WO1998054470A1

WO1998054470A1 - A fan with outer band

Info

Publication number: WO1998054470A1
Application number: PCT/CN1997/000125
Authority: WO
Inventors: Wei Han
Original assignee: Wei Han
Priority date: 1997-05-28
Filing date: 1997-11-14
Publication date: 1998-12-03
Also published as: AU5114898A; CN2304777Y

Abstract

A fan includes a rotating shaft (2) and a polarity of blades (3) mounted on said shaft (2), characterized in that an annular outer band (1) is mounted on the top of said blades (3). The fan can be worked in low resistant, concentrated effort and centralized direction. The top lost can be eliminated and main working area can be extended to the top of said blades. The power transform efficiency from the shaft to air flow can be increased in 40 % or higher, and the power transform efficiency in supersonic condition can be increased in 60 % or higher. The structure strength can also be improved.

Description

The present invention relates to a paddle fan mainly used for actively performing work on a fluid, and is mainly used for the propulsion of an aircraft, a ship, a fluid transfer such as an axial flow pump, an axial compressor and a fluid blowing such as a fan. , Ventilator, etc.

The existing paddle fan generally consists of a rotating shaft and paddle leaves fixed on it. Its main working area is 0.7 leaf lengths. From 0.7 leaf length to the leaf end, it is the fastest moving area. According to area, this area occupies about half of the entire rotation area of the pulp fan. According to the generated force, this area accounts for Above 75%, in this area, due to the loss of the blade end, the pressure difference between the positive pressure surface and the negative pressure surface of the blade decreases, and it drops to almost 0 at the blade end. A fast position, but it is the position where the maximum effective power contribution of the ordinary paddle fan is zero, and the blade end is seriously lost. Therefore, the efficiency of converting the rotational energy of the existing paddle fan to the axial kinetic energy of the fluid is low, and the paddle thickness is also low. , The large amount of raw materials, no positive interface between the positive and negative pressure at the blade end and between the surrounding media and the surrounding medium, vulnerable to the disadvantages of external conditions.

The object of the present invention is to provide a pulp fan, which can make up for the above-mentioned disadvantages of the existing pulp fans.

The paddle fan of the present invention has a rotating shaft on which paddle leaves are mounted, and is characterized in that a round wheel edge is fixed by the blade ends of the paddle leaves.

According to the application occasion of the present invention, a hole can be made on the wheel edge of the paddle fan as required.

According to the paddle fan of the present invention, all products are axisymmetric in shape.

The paddle fan of the present invention has small rotation resistance, concentrated force, and good directivity, which completely eliminates the blade end loss, expands the main working area of the blade from 0.7 blade length to the blade end, and converts the real work on the rotating shaft into fluid flow. The efficiency of flow work has been increased by more than 40%. The rotational force of the shaft is efficiently converted to thrust under supersonic conditions. Its efficiency is about 60% higher than that of turbojet engines, while also improving the structural strength.

The invention will be described below by means of examples and drawings.

The drawing is a schematic diagram of a paddle fan of the present invention.

Embodiment 1 The paddle of the present invention has a rotating shaft (2), and a paddle (3) is mounted on the paddle. The angle is 45. It is placed in a thin cylinder with a corresponding inner diameter, that is, the rim (1), which is welded to the blade end of each paddle (3). The width of the rim (1) is 0.1 meters and the inner diameter It is 0.8 meters, and its plate surface is parallel to the rotation axis (2) and surrounds the latter. The wheel rim (1) is a revolving body with a very smooth surface, which is concentric with the axis (2) that drives it. When working, the wheel edge (1) only generates frictional resistance in the direction of rotation, and the power lost by the latter accounts for only a few thousandths to a few percent of the output power of the pulp fan. And as the speed increases, this part of the loss will be relatively cut back. Experiments have shown that the resistance of this product is less than that of ordinary pulp fans of the same size.

The product of the present invention is axially symmetrical in shape or the generated force is basically symmetrical, so the forces acting on the wheel rim (1) in the radial direction cancel each other, and the resultant force is zero (except for gravity). Because the paddle (3), the wheel edge (1) and the hub (2) are connected into multiple triangles and I-shaped shapes. Therefore, the structural strength, stability and bearing capacity of the pulp fan are greatly enhanced. Compared with ordinary propellers, the thickness of the blade can be reduced, which not only reduces weight but also reduces losses.

