阅读说明：本技术 一种离心风机转向蜗壳 (Centrifugal fan turns to spiral case ) 是由 王军 蒋博彦 肖千豪 杨筱沛 梁钟 于 2019-09-16 设计创作，主要内容包括：本发明属于流体机械领域,并具体公开了一种离心风机转向蜗壳,包括收集段和转向段,收集段由环壁面、前螺旋面和后螺旋面包络而成,环壁面下边按型线<Image he="77" wi="314" file="DDA0002202949320000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>设计而成,上边按型线<Image he="77" wi="399" file="DDA0002202949320000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>设计而成,前螺旋面和后螺旋面均垂直于环壁面,分别与环壁面下边和上边相连；转向段是由大圆弧面、小圆弧面、环壁侧平面和蜗舌侧平面包络成的肘形流道,大圆弧面、小圆弧面、环壁侧平面分别与前螺旋面、后螺旋面、环壁面末端相切,蜗舌侧平面连接大圆弧面和小圆弧面,且与环壁侧平面平行。本发明蜗壳融合了传统蜗壳及转向通道,以紧凑的结构、较小的尺寸和流动损失实现气流流向在蜗壳内向特定方向的偏转。(The invention belongs to the field of fluid machinery, and particularly discloses a centrifugal fan steering volute, which comprises a collecting section and a steering section, wherein the collecting section is formed by enveloping a ring wall surface, a front spiral surface and a rear spiral surface, and the lower edge of the ring wall surface is provided with a molded line Designed to be formed by an upper edge pressing line The design is that the front spiral surface and the rear spiral surface are both vertical to the annular wall surface and are respectively connected with the lower edge and the upper edge of the annular wall surface; the turning section is an elbow-shaped runner enveloped by a large arc surface, a small arc surface, a ring wall side plane and a volute tongue side plane, the large arc surface, the small arc surface and the ring wall side plane are respectively tangent with the front spiral surface, the rear spiral surface and the tail end of the ring wall surface, and the volute tongue side plane is connected with the large arc surface and the small arc surface and is parallel to the ring wall side plane. The volute combines the traditional volute and the steering channel, and has a compact structure and smaller sizeThe size and flow losses effect a deflection of the gas flow direction in a particular direction within the volute.)

1. The utility model provides a centrifugal fan turns to spiral case, its characterized in that includes collection section (1) and turns to section (2), wherein:

the collecting section (1) is formed by enveloping a ring wall surface (13), a front spiral surface (11) and a rear spiral surface (12), wherein the lower edge of the ring wall surface (13) is provided with a molded lineDesigned to be formed by an upper edge pressing lineThe design is that the material is formed by designing,in order to be the azimuth angle,the distance between the point on the profile and the axis of the volute,is an axial offset which is a continuous monotonically increasing function and is initially setB is the width of the annular wall surface (13); the front spiral surface (11) and the rear spiral surface (12) are perpendicular to the ring wall surface (13), the front spiral surface (11) is connected with the lower side of the ring wall surface (13), and the rear spiral surface (12) is connected with the upper side of the ring wall surface (13); when in use, the volute is internally provided with an impeller, and the outlet surface of the impeller is positioned between the front spiral surface (11) and the rear spiral surface (12), so that the collecting section (1) and the outlet surface of the impeller jointly form a collecting flow channel;

the turning section (2) is an elbow-shaped runner formed by enveloping a large arc surface (21), a small arc surface (22), a ring wall side plane (23) and a volute tongue side plane (24), the large arc surface (21), the small arc surface (22) and the ring wall side plane (23) are tangent to the tail ends of the front spiral surface (11), the rear spiral surface (12) and the ring wall surface (13), and the volute tongue side plane (24) is connected with the large arc surface (21) and the small arc surface (22) and is parallel to the ring wall side plane (23).

2. The centrifugal fan turn volute of claim 1, wherein the axial offset isDerivative function ofContinuously monotonically does not decrease.

3. The centrifugal fan turn volute of claim 1, wherein the maximum axial offset value

4. The centrifugal fan turning volute according to claim 1, wherein the cross-sectional area of the collecting flow path formed by the collecting section (1) and the impeller outlet face is gradually increased.

5. The centrifugal fan turning volute according to claim 1, wherein the turning section (2) has a decreasing cross-sectional flow area.

