the main choice for the energy conversion system of movable SMRs. The existing working fluids for the Brayton cycle mainly include helium, supercritical carbon dioxide, air, etc. Compared with other working fluids, the air Brayton cycle does not require a complex working fluid replenishment system and has no safety issues, and can adapt to the complex and changeable environment and the demand of immediate stop and use of movable SMRs, showing great application prospects. The air centripetal turbine is a key component in the air Brayton cycle system, and its performance directly affects the heat conversion efficiency of the cycle system. Therefore, it is of great significance to carry out research on the optimized design of air turbines applicable to movable SMRs.

[0003] The flow of the gas in the turbine flow passage is affected by the blade profiles of the stator blades and the rotor blades. The blade profiles determine the working performance of the turbine. After the blades are three-dimensionally formed based on the basic two-dimensional profiles with corresponding forming rules, complex three-dimensional flows are generated in the blade flow passages. Secondary flow losses mainly occur in the blade tip regions, and profile losses occur in the blade middle regions. In addition, the blade profiles of the turbine also directly affect the axial thrust during the operation of the turbine. A reasonable blade profile design can enable the turbine to have high efficiency while reducing the axial thrust. Summary of the Invention

[0004] Aiming at the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a centripetal turbine rotor blade, which can reduce the profile loss of the blade, improve the aerodynamic performance of the blade and reduce the flow loss.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A centripetal turbine rotor blade is stacked by a plurality of two-dimensional profiles along the inlet blade height direction. The stacking point of the rotor blade is the leading edge of the rotor blade. The leading edge positions of the plurality of two-dimensional profiles are a straight line along the blade height direction, and this straight line is parallel to the blade height direction. The mean camber line of the two-dimensional profile is defined by a second-order Bezier curve, and the mean camber line includes the following parameters: the inlet geometric angle of the blade, the outlet geometric angle of the blade, and the blade turning angle.

[0007] A further preferred technical solution is that the two-dimensional profile has the parameters: the inlet height of the blade, the outlet height of the blade.

[0008] The two-dimensional blade profile is formed by sequentially connecting the leading edge of the blade, the suction surface, the trailing edge of the blade, and the pressure surface.

[0009] The cross-sectional profile of the two-dimensional blade profile is a curved thin plate with a uniform thickness distribution.

[0010] The inlet geometric angle of the blade satisfies the following relationship:

[0011] B1 = 5.68x 2 + 5.55x - 1.28

[0012] Where B1 is the inlet geometric angle of the blade and x is the percentage of blade height.

[0013] The outlet geometric angle of the blade satisfies the following relationship:

[0014] B2 = 20x 2 - 9.22x + 51.92

[0015] Where B2 is the outlet geometric angle of the blade and x is the percentage of blade height.

[0016] The blade turning angle satisfies the following relationship:

[0017] GA = 0.23x + 17.06

[0018] Where GA is the blade turning angle and x is the percentage of blade height.

[0019] The connections between the cross-sections of each two-dimensional blade profile are continuously and smoothly transitioned.

[0020] The beneficial effects of the present invention are as follows: The radial inflow turbine rotor blade of the present invention is formed by stacking a number of two-dimensional blade profiles along the inlet blade height direction at the leading edge position of the blade. The camber line parameters of the two-dimensional blade profile are determined according to the equation, reducing the inlet and outlet geometric angles at the blade root position, which can simultaneously reduce the secondary flow loss and the blade profile loss, and can also significantly reduce the flow separation phenomenon at the middle position of the blade.

[0021] The radial inflow turbine rotor blade provided by the present invention parameterizes and fits different cross-sections of the blade, improving the flow separation phenomenon on the suction surface of the rotor blade, reducing the secondary flow and eddy current regions, and further reducing the secondary flow loss. In addition, due to the improvement of the flow separation phenomenon in the flow passage, the temperature field and pressure field in the flow passage are further optimized, and the temperature difference and pressure difference between the suction surface and the pressure surface of the blade are further reduced. Therefore, the turbine can maintain high efficiency while reducing the axial thrust of the impeller, and can simultaneously ensure that the blade twist is within a reasonable angle range without affecting the strength performance of the blade.

[0022] The turbine blade modeling method provided by the present invention is simple, can quickly obtain the mid-arc line parameters of different blade height sections according to the equation, and can quickly determine the shape of the three-dimensional blade body based on the mid-arc line parameters. It is conducive to large-scale utilization and promotion, and has strong operability. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the geometric structure of the centripetal turbine moving blade of the present invention;

[0024] Figure 2 is Figure 1 a schematic diagram of the two-dimensional blade profile of the middle section of the shown turbine moving blade;

[0025] Figure 3 is Figure 2 a schematic diagram of the mid-arc line of the shown middle section;

[0026] The marks in the figure are respectively: 1 - inlet blade height, 2 - outlet blade height, 3 - root section blade profile, 4 - 25% blade height section blade profile, 5 - 50% blade height section blade profile, 6 - 75% blade height section blade profile, 7 - top section blade profile, 8 - blade trailing edge, 9 - blade suction surface, 10 - blade leading edge, 11 - blade pressure surface, B1 - blade inlet geometric angle, B2 - blade outlet geometric angle, GA - blade turning angle. Detailed Embodiment

[0027] The present invention will be explained in detail below by combining examples with the drawings.

