CN214742327U

CN214742327U - Impeller comprising partially stepped blades

Info

Publication number: CN214742327U
Application number: CN202120641300.3U
Authority: CN
Inventors: 徐天赐; 裘鑫
Original assignee: Zhejiang Kemao Intelligent Electromechanical Co ltd
Current assignee: Zhejiang Kemao Intelligent Electromechanical Co ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2021-11-16
Anticipated expiration: 2031-03-30

Abstract

The utility model relates to an impeller comprising partial step-shaped blades, which comprises a plurality of arc-shaped backward blades, and the working surface of each blade comprises a smooth section and a platform stage; the stage is close to the outer edge of the blade; the inner edge of the stage is: the diameter is phi D by taking the center of the impeller as the center of a circle_nThe arc segment of (a); the step section comprises n continuous steps which gradually protrude towards the rotation direction of the impeller. In the closed impeller flow channel of the centrifugal ventilator, the boundary layer separation of the air flow is continuously developed and deteriorated along with the increase of the diameter, and the angle and the diameter of the inlet and the outlet of the blade are increasedOn the premise that the number of the blades and the width of the blade channel inlet are not changed, a series of local micro step shapes are additionally arranged on the blade outlet section, so that the continuous development and deterioration of boundary layer separation are restrained to a certain extent, the reduction of the area of a main airflow channel and the larger loss caused by the boundary layer separation are reduced, and the working capacity and the working efficiency of the impeller can be improved to a certain extent.

Description

Impeller comprising partially stepped blades

Technical Field

The utility model relates to a ventilation blower technical field especially relates to an impeller including local step form blade.

Background

Generally, the backward centrifugal fan impeller is mostly a closed impeller, and mainly includes a back disk 3, a front disk 2 and a plurality of blades 1 disposed therebetween, wherein an inner hole of the front disk is an impeller inlet, as shown in fig. 1. The blade flow passage of the closed impeller is a passage enclosed by adjacent blades, an impeller front disk and an impeller rear disk. The inlet width of the blade channel is an important structural parameter, and refers to the width of the channel at the inlet side of the blade. The diameters of the inlet and the outlet of the blades, the shapes of the blades, the mounting positions and the number of the blades determine the shape of the blade channel, the quality of the shape of the blade channel determines the severity of boundary layer separation on the surface of the blades, and the blade channel has great influence on the work efficiency and the work capacity of the impeller.

In the closed centrifugal impeller, because the number of the blades is not infinite but a certain number of finite blades, the velocity distribution along the circumferential direction on the cross section of the blade path is uneven, the uneven circumferential velocity distribution is caused by the axial vortex in the rotating blade path, so that the theoretical pressure of the impeller when the number of the blades is finite is certainly less than the theoretical pressure when the number of the blades is infinite, and the ratio of the former to the latter is the circulation coefficient or the slip coefficient. Since the gas medium has viscosity, a boundary layer is generated by flowing in the blade path, and although the thickness of the boundary layer is small, the influence on the flowing state is large, and the friction force generated when the gas flows is generated in the boundary layer. The existence of the boundary layer reduces the effective flow cross section of the blade channel, so that the speed of the main air flow is slightly increased, and the main air flow is interfered. The interference of the boundary layer on the main air flow and the separation of the boundary layer form larger loss, and the work efficiency and the work capacity of the impeller on the air are reduced.

SUMMERY OF THE UTILITY MODEL

The utility model discloses in present widely used backward centrifugal fan closed impeller, through set up the small step form of a series of local on blade periphery position is the working face promptly to try to weaken the boundary layer separation in the blade way and the degree that lasts the development and the loss that leads to thereof, with the efficiency that improves the impeller and do work to gas and then improve the aerodynamic performance and the efficiency of impeller and ventilation blower, and impeller major structure size keeps unchangeable with exit installation angle.

The utility model discloses a following technical scheme realizes above-mentioned purpose: an impeller comprising a partially stepped blade, the impeller comprising a plurality of arc-shaped backward blades, the working face of the blades comprising a smooth section and a plateau section; the stage is close to the outer edge of the blade; the inner edge of the stage is: the diameter is phi D by taking the center of the impeller as the center of a circle_nThe arc segment of (a); the step section comprises n continuous steps which gradually protrude towards the rotation direction of the impeller.

