RU2234002C2 - Water-cooling tower fan - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: invention relates to cooling fans for circulating water cooling towers. Proposed fan has shaft with hub, blades and drive. Novelty is that fan is provided with pylons installed on each blade and made in form of variable-curvature envelopes.

EFFECT: improved aerodynamic characteristics of fan, reduced losses and discharge of harmful matter into ambient atmosphere.

16 cl, 15 dwg

Description

The invention relates to industrial power engineering, in particular to a device for fan cooling towers for cooling circulating water.

Known fan blades of the cooling tower, made tapering to the end and containing spars, ribs connected to them, stringers and casing, and the spars are made in the form of longitudinal elements diverging from the bearing axis, and each spar consists of two halves intersecting in the area of reinforced ribs, while closer to the center of rotation of the fan, the outer parts are connected to their ends and laid along the blade (analog) [1].

However, the aerodynamic properties of the blade do not allow to fully ensure the efficient operation of the fan due to the flow of the working medium along the blade.

A fan for a cooling tower is also known, comprising a shell body, an axis with a hub, blades with spars and ribs. The spars are docked with the hub in one piece. Adjacent spars of adjacent blades are rigidly bonded to each other, and their attachment site is connected to the hub. With an unpaired number of spars of one blade, the attachment point of adjacent spars of adjacent blades is connected to the hub by means of a jumper, and the central spars are joined at a nodal point representing a hub. With a pair of spars of one blade, adjacent spars of adjacent blades are connected to the hub without a bridge. Adjacent spars of adjacent blades with a bend pass into each other. The fan drive is carried out through the drive gear eccentrically located relative to the axis of rotation, which is meshed with the wheel located inside the sleeve (prototype) [2].

Known fan for the tower has the following disadvantages:

a) during the operation of the fan, the flows of the working medium move from the high-pressure zone to the low-pressure zone, the medium flows not only in the required pumping direction, but also along the blade, which leads to loss of fan power;

b) an uneven flow of the working medium is formed behind the fan, which causes inefficient use of the expanding part of the diffuser;

c) the emerging local cross-sectional flow causes the formation of a zone of reduced pressure, which contributes to a more intense release of water vapor into the atmosphere;

d) together with water vapor, a large amount of harmful substances contained in the working environment is released, which leads to environmental degradation.

The objectives (goal) of the present invention are to improve the aerodynamic characteristics of the fan, reduce losses, as well as reduce emissions of harmful substances into the environment.

These tasks are achieved in that the fan for the cooling tower, containing a shaft with a hub, blades and a drive, has pylons installed on each blade and made in the form of shells of variable curvature. In particular, the pylons can be made and arranged in an Archimedean spiral in the plane of rotation of the fan. In another embodiment, the curvature of each pylon is made in accordance with the radius of the circle corresponding to the points of their removal from the center of rotation of the fan. Pylons can be not only curved, but also flat. In the particular case, the pylons are made in the form of shells of zero curvature, namely in the form of plates. Pylons can have a plan shape in the form of a rectangle, parallelogram, trapezoid, circle, ellipse and other geometric shapes, or composite of their fragments, selected depending on the operating mode of the fan. Pylons can have different angles of location relative to the plane of rotation of the fan. So, the pylons are located at a certain angle to the plane of rotation of the fan, and in the simplest case, perpendicular to the specified plane. Pylons of the same blade can have both different sizes in plan and the same size. It is desirable that the pylons located closer to the center of rotation have a smaller surface area in plan compared to pylons located on the periphery. As an embodiment, the pylons may have a larger area on the suction side of the fan from the total area in plan than at the outlet.

