RU2429386C2 - Fan unit with free radial wheel rotor - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: fan unit comprises radial wheel rotor 1 with front 3 and main 4 plates, vanes 5 bent backward and arranged there between and provided with slats 24, and outlet collector 2 with taper inlet section 12, outlet section 13 and additional section 16 with slightly curved surface arranged there between, its length L_wr making at least 0.04 of diameter D of wheel rotor 1. Front plate 3 and collector outlet section 13 are arranged to form circular clearance 15 ahead of which plates 18 are mounted. Straight line connecting axis 6 and tip 27 of slat 24 does not extend beyond ±0.05 of angular pitch t of vanes 5 relative to straight line connecting point 6 and point 29 of adjunction to front plate 3 of the next vane in projection on plane perpendicular to axis 6 of wheel rotor 1.

EFFECT: higher efficiency at increased static pressure, reduced noise.

10 cl, 23 dwg

Description

Technical field

The invention relates to the field of fan building, namely to fan units with a free radial impeller, intended for use mainly in duct fans with low noise.

State of the art

The prior art fan units with a free radial impeller, designed for installation mainly in duct fans.

The Centrifugal fans with asynchronous external rotor motor catalog, 11.2004, Ziehl-Abegg, on pages 9/1 ... 9/23, [1], presents a fan unit with a free radial impeller of the RH ... G type, including a radial impeller and the input manifold, the radial impeller contains the main and front disks, the blades located between the disks and made curved back relative to the direction of rotation, the input manifold contains a tapering inlet section and an output section, the edge of which is located between the main disk and the input edge of the front disk th wheel with the formation of an annular gap.

Aerodynamic and acoustic tests of a fan unit with an impeller RH31G-4DK.0F / 1R (complete with an electric motor and a collector), pressure and acoustic characteristics of which are given on page 9/7 of the Catalog [1], showed that the pressure characteristic of the fan unit with an impeller of this type can be significantly improved in terms of expanding productivity by increasing the static pressure created by it by changing the inlet manifold and impeller blades. In addition to improving the pressure characteristics, the noise level at the inlet to the duct fan with such a fan unit is reduced.

In the description of the invention to the patent of the Russian Federation No. 2287091, IPC F04D 29/42, publication date 10.11.2006, [2], a channel fan is provided, equipped with a fan unit containing a radial impeller formed by a main and cover disks and bent between the disks back by the blades, a symmetrical inlet manifold made with a curved profile in the meridional section with the formation of a tapering inward radial wheel (i.e. confuser) gap between the surfaces of the coating disk and the inlet manifold, and eddy absorber m, which can be performed comprising at least one plate connected to the wall of the inlet manifold.

In the invention [2] it is shown that the presence of a vortex suppressor increases the static pressure coefficient, however, there is no information about the influence of the shape of the inlet manifold on the pressure characteristic of a channel fan with such a fan unit.

The fan unit presented in the Catalog [1] is taken as the closest analogue of the claimed invention.

Disclosure of invention

The technical task to be solved is the improvement of aerodynamic characteristics while reducing the noise level of the impeller and, accordingly, the channel fan.

The technical result consists in increasing productivity while increasing the static pressure of the fan unit.

The technical result also consists in reducing the noise level at the entrance to the channel fan, equipped with the inventive fan unit.

The solution of the technical problem is provided when carrying out the invention with the following set of features essential to achieve the claimed technical results.

The fan unit with a free radial wheel, as in the closest analogue [1], contains a radial impeller and an inlet manifold, a radial impeller contains a main and front disks, vanes located between the disks and made backward curved relative to the direction of rotation, the inlet manifold contains tapering inlet section and outlet section, the edge of which is located between the main disk and the input edge of the front wheel of the impeller with the formation of an annular gap, but in contrast to the most close analogue [1], the input collector is made with an additional section located between the input and output sections with a surface conjugated with the surfaces of the input and output sections of the input collector and having a generatrix of small curvature, the length of the additional section is not less than 0.04 diameter of the circle described by the ends impeller blades, and a vortex suppressor is installed in front of the annular gap.

