JPH08284884A - Fluid machinery - Google Patents

Abstract

PURPOSE: To improve performance in fluid machinery by chipping the backside of a moving blade by fixed height from the tip end, and forming a thin wall part at the web side. CONSTITUTION: A backside 1b of a moving blade 1 is chipped as far as constant height from the chip end 4, and ship thinning work to chip a cut part 2 is carried out, whereby a thin wall part 3 consisting in height (a) and thickness (b) along the profile is being formed. Accordingly, since a camber angle at a tip part of the moving blade 1 is not increased at all, any pressure rise based on this chip thinning work is thus restrained. In consequence, since the occurrence of any pressure grade in the height direction of the moving blade 1 is checkable, a mixing loss in a secondary flow on the basis of this pressure grade and any increase of fluid quantity to be leaked to the backside 1b from the web side 1a by way of a chip clearance are all preventable. With this constitution, fluid machinery (for example, a fan, a compressor and the like) is well improved in terms of performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial or mixed flow type fan, blower, compressor, pump or other fluid machine.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a rotor blade of a conventional axial blower, which has been subjected to tip thinning processing. The ventral side 1a of the rotor blade 1 having the contour of the airfoil is cut from the tip end 4 of the tip end 4 by a certain height and the cut portion 2 is removed so that the back side is removed.
A thin portion 3 having a constant thickness is formed on 1b along the back curve. 5 is a casing, c is a tip end 4 and a casing 5
2 shows the tip clearance with the inner surface of the.

The tip thinning process is carried out to prevent troubles due to the tip rub and to reduce the tip clearance c to reduce the fluid leaking from the ventral side 1a to the back side 1b of the moving blade 1 to improve the efficiency of the blower. It

[0004]

When subjected to INVENTION Problems to be Solved] chip thinning processing, as shown in FIG. 3, the warp angle theta _O of the tip portion of the blade 1, i.e., blade camber line 6 and chord 7, That is, the angle formed by the straight line connecting the blade leading edge 1c and the blade trailing edge 1d is larger than the warp angle θ when the chip thinning process is not performed.

As a result, the portion subjected to the tip thinning process causes a considerably larger pressure rise than the portion not subjected to the tip thinning process, and causes a large pressure gradient in the blade height direction. Along with this, the mixing loss due to the secondary flow increases and the amount of fluid leaking from the ventral side 1a to the back side 1b through the tip clearance c increases, so that there is a problem that the efficiency of the blower decreases. .

[0006]

SUMMARY OF THE INVENTION The present invention has been invented to solve the above-mentioned problems, and the gist of the present invention is to provide a blade having a wing-shaped contour, and a tip of the blade. In a fluid machine in which a tip clearance is kept between the end and the inner surface of the casing, a thin portion is formed on the ventral side by removing the back side of the moving blade from the tip end by a certain height. It is in fluid machinery.

[0007]

In the present invention, because of the above-mentioned structure, the warp angle of the tip of the moving blade does not increase, so that the pressure increase due to the tip thinning process is suppressed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENT One embodiment of the present invention is shown in FIG. By thinning the back side 1b of the rotor blade 1 from the tip end 4 of the tip end 4 and removing the cut portion 2, a thin portion having a height a and thickness b along the contour of the ventral side 1a 3 is formed.

The warp angle of the tip portion of the moving blade 1 is the same as that when the tip thinning process is not applied, and therefore, as shown in FIG.
It is possible to suppress the pressure rise at the tip of the moving blade as in the case of the conventional one shown in FIG. 1 and prevent the generation of the pressure gradient in the height direction of the moving blade due to this pressure increase.

The case where the present invention is applied to an axial blower has been described above. However, the present invention can be applied to a compressor, a pump, etc., and is not limited to an axial flow type fluid machine. Of course it is possible.

[0011]

According to the present invention, since the thin portion is formed on the ventral side by removing the back side of the moving blade from the tip end by a certain height, the warp angle of the tip of the moving blade does not increase. The pressure increase due to processing can be suppressed. As a result, it is possible to prevent the generation of a pressure gradient in the height direction of the moving blade, and thus prevent an increase in the amount of fluid leaking from the ventral side to the dorsal side through the mixing loss of the secondary flow and the tip clearance due to this pressure gradient. You can.

Thus, the conventional tip thinning processing is carried out without impairing the advantages of the tip thinning processing, that is, the advantages of preventing troubles due to the tip rub and reducing the amount of fluid leaking from the ventral side of the moving blade to the back side through the tip clearance. The problem of can be solved and the performance of the fluid machine can be improved.

[Brief description of drawings]

FIG. 1 is one of rotor blades of an axial flow fan according to an embodiment of the present invention.
An example is shown, (A) is a perspective view of the tip portion of the moving blade, and (B) is a sectional view taken along the line BB of (A).

FIG. 2 shows a moving blade of a conventional axial-flow blower, (A) is a perspective view of a tip portion of the moving blade, and (B) is a cross-sectional view taken along line BB of (A).

FIG. 3 is an explanatory diagram showing a warp angle of the conventional blade tip portion.

[Explanation of symbols]

 1 Blade 1a Ventral side 1b Dorsal side 2 Cut section 3 Thin section

Claims (1)

[Claims] 1. A fluid machine comprising a moving blade having an airfoil profile, wherein a tip clearance is left between the tip end of the moving blade and the inner surface of the casing. A fluid machine characterized in that a thin portion is formed on the ventral side by removing a certain height from the end.