JPS61212603A - Turbine vane wheel - Google Patents

Abstract

PURPOSE:To prevent the generation of resonance by alternately planting the movable vanes in which only the downstream side of the root part is attached onto a van wheel board and the movable vanes in which only the upstream side is attached, in the circumferential direction. CONSTITUTION:The first turbine movable vane 11A for which only the downstream side 12a is attached among the contact surfaces with a root part 4 and a vane wheel board 1 and the second turbine movable vane 11B for which only the upstream side 12b is attached are planted alternately in the circumferential direction. Therefore, a circular shroud 6 is firmly fixed, and the gap of the shroud 6 can be offset, and the variation of the characteristic frequency of the movable vane is prevented, and the generation of resonance can be prevented.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a turbine wheel.

2. Description of the Related Art A conventional turbine wheel has a structure as shown in FIG. That is, 1 is a blade wheel disk, and a key groove 2 having a 1-shaped cross section and extending in the circumferential direction A is formed on its outer surface. Reference numeral 3 indicates a circumferentially embedded type turbine rotor blade, which includes a root portion 4 that engages with the keyway 2, a 1ζ blade portion 5 attached to the root portion 4, and an arc-shaped shroud provided at the tip of the shoulder portion 5. 6. 7 is a fin formed on the shroud portion 6. A plurality of such turbine blades 13 are implanted in the circumferential direction A of the second blade 1 using the keyway 2, but the roots 4 and shroud parts 6 of adjacent turbine blades 3 are mutually By sliding them together, they are assembled with almost no gaps.

The wheel disk 1 rotates in the circumferential direction, and the centrifugal force generated in the turbine drive 113 due to this rotation is received by the engagement between the keyway 2 and the root 4 . 8 is root 4
This is the contact surface with the blade wheel disk 1 in . Note that B in the figure indicates the direction in which the fluid flows, but the circumferential direction component of the flow is ignored.

Problems to be Solved by the Invention However, in such a conventional configuration, the root portions 4 and the shroud portions 6 are slid together with almost no gap during assembly as described above. However, in regular inspections for actual wear and tear, there were many cases in which gaps 9 in the circumferential direction were found between the shroud parts 6, as shown in the figure. The gap 9 generated in this shroud part 6 is due to the turbine gap 113 adjusted without a gap.
, which could cause dangerous resonances.

SUMMARY OF THE INVENTION An object of the present invention is to solve these conventional problems and to compensate for the gaps generated in the shroud.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides that, of the contact surfaces of the roots of the turbine rotor blades with the blade wheel disk, only the downstream side in the axial direction of the blade wheel disk is connected to the blade wheel disk. A first turbine rotor blade that is in contact with the blade wheel disk and a second turbine rotor blade that is in contact with the blade wheel disk only on the upstream side in the axial direction of the blade wheel disk are alternately implanted in the circumferential direction of the shoulder wheel. It is something.

If the action is like this, when the impeller rotates, the turbine!
Centrifugal force acts on 1JII, but since the surface load on the contact surface of the root is eccentric, a moment acts in a direction that tilts the turbine rotor blade. As a result, the first turbine rotor blade is tilted downstream, the second turbine rotor blade is tilted upstream, and the arcuate shroud portions are firmly fixed to each other. This compensates for the gaps in the shroud that occur after long-term operation.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on FIG. 1, with the same numbers assigned to the same members as in FIG. 3. In FIG. 1, 11A is the first turbine rotor blade, and only the downstream contact surface 12a contacts the blade wheel disk 1, and a gap 13b is provided between the upstream contact surface 12b and the blade wheel disk 1. It is being In addition, 11B is the second turbine rotor blade;
11, only the upstream contact surface 12b contacts, and a gap 13a is provided between the downstream contact surface 12a and both vehicle panels 1. These first and second turbine engines l111A
111B uses keyway 2 to ride on the shoulders! 11 are implanted alternately in the circumferential direction. Incidentally, when implanting, the root portion 4 and the shroud portion 6 are spaced apart from each other so that there is no gap, as in FIG. 3.

In such a configuration, when the turbine intervening wheel 15 rotates, centrifugal force acts on the turbine motion IllIIA, 11B, but since the surface loads of the contact surfaces 12a, 12b are eccentric, the direction in which these I[lJmllA, 11B are inclined is moment acts. In addition, the first turbine rotor blade 1
1A, a moment 14A toward the downstream side centering on the downstream hit point 12a acts, resulting in a tilt toward the downstream side, and on the other hand, in the second turbine motion 11i1B, a moment 14B toward the upstream side acts. This causes a tilt toward the upstream side. As a result, the first and second turbines l! ! The palanquins 11A and 11B are inclined in opposite directions in the axial direction C, and the adjacent arcuate shroud portions 6 are firmly fixed to each other.

Therefore, the gap 9 in the shroud section 6 that occurs during operation is sufficiently compensated for, and changes in the natural frequencies of the turbine rotor blades 11A and 11B due to the gap 9 are prevented, thereby preventing the occurrence of dangerous resonance. Prevented. Note that the turbine engines 11A and 11B are in the first position due to their inclinations.
As shown in Figure a, some movement occurs in the axial direction C, but the gap 9 is usually small (about 0.1 shield), so it does not actually become a problem.

FIG. 2 shows another embodiment of the invention.

In this example, in the first turbine rotor blade 11A, in which only the downstream contact surface 12a contacts the WaX board 1, there is no upstream contact surface, and similarly, in the second turbine rotor blade 11B, the downstream contact surface is eliminated. The configuration is such that the . With such a structure, the structure of the root portion 4 is simpler than that shown in FIG. 1, so that it has the advantage that IIl'ftL is easier.

Effects of the Invention As described above, according to the present invention, the first turpin intercostal space and the second turbine initial water are tilted in opposite directions in the axial direction of the width Im, and the arcuate shroud portions are firmly fixed to each other. Therefore, it is possible to compensate for the gaps in the shroud that occur after long-term operation. Therefore, it is possible to prevent the natural frequency of the turbine rotor blade from changing, and to prevent dangerous resonance from occurring.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing another embodiment of the present invention, and FIG. 3 is a three-sided view of a conventional example. 1... Blade wheel board, 2... Keyway, 4... Root, 11
A: first turbine rotor blade, tiB: second turbine rotor blade, 12a: downstream contact surface, 12b: upstream contact surface, 15: turbine pulley, A. ... Circumferential direction, B... Flow direction, C... Axial direction agent Yoshihiro Morimoto Fig. 2 (4) (N2 Fig. 3 (a> tG)

Claims (1)

[Scope of Claims] 1. A blade wheel disk in which a key groove having an inverted T-shaped cross section is formed in the circumferential direction, and a root portion in the circumferential direction that is engaged with the key groove so as to withstand centrifugal force during rotation. A turbine wheel equipped with a built-in type turbine rotor blade, wherein only the downstream side in the axial direction of the blade wheel disk of the contact surface of the root portion that contacts the blade wheel disk is brought into contact with the blade wheel disk. The first turbine rotor blade and the second turbine rotor blade, in which only the upstream side in the axial direction of the blade wheel disk is in contact with the blade wheel disk, are alternately implanted in the circumferential direction. Turbine wheel.