RU8428U1 - DIAMETER FAN - Google Patents

Abstract

1. A diametrical fan comprising a blade impeller and a profile vortex generator installed in the housing with inlet and discharge nozzles connected by an adjacent wall forming a recirculation channel with the vortex generator, characterized in that the housing is provided with a tongue placed in the recirculation channel made in the form of a flat plate , the end section of which has periodically repeating curly cuts, and mounted on an adjacent wall with the possibility of movement in the recirculation channel along tion to the surface, equidistant working kolesu.2. The fan according to claim 1, characterized in that each of the curly cutouts of the tongue has the shape of an isosceles triangle facing the impeller with a height and a base, respectively, equal to (D + δ) tg (2π / z) and B / m, where D, B is the impeller diameter and width, respectively; m = E (Z / c) is the integer part of Z / c, c = 4 - 6, δ = (0.04 - 0.1); D is the radial clearance between the top of the triangle and the circumference of the wheel at the outer ends of the blades; Z is the number of blades. 3. The fan according to claim 1, characterized in that each of the curved cutouts of the tongue has the shape of a curved arc with a chord and deflection arrow, respectively equal to (B / K-α) and (D + δ) tg (2π / z), where K = E (Z / c) is the integer part of Z / c, c = 4 - 6; α = (0.01 - 0.03) D is the length of the jumper between the cutouts; δ = (0.04 - 0.1) D - the radial clearance between the jumper and the wheel circumference at the outer ends of the blades; Z is the number of blades. 4. The fan according to claim 1, characterized in that the end edge of the end portion of the tongue has a waveform with doubled amplitude and period, respectively, equal to (D + δ) tg (2π / z) and B / m, where D, B are the diameter and impeller width; m = E (Z / c) - int

Description

Diametric fan

IPC F04P, 17E) 4, 29/46.

The utility model relates to fan engineering. in particular to diametrically fans.

Javesfna diametrical fans, containing a gouging working rut and a profiled shear gauge installed in the housing with the inlet and outlet nozzles connected by an adjacent wall, in the form of a “cell with vortex generators recirculation channel. 1978,) P62EOOO, cl. P04Z. 1978, 812971 kya, F04D, 1980 ,, MeOI642 class F04D, G980, “553761 nl. F043, 19Sh., Hi II06923 cl. P04P, 1983 etc.), These diametrical fans are classified as so-called highly loaded (high-pressure) fans and have very

BucoJuie pressure coefficients in operating modes С j, j - total fan pressure; / 9 - power, - wheel peripheral speed) This allows them to be used as built-in fans in equipment to significantly reduce either the dimensions of the fan or the speed. but

a big drawback of these fans is the relatively high power of the noise they create, the spectrum of which is at frequencies

the blade harmonics contains 1 intense discrete components, making the main contribution to the ommarnu noise power and greatly worsen its subjective perception by a person.

Some types of diametrical fans are also known.

holding devices integrated in the housing or impeller, which help reduce both the scraper and the broadband noise level (see .. Kagfkmer, autoswitch. I6I5443 class. F04D, 1968. 1265399 class., G04R, Shbgm patent US 1 12976 kya. / B4, 1987.,.

) (3477635 cells., 1969, 3940215 cells. 415/54 1976, Europe 0233174 nl. G04 /, 1987, 0132793, cells TQ4D, 1987, German patents f g728727 C 2 KJT. FC4A 198, g. , M 32245Z7 class G04P 1985, i 545036 class F04J, 1979 prospectus-catalog of the Schwel staipMH Fergas, which serialized releases diametrical fans). However, the diametrical fans described in these materials relate to their class, in a more detailed manner, to the class of fully recognizable low- and medium-loaded ventilators and have K09ffkts1 (pressure coefficients of no more than O, B 4-. This does not allow to obtain high: absolute pressure) reduce the size of the nanny and reduce the frequency of the fan,

In order to obtain sufficiently high absolute energy values for such low- or medium-loaded spectrometers (i.e., as well as for highly-loaded types of fans, it is necessary to: significantly increase the diameter of the impeller 1 (and, accordingly, the external dimensions of the fan c), increase the circumferential the speed of the wheel is due to great frequency and frequency (which is not always the case with standard abortions of asynchronous electric motors. All spare parts will go to the best of both the discrete fan and the widely treated fan in combination with H SBecTHiJMH patterns. Lo Lizzychami that the noise of different fans is blocked by

wheel ra (D) and from peripheral speed C), or from; 1rokz

these values (/,

The purpose of this useful model lies in crosstalk in the Ulph a | bottom.

on the working area of the workers on the basis of secreted components and broadly || (parts of the carcasses of the whole class of highly loaded types of vecticles for: rohrs, (having, as indicated above, cneuMaj bHue profile (wing) viv: high-temperature reefs in :, absolute values (1a8) Laziness and 1 # empty dimensions and fan speeds, used, in particular, as ground or air transport vehicles built into ultracompact equipment, technological installations, heat exchange units with tems life support, etc.