6. The centrifugal fan turning volute of claim 1, wherein the plane (24) on the volute tongue side is spaced from the axis of the volute at a minimum distance of no more than the radius of the impeller in the volute.

7. The centrifugal fan turn volute of claim 1, wherein the overall axial width of the volute is H, and 1.5B < H < 2.5B.

8. The centrifugal fan turning volute according to any of the claims 1-7, wherein the collecting section (1) and the turning section (2) are integrally formed.

Technical Field

The invention belongs to the field of fluid machinery, and particularly relates to a centrifugal fan steering volute.

Background

The centrifugal fan is widely applied to agriculture, industry, traffic and various places with ventilation requirements, and the design of the centrifugal fan with high pressure, large air quantity, high efficiency and low noise is the leading development direction of the related technology. Because the impeller is centrifugal, the air current radially flows out from all around after entering the impeller along the axial, if do not pass through collection of spiral case and diffuser fan just can't concentrate to the direction of appointing and carry, therefore the spiral case is the essential component of centrifugal fan, and the design of spiral case is the key of centrifugal fan design. The appropriate volute shape design can not only reduce the flow loss of the air flow when passing through the volute, but also can reversely promote the energy transfer of the impeller to the air flow, thereby improving the overall aerodynamic performance of the centrifugal fan.

Generally, a volute of a centrifugal fan has no complex three-dimensional structure and is designed by axially stretching a section of two-dimensional volute profile curve by a certain width, and the through-flow section is generally rectangular. At this time, the airflow enters the fan along the axis, and the outlet direction of the volute is tangential to the impeller, so that the air inlet direction and the air outlet direction of the centrifugal fan have a deflection angle of 90 degrees. However, some special application scenarios have additional requirements on the conveying direction of the fan, which requires an additional turning duct to be connected in front of or behind the fan to deflect the outlet airflow direction, but this approach increases the size of the fan system greatly, and also brings unnecessary flow loss, which is not favorable for fan performance.

Disclosure of Invention

In view of the above defects or improvement needs in the prior art, the present invention provides a centrifugal fan turning volute, which includes a collecting section and a turning section, wherein an axial offset is introduced into the collecting section, and the tail end of the collecting section is smoothly connected with an elbow-shaped turning channel, so that the deflection of the airflow flow direction to a specific direction in the volute is realized, and the structure is compact and the flow loss is small.

In order to achieve the purpose, the invention provides a centrifugal fan steering volute, which comprises a collecting section and a steering section, wherein:

the collecting section is formed by enveloping a ring wall surface, a front spiral surface and a rear spiral surface, wherein the lower edge of the ring wall surface is provided with molded linesDesigned to be formed by an upper edge pressing lineThe design is that the material is formed by designing,in order to be the azimuth angle,the distance between the point on the profile and the axis of the volute,is an axial offset which is a continuous monotonically increasing function and is initially setB is the width of the annular wall surface; the front spiral surface and the rear spiral surface are both vertical to the annular wall surface, the front spiral surface is connected with the lower side of the annular wall surface, and the rear spiral surface is connected with the upper side of the annular wall surface; when in use, the volute is internally provided with the impeller, and the outlet surface of the impeller is positioned between the front spiral surface and the rear spiral surface, so that the collecting section and the outlet surface of the impeller form a collecting flow channel together;

the turning section is an elbow-shaped runner formed by enveloping a large arc surface, a small arc surface, a ring wall side plane and a volute tongue side plane, the large arc surface, the small arc surface and the ring wall side plane are respectively tangent with the tail ends of the front spiral surface, the rear spiral surface and the ring wall surface, and the volute tongue side plane is connected with the large arc surface and the small arc surface and is parallel to the ring wall side plane.

As advance intoPreferably, the axial offset amountDerivative function ofContinuously monotonically does not decrease.

Further preferably, the axial offset amount is maximum

Preferably, the cross-sectional area of the collecting channel formed by the collecting section and the outlet face of the impeller is gradually increased.

Preferably, the turning section has a gradually decreasing flow passage cross-sectional area.

It is further preferred that the distance value of the volute tongue side plane from the smallest volute axis is not greater than the radius of the impeller in the volute.

As a further preference, the overall axial width of the volute is H, with 1.5B < H < 2.5B.

As a further preference, the collecting section and the deflecting section are integrally formed.

Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. the axial offset is introduced into the volute collecting section, so that the molded line of the volute presents a spiral rising trend, and the