A split-type impulse water turbine model runner measurement structure

Abstract

The present invention discloses a measuring structure for a split-type impulse water turbine model runner, which is composed of a bracket, a depth gauge, screws, buckets, bolts, nuts, cylindrical pins, a hub, and gaskets. The water dividing edge of the bucket abuts against the first prism plane of the bracket, and a feeler gauge is used to measure the radial clearance between the second prism plane of the bracket and the reference bucket. A depth gauge is used to measure the distance from the upper plane of the reference bucket to the upper plane of the bracket, and the thickness of the gasket is adjusted to make the measured value meet the design requirements. By adopting the measuring structure of the present invention, the circumferential angle, radial dimension, and axial dimension between the buckets can be accurately measured, the operation difficulty can be reduced, the measuring accuracy can be improved, the assembly accuracy of the runner can be guaranteed, and the accuracy of the model test can be improved.

Description

Technical Field

[0001] The present invention relates to the field of impulse turbines, and particularly to a measuring structure for a split impulse turbine model runner. Background Art

[0002] An impulse turbine uses a high-speed jet to impact the runner buckets to make them rotate and do work, thereby completing the conversion of water energy into mechanical energy. The impulse runner, as the core component for energy conversion of the turbine, is usually composed of 18 to 25 buckets with the same shape. The bucket whose outlet edge plane is parallel to the vertical coordinate axis is defined as the reference bucket, and the remaining buckets are positioned with reference to the reference bucket. Due to the small size of the impulse model runner, it is difficult to machine the roots of the buckets and the leading edges of the outlet edges during overall machining. Therefore, in the model structure design, split machining and then combined assembly are often adopted. During assembly, each bucket is evenly distributed at 360° equal divisions in the circumferential direction, and the axial and radial positions are the same. When the circumferential, axial, and radial positions of the buckets exceed the design deviation, the jet flow rate and force received by each bucket will deviate from the design value, and further, the performance such as the runner efficiency and runaway in the model test cannot accurately reflect the true design value. If the model runner is scaled up to the prototype machine according to this model, it will lead to a decrease in the unit efficiency, an increase in the radial force, and even cause the vibration of the unit and shorten the service life of the runner. Therefore, there is an urgent need for a measuring structure for a split impulse turbine model runner to solve the measurement and installation problems of each bucket and ensure the overall accuracy of the runner.

[0003] As Figure 1 shown in the schematic diagram of the impulse turbine, high-pressure water is ejected from the nozzle and impacts on the runner buckets to drive the runner to rotate and do work to generate electricity. To ensure the efficient and stable operation of the runner, the position of each bucket relative to the jet needs to be consistent, that is, the circumferential, axial, and radial positions of each bucket on the hub are the same and meet the design requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a measuring structure for a split impulse turbine model runner. The technical solution of the present invention is specifically described as follows: A measuring structure for a split impulse turbine model runner is composed of a bracket, a depth gauge outer sleeve, screws, a depth gauge handle, buckets, bolts, nuts, cylindrical pins, a hub, a first gasket, and a second gasket. The buckets are fixedly connected to the hub through bolts and nuts, and a 0.5-mm gap is left between adjacent buckets. The depth gauge outer sleeve is fixed on the upper plane of the bracket through screws. The outer circular surface of the bracket is inserted into the inner hole of the hub and positioned through a cylindrical pin. The first gasket and the second gasket are installed in the axial end face gap between the bucket handle groove and the hub disc.

[0005] In the above-mentioned measuring structure for a split impulse turbine model runner, N first pin holes with the same size are evenly distributed on the upper plane of the hub. The number N of the first pin holes is equal to the number of buckets, and the diameter of the distribution circle of the first pin holes is coaxial with the diameter of the inner hole of the hub.

[0006] In the above-mentioned split-type impulse water turbine model runner measurement structure, the bracket has a second pin hole, the diameter of the second pin hole is the same as that of the first pin hole of the hub, and the diameter of the distribution circle of the second pin hole is the same as that of the distribution circle of the first pin hole; the outer diameter of the bracket is the same as the inner diameter of the hub and they are coaxial, and the lower plane of the bracket is coplanar with the upper plane of the hub.