This goal is achieved by the fact that the casing of the highly loaded fan is equipped with a so-called language located in the recirculation channel of the casing. In this case, the tongue is made in the form of a relatively thin flat plate, in which the end portion on the side of the impeller has periodically repeating figured cuts, the tongue being mounted on an adjacent wall between the inlet and outlet pipe of the housing and has the ability to move in the recirculation channel of the housing tangentially to cylindrical surface equidistant to the external impeller. Depending on the position of the operating point of the fan, three variants of the shape of the curved cut-outs of the tongue are declared on its pressure-flow characteristic: a) in the form of isosceles triangles for operating modes with average performance factors (-C / A e de j - fan performance, S - impeller width) V in the form of curved circular arcs for modes of small performance coefficients; c) in the form of a wave for the modes

: BIG

 . In this case, the optimal geometric aspect ratios of the indicated contours of the cutouts of the tongue are obtained experimentally obtained as a result of parametric studies of real samples, which ensure a positive effect, i.e. reduction of discrete and broadband noise of a heavily loaded fan. To enhance the effect of noise reduction, the impeller of the proposed fan is partitioned (i.e., with intermediate disks intermediate to the width of the wheel mounted normally to the axis of the wheel) should be performed with an even number of sections, which

have the same width (blade length), in particular adjacent (adjacent) sections should be offset relative to each other in the diametrical plane by half of the blade pitch. Unlike the prototype, this allows, instead of a single dipole source of noise, the interaction of the flow with the elements of the casing and the impeller (the main sound source of discrete frequencies) to create an even number of dipole sources of interaction noise of the same power in a closed volume of the fan casing, half of which emits sound in antiphase relative to the other. Sound waves from antiphase sources due to interference in the discharge and inlet pipes of the fan housing will be mutually suppressed, as a result of which the noise intensity of the fan, especially on discrete components, will be reduced.

To rug. 1.2 shows a cross section of the proposed fan, the details of the languages and its node in the field of the vortex generator and the recirculation channel; Figures 3 and 4 show the acoustic characteristics of the proposed fan and prototype; on page 5, b, 7 graphs of changes in acoustic characteristics are presented depending on the geometry of the end portion of the tongue and impeller obtained as a result of optimization of the fan elements.

The fan has a blade wheel I (see Fig. 1.2) installed in Kopiryce 2 with an inlet 3 and a discharge 4 nozzles connected by an adjacent wall 5, which forms a recirculation channel 7 with the vortex generator 7. The casing is provided with a tongue 8 placed in the recirculation channel 7 . Language 8 is made in the form of a flat plate,

9 terminal section, which has periodically repeating curly

cutouts. The language 8 is installed with the possibility of movement along a tangent to a cylindrical surface 10, equidistant to the impeller. Figured cutouts can have a different shape. The first option is the formg (in the form of isosceles triangles (see Fig. D, option a) with a height of II and a base of 12, respectively equal to / L: // and 1, where J is the diameter of the wheel, o is the width (length of the blades) of the wheels C® part of Д /, 6, (0.4 4-0, I) J7 - minimum radial clearance between the edge of the tongue and the circumference: the length of the wheel at the outer ends of the blades; - the number of blades. The second option - the cutouts of the wheel have a curved arc (see option b) with the chord 13 and arrow 14, respectively equal to S / r7J-c))) J) - the integer part of 2/4 {- 6; О СО, 01 4-0.03) - the length of the jumper between the cutouts; (0.04-0.1) - the radial clearance between the end of the jumper and the circumference of the wheel at the outer ends of the blades; - the number of blades. The third option - the cutouts are in the form of a wave (see Fig. I, var. Current r b., R) c1 1MSh1 of 15 and period 16, respectively) n) w (27 // and t y where is the diameter of the wheel; S - wheel width; n7 - (/ Cj is the integer part of D /, 4-6; and (0.04 4-0.1) is the minimum radial clearance between the edge of the tongue and the circumference of the wheel at the outer ends of the blades;% is the number of blades. The proposed fan in the case of its sectioning (see Fig. 2-B) is performed with an even number of scissors having the same width along the blades and offset in adjacent sections (on (rig. IB sections I and P, P-Sh, Sh-1U) in diametrical flat the bones are exactly half the blade step / 2. When the fan is operating, the flow through the suction pipe 3 of the housing I enters the impeller I and leaves the pipe 4. A part of the flow in the housing circulates around the vortex generator b through the recirculation channel 7, flowing around an adjacent wall 5, tongue 8 and end section 9 with profile cutout 9, insulated)

