RU2726969C1 - Radial impeller of fan - Google Patents

Abstract

FIELD: fan engineering.SUBSTANCE: invention relates to fan engineering, namely to radial impellers of fans. Radial impeller comprises front 1 and main 2 discs and blades 3 arranged there between. Surface of front disc 1 has the shape of truncated cone with curvilinear generatrix, blades 3 are made sheet, with adjoining to front disc swell 5 at outlet of impeller, and with leading edge 6 with vortex former in form of rod 8, and with cutout 7 near main disc 2. Rod 8 is connected to main disk 2 with formation of gap 9 between it, front edge 6 and main disk 2. In gap 9 and on rod 8, vortex flow around blade 3 is formed, which tightens the separation of the boundary layer from the surface of blade 3 and main disc 2, with simultaneous increase in the strength of blade 3 and the impeller.EFFECT: increased pressure characteristics at increased strength of blades and radial impeller.1 cl, 6 dwg

Description

The invention relates to fan technology, namely, to radial fan impellers.

Radial fan impellers are known in the art.

In the description of the invention KR 20190063079, IPC F04D 17/10; F04D 29/28; F04D 29/30; F04D 29/66, publication date 06/07/2019, [1], a radial fan impeller is presented containing a front disc, a main disc located between the blade discs, the surface of the front disc is made in the form of a truncated cone with a curved generatrix, the blades are made of sheet , the leading edge of the blade is connected to the vortex generator. A feature of the radial impeller presented in the invention [1] is the execution of the vortex generator in the form of a well-streamlined pad on the leading edge of the impeller, as well as the execution of the leading and trailing edges of the blades rectilinear. The result is a continuous flow around the blade. However, with automatic control of the fan performance, for example, by changing the rotation speed of the radial impeller, with straight edges and a streamlined vortex generator, flow stalls can occur, which limits the range of angular speeds of rotation of the impeller.

In the description of the invention RU 2013664, IPC F04D 29/28, publication date 05/30/1994, [2], a radial fan impeller is presented containing a front disk, a main disk located between the blade disks, the surface of the front disk is made in the form of a truncated cone with a curvilinear generatrix, the leading edge of the blade is connected to the vortex generator. A feature of the radial impeller presented in the invention [2] is the execution of the blades profiled, the execution of the vortex generator in the form of a hollow slat forming a cavity and a slot on the side of the wall. Through-holes are made in the disks, communicated with the cavity of the hollow slat, made in the form of two truncated cones, coupled with smaller bases, with helical grooves on the side surfaces. Such an implementation of the blade and the vortex generator is complex in design and manufacturing technology.

In the description of the invention RU 2617636, IPC F04D 29/28, F04D 29/66, publication date 04/25/2017, [3], a radial fan impeller is presented, containing a front disc, a main disc located between the blade discs, the surface of the front disc is made in the form of a truncated cone with a curvilinear generatrix, the blades are made of sheet, the trailing edge of each of the blades is made with a projection adjacent to the front disc. The weakest point of the impeller presented in the invention [3] is the leaf blade, which undergoes deformation of fracture in the middle of the blade along the width of the wheel with an increase in the speed and diameter of the impeller. This is a disadvantage and can limit the width of the radial impeller presented in the invention [3]. In addition, on the surface of the blade near the main disk, there is a complex turn of the flow from the axial direction to the radial direction, which limits the range of the flow incidence angles and the rotation speed due to the possible separation of the boundary layer at the point where the blade adjoins the main disk of the impeller.

The radial impeller presented in the description of the invention [3] is adopted as the closest analogue of the claimed invention.

The technical problem being solved is to increase the aerodynamic characteristics of the radial impeller.

The technical result consists in increasing the pressure characteristic while increasing the strength of the blades and the radial impeller.

The essence of the invention is as follows.

The radial impeller of the fan, like the closest analogue [3], contains a front disk, a main disk located between the disks of the blades, the surface of the front disk is made in the form of a truncated cone with a curved generatrix, the blades are made of sheet, the outlet edge of each of the blades is made with a protrusion adjacent to the front disc, but unlike the closest analogue [3], the leading edge of the blade about the side of the main disc is made with a cutout, the leading edge of the blade is connected to a vortex generator made in the form of a rod connected to the main disc with the formation of a gap between the rod, the leading edge of the blade and the main disc.

The radial impeller of the fan is characterized by the fact that the surface of the vortex generator is made with a relief cut directed from the front disk to the main disk and towards the exit from the radial impeller, and the free end of the rod is made with a bevel.

The invention is illustrated by graphic materials.

In FIG. 1 is a side view of a radial impeller.

In FIG. 2 shows view A in FIG. 1.

In FIG. 3 shows the remote element B in Fig. 1.

In FIG. 4 is an isometric view of the radial impeller as viewed from the inside of the blades.

In FIG. 5 is an isometric view of the radial impeller seen from the outside of the blades.