The fan unit with a free radial wheel is characterized in that the additional section is made with a cylindrical inner surface.

A fan unit with a free radial wheel is characterized in that the vortex suppressor is made in the form of at least one plate connected to the external walls of the collector.

The fan unit with a free radial wheel is characterized in that the annular gap in the meridional section is made tapering inward of the radial wheel.

A fan block with a free radial wheel is characterized in that each impeller blade is made with a slat located between the blade contacting the surface of the front disk and the axis of rotation of the impeller, while in a projection onto a plane perpendicular to the axis of rotation of the impeller, a straight line connecting the axis of rotation the impeller and the slat toe does not extend beyond the sector limited by beams located in the range of ± 0.05 angular pitch of the blades relative to the straight line connecting the axis of rotation of the impeller ECA and the abutment point of the leading edge of the blade following the rotation of the blade to the surface of the front disc.

The fan unit with a free radial wheel is characterized in that the lateral edge of the slat of the impeller vanes is located at an acute angle to the leading edge of the slat.

In this case, the fan unit with a free radial wheel is characterized in that the leading edge of the slat blade of the impeller blade in a section perpendicular to the axis of rotation of the impeller is made in a circular arc.

In addition, the fan unit with a free radial wheel is characterized in that the diameter of the front disk is 1.1 ... 1.2, and the diameter of the main disk is 1.05 ... 1.15 of the diameter of the circle described by the ends of the impeller blades, with the formation in the meridional the plane between the generators of the front and main discs in the direction from the axis of rotation to the ends of the blades of the impeller of the non-expanding channel.

A fan unit with a free radial wheel is characterized in that the width of the blade at the exit of the impeller is at least 0.25 of the diameter of the circle described by the ends of the impeller blades.

A fan unit with a free radial wheel is characterized in that the impeller is equipped with at least one ring connecting the side edges of the blade slats.

A brief description of the figures by drawings.

In the following invention is illustrated by a detailed description of a fan unit with a free radial wheel with reference to the accompanying drawings, in which:

Figure 1 presents a longitudinal section of a fan unit adopted for the closest analogue [1].

Figure 2 presents a section aa in figure 1.

Figure 3 shows the remote element In figure 1.

Figure 4 presents a longitudinal section of the claimed fan unit.

Figure 5 presents a longitudinal section of the claimed fan unit with a radial impeller with enlarged front and main discs.

Figure 6 shows the remote element C in figures 4 and 5.

Fig.7 shows a section D-D in Fig.4.

On Fig shows the shoulder blade when viewed from the side.

Figure 9 shows a view of E on a blade of a single sheet.

Figure 10 shows a view of E on a compound blade.

Figure 11 shows a section F-F in figure 5 in a preferred embodiment of the fan unit.

On Fig shows a fragment of the impeller with the location of the blades in the zone of permissible deviations from the angular pitch.

On Fig shows the pressure characteristic ψ _S = F (φ) of the fan with a fan unit in various versions.

On Fig shows the pressure characteristic ψ _S = F (φ) of the fan with a fan unit with different lengths of the additional section of the collector.

On Fig shows a graph of ψ _S = F (L _CC / D) with φ = const when using a fan unit without eddy current suppressor in the duct fan.

16 shows a graph ψ _{S (B-F)} = F (L _CC / D) at φ = const using a fan unit with a fan vihregasitelem in the channel.

17 shows a graph Δψ _S = ψ _{S (B T)} -ψ _S = F (L _CC / D) at φ = const.

On Fig presents a graph of L _P = F (f) narrow-band spectra of sound pressure levels at the inlet of the channel fan with a fan unit - the closest analogue and with a fan unit equipped with slats and a vortex suppressor.

On Fig presents a diagram L _W = F (f) of the octave spectra of sound power levels at the input of the channel fan with a fan unit - the closest analogue and with a fan unit equipped with slats and a vortex suppressor.