Further, the width of the inlet of the flow channel of the adjacent blade is W, the diameters of the inlet and the outlet of the working surface arc of the blade respectively correspond to a point c and a point a of a blade bus, W is the minimum distance from the point c to the non-working surface of the adjacent other blade and corresponds to a point c ' of the non-working surface, and the intersection point of the cc ' extension line and the working surface of the blade is a point c '; making a first circle by taking a connecting line of the point c' and the center of the impeller as a radius, wherein the diameter of the first circle is phi D_W(ii) a The phi D_n＝(1.015～1.045)×ΦD_w。

Further, the height of the inclined plane of the step is smaller than the thickness of the blade.

Further, the diameter of the outlet of the blade is phi D₂The stage is located at a diameter phi D_nAnd Φ D₂In the meantime.

Compared with the prior art, the beneficial effects of the utility model are as follows: in a closed impeller flow channel of a centrifugal fan, boundary layer separation of air flow continuously develops and deteriorates along with the increase of the diameter, and on the premise that the inlet and outlet angles of blades, the inlet and outlet diameters, the number of the blades and the inlet width of a blade channel are not changed, a series of local micro step shapes are additionally arranged at the outlet section of the blades, so that the continuous development and deterioration of the boundary layer separation are restrained to a certain extent, the area reduction and the larger loss of a main air flow channel caused by the boundary layer separation are reduced, and the working capacity and the working efficiency of the impeller can be improved to a certain extent.

Drawings

FIG. 1 is a schematic cross-sectional view of an impeller;

FIG. 2 is a perspective view of the impeller of the present application;

FIG. 3 is a circumferential surface view of an impeller blade;

FIG. 4 is a sectional view of the peripheral camber line of the blade;

FIG. 5 is a schematic view of the deflection of the blade after the blade peripheral camber line has been bisected;

FIG. 6 is an enlarged view of part I of FIG. 5;

FIG. 7 is an enlarged view of section II of FIG. 6;

FIG. 8 is a view of the peripheral vane step forming process of FIG. 1;

FIG. 9 is a view of the peripheral vane step forming process of FIG. 2;

FIG. 10 is a step forming process of the outer peripheral blade FIG. 3;

FIG. 11 is a view of the outer peripheral vane step forming process of FIG. 4;

FIG. 12 is an enlarged view of section III of FIG. 11;

FIG. 13 is a perspective view of the blade;

FIG. 14 is a static pressure comparison graph of the first example and the first comparative sample;

FIG. 15 comparison graph of the static pressure efficiency of the example one and the comparison prototype one;

FIG. 16 is a static pressure comparison graph of example two and comparative sample two;

FIG. 17 comparative static pressure efficiency plots for example two versus comparative prototype two;

FIG. 18 is a static pressure comparison graph of example three and comparative sample three;

FIG. 19 static pressure efficiency comparison graph of example three and comparative sample three.

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

the utility model provides an impeller including local step form blade, the impeller includes 7 arcings form backward to the blade, and the working face of blade includes smooth section and platform stage, and the step section is close to the blade outer fringe. The inner edge of the stage is: the diameter is phi D by taking the center of the impeller as the center of a circle_nThe arc segment of (a); the step section comprisesn continuous steps gradually protruding toward the rotation direction of the impeller. The width of the inlet of the runner of the adjacent blade is W, the diameters of the inlet and the outlet of the working surface arc of the blade respectively correspond to the point c and the point a of the blade bus, W is the minimum distance from the point c to the non-working surface of the adjacent other blade and corresponds to the point c ' of the non-working surface, and the intersection point of the cc ' extension line and the working surface of the blade is the point c '; making a first circle by using the connecting line of the point c' and the center of the impeller as the radius, wherein the diameter of the first circle is phi D_W；ΦD_n＝(1.015～1.045)×ΦD_w。

The diameter of the outlet of the blade is phi D₂Stage at diameter Φ D_nAnd Φ D₂In the meantime.

As shown in FIG. 2, the diameters of the inlet and outlet of the blade are phi D₁And Φ D₂I.e. the length from the center of the impeller as the center o to the inlet of the working surface of the blade is D₁A length of D reaching the outlet of the working surface of the blade₂The end points of the blade generatrix are point c and point a, the blade wrap angle is

I.e. the angle between oc and oa is

The width of the inlet of the flow channel of the adjacent blade is W, W is the minimum distance from the point c to the non-working surface of the adjacent blade, the point c ' of the non-working surface of the adjacent blade corresponds to, and the intersection point of the extension line of cc ' and the working surface of the blade is the point c '.