[0007] In the above-mentioned split-type impulse water turbine model runner measurement structure, the lower plane of the outer sleeve of the depth gauge is coplanar with the upper plane of the bracket, and the center line of the inner hole of the hub is perpendicular to the lower end face of the handle of the depth gauge.

[0008] In the above-mentioned split-type impulse water turbine model runner measurement structure, the center line of the outer cylindrical surface of the bracket is parallel to the first prism plane of the bracket, and the following relationship is satisfied:

[0009] a1 = a2

[0010] In the formula:

[0011] a1 is the angle between the vertical coordinate axis and the first prism plane of the bracket, in degrees;

[0012] a2 is the angle between the vertical coordinate axis and the theoretical profile line of the dividing edge of the reference bucket, in degrees.

[0013] In the above-mentioned split-type impulse water turbine model runner measurement structure, the distance from the center line of the outer cylindrical surface of the bracket to the second prism plane of the bracket satisfies the following relationship:

[0014] H = R + 0.05

[0015] In the formula:

[0016] H is the distance from the center line of the outer cylindrical surface of the bracket to the second prism plane of the bracket, in millimeters;

[0017] R is the theoretical maximum outer radius of the reference bucket, in millimeters;

[0018] And the second prism plane of the bracket is tangent to the cylindrical surface with a radius of H and the center of the circle being the center line of the outer cylindrical surface of the bracket.

[0019] The beneficial technical effects of the present invention are:

[0020] 1. Realize the measurement of the circumferential angle, radial dimension and axial dimension between the buckets of the split-type impulse water turbine model runner, provide a basis for the adjustment of the bucket position, and make the installation position of the runner meet the design requirements.

[0021] 2. High measurement accuracy and simple operation: The water bucket's water dividing edge is closely attached to the first prism plane of the bracket. Use a feeler gauge to check the radial clearance between the water bucket and the second prism plane of the bracket, and use a depth gauge to measure the axial dimension, ensuring the accuracy and reliability of the measurement results. Eliminate the errors during the assembly of the water buckets of the split-type impulse turbine model runner, and avoid the deviation of the assembly results caused by different operators' proficiency levels. Description of the Drawings

[0022] Figure 1 is the working principle diagram of the impulse turbine;

[0023] Figure 2 is the sectional view of the measurement structure of the split-type impulse turbine model runner;

[0024] Figure 3 is the top view of the measurement structure of the split-type impulse turbine model runner;

[0025] Figure 4 is the assembly drawing of the bracket of the measurement structure of the split-type impulse turbine model runner.

[0026] Explanation of the component markings in the figure: 1 - bracket, 2 - depth gauge outer sleeve, 3 - screw, 4 - depth gauge handle, 5 - reference water bucket, 6 - bolt, 7 - nut, 8 - cylindrical pin, 9 - hub, 10 - first pin hole, 12 - second pin hole, 13 - outer circular surface of the bracket, 14 - first prism plane of the bracket, 15 - second prism plane of the bracket, 16 - first gasket, 17 - second gasket, 18 - adjacent water buckets. Detailed Implementation Manner

[0027] The present invention will be further described below in conjunction with the drawings and the detailed implementation manner.

[0028] As Figure 2 、 Figure 3 、 Figure 4 shown, a measurement structure of a split-type impulse turbine model runner is composed of a bracket 1, a depth gauge outer sleeve 2, a screw 3, a depth gauge handle 4, a reference water bucket 5, a bolt 6, a nut 7, a cylindrical pin 8, a hub 9, a first gasket 16, and a second gasket 17. The reference water bucket 5 is fixedly connected to the hub 9 through the bolt 6 and the nut 7, and there is a 0.5 mm gap between the reference water bucket 5 and the adjacent water bucket 18. The outer circular surface 13 of the bracket 1 is inserted into the inner hole of the hub 9 and positioned by the cylindrical pin 8. The depth gauge outer sleeve 2 is fixed on the upper plane of the bracket 1 through the screw 3. The first gasket 16 and the second gasket 17 are installed in the axial end face gap between the handle groove of the reference water bucket 5 and the disk of the hub 9.