On Fig presents a graph of L _P = F (f) narrow-band spectra of sound pressure levels at maximum performance at the inlet of the channel fan with a fan unit - the closest analogue and with a fan unit in the preferred embodiment.

On Fig presents a graph of L _P = F (f) narrow-band spectra of sound pressure levels in the average performance mode at the inlet of the channel fan with a fan unit - the closest analogue and with a fan unit in the preferred embodiment.

On Fig presents a diagram L _W = F (f) of the octave spectra of sound power levels in maximum performance mode at the input of the channel fan with a fan unit - the closest analogue and with a fan unit in the preferred embodiment.

On Fig presents a diagram L _W = F (f) of the octave spectra of sound power levels in the average performance mode at the input of the channel fan with a fan unit - the closest analogue and with a fan unit in the preferred embodiment.

Best Embodiments

The fan unit with a free radial wheel, as in the closest analogue [1], shown in figures 1, 2 and 3, contains a radial impeller 1 and the input manifold 2, interconnected by a support (not shown in Fig.) Or in the duct fan housing (not shown in FIG.). The radial impeller 1 includes a front 3 and a main 4 discs, blades 5 mounted between them, and is equipped with means for connecting with an electric drive (not indicated in FIG.) For rotating the radial impeller 1 around its axis 6. The blades 5 are made bent backward in the direction rotation of the radial impeller 1 (figure 2). The inlet 7 of the air flow into the radial impeller 1 is located in the plane formed by the input edge 8 of the front disk 3 (Fig.3), and the outlet 9 of the air flow from the radial impeller 1 is located between the outer edges 10 and 11 of the front 3 and the main 4 disks, respectively (figure 1). The input manifold 2 contains a tapering input 12 and output 13 sections. The edge 14 of the output sections 13, as shown in figures 1 and 3, is located between the main disk 4 and the input edge 8 of the front disk 3 of the radial impeller 1 with the formation of an annular gap 15 (figure 3).

The claimed fan unit, in addition to the above elements in the closest analogue [1], contains an additional section 16 located between the tapering input 12 and output 13 sections (Figs. 4, 5, 6), the surface of which is mated to the surfaces of the input and output sections of the input collector. The generatrix of the inner surface of the additional section 16 can be performed with a small curvature 1 / R _CK → 0, including cylindrical, in which 1 / R _CK = 0. Length L _CC secondary portion 16 of the inlet header 2 is not less than 0.04 the diameter D of the impeller 1, equal to the diameter of the circle described by the ends 17 of the blades 5 during rotation of the impeller 1: L _CC / D≥0,04.

The annular gap 15, as shown in Fig.6, is made tapering inward of the radial wheel, that is, confuser. An annihilator is installed in front of the annular gap 15, which can be made in the form of at least one plate 18, the lateral edges of which are connected to the walls of the inlet manifold 2 (Figs. 4, 5), and the trailing edge 19 is located in front of the annular gap 15 (Fig. .6).

Radial impeller 1 can be performed with enlarged front 20 and main 21 disks (figure 5). The blades 5 of the radial impeller 1 can be performed with the main section 22, the front edge 23 of which is adjacent to the front disk 3, and the section located closer to the axis 6 of the radial impeller 1, hereinafter referred to as the "slat" 24 (4, 5, 7 , 8). The main section 22 and the slat 24 (Fig.7, 8) of the blade 5 can be made as a whole, for example, from a sheet of metal (Fig.9) or in the form of an aerodynamic profile (not shown), and composite (Fig.10), by attaching the slat 24 to the main portion 22 of the blade 5. The leading edge 25 of the slat 24 can be located in a range of angles of ± 10 degrees. to the plane perpendicular to the axis of rotation 6 of the impeller 1, and the side edge 26 is at an acute angle to the leading edge 25 (Fig. 8), and are interconnected by a smooth curve, for example an arc of a circle, forming the nose 27 of the slat 24. The front edge 25 of the slat 24 in a projection onto a plane perpendicular to the axis of rotation 6 of the impeller 1, is made curved, for example, along an arc of a circle (Figs. 7, 9, 10), and its side edge 26 can be made with increasing local radius with increasing distance from the leading edge 22 R _BK (Fig. 8). To ensure the rigidity of the slats 24 of the blades 5, the lateral edges 26 of the slat 24 can be connected by a ring 28 (Fig. 5). Similar rings can be installed at the ends 17 of the blades 5, and also in addition to the already installed ring 28 on the lateral edges 26 of the slat 23 (not shown).