The following theoretically calculates the static thrust F of the present embodiment using the atmosphere as a medium:

F = PAV flat V flat

Where P is the air density of 0.125 kg s ² / m ⁴ , A is the area of the paddle fan 0.5 m ² (the diameter of the paddle fan is 0.8 m), and V is the average air velocity. In this embodiment, the tip speed is set. The V tip is 550 m / s, which is the speed of the compressor blade tip reached by the American IHPTET plan. The effect of gas compressibility is not considered in the calculations. In this embodiment, the tip speed is the largest, and the center is zero. Therefore, when calculating F using the above formula, the speed should be the average value. It can be proved that V flat ² = 0.5 V tip ² in this case.

F = 0.5PAV tip ² = 9453 (kg force)

Then use the known plate resistance formula {refer to Xu Weide's "Fluid Mechanics" (published in December 79, National Defense Industry Press) P253 P259 friction resistance calculation formula} to calculate the resistance Z generated by the wheel edge of the device in order to estimate the wheel edge loss Percentage of output power:

Z = 0.5CPWM

Where C is the coefficient of resistance, P is the density of air, V is the loss of V, M is the area of the wheel edge, and the wheel edge is a rectangular plate with a length of L = 2πκ = 2.5 meters, and the sum of its internal and external surface areas, M 0.5 square meters. The resistance coefficient in the above formula can be obtained from the following formula

C = ⁰⁴⁵⁵ = 0.0021

(lgR) 2.58

Where R is the thunder number can be obtained by the following formula:

R = ~~ ― · ~ = ^{2 5 x 550} = 94827586

1.45 x 0.00001 1.45 x 0.00001

So

Ζ = 0.5CPV tip ^{2 · Μ = 0.5 X 0.0021 χ} 0.125 χ 550 2 χ 0.5 = 19.85 ( kgf)

If the torque factor is not considered, the ratio of wheel edge resistance to total thrust:

Resistance / Thrust =-= 0.0021

9453

It is not difficult to conclude from the above rough estimation, even if the resistance of the wheel is 10 times larger than the above estimate, its resistance is not only 2.1% of the total thrust.

Practical Example 2 In a water tank, a paddle fan with a diameter of 150MM was tested with seawater as the medium. The paddle's rim was stamped from 0.5MM thick metal without quilting. The paddle blade end and the rim were fixed by soldering. With a wheel edge width of 20 MM and a wheel-shaped paddle fan speed of 1400 rpm, the V tip = 10.8 meters can be obtained from this, so it can be calculated using the following formula

F = 0.5PAV tip ² = 107 (kg force)

Wherein the sea water density 104 kg Ρ ² sec / m ^{4, Α} fan area of the pulp, in this embodiment, ^{A = π (^^) 2 =} 0.0177 m ²

The following is an example of calculating the resistance Z generated by the wheel edge of the pulp fan in accordance with Example 1:

Z = 0.5CPV tip ² Μ = 0.388 kgf,

In this embodiment, the length of the bell is L = π · 0.15 m = 0.47 m, and the wheel area M = 2 X 0.47 m X 0.02 m = 0,0188 m ² .

Finally, following the example of real pants, the ratio of wheel resistance to total thrust is estimated

Resistance / Thrust = ^ = 0, 0036

107

That is to say, when the medium is seawater, the wheel thrust only accounts for 3.6% of the total thrust. When the pulp fan of the present invention is used as a fan, a fan decompression hole (4) may be opened on the wheel edge (1). The above-mentioned appendixes and embodiments are only used to illustrate the present invention. Any person skilled in the art can make technical and technical modifications within the protection scope of the claims of the present invention, such as the size changes of the pulp fan and the wheel edge. And glued or integrally cast between them, or the angle between the wheel edge and the axial direction, etc., are not beyond the scope of the present invention.

Claims

1. A paddle fan with a wheel edge, which has a rotating shaft (2) and is equipped with paddle leaves (3), which is characterized in that a round wheel edge (1) is fixed by the blade ends of the paddle leaves (3).

2. The paddle fan according to claim 1, characterized in that the wheel edge (1) is a circularly rotating body with a smooth and dynamic surface, which is concentric with the rotation axis (2).

3. The paddle fan according to claim 1, characterized in that the wheel edge (1) is provided with a pressure relief hole (4).