JPS62142805A - Moving blade for axial-flow fluid machine - Google Patents

Abstract

PURPOSE:To prevent leakage flow due to the presence of a moving-blade tip clearance from taking place by providing a plate-like part which is placed in a slit-shaped groove extending virtually in the direction of the chord of the blade tip so as to be able to move radially, and then providing the plate-like part in such a manner as to move outward freely by the centrifugal force. CONSTITUTION:In a slit-shaped groove 7, which is provided on the blade tip of a moving blade 1 in such a manner as to be curved a little in line with its camber, is fit a plate-like part 6 so that it may be free to travel radially, and then, its movement in the direction of the chord of blade is regulated by means of the leading edge of the groove 7. In addition, on the plate-like part 6 is provided a radial hole 9, and into the hole 9 is inserted a check pin 8, which penetrates the moving blade 1 perpendicularly, so as to guide the radial movement of the plate-like part 6. And further, the centrifugal force resulted from the rotation of the moving blade 1 causes the plate-like part 6 to move outward radially so that it comes onto sliding contact with a casing 2 and thereby, leakage flow from the front side of the moving blade 1 toward the back side thereof, which was caused by the presence heretofore of a clearance between the tip of the moving blade 1 and the casing 2, can now be checked by means of the plate-like part 6 as mentioned above.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an improved counterfeiting of the motion of an axial fluid machine, particularly at the end.

[Technical background of the invention and its problems]

The aerodynamic performance of trickle-flow compressors and turbines has improved significantly, thanks in part to recent significant improvements in computer performance.

Problems with improving efficiency in such axial flow type fluid machines include losses mainly due to fluid viscosity such as secondary flow and wall friction, as well as large losses due to leakage at various locations. Particularly in axial flow fluid machines, there are always gaps between the rotor blades and casing, or between the stator vanes and the rotor due to the structure, but losses due to leakage from these parts account for a very large proportion of the total loss in fluid machines. It is clear that the majority of

The most effective way to reduce this leakage loss is to make the gap as small as possible, but this requires great precision in the workmanship, and also because of the elongation caused by centrifugal force during operation. , expansion due to temperature increase.

In reality, there is a limit to how small this gap can be made, since deflection due to its own weight has a complicated effect.

For these reasons, especially for high-performance axial flow fluid machines, efforts are being made to minimize the loss due to gaps at the blade tips by the following means.

1. A shroud is provided at the wing tip.

2. By using honeycomb etc. on the part facing the wing tip, there will be no effect even if the wing slides.

3. The portion facing the blade tip can be deformed by using mechanical or thermal control.

Therefore, in the conventional technology, in order to suppress the loss due to the blade tip gap, it is necessary to provide a very complicated and expensive device, and there is a limit to the application of such technology. It was hoped that an effective, simple, and inexpensive method would emerge to suppress this.

[Purpose of the invention]

An object of the present invention is to provide a simple and inexpensive method for obtaining a highly efficient axial flow machine by minimizing the loss caused by leakage from the blade tip gap of an axial flow machine, in place of the above-mentioned conventional device. It is about providing.

[Summary of the invention]

In order to achieve the above object, the invention of item 1 has a slit-like groove at the tip of a rotor blade of an axial flow fluid machine, the length extending in the direction of the 8th chord and extending over most of the chord length of the blade. , is fitted into this slit-like groove and is provided with a plate-like part that is movable in the radial direction. The plate-shaped part is held in the slit-shaped groove and receives a radially outward force due to the centrifugal force generated when the rotor blade rotates, and is pressed against the opposing casing part, filling the gap between the blade tip and the casing with the blade. This seals the leakage flow from the ventral side to the dorsal side.

The plate-like part can be made smaller than the blade, and its shape and material are selected so that it has enough weight to slide against the casing with an appropriate force depending on the size and rotational speed of the machine. Depending on the conditions, using Teflon (trade name) or a polishable material can further enhance the effects of the present invention. Further, it is preferable that the outer peripheral end of the plate-like member is finished in an arcuate shape or in a manner that the width gradually decreases to reduce the contact resistance.

The slit-like groove is provided for the purpose of holding the plate-like portion. The grooves may run chordwise or may be sealed at the leading edge and/or the trailing edge. However, except in the last case, a means for restraining the plate-like portion in the chord direction is required. The present invention does not limit the means.

Both the slit-like groove and the plate-like part do not have to be straight,
Depending on the camber angle of the wing, it may be good to have some degree of warpage.

It is conceivable that the leading edge side end and trailing edge side end of the plate-shaped portion be finished with a curvature or that the plate thickness be gradually reduced in order to reduce the thickness of the blade and fluid resistance. In this case, it goes without saying that the shape of the groove also needs to correspond to the shape of the plate-like portion.

Although the plate-shaped portion is movable in the radial direction, there is no need for any means to limit the range of movement.

However, depending on the restraint means in the chord direction, the work at the time of assembly can be simplified by serving both purposes.

It is sufficient that the radial movement is limited only by the casing surface after assembly, but if no other horizontal bundling means is provided, the plate-like portion may fall off before the rotor and casing are assembled. Requires a means to prevent this.