An example of a preferred embodiment of a fan unit with a free radial impeller.

In a preferred embodiment, the additional section 16 of the intake manifold 2 is made with a cylindrical inner surface (1 / R _CC = 0) and with a relative length in the range of L _CC / D = 0.04 ... 0.06, the radial impeller 1 of the fan unit (FIG. .4, 5) contains at least 6 blades 5, the width H of the blades 5, equal to the distance between the front 3 and the main 4 disks at the point of their intersection with the ends 17 of the blades 5 at the exit 9 of the impeller 1, is 0.25 ... 0, 37 of the diameter D of the circle described by the ends of the 17 blades 5 of the impeller 1: 1 / R _CK = 0, L _CK / D = 0.04 ... 0.8; H = (0.25 ... 0.37) D.

When performing the impeller 1 with 6 ... 10 blades 5, the surface of the main section 22 and the adjacent slat 24 of the blades 5 are made with single or double curvature (Fig.7). When performing the impeller with more than 11 blades 5 (Fig.9, 11), the main section 22 of the blades 5 can be made flat, and the adjacent slat 24 in a section perpendicular to the axis of rotation 6 of the impeller 1, in the form of an arc of a circle, the front 25 and the side 26 of the edge of the slat 24 are connected around the circumference, and the side edge 26 is made with a local radius R _BK equal to at least 0.5 D near the front edge 25, and parallel to the axis of rotation 6 of the radial impeller 1 (i.e. equal to infinity) near the main disk 4 (figures 4, 5, 8).

In a projection onto a plane perpendicular to the axis of rotation of the impeller 1, the straight line connecting the axis of rotation of the impeller 1 and the nose 27 of the slat 24 does not extend beyond the sector limited by rays located in the range Δt = ± 0.05 of the angular step t relative to the straight line connecting the rotational axis 6 of the impeller 1 and the abutment point 29 of the leading edge 25 following along the rotation of the blade 5A to the front disk 3, or lies on this straight line (Fig. 12). In the case of a radial impeller 1 with enlarged front 20 and rear 21 discs, their diameters are equal to (1.1 ... 1.2) D and (1.05 ... 1.15) D (Figs. 5, 11), and a meridional section between the generators of the front 20 and the main 21 disks in the direction from the axis of rotation 6 to the ends 17 of the blades 5 of the impeller 1 is made non-expanding channel (figure 5).

When performing the impeller 1 with 11 or more blades 5, the main section 22 of the blades 5 is made flat with a straight front edge 23, and the generatrix of the front disk 3 at the abutting section of the front edge 23 of the main part 22 of the blade 5 (Fig. 5) is made in accordance with the equations :

y = (0.29 ± 0.01) x + 0.37

z = (- 0.39 ± 0.01) x-0.27

r ² = x ² + y ² ,

where z = Z / D is the relative coordinate directed along the axis of rotation 6 of the radial impeller 1 in the direction from the main disk 4 to the input 7 of the radial impeller 1;

x = X / D is the relative coordinate perpendicular to the axis of rotation 6 of the radial impeller 1;

y = Y / D is the relative coordinate perpendicular to the 0Z axis and 0X axis;

r = R / D is the relative current radius of the radial impeller 1;

R is the current radius of the impeller 1;

X, Y, Z - current coordinates;

D is the diameter of the radial impeller 1, equal to the diameter of the circle described during its rotation by the ends 17 of the blades 5.