[0029] In this embodiment, the installation reference of the water bucket and the positioning reference of the bracket are unified to the hub, realizing the unity of the installation reference of the water bucket and the positioning reference of the measuring tool, and avoiding the measurement errors caused by different references.

[0030] On the upper plane of the hub 9, N first pin holes 10 with the same size are evenly distributed. The number of the first pin holes 10 is equal to the number of buckets. The distribution circle of the first pin holes 10 is coaxial with the inner hole of the hub 9. There is a second pin hole 12 on the bracket 1. The diameter of the second pin hole 12 is the same as that of the first pin hole 10 of the hub 9. The diameter of the distribution circle of the second pin hole 12 of the bracket 1 is the same as that of the distribution circle of the first pin hole 10 of the hub 9. The distribution circle of the second pin hole 12 of the bracket 1 is coaxial with the outer circular surface 13 of the bracket 1. The diameter of the outer circular surface 13 of the bracket 1 is the same as and coaxial with the diameter of the inner hole of the hub 9. The lower plane of the bracket 1 is coplanar with the upper plane of the hub 9. The lower plane of the outer sleeve 2 of the depth gauge is coplanar with the upper plane of the bracket 1. The center line of the inner hole of the hub 9 is perpendicular to the lower end surface of the depth gauge handle 4.

[0031] In this embodiment, the bracket is radially positioned by using the diameter of the inner hole of the hub, axially positioned by using the upper plane of the hub, and circumferentially positioned by using the pin holes, ensuring that the installation position of the bracket is accurate and unique, that is, ensuring that the measurement reference position is accurate and unique.

[0032] The center line of the outer circular surface 13 of the bracket 1 is parallel to the first prism plane 14 of the bracket 1, and satisfies the following relationship:

[0033] a1 = a2

[0034] In the formula:

[0035] a1 is the angle between the vertical coordinate axis and the first prism plane 14 of the bracket 1, in degrees;

[0036] a2 is the angle between the vertical coordinate axis and the theoretical profile line of the water dividing edge of the reference bucket 5, in degrees;

[0037] The distance from the center line of the outer circular surface 13 of the bracket 1 to the second prism plane 15 of the bracket 1 satisfies the following relationship:

[0038] H = R + 0.05

[0039] In the formula:

[0040] H is the distance from the center line of the outer circular surface 13 of the bracket 1 to the second prism plane 15 of the bracket 1, in millimeters;

[0041] R is the theoretical maximum outer circle radius of the reference bucket 5, in millimeters;

[0042] And the second prism plane 15 of the bracket 1 is tangent to the cylindrical surface with a radius of H and a center at the center line of the outer circular surface 13 of the bracket 1.

[0043] In this embodiment, the extraction of the reference features of the complex curved surface of the bucket is realized. Taking the straight line segment feature of the water dividing edge profile line of the reference bucket and the feature of the theoretical maximum outer circular surface of the reference bucket as the measurement reference for the bucket position, the measurement structure is simplified and the measurement accuracy of the bucket position is improved.

[0044] When the measuring structure of the split impulse turbine model runner is in use, install the relevant parts at the positions shown in the figure. Loosen the bolt 6 and the nut 7 to make the dividing edge of the reference bucket 5 close to the first prism plane 14 of the bracket 1. Use a feeler gauge to measure the radial clearance between the second prism plane 15 of the bracket 1 and the reference bucket 5, and adjust the radial position of the reference bucket 5 until the clearance meets the requirement of 0 to 0.1 mm. Tighten the bolt 6 and the nut 7, and use the shank 4 of the depth gauge to measure the distance L1 from the upper plane of the reference bucket 5 to the upper plane of the bracket 1. Repeatedly adjust the thicknesses of the first gasket 16 and the second gasket 17 between the handle groove of the reference bucket 5 and the axial end face of the disc of the hub 9 until the measured dimension L1 is equal to the designed dimension L. Pull out the cylindrical pin 8, rotate the bracket 1 to the position where the adjacent bucket 18 is located, insert the cylindrical pin 8 to position the bracket 1, and adjust the installation position of the bucket 6 according to the above steps to meet the design requirements; repeat the above steps to measure and adjust the positions of all N buckets.