In FIG. 1 is a schematic representation of a fan cooling tower with a proposed fan;

in FIG. 2 shows a diagram of a fan blade of a cooling tower with pylons of the same configuration and the same size, located parallel to the axis of rotation of the fan shaft and mounted symmetrically relative to the profile of the blade;

in FIG. Figure 3 shows an option for attaching a plate pylon to a fan blade;

in FIG. 4 shows a direct attachment of the pylon to the blade;

in FIG. 5 shows a diagram of a fan blade with different-sized pylons located perpendicular to the plane of rotation of the fan and fixed symmetrically relative to the profile of the blade;

in FIG. 6 is a diagram of a fan blade of a cooling tower with pylons perpendicular to the plane of rotation of the fan and secured asymmetrically with respect to the profile of the blade;

in FIG. 7 is a diagram of a fan blade of a cooling tower with pylons located at an angle to the plane of rotation of the fan;

in FIG. 8 is a view A of FIG. 2, 5 and 6;

in FIG. 9 shows a rectangular (in plan) pylon (section B B), one side of which is parallel to the plane of rotation of the fan, for example, for the variants of FIGS. 2 and 5;

in FIG. 10 shows a rectangular (in plan) pylon, one side of which is located at an angle to the plane of rotation of the fan;

in FIG. 11 is the same for the embodiment of FIG. 6;

in FIG. 12 shows a pylon in the form of a circle (in plan);

in FIG. 13 - pylon in the form of an ellipse (in plan);

in FIG. 14 - fan with blades on which pylons are mounted, bent around circles with radii corresponding to the pylon removal points from the center of rotation of the fan;

in FIG. 15 shows a fan with pylons of arbitrary curvature located with a certain angle of attack relative to the direction of rotation.

The fan for the cooling tower is installed on the central rack 1 of the cooling tower, which consists of a casing 2, a supporting part 3, a drainage basin 4, an irrigation system 5, a water distributor 6, and a droplet eliminator 7. The hub 8 of the fan is rigidly mounted on a shaft 9 having a drive (not shown). On the hub 8, blades 10 are installed, on each of which pylons are fixed 11. The pylons are made in the form of shells of variable curvature. In the particular case, they can be made in the form of shells of zero curvature, namely, plates.

The pylons in the plan can be in the form of a rectangle 12 (Fig. 9, 10, 11), a circle 13 (Fig. 12), an ellipse 14 (Fig. 13), a parallelogram, a trapezoid and other geometric shapes, or can be composed of fragments thereof (composite pylon), selected depending on the operating mode of the cooling tower fan and design considerations. Some of these geometric figures are not shown in the drawings. The surface (forming line) of the pylons 11 is oriented at a certain angle to the plane of rotation of the fan, in the simplest case, perpendicular to the plane of rotation of the fan.

The pylons can be either the same (Fig. 2, 6, 7), or of different sizes in plan (Fig. 5), that is, equally large and different. It is desirable that the pylons located closer to the center of rotation were made with a smaller surface area in plan than the surface area of the pylons located on the periphery.

Pylons can be fixed both symmetrically (Fig. 2, 5, 7) and asymmetrically (Fig. 6, 11) relative to the blade profile (depending on the fan operation mode). As an embodiment of the fan, the pylons may have a larger area on the suction side of the fan from the total area in plan than at the outlet.

Pylons 11 can be fixed either to the blades by means of the connecting corners 15 and 16 (Fig. 3), or directly to the blades (Fig. 4). Pylons can be made either single-layer (Fig. 3), or two-layer without fillers (Fig. 4), or two-layer with an inner layer of filler (three-layer), depending on the necessary stiffness characteristics of the pylon for bending.

The pylon, rectangular in plan, can be positioned so that one side is either parallel to the plane of rotation of the fan, or at an angle to the specified plane.

When making pylons with arbitrary curvature, they are usually placed with a certain angle of attack relative to the direction of rotation of the fan. Pylons can have variable curvature in the plane of rotation, in particular, can be executed and arranged in an Archimedean spiral.

When making pylons of constant curvature (with a constant radius of curvature), the curvature of each of them is performed in accordance with the radius of the circle corresponding to the point of removal of a particular pylon from the center of rotation of the fan.

The cooling tower fan operates as follows.