The invention operates as follows.

The implementation of the input manifold 2 with an additional section 16, the inner surface of which has a small curvature 1 / R _CK → 0 and is conjugated with the surfaces of the tapering input 12 and output 13 sections, provides alignment along the cross section of the collector 2 velocity profile in front of the edge 14 of the output section 13 of the input manifold 2 and the uniform flow at the inlet 7 to the radial impeller 1 and on the surface of the front disk 3 (or 20) of the impeller 1. Installing an additional section 16 of the input manifold 2 as a whole increases the coefficient static pressure coefficient ψ _S (equal to the ratio of the static pressure Psv to the product of air density ρ and the square of the peripheral speed and the impeller blade ψ _S = 2Psv / ρu ² ) in the absence of an eddy suppressor. The installation of a vortex suppressor made, for example, in the form of a plate 18 with a trailing edge 19 located in front of the annular gap 15, inhibits the annular flow formed on the outer surfaces of the rotating front disk 3 and the stationary intake manifold 2. As a result, the magnitude of the static component of the total pressure. This increases the momentum of the annular jet flowing from the annular gap 15 to the inner surface of the front disk 3. The blown jet delays the flow stall from the inner surface of the front disk 3, which allows to increase the width H of the blades 5 to the values H = (0.25 ... 0.37) D. The implementation of the annular gap 15 tapering inward of the radial wheel (i.e. confuser) also contributes to an increase in the pulse of the annular jet.

The above is confirmed experimentally and shown in the graphs in Fig.13 ... 23. In this case, the fan block adopted as the closest analogue [1] with the impeller RH31G-4DK.0F / 1R assembled with an electric motor with an external rotor and an input collector is taken as the basis. Subsequently, in the fan unit [1], the blades 5 of the impeller 1 were modified in terms of the execution of the slat 24 in the form shown in Fig. 8, a vortex suppressor made in the form of four plates 18 was installed, and between the tapering inlet 12 and outlet 13 sections of the inlet manifold 2 was mounted the secondary portion 16 of different lengths L _CC / D = 0,032, 0,065 and 0,097 with the cylindrical inner surface (1 / R _CC = ∞), the tapered surfaces mating with input 12 and output 13 portions inlet manifold 2. The fan unit [1] with input collector 2 and the slat 24 with the shape shown in Fig. 8 corresponds to a zero relative length (L _CK / D = 0) of the additional section 16 of the inlet manifold 2. To study the aerodynamic and acoustic characteristics, the fan unit was installed in the same commercially available duct fan case with noise absorbing walls with a cross-sectional area of the channel S _K exceeding the area of the impeller 1 S _PK not less than 2.4 times (S _K / S _PK ≥2.4) in a section perpendicular to the axis 6 of rotation of the impeller 1.

In the graphs presented in Fig.13 ... 23, the following notation is used:

(one). “Prototype” - a channel fan with a fan unit adopted for the closest analogue [1] with an impeller RH31G-4DK.0F / 1R assembled with an input manifold and an electric motor with an external rotor;

(2) "prototype + slat" - channel fan (1), with modified slats 24 blades 5;

(3) “prototype + slat + eddy suppressor” - a duct fan (2) equipped with an eddy suppressor in the form of four plates 18;

(4) "prototype + slat vihregasitel + _CC + L / D = ...» channel fan (3) to the collector 2, taken with the additional insert 16 having the relative length L _{of the CC} / D;

(5) "prototype + slat + L _CC / D = ..." - channel fan (2) with a collector 2 made with an additional section 16 with the specified relative length L _CC / D,

(6) “the preferred embodiment of the fan unit” is a channel fan (4) with a collector 2 made with an additional section 16 with a relative length L _CC / D = 0,065.