In FIG. 6 shows the pressure characteristic of a fan with an impeller with a vortex generator in the form of a rod and without a vortex generator.

The radial impeller of the fan is designed as follows.

The radial impeller of the fan contains a front disc 1, a main disc 2, and blades 3 located between them (Fig. 1). The main disk 2 is connected to the hub 4 (Fig. 1, 2, 3). The surface of the front disk 1 is made in the form of a truncated cone with a curved generatrix. The blades 3 are made of sheet metal. The blade 3 at the outlet of the impeller is made with an overflow 5, adjacent to the surface of the front disc 1 (Fig. 1, 4, 5). The leading edge 6 of the blade 3 is made with a cutout 7 from the side of the main disk 2 and is equipped with a vortex generator made in the form of a rod 8. The rod 8 is connected to the main disk 2 with the formation of a gap 9 between the rod 8, the leading edge 6 of the blade 3 and the main disk 2 (Fig. . 1, 3, 4) ..

In a preferred embodiment, the surface of the rod 8 is made with an inclined relief notch 10 directed from the front disk 1 to the main disk 2 and towards the exit from the radial impeller, and the free end of the rod 8 is made with a bevel 11 (Fig. 3).

The radial impeller operates as follows.

When the radial impeller rotates into the gap 9 between the vortex generator, made in the form of a rod 8, the leading edge 6 of the blade 3 and the main disk 2, air is drawn in, which is formed into a vortex. Due to the gap 9, the flow around the vortex generator made in the form of a rod 8 and the leading edge 6 of the blade 3 is improved in a wide range of flow angles, since the flow is blown through the gap 9 and the flow is stabilized on the surface of the blade 3 near the main disk 2, where a complex turn of the flow occurs from axial to radial. The overflow 5 of the blade 3 adjacent to the front disc 1 tightens the separation of the boundary layer from the blade 3 and the front disc 1.

The design of the blade 3 with the vortex generator in the form of a rod 8 increases the rigidity and strength of the blade 3, preventing the blade 3 from folding with an increase in the rotational speed.

The diameter of the vortex generator in the form of a rod 8 is several times greater than the thickness of the blade 3. This brings the shape of the blade 3 closer to the profile shape and improves its flow over a fairly wide range of angles of flow on the leading edge 6 of the blade 3.

The presence of an overflow 5 on the blade 3, adjacent to the surface of the front disc 1 at the exit from the radial impeller, provides an increase in the pressure characteristic as compared to the radial impeller with a straight trailing edge of the blade 3. Presented in the graph in FIG. 6 comparison of dimensionless aerodynamic and power characteristics of a radial fan with a volute casing with a radial impeller, similar to that presented in the invention [3], in its original form without vortex generators, and after installation on the leading edges 6 of the blades 3 of vortex generators in the form of rods 8, indicates the achievement of the declared technical result.

In the graph in FIG. 6 shows the following aerodynamic characteristics:

"PSI" = Ψ = 2P _v / ρu ² - coefficient of total pressure;

"PSIs" = Ψs = 2Ps / ρu ² - static pressure coefficient;

P _v is the total pressure generated by the fan;

P _vs - static pressure generated by the fan;

"Phi" = ϕ = Q / (uS) - productivity factor;

ρ is the air density;

u = πDn / 60 - circumferential speed of the impeller blade;

n is the rotation frequency;

Q - volumetric performance of the fan;

S = πD ^2/4 - Area of the impeller;

D is the impeller diameter;

η = P _v Q / N - efficiency;

N is the mechanical power supplied to the impeller shaft;

"Lambda" = λ = Ψ × ϕ is the power factor;

the index "1" refers to a fan with a radial impeller, similar to that presented in the invention [3];

the index "2" refers to a fan with a radial impeller, similar to that presented in the invention [3], with the installation on the leading edge 6 of the blades 3 of vortex generators in the form of rods 8 with an inclined relief notch 10.

Thus, the data presented in the description of the invention ensure the achievement of the claimed technical result, consisting in increasing the pressure characteristic with increasing strength of the blades and the radial impeller, which is confirmed by the measured aerodynamic characteristics.

The disclosure is sufficient for the design and manufacture of a radial fan impeller. The invention meets the "industrial applicability" requirement of patentability.

Claims (2)

1. Radial fan impeller containing a front disk, a main disk located between the disks of the blade, the surface of the front disk is made in the form of a truncated cone with a curved generatrix, the blades are made of sheet, the trailing edge of each of the blades is made with a protrusion adjacent to the front disk, which differs in that the leading edge of the blade on the side of the main disk is made with a cutout, the leading edge of the blade is connected to a vortex generator made in the form of a rod connected to the main disk with the formation of a gap between the rod, the leading edge of the blade and the main disk. 2. The radial impeller of the fan according to claim 1, characterized in that the surface of the rod is made with an inclined relief notch directed from the front disk to the main disk and towards the exit from the radial impeller, and the free end of the rod is made with a bevel.

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