The design method of the impeller with the partially stepped blades comprises the following steps:

1) making a first circle by using the connecting line of the point c' and the center of the impeller as the radius, wherein the diameter of the first circle is phi D_W(ii) a The center of the impeller is taken as a circular point, and the diameter on the arc line of the blade is less than phi D_WIs an inner arc line larger than phi D_WIs an outer end arc.

2) Selecting diameter PhiD_n，ΦD_n＝(1.015～1.045)×ΦD_w。

3) The diameter phi D is measured along the radial direction of the impeller_nAnd Φ D₂The outer end arc of the blade between the two arc segments is divided into n arc segments as shown in fig. 3.

So as to select the diameter phi D_nAnd Φ D₂The outer end arc of each blade is divided into n sections of arcs because W is the inlet width of the flow channel between the adjacent blades, the influence of the W on the flow state in the blade channel is large, and the diameter phi Dn at the initial position of the step section is larger than the diameter phi D corresponding to the inlet width W_WIt is ensured that the inlet width W does not change due to the segmentation of the blade peripheral camber line and its deflection.

Diameter phi D of blade bus_nThe corresponding point is a_nThe dividing method is as follows: d_i＝D₂-(D₂-D_n) X i/n, wherein i ═ 1, n]，n＝[3,20]From diameter Φ D₂To Φ D_nThe intersection point of each concentric circle and the blade generatrix is as follows in sequence: a is₁,…，a_i,…，a_(n-1),a_nI.e. from point a to a on the blade outer end generatrix_nThe bus-section of a point is divided into: aa₁,a₁a₂,…，a_(i-1)a_i，…，a_(n-1)a_nAnd n sections.

4) And taking the center of the impeller as a center, outwards rotating the n sections of arc lines by a certain rotation angle respectively, and sequentially connecting adjacent arc line sections obtained after rotation, thereby forming a series of steps on the surface of the blade.

As shown in fig. 4-6, aa₁,a₁a₂,…，a_(i-1)a_i，…，a_(n-1)a_nRespectively rotate to a new position aa₁Rotation to bb₁，a₁a₂Rotation is c₁b₂,…，a_(i-1)a_iRotation is c_(i-1)b_i，…，a_(n-1)a_nRotation is c_(n-1)b_n,a_(n-1)a_nThe angle of rotation of the segments being theta_n＝θ，a_(n-2)a_(n-1)The angle of rotation of the segments being theta_(n-1)＝2×θ，…，θ_i＝a_(i-1)a_iThe rotation angle of the segment is (n-i +1) x theta, …, a₁a₂The angle of rotation of the segments being theta₂＝(n-1)×θ，aa₁The angle of rotation of the segments being theta₁N × θ; the wrap angle of the blade is respectively rotated by the arc sections

Is reduced to

Wherein θ is [0.05 °,0.25 °]And because the numerical value of theta is small and the number of n is limited, the numerical value of the reduction of the blade wrap angle is not obvious, and the outlet installation angle is kept unchanged after the outermost arc line segment rotates.

As shown in fig. 7-13, the adjacent arc segments obtained after rotation are connected in sequence in the following manner: straight connection c_iPoints b and b_iPoint, i ═ 1, n]Passing through its midpoint e_iDrawing line segment c_ib_iPerpendicular line f_ig_iAnd the arc segment c_(i-1)b_iIntersect at f_iAnd the arc segment c_ib_(i+1)Intersect at g_iWith e_iPoint as center, straight line f_ig_iRotating the impeller by an angle gamma opposite to the rotation direction of the impeller, wherein the angle gamma is [5 DEG ], and the angle gamma is 40 DEG]And the arc segment c of the blade_(i-1)b_iIntersect at u_iAnd the arc segment c of the blade_ib_(i+1)Intersect at v_iThereby forming u₁v₁，u₂v₂，…，u_iv_i，…，u_nv_nN local step shapes in total, and a compound arc line 'bu' comprising the n local step shapes₁v₁u₂v₂…u_iv_i…u_nv_nc' is used as the cambered surface molded line of the working surface of the blade. Wherein step-like inclined plane height is less than blade panel thickness, promptly: delta_i＜t。

The improvement scheme of this patent does not change impeller major structure size and exit installation angle, and the camber of each arc line section of blade also keeps unchangeable. A series of partial step shapes of the working surface of the blade weaken boundary layer separation in a blade channel and the degree of continuous development and loss caused by the boundary layer separation to a certain extent so as to improve the efficiency of the impeller applying work to gas and further improve the aerodynamic performance and efficiency of the ventilator.

Three sets of examples were set up below to demonstrate the effect of the improved impeller on ventilator static pressure and static pressure efficiency.