The studies showed that, as shown in the graph in Fig. 13, the pressure characteristic ψ _S = F (φ) (φ = Q / uS _PK is the performance coefficient, where Q is the fan capacity, u is the peripheral speed, S _PK is the area the impeller, S _PK = 0.25πD ² ) the channel fan with the fan unit installed in it is affected by the shape of the slat 24 of the blade 5 and the presence of a vortex suppressor. The graph ψ _S = F (φ) shown in Fig. 14 shows the pressure characteristic of the channel fan with a fan unit installed in it, the impeller 1 of which is equipped with a slat 24, and the input manifold 2 is made with different relative lengths L _CC / D of an additional section 16 in the presence of a vortex suppressor and without it. The graph shows that the presence of the secondary portion 16 manifold 2 increases the static pressure coefficient ψ _S at equal performance coefficient φ, and the presence vihregasitelya at the same relative length L _CC / D 2 of the secondary portion collector also increases the static pressure coefficient ψ _S.

As shown in the graph ψ _S = F _(CC L / D) at φ = const, shown in Figure 15, for ducted fan unit without fan vihregasitelya, static pressure coefficient ψ _S increases as the relative length L _{of the CC} / D additional section 16 of the inlet manifold 2. Installing a vortex suppressor, as shown in the graph ψ _{S (B-G)} = F (L _CK / D) at φ = const shown in Fig. 16, leads to a more intensive increase in the values of the static pressure coefficient φ _{S (B-D)} duct fan with swirl arrestor. Thus for values of the coefficient of performance φ = 0,20 ... 0,30, corresponding to channel fan working area, the intensity of the static pressure coefficient increment ψ _{S (B-D)} is significantly higher at a relative length L _CC / D <0,04D, and reduced _CC when L / D> 0,04D. Thus, the relative length of the additional section 16 of the intake manifold 2 L _CC / D≥0.04 is an essential feature of the claimed invention. The optimal length of the additional section 16 of the intake manifold 2, as follows from the graph ψ _{S (B-G)} = F (L _CK / D) shown in Fig.16, was L _CK / D = 0.04 ... 0.8.

Comparing the magnitude of the static pressure coefficient of the channel fan with a fan unit slats 24 and the secondary portion 16 of the inlet header 2 with and without vihregasitelem vihregasitelya represented on the graph Δψ _S = ψ _{S (B T)} -ψ _S = F (L _CC / D) at φ = const in Fig.17, confirms the essential equipment of the fan unit as a vortex suppressor, and an additional section 16 on the collector 2 to increase the pressure characteristics.

Changing the shape of the slat 24 and installing a vortex suppressor made in the form of at least one plate 18, which provides an increase in the static pressure coefficient ψ _S (graphs in Figs. 13 and 14) with an equal productivity coefficient φ = const, in comparison with the closest analogue [1] resulted, as shown in the graph L _p = F (f) in FIG. 18 and in the graph L _W = F (f) in FIG. 19, to increase the sound pressure levels L _P and sound power L _W at the input to duct fan at all frequencies f.

However, the implementation of the inlet header 2 with the additional portion 16 having a relative length L _CC / D≥0,04, provide the highest aerodynamic characteristics, it led to a reduction in noise at the input to channel fan equipped with the fan unit declared. As shown in the graphs L _P = F (f) shown in Figs. 20 and 21, the sound pressure levels L _P decreased over almost the entire frequency range f both in the maximum performance mode (Fig. 20) and in the average performance mode ( Fig.21) the operation of the channel fan. As a result, as shown in the diagrams L _W = F (f) in Figs. 22 and 23, the sound power levels also decreased in both the maximum performance mode (Fig. 22) and the average performance mode (Fig. 23) of the channel operation fan.

Thus, in a preferred embodiment, the fan module presence vihregasitelya recommended shape of the blade 5 with the slat 24 as well as the additional portion 16 on the inlet manifold 2 to the relative length L _{of the CC} / D≥0,04 is essential for achieving the technical result of noise reduction at the entrance to the channel fan equipped with the declared fan unit.