[0045] In this embodiment, to improve the actual operability of the measuring structure, based on the difficult-to-measure circumferential positioning, the radial and axial dimension accuracies are appropriately relaxed. While ensuring a certain accuracy of the measuring structure, the operability of the measuring structure is also improved.

[0046] This measuring structure can measure the circumferential angle, radial dimension and axial dimension between the buckets of the split impulse turbine model runner, and adjust the installation position of the buckets to meet the design requirements; this measuring structure has high accuracy, and there are positioning references between all connecting components, without too much manual adjustment, so the influence of human factors on the measurement results can be eliminated, ensuring the reliability and repeatability of the measurement results.

Claims

1. A split-type impulse water turbine model runner measurement structure, characterized in that: It is composed of a bracket (1), a depth gauge outer sleeve (2), a screw (3), a depth gauge handle (4), a reference bucket (5), a bolt (6), a nut (7), a cylindrical pin (8), a hub (9), a first gasket (16), and a second gasket (17); the reference bucket (5) is fixedly connected to the hub (9) through the bolt (6) and the nut (7), and there is a 0.5 mm gap between the reference bucket (5) and the adjacent bucket (18). The outer circular surface (13) of the bracket (1) is inserted into the inner hole of the hub (9) and positioned by the cylindrical pin (8). The depth gauge outer sleeve (2) is fixed on the upper plane of the bracket (1) by the screw (3). The first gasket (16) and the second gasket (17) are installed in the axial end face gap between the bucket handle groove of the reference bucket (5) and the disk of the hub (9); the center line of the outer circular surface (13) of the bracket (1) is parallel to the first prism plane (14) of the bracket (1), and the following relationship is satisfied: a1 = a2 In the formula: a1 is the angle between the vertical coordinate axis and the first prism plane (14) of the bracket (1), in degrees; a2 is the angle between the vertical coordinate axis and the theoretical profile line of the water dividing edge of the reference bucket (5), in degrees; The distance from the center line of the outer circular surface (13) of the bracket (1) to the second prism plane (15) of the bracket (1) satisfies the following relationship: H = R + 0.05 In the formula: H is the distance from the center line of the outer circular surface (13) of the bracket (1) to the second prism plane (15) of the bracket (1), in millimeters; R is the theoretical maximum outer radius of the reference bucket (5), in millimeters; And the second prism plane (15) of the bracket (1) is tangent to the cylindrical surface with a radius of H and a center at the center line of the outer circular surface (13) of the bracket (1).

2. A split-type impulse water turbine model runner measurement structure according to claim 1, characterized in that: The upper plane of the hub (9) is evenly provided with N first pin holes (10) of the same size. The number N of the first pin holes (10) is equal to the number of buckets. The distribution circle diameter of the first pin holes (10) is coaxial with the inner hole diameter of the hub (9).

3. A split-type impulse water turbine model runner measurement structure according to claim 2, characterized in that: The bracket (1) has a second pin hole (12). The diameter of the second pin hole (12) is the same as the diameter of the first pin hole (10) of the hub (9). The distribution circle diameter of the second pin holes (12) is the same as the distribution circle diameter of the first pin holes (10); the diameter of the outer circular surface (13) of the bracket (1) is the same as and coaxial with the inner hole diameter of the hub (9). The lower plane of the bracket (1) is coplanar with the upper plane of the hub (9).

4. A split-type impulse water turbine model runner measurement structure according to claim 1, characterized in that: The lower plane of the depth gauge outer sleeve (2) is coplanar with the upper plane of the bracket (1). The center line of the inner hole of the hub (9) is perpendicular to the lower end face of the depth gauge handle (4).

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