阅读说明：本技术 一种后向离心叶轮及通风机 (Backward centrifugal impeller and ventilator ) 是由 裘鑫 徐天赐 于 2021-07-15 设计创作，主要内容包括：本发明涉及一种后向离心叶轮及通风机,包括叶片、前盘和后盘,其特征在于,所述前盘与所述后盘之间固定设有多个叶片,所述叶片截面为月牙形状的机翼型,本发明叶片采用特定形状的机翼型叶片,可减弱叶道进口时的冲击损失和入口冲击噪声,同时改善了气流进入叶片流道前的流动状态,本发明叶片间流道形状得到一定程度优化,减小轴向涡流及其损失,减弱叶片出口边缘气流尾迹扩大的程度,从而提高了叶轮对气体做功的效率进而提高叶轮及通风机的气动性能和效率,并主动降低叶轮运转所产生的气动噪声。(The invention relates to a backward centrifugal impeller and a ventilator, which comprises a blade, a front disc and a rear disc, and is characterized in that a plurality of blades are fixedly arranged between the front disc and the rear disc, the cross section of each blade is in a crescent-shaped airfoil shape, the blade adopts the airfoil-shaped blade in a specific shape, the impact loss and the inlet impact noise of the blade channel at the inlet can be weakened, and the flowing state of airflow before entering the blade channel is improved.)

1. The utility model provides a backward centrifugal impeller and ventilation blower, includes blade, front disc and back dish, its characterized in that, the front disc with fixed a plurality of blades that are equipped with between the back dish, the blade cross-section is crescent shape's airfoil.

2. A backward centrifugal impeller and fan as claimed in claim 2, wherein said inlet-side head of the blade is shaped without a sharp right-angle edge, but is smoothly rounded.

3. A backward centrifugal impeller and fan according to claim 3 wherein the outlet-side tail of the blade is tapered to a thickness where the thickness is smallest across the chord of the blade.

4. A backward centrifugal impeller and ventilator according to claim 3, characterized in that the leading edge point of the blade profile, i.e. the midpoint of the head arc, is set to m, the trailing edge point, i.e. the midpoint of the tail arc, is set to p, the straight line segment "pm" is the chord length of the blade, the length is L, the main body parts of the upper arc and the lower arc are both on the upper side of the straight line segment "pm" of the chord length, the arc line "mep" is the center line of the crescent, the maximum camber point of the center line "mep" relative to the chord length line is set to e, the maximum camber value is set to f, and the maximum thickness of the blade profile in the normal direction of the chord length is set to c.

5. A backward centrifugal impeller and ventilator according to claim 3 in which "mp" is the chord length of the blade.

6. A backward centrifugal impeller and ventilator according to claim 6 in which the maximum relative thicknesses of the profiles are within a suitable range:in particularThe appropriate range of the maximum relative camber of the blade profile is as follows:in particular

7. A backward centrifugal impeller and ventilator according to claim 6 wherein the blade intermediate body section is of a concave crescent shape, the blade intermediate section being thicker.

8. A backward centrifugal impeller and ventilator according to claim 6 in which the vane midportion limits the development of axial vortices and the resulting flow losses.

Technical Field

The invention relates to the field of ventilators, in particular to a backward centrifugal impeller and a ventilator.

Background

The ventilator is a machine which increases the gas pressure and discharges the gas by depending on the input mechanical energy, generally, for the convenience of processing, the blade of the impeller of the centrifugal ventilator is usually made of metal plate, the section of the blade is of the equal thickness type, because the actual blade has certain thickness, near the edge of the outlet of the blade, because the pressure of the working surface and the non-working surface of the blade is different, the airflows at the two sides form vortex and are continuously expanded in the confluence process, the main airflow is disturbed, and the pressure loss and the airflow noise are formed;

the ventilator gas forms an axial vortex opposite to the rotation direction of the impeller in the blade flow passage, so that the relative speed of the gas flow at the outlet of the impeller deviates and the gas flow does not flow out from the tangential direction of the point to cause pressure reduction in the relative flow process of the main gas flow from the inlet to the outlet of the blade passage when the gas flow flows through the passages among the blades;

when the ventilator is actually operated, the flow rate of the operating working point of the ventilator cannot be ensured to be always operated at the designed flow rate, and thus, the impact of the airflow and the blades can be generated.