[0028] As Figure 1 shown, a centripetal turbine moving blade of the present invention is formed by stacking multiple two-dimensional blade profiles along the inlet blade height direction, which are successively the root section blade profile 3, 25% blade height section blade profile 4, 50% blade height section blade profile 5, 75% blade height section blade profile 6 and top section blade profile 7 from bottom to top.

[0029] As Figure 2 shown, the contour of the two-dimensional blade profile section is a curved thin plate blade profile, which is enclosed by connecting the blade trailing edge 8, suction surface 9, blade leading edge 10 and pressure surface 11 in sequence.

[0030] As Figure 3 shown, the mid-arc line of the two-dimensional blade profile section is a second-order Bezier curve, including parameters: blade inlet geometric angle B1, blade outlet geometric angle B2, blade turning angle GA.

[0031] In this embodiment, the mid-arc line parameters of the two-dimensional blade profile section satisfy the following relationship:

[0032] B1 = 5.68x 2 + 5.55x - 1.28;

[0033] B2 = 20x 2 -9.22x + 51.92;

[0034] GA = 0.23x + 17.06;

[0035] In this embodiment, the two-dimensional blade profile takes the blade leading edge as the stacking point, and the cross-sections of the two-dimensional blade profiles are smoothly connected to each other. Finally, the connection line of the blade leading edges presents a straight line.

[0036] In this embodiment, the blade body of the turbine moving blade is shaped under the condition that the blade inlet height, the blade outlet height, and the number of blades are certain. The specific process is as follows:

[0037] First, determine the position of the middle section according to the inlet and outlet blade heights, and determine the parameters of the median line of the two-dimensional blade profile cross-section according to the above formula;

[0038] Secondly, after determining the median line parameters, use a second-order Bezier curve for fitting to complete the construction of the median line of the two-dimensional blade profile cross-section;

[0039] Thirdly, select appropriate blade thickness, blade leading edge radius and blade trailing edge radius according to the inlet and outlet blade heights, and check whether the two-dimensional blade profile cross-section is smooth;

[0040] Then, move the determined two-dimensional blade profile cross-sections with the center of the blade leading edge as the stacking point, and ensure that the leading edges of all two-dimensional blade profiles are on a straight line, and this straight line is parallel to the inlet blade height direction;

[0041] Finally, smoothly connect the moved two-dimensional blade profile cross-sections to form a three-dimensional blade. And check whether the blade body of the moving blade is smooth. If it is not smooth, fine-tune the bending curve and regenerate the moving blade.

[0042] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. According to the technical essence of the present invention, within the spirit and principle of the present invention, any simple modifications, equivalent replacements, and improvements made to the above embodiments still fall within the protection scope of the technical solution of the present invention.

Claims

1. A centripetal turbine moving blade, characterized in that: The centripetal turbine rotor blade is formed by stacking multiple two-dimensional airfoils along the inlet blade height direction. The stacking point of the rotor blade is the leading edge of the rotor blade. The leading edge positions of the multiple two-dimensional airfoils are a straight line along the blade height direction, and this straight line is parallel to the blade height direction. A second-order Bezier curve is used to define the mean camber line of the two-dimensional airfoil. The mean camber line includes the following parameters: the inlet geometric angle of the blade, the outlet geometric angle of the blade, and the blade turning angle.

2. The centripetal turbine moving blade according to claim 1, characterized in that: The two-dimensional airfoil has the parameters: the inlet height of the blade and the outlet height of the blade.

3. The centripetal turbine moving blade according to claim 1, characterized in that: The two-dimensional airfoil is formed by sequentially connecting the leading edge of the blade, the suction surface, the trailing edge of the blade, and the pressure surface.

4. The centripetal turbine moving blade according to claim 1, wherein: The cross-sectional profile of the two-dimensional airfoil is a curved thin plate with a uniform thickness distribution.

5. The centripetal turbine moving blade according to claim 1, characterized in that: The inlet geometric angle of the blade satisfies the following relationship: B1 = 5.68x 2 + 5.55x - 1.28 where B1 is the inlet geometric angle of the blade and x is the percentage of the blade height.

6. The centripetal turbine moving blade according to claim 1, characterized in that: The outlet geometric angle of the blade satisfies the following relationship: B2 = 20x 2 -9.22x + 51.92 where B2 is the outlet geometric angle of the blade and x is the percentage of the blade height.

7. The centripetal turbine moving blade according to claim 1, wherein: The blade turning angle satisfies the following relationship: GA = 0.23x + 17.06 where GA is the blade turning angle and x is the percentage of the blade height.

8. The centripetal turbine moving blade according to claim 1, characterized in that: The connections between the cross-sections of the respective two-dimensional airfoils are continuously and smoothly transitioned.

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