TABLE 1

Example one

The embodiment is that the impeller and the ventilator are formed by arranging the step-shaped improvement on the periphery of the blade on the basis of a comparison model I, and other main dimensions of the impeller and the ventilator are consistent with those of the comparison model I, and relevant dimensions are shown in a table 1.

The performance curves of example one and comparative sample one are compared and shown in fig. 14-15; the comparison of performance parameters of the same air volume working condition points is shown in Table 2.

TABLE 2

	Rotating speed (r/min)	Air volume (m)³/h)	Static pressure (Pa)	Static pressure efficiency (%)
					Comparison prototype 1	1450	14760	886	69.23
Example one	1450	14760	935	70.42

Under the working condition of the same air volume, the static pressure of the first embodiment is improved by 49Pa and the static pressure efficiency is improved by 1.19 percent compared with that of the first comparative sample machine.

Example two

The second embodiment is formed by improving the outer periphery of the blade in a step shape on the basis of the second comparison sample machine, and other main sizes of the impeller and the ventilator are consistent with those of the second comparison sample machine. The relevant dimensions are shown in table 1.

The performance curves of example two and comparative sample two are compared and shown in FIGS. 16-17; the comparison of the performance parameters of the working points with the same air volume is shown in Table 3.

TABLE 3

	Rotating speed (r/min)	Air volume (m)³/h)	Static pressure (Pa)	Static pressure efficiency (%)
					Comparison prototype 2	1780	8640	819	68.39
Example two	1780	8640	843	69.59

Under the working condition of the same air volume, the static pressure of the second embodiment is improved by 24Pa and the static pressure efficiency is improved by 1.2 percent compared with that of the second comparative sample machine.

EXAMPLE III

The third embodiment is formed by arranging the step-shaped improvement on the periphery of the blade on the basis of the third comparative sample, and other main sizes of the impeller and the ventilator are consistent with those of the third comparative sample. The relevant dimensions are shown in table 1.

The performance curves of example three and comparative sample three are compared and shown in FIGS. 18-19; the comparison of performance parameters of the same air volume working condition points is shown in Table 4.

TABLE 4

	Rotating speed (r/min)	Air volume (m)³/h)	Static pressure (Pa)	Static pressure efficiency (%)
					Comparison prototype three	2180	5400	815.2	67.71
EXAMPLE III	2180	5400	843.7	68.85

Under the working condition of the same air volume, the static pressure of the third embodiment is improved by 28.5Pa and the static pressure efficiency is improved by 1.14 percent compared with that of the third comparative sample machine.

Therefore, the improvement scheme of the invention mainly aims to inhibit boundary layer separation and continuous development deterioration to a certain extent by improving the arc line section at the outer end of the blade into a series of local tiny step-shaped zigzag arcs under the condition that the main sizes of the impeller, the air inlet and the ventilator are not changed, so that the reduction of the area of a main airflow channel and the larger loss caused by the boundary layer separation are reduced, the work-doing capability and the work-doing efficiency of the impeller are improved to a certain extent, the performance and the efficiency of the ventilator are improved, the energy consumption and the noise are reduced, and the positive significance is achieved.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.

Claims

1. The impeller comprising the partial step-shaped blades is characterized by comprising a plurality of arc-shaped backward blades, and the working surfaces of the blades comprise a smooth section and a platform stage; the stage is close to the outer edge of the blade; the inner edge of the stage is: the diameter is phi D by taking the center of the impeller as the center of a circle_nThe arc segment of (a); the step section comprises n continuous steps which gradually protrude towards the rotation direction of the impeller.

2. The impeller comprising the partially stepped vane as claimed in claim 1, wherein the inlet width of the flow channel of the adjacent vane is W, the inlet and outlet diameters of the camber line of the working surface of the vane correspond to the point c and the point a of the generatrix of the vane, respectively, W is the minimum distance from the point c to the non-working surface of the adjacent other vane, corresponding to the point c ' of the non-working surface, and the intersection point of the extension line cc ' and the working surface of the vane is the point c '; making a first circle by taking a connecting line of the c '' point and the center of the impeller as a radius, wherein the diameter of the first circle is phi D_W；

The phi D_n=（1.015～1.045）×ΦD_w。

3. Impeller comprising partly stepped vanes according to claim 2, characterised in that the vane outlet diameter is Φ D₂The stage is located at a diameter phi D_nAnd Φ D₂In the meantime.

4. An impeller comprising a partially stepped vane according to claim 1, wherein the step has a ramp height less than the vane thickness.