Disclosure of Invention

The invention aims to provide a backward centrifugal impeller and a ventilator, and solves the problems.

The invention realizes the purpose through the following technical scheme: the utility model provides a backward centrifugal impeller and ventilation blower, includes blade, front disc and back dish, its characterized in that, the front disc with fixed a plurality of blades that are equipped with between the back dish, the blade cross-section is crescent shape's airfoil.

Preferably, the shape of the inlet side head of the blade is smooth and circular without a right-angle sharp edge, so that the impact loss and the inlet impact noise at the inlet of the blade channel can be reduced, and the flow state of the airflow before entering the blade channel is improved.

Preferably, the shape of the outlet-side tail part of the blade is gradually reduced, and the thickness of the outlet-side tail part is the smallest thickness of the outlet-side tail part of the blade in the chord direction of the whole blade, so that the expansion degree of the airflow wake at the outlet edge of the blade can be weakened, and the outlet pressure loss and the outlet airflow noise can be reduced.

Preferably, the center point of the head arc, which is the leading edge point of the blade profile, is m points, the center point of the tail arc, which is the trailing edge point, is p points, the straight line segment "pm" is the chord length of the blade, the length is L, the main body parts of the upper arc and the lower arc are positioned on one side above the straight line segment "pm" of the chord length, the arc line "mep" is the center line of the crescent, the maximum camber point of the center line "mep" relative to the chord length line is e points, the maximum camber value is f, and the maximum thickness of the blade profile in the normal direction of the chord length is c.

Preferably, in the present invention, "mp" ═ L is the blade chord length.

As a preferable range of the present invention, the maximum relative thickness of the airfoil is in a suitable range:in particularThe appropriate range of the maximum relative camber of the blade profile is as follows:in particular

Preferably, the middle main body section of the blade is in an airfoil shape with an upper concave crescent shape, and the thickness of the middle part of the blade is larger.

Preferably, the vane midsection occupies a small portion of the flow area, but limits the development of axial swirl and the resulting flow losses to some extent.

Compared with the prior art, the invention has the following beneficial effects: the blades of the invention adopt airfoil-shaped blades with specific shapes, which can weaken the impact loss and the inlet impact noise when the blade channel is at the inlet and simultaneously improve the flowing state of airflow before entering the blade channel.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a schematic view of the blade of FIG. 1 according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the overall appearance of the product in FIG. 1 according to the embodiment of the present invention;

FIG. 4 is a static pressure comparison graph of a comparative prototype according to a first embodiment of the present invention;

FIG. 5 is a graph comparing the static pressure efficiency of a comparative prototype to that of a comparative prototype according to the first embodiment of the present invention;

FIG. 6 is a static pressure comparison graph of example two of the present invention and a comparison sample machine two;

FIG. 7 is a graph comparing the static pressure efficiency of the second embodiment of the present invention with that of the second comparative sample.

Detailed Description

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

a backward centrifugal impeller and ventilator, as shown in fig. 1-7, comprises a blade 11, a front disk 12 and a rear disk 13, and is characterized in that a plurality of blades 11 are fixedly arranged between the front disk 12 and the rear disk 13, and the cross section of each blade 11 is a crescent-shaped airfoil.

Preferably, the shape of the inlet-side head of the vane 11 is smooth and circular without a right-angled sharp edge, so that the impact loss and the inlet impact noise at the inlet of the vane passage can be reduced, and the flow state of the airflow before entering the passage of the vane 11 can be improved.

Preferably, the shape of the outlet-side tail of the blade 11 is gradually reduced, and the thickness of the outlet-side tail is the smallest thickness of the whole blade 11 in the chord direction, so that the expansion degree of the airflow wake at the outlet edge of the blade 11 can be weakened, and the outlet pressure loss and the outlet airflow noise can be reduced.

Preferably, the center point of the head arc, which is the leading edge point of the blade profile, is m points, the center point of the tail arc, which is the trailing edge point, is p points, the straight line segment "pm" is the chord length of the blade 11, the length is L, the main body parts of the upper arc and the lower arc are both on the upper side of the straight line segment "pm" of the chord length, the arc line "mep" is the center line of the crescent, the maximum arch height point of the center line "mep" relative to the chord length line is e points, the maximum arch height value is f, and the maximum thickness of the blade profile in the normal direction of the chord length is c.