The rotation from the drive through the shaft 9 is transmitted to the hub 8 with the blades 10. The blades 10 act on the working medium and drive it through the internal cavity of the tower. When carrying out the working process, the working medium moves at an angle to the axis of the blade 10. A part of the flow, moving parallel to the axis of rotation of the fan and flowing around the profile of the blade 10, creates a useful pressure for pumping the working medium. Another part of the flow, trying to move along the longitudinal axis of the blade 10, is delayed from unproductive movement by the pylons 11 and reoriented in the desired direction, creating additional useful traction and aligning the flow density in the cross section of the tower. Thus, the pylons impede the movement of the flow of the working medium along the blade, increasing the efficiency of the fan.

To increase the efficiency of the fan under different operating conditions, the pylons 11 are made of various shapes in plan with different areas in plan within the same blade, installation angle, curvature and configuration. This design of the pylons 11 further equalizes the flows, optimizing the modes of operation of the fan. In particular, the curved design of the pylons allows to reduce the aerodynamic drag of the pylons themselves, and the design and arrangement of the pylons, for example, along an Archimedean spiral, significantly increases the pumping head due to the active reorientation of the incoming flow.

Thus, energy losses are eliminated due to reorientation of the unproductive part of the flow in the desired direction. In addition, a fairly uniform field of the working medium is created above the fan. All this provides additional draft flow in the tower, reduces water loss and the release of harmful substances into the atmosphere. Increases the efficiency of cooling the circulating water. It becomes possible to reduce the fan speed.

The annual economic effect of the use of this invention is approximately 690-1732 thousand rubles per tower (depending on the class of the tower).

Sources of information taken into account

1. Patent of the Russian Federation No. 2101640, M. Cl. F 28 C 1/00, publ. 01/10/98 (Bulletin No. 1).

2. Patent of the Russian Federation No. 2123139, M. Cl. F 04 D 17/00, publ. 12/10/98 (Bulletin No. 34).

Claims (16)

1. A fan for a cooling tower, comprising a shaft with a hub, blades and a drive, characterized in that on each blade there are pylons made in the form of shells of variable curvature. 2. The fan for the tower according to claim 1, characterized in that the pylons are made and arranged along an Archimedean spiral in the plane of rotation of the fan. 3. The fan for the tower according to claim 1, characterized in that the curvature of each pylon is made in accordance with the radius corresponding to the points of their removal from the center of rotation of the fan. 4. The fan for the tower according to claim 1, characterized in that on each blade installed pylons made in the form of plates. 5. The fan for the cooling tower according to any one of claims 1 to 4, characterized in that the pylons have a plan in the form of a rectangle. 6. The fan for the cooling tower according to any one of claims 1 to 4, characterized in that the pylons have a plan shape in the form of a parallelogram. 7. The fan for the cooling tower according to any one of claims 1 to 4, characterized in that the pylons have a trapezoidal shape in plan. 8. The fan for the cooling tower according to any one of claims 1 to 4, characterized in that the pylons have a circular shape in plan. 9. A fan for a cooling tower according to any one of claims 1 to 4, characterized in that the pylons are elliptical in plan view. 10. The fan for the cooling tower according to any one of claims 1 to 4, characterized in that the pylons are made in plan of the composite of fragments of geometric shapes. 11. The fan for the tower according to any one of paragraphs.4-10, characterized in that the pylons are located at an angle to the plane of rotation of the fan. 12. The fan for the tower according to any one of paragraphs.4-10, characterized in that the pylons are perpendicular to the plane of rotation of the fan. 13. The fan for the tower according to any one of claims 1 to 12, characterized in that the pylons of each blade have different dimensions in plan. 14. The fan for the tower according to any one of claims 1 to 12, characterized in that the pylons of each blade have the same size in plan. 15. A fan for a cooling tower according to any one of claims 1 to 13, characterized in that the pylons located closer to the center of rotation have a smaller surface area in plan compared to pylons located on the periphery. 16. The fan for the tower according to any one of claims 1 to 15, characterized in that on the suction side of the fan, the pylons have a larger area from the total area in plan than at the outlet.

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