The implementation of the impeller 1 of the fan unit with blades 5 with slats 24 of a cylindrical shape and a flat main part 22, the front edge 23 of which is made rectilinear, as well as the implementation of the front disk 3 with a hyperbolic surface, the generatrix of which is oriented along the installation line of the main part 22 of the blades 5, simplifies tooling for the manufacture of the impeller 1 when achieving a higher aerodynamic characteristics and lower noise levels compared with the closest analogue [1].

The implementation of the fan unit with an impeller made with enlarged disks 20, 21, provides an increase in the coefficient of static pressure of the impeller 1 and, consequently, the channel fan with the claimed fan unit.

The connection of the side edges 26 of the slats 24 of the blades 5 with the ring 28 increases the rigidity of the impeller and prevents the deformation of the blades 5 at a high speed. With large sizes of the fan unit, if necessary, similar rings are installed both on the side edges 26 and at the ends 17 of the blades 5.

Industrial applicability

The fan unit with a free radial impeller, presented in the description of the present invention, can be installed in duct and radial fans in spiral housings and compressors. SUMMARY OF THE INVENTION Disclosure of the invention allows the development and manufacture of fan units at specialized enterprises. The fan unit with a free radial impeller meets the patentability condition “industrial applicability”.

LIST OF POSITIONS AND REFERENCES TO THE DESCRIPTION OF THE INVENTION “FAN UNIT WITH A FREE RADIAL DRIVING WHEEL”

1 - radial impeller 1;

2 - input collector;

3 - front impeller disk 1;

4 - the main disk of the impeller 1;

5 - the blade of the impeller 1;

6 - axis of rotation of the impeller 1;

7 - entrance to the impeller 1;

8 - input edge of the front disk 3;

9 - exit from the impeller 1;

10 - the outer edge of the front 3 of the disk;

11 - the outer edge of the front main 4 disk;

12 - tapering inlet section of the input manifold 2;

13 - output section of the input manifold 2;

14 - edge of the output section 13 of the input manifold 2;

15 - annular gap;

16 - an additional section of the intake manifold 2;

17 - the end of the blade 5;

18 - vortex suppressor plate;

19 - the trailing edge of the vortex suppressor plate;

20 - an enlarged front disc;

21 - an enlarged main disk;

22 - the main section of the blade 5;

23 - the leading edge of the blade 5;

24 - slat blades 5;

25 - the front edge of the slat 24;

26 - lateral edge of the slat 24;

27 - toe slat 24;

28 - a ring connecting the side edges 26 of the slats 24;

29 - the abutment point of the leading edge 23 of the next along the rotation of the blade 5A with the front disk 3.

R _CC - the radius of the generatrix of the inner surface of the additional section 16 of the input manifold 2;

L _CC - the length of the additional section 16 of the intake manifold 2;

D is the diameter of the impeller 1, equal to the diameter of the circle described by the ends 17 of the blades 5 during rotation of the impeller 1;

R is the current radius of the impeller 1;

X, Y, Z - current coordinates;

x = X / D is the relative coordinate perpendicular to the axis 6 of rotation of the impeller 1;

y = Y / D is the relative coordinate perpendicular to the 0Z axis and 0X axis;

z = Z / D is the relative coordinate directed along the axis 6 of rotation of the impeller 1 in the direction from the main disk 4 to the input 7 of the impeller 1;

r = R / D is the relative radius of the impeller 1;

H - the width of the blades 5, equal to the distance between the front 3 and the main 4 disks at the exit 9 of the impeller 1;

Rbq is the local radius of the lateral edge 26 of the slat 24 of the blade 5;

t is the angular interscapular pitch;

Δt is the deviation from the angular blade pitch;

S _K - the area of the fan channel in the cross section perpendicular to the axis 6 of rotation of the impeller 1;

S _PK = 0.25πD ² - the area of the impeller 1;

ψ _S = 2Psv / ρu ² is the static pressure coefficient;

Psv - static pressure of the fan;

ρ is the air density;

u is the peripheral speed of the blades 5 of the impeller 1;

φ = Q / uS _PK - productivity coefficient;

Q - fan performance;

S _PK = 0.25πD ² - the area of the impeller 1;

L _P - sound pressure level;

L _W - sound power level;

f is the frequency, kHz.