Preferably, in the present invention, "mp" ═ L is the chord length of the blade 11.

As a preferable range of the present invention, the maximum relative thickness of the airfoil is in a suitable range:in particularThe appropriate range of the maximum relative camber of the blade profile is as follows:in particular

Preferably, the middle main body section of the blade 11 is of a wing shape with a concave crescent shape, and the middle part of the blade 11 has a larger thickness.

Preferably, the vane 11 occupies a small part of the flow area in the middle, but limits the development of axial vortices and the resulting flow losses to some extent.

In use, the blade 11 of the first and second embodiments has a crescent-shaped cross section, the main dimensions of which are shown in fig. 1, and the main data are shown in the following table:

vane exit diameter Φ D for example one and comparative sample one₂The diameter phi of each blade is 226.6mm, the number of the blades is 7, the blades of the comparison sample machine I are arc-shaped blades with equal thickness, the blades of the embodiment I are crescent airfoil-shaped blades, and the diameter phi D of the inlet of the blades of the comparison sample machine I is₁Is 130.8mm phi, and the inlet diameter phi D of the vane of the first embodiment₁Phi is 151.9 mm;

the embodiment is that on the basis of a comparison model I, the blade is formed by improving the shape of the blade, namely the original conventional uniform-thickness arc-shaped blade is improved into a crescent-shaped airfoil shape with the concave bottom, and other main sizes of an impeller and a ventilator are kept unchanged.

The ratio of the maximum camber of the blade midline to the blade chord length of the first embodiment is as follows: f/L is 0.068;

the diameter ratio of the chord length of the vane to the outlet of the first embodiment is as follows: L/D₂＝0.356；

The blade installation angle of the first embodiment is 42.18 degrees;

the diameter ratio of the inlet and the outlet of the blade in the first embodiment is as follows: d₁/D₂＝0.672；

The performance curves of example one and comparative sample one are compared and shown in FIGS. 4-5; the main performance parameters for the highest efficiency operating point are compared as shown in the following table:

	rotating speed (r/min)	Air volume (m)3/h)	Static pressure (Pa)	Static pressure efficiency (%)
					Comparison prototype 1	2500	720	300.8	57.92
Example one	2500	720	309.8	61.97

Under the working condition of the same air quantity, the static pressure of the first embodiment is improved by 9Pa and the static pressure efficiency is improved by 4.05 percent compared with that of the first comparative sample machine;

vane exit diameter Φ D for example two and comparative sample two₂Phi 263.4mm, 7 blades, equal thickness arc blade, crescent wing blade, and inlet diameter phi D₁Is phi 159.1mm, the inlet diameter phi D of the vane of the second embodiment₁Phi 177.8 mm;

the second embodiment is formed by improving the shape of the blade on the basis of comparing with the second embodiment, namely the original conventional uniform-thickness arc-shaped blade is improved into a crescent-shaped airfoil shape with the concave bottom, and other main sizes of an impeller and a ventilator are kept unchanged;

the ratio of the maximum camber of the blade midline to the blade chord length of the second embodiment is as follows: f/L is 0.07;

the diameter ratio of the chord length of the vane to the outlet of the second embodiment is as follows: L/D₂＝0.372；

The blade setting angle of the second embodiment is 42.45 °;

the diameter ratio of the inlet and the outlet of the blade of the second embodiment is as follows: d₁/D₂＝0.675；

The performance curves of example two and comparative sample two are compared and shown in FIGS. 6-7; the main performance parameters for the highest efficiency operating point are compared as shown in the following table:

	rotating speed (r/min)	Air volume (m)3/h)	Static pressure (Pa)	Static pressure efficiency (%)
					Comparison prototype 2	3700	2146	963	64.82
Example two	3700	2146	1017.8	67.14

Under the working condition of the same air volume, the static pressure of the second embodiment is improved by 54.8Pa and the static pressure efficiency is improved by 2.32 percent compared with that of the second comparative sample machine.

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 as defined in the appended claims.