Experimental studies have established that the proposed three options for the shape of the end portion of the tongue are optimal from the point of view of reducing fan noise and maintaining its high aerodynamic parameters. Moreover, for all three variants, the geometry-determining parameters С and / have the same ranges of optimal values, which are for с «4 4-б, for о (0.04 4 -0,1) J. This is illustrated in Fig. 5, where typical dependences of the noise criterion of the main blade harmonic of the productivity coefficient are presented, and in Fig. 6, where the dependence Lf Q d is summarized by the results of a large series of measurements, Here L is the acoustic noise power level of the fan at the main blade harmonic frequency j-. Dependence on in fig. 5a corresponds to the leading edge of the tongue having triangular cutouts. Similar dependences in fig. 5 b and 5 c are obtained respectively for the second and third variants of the shape of the leading edge of the tongue. It can be seen from these figures that, as indicated above, with the position of the fan operating point in the region of small scientific research institutes, it is more expedient to use the second variant of the shape of the terminal portion of the tongue, and in the region of large values - the third variant.

The results presented in Fig. 5 correspond to tests of a fan with a conventional impeller design. The use of a wheel made with an even number of sections having the same width along the length: the blades and shifted in the diametric plane exactly half the blade pitch relative to adjacent sections, can further reduce the intensity of discrete and broadband noise. This is illustrated by the typical L / V dependencies shown in FIG. 7. Here, the curves I correspond to the tests of a fan with an ordinary wheel, and the curves of the 2nd wheel with offset blades. Each graph in Fig. 7, as well as in Fig.5, corresponds to one of the options

.- g

forms of the terminal portion of the tongue.

FIG. 3 and 4 illustrate the final results of aoroacoustic studies, obtained as a result of testing about 500 different variants of prototype fans, which are shown by the aerodynamic pattern of the tongue, the size of the gaps between the impeller and housing elements, the geometric layouts and the number of impeller blades, and also by the frequency of its rotations. FIG. Figure 3 shows typical noise spectra of the proposed fan (spectrum 2) and the basic prototype C, the fan according to the a.s. No. 64II7I, cl. G04, 29/46. Here /, the sound pressure level in the frequency band of 8 Hz. A similar comparison (curves I - the basic prototype, curves 2 proposed fan) dependencies) and / L // / V / is shown in Fig. 4. Here Ij1 / 0 is the fan noise criterion for the total acoustic noise power of the fan relative to 10 W.As can be seen from these figures, the broadband noise intensity of the proposed fan is more than 10 dB lower than that of the basic prototype C in the region of small 4, the decrease reaches 15 dB ) and the decrease in the intensity of the main scapular harmonic reaches 25D6. Moreover, in a rather wide range of 9, its almost complete suppression is observed (see FyG.Z).

- -All studies whose results are given in this application were carried out according to standard aerodynamic and acoustic test methods (3 using modern automated measuring systems. In the development process of the low-noise fan, multiple control tests were performed that showed the reliability and high degree of repeatability of the research results.

Claims (5)

1. A diametrical fan comprising a blade impeller and a profile vortex generator installed in the housing with inlet and discharge nozzles connected by an adjacent wall forming a recirculation channel with the vortex generator, characterized in that the housing is provided with a tongue placed in the recirculation channel made in the form of a flat plate , the end section of which has periodically repeating curly cuts, and mounted on an adjacent wall with the possibility of movement in the recirculation channel along tion to the surface, equidistant impeller. 2. The fan according to claim 1, characterized in that each of the curly cutouts of the tongue has the shape of an isosceles triangle facing the top of the impeller with a height and a base respectively equal
(D + δ) tg (2π / z) and B / m,
where D, B - respectively, the diameter and width of the impeller;
m = E (Z / c) is the integer part of Z / c, c = 4 - 6,
δ = (0.04 - 0.1);
D is the radial clearance between the top of the triangle and the circumference of the wheel at the outer ends of the blades;
Z is the number of blades. 3. The fan according to claim 1, characterized in that each of the curly cutouts of the tongue has the shape of a curved arc with a chord and an arrow of deflection, respectively equal
(B / K-α) and (D + δ) tg (2π / z),
where K = E (Z / c) is the integer part of Z / c, c = 4 - 6;
α = (0.01 - 0.03) D is the length of the jumper between the cutouts;
δ = (0.04 - 0.1) D is the radial clearance between the jumper and the wheel circumference at the outer ends of the blades;
Z is the number of blades. 4. The fan according to claim 1, characterized in that the end edge of the end portion of the tongue has a wave shape with doubled amplitude and period, respectively, equal
(D + δ) tg (2π / z) and B / m,
where D, B - respectively, the diameter and width of the impeller;
m = E (Z / c) is the integer part of Z / c, c = 4 - 6;
δ = (0.04 - 0.1) D is the minimum radial clearance between the edge of the tongue and the circumference of the wheel at the outer ends of the blades;
Z is the number of blades. 5. The fan according to claims 1 to 5, characterized in that the impeller is made with an even number of isolated sections having the same width and mixed in adjacent sections in the diametrical plane by half of the blade pitch.