Claims (10)

1. A fan unit with a free radial wheel, including a radial impeller (1) and an inlet manifold (2), a radial impeller (1) contains the main (4) and front (3) disks, blades (5) located between the disks ( 3, 4) and made curved backward relative to the direction of rotation, the input manifold (2) contains a tapering inlet section (12) and an outlet section (13), the edge (14) of which is located between the main disk (4) and the front edge (8) of the front disk (3) of the impeller (1) with the formation of an annular gap (15), characterized in that the inlet manifold (2) is made with an additional section (16) located between the tapering inlet (12) and the outlet (13) sections with a surface mating with the surfaces of the tapering inlet (12) and outlet (13) sections of the inlet manifold (2) and having a generatrix of small curvature (1 / R _CC ), the length (L _CC ) of the additional section is not less than 0.04 diameter (D) of the circle described by the ends (17) of the blades (5) of the impeller (1), and in front of the annular gap ( 15) a vortex suppressor is installed. 2. A fan unit with a free radial wheel according to claim 1, characterized in that the additional section (16) of the inlet manifold (2) is made with a cylindrical inner surface. 3. A fan unit with a free radial wheel according to claim 1 or 2, characterized in that the vortex suppressor is made in the form of at least one plate (18) connected to the external walls of the collector (2). 4. A fan unit with a free radial wheel according to claim 1 or 2, characterized in that the annular gap (15) in the radial section is made tapering inward of the radial impeller (1). 5. A fan unit with a free radial wheel according to claim 1, characterized in that each blade (5) of the impeller (1) is made with a slat (24) located between the blade (5) adjoining the front disk surface (3) and the axis (6) the rotation of the impeller (1), while in the projection onto the plane perpendicular to the axis (6) of the rotation of the impeller (1), a straight line connecting the axis (6) of rotation of the impeller (1) and the toe (27) of the slat (24) ), does not go beyond the sector limited by rays located in the range of ± 0.05 of the angular interscapular pitch (t) of the blades (5) relative to itelno straight line connecting the axis (6) of rotation of the impeller (1) and the point (29) abutting the front edge (23) following the course of rotation of the blade (5A) to the front surface of the disc (3). 6. A fan unit with a free radial wheel according to claim 5, characterized in that the lateral edge (26) of the slat (24) of the blade (5) of the impeller (1) is located at an acute angle to the leading edge (25) of the slat (24). 7. A fan unit with a free radial wheel according to claim 5 or 6, characterized in that the front edge (25) of the slat (24) of the blade (5) of the impeller (1) in a section perpendicular to the axis (6) of rotation of the impeller (1 ), made along an arc of a circle. 8. A fan unit with a free radial wheel according to claim 5 or 6, characterized in that the diameter of the front disk (20) is 1.1 ... 1.2, and the diameter of the main disk (21) is 1.05 ... 1.15 diameter (D) the circle described by the ends (17) of the blades (5) of the impeller (1), with the formation in the meridional plane between the generatrices of the front (20) and main (21) disks in the direction from the axis (6) of rotation to the ends (17) blades (5) of the impeller (1) of a non-expanding channel. 9. A fan unit with a free radial wheel according to claim 5 or 6, characterized in that the width (H) of the blade (5) at the outlet (9) of the impeller (1) is equal to at least 0.25 circle diameter (D), described by the ends (17) of the blades (5) of the impeller (1). 10. A fan unit with a free radial wheel according to claim 5 or 6, characterized in that the impeller (1) is equipped with at least one ring (28) connecting the side edges (26) of the slats (24) of the blades (5) .

Images