For this purpose, it is necessary to remove it after 711, so it is conceivable to use a clip-like object, or simply an adhesive tape.

The invention of item 2 is included in the invention of item 1, but in order to be especially applicable to machines that operate at low rotational speeds and stages with low circumferential speed, the invention uses a force directed outward in the radial direction as an auxiliary guard. It is equipped with an elastic body that provides Further, this elastic body can serve both of the purposes of preventing the plate-shaped component from falling off and restraining the blade in the chord direction, as described in the first aspect of the invention.

〔Effect of the invention〕

According to the present invention, a relatively simple structure can reliably reduce the leakage flow due to the gap between the rotor blade tips.

According to the present invention, accurate leakage prevention can be performed for each moving blade, so for example, if there is variation in the gap between the blades due to slight eccentricity, etc., it is difficult to deal with this with the conventional technology, but with the present invention, It is possible.

[Embodiments of the invention]

The present invention will be read in one piece based on the figures. FIG. 1 shows a perspective view of a first embodiment of the invention.

Due to the centrifugal force caused by the rotation of the moving blades, the plate-shaped portion 6 is caused by the moving tool tip 5.
It protrudes and moves radially outward.

Although the plate-shaped portion 6 is omitted in FIG. 1, its radial movement is restrained by the casing 2. Therefore, the leakage flow from the ventral side to the dorsal side of the rotor blade, which was caused by the gap existing between the blade part of the conventional wJ blade and the casing, is blocked by the plate-shaped part 6, and the loss caused by this leakage flow is reduced. It is reduced to a large extent. In the example shown in FIG. 1, the plate-like portion 6 is slightly curved to accommodate the curvature of the rotor blade 1. Further, movement in the chord direction is restrained by the slit-like groove 2 being closed at the leading edge and by the pin 8, and the pin 8 is fixed at the radius of the plate-like part 6 to the extent that the assembly work is easy. Movement in the direction is also restricted. FIG. 2 shows a side view and a front view with respect to FIG. 1, and FIG. 3 shows a side view and a front view similar to those shown when the rotating blade is stopped. In FIG. 3, the plate-shaped portion 6 is separated from the casing 2 because no centrifugal force is applied. (Depending on the stopping position of the rotor blade, the state may be exactly the same as shown in Fig. 2 due to the influence of gravity.) The slit-like groove 7 and the plate-like portion 6 are the plate-like portion when the rotor blade rotates. 6 is made to move smoothly. Further, in the example shown here, the outer end of the plate-shaped portion is made at a right angle, but it may be finished into an arcuate end face in order to reduce contact resistance. Next, a second embodiment of the present invention will be described with reference to FIG. This is achieved by adding an elastic body 10 to the first embodiment described above to constantly apply outward force in the radial direction, and even during low speed rotation, etc. Similar effects can be expected. The shape of the elastic body 10 shown in FIG. 4 is an example, and is not limited to this shape.

By engaging the elastic body 10 between the rotor blade 1 and the plate-like portion 6, it is also possible to restrict the movement range of the plate-like portion 6 in the axial direction and the radial direction.

[Other embodiments of the invention]

The embodiments described above merely show examples of applying the present invention, and needless to say, they do not limit the present invention. For example, the shape of the plate-like portion 6, the slit-like groove 7, the material of the plate-like portion 6, etc. can be freely selected depending on the performance required for the stage of the applied axial flow fluid machine, the cost, etc. The means for restraining the portion 6 in the axial and radial directions are also not limited,
For example, in the example shown in FIG. 1, if the plate-like portion 62 and the slit-like groove are made straight, the processing cost can be greatly reduced.
And almost the same effect can be expected.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the first embodiment of the present invention, and FIG. 2 is a perspective view of the first embodiment of the present invention.
FIG. 3 is a diagram showing the state of the embodiment of the present invention shown in FIG. 1 when it is stopped; FIG. 4 is a diagram showing the state of the embodiment of the present invention shown in FIG. A side view of the embodiment, and FIG. 5 is a perspective view of the conventional example. 1... Moving blade 2... Casing 3...
Rotor 4...Flip flow 5...Rotor blade tip
6... Plate-shaped portion 7... Slit-shaped groove 8.
... Stopper pin 9 ... Stopper hole 10 ... Elastic body 11 ... Notch 12 ... Ventral side of the opening 13 ...
・Dorsal side of the wing 14... Leading edge of the wing 15... Trailing edge of the wing Agent Patent attorney Nori Chika Ken Yudo Kikuo Takehana Figure 1 Figure 2 (a) (b) Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) It has a slit-like groove extending almost in the chord direction of the blade tip and spanning most of the chord length, and a plate-like part that is fitted into the slit-like groove and movable in the radial direction, and the machine rotates. A rotor blade for an axial flow fluid machine, characterized in that the plate-shaped portion is provided so as to be movable in a direction toward an opposing casing by centrifugal force caused by motion. (2) A rotor blade for an axial fluid machine according to claim 1, characterized in that an elastic body is provided between the slit and the plate-shaped part to push the plate-shaped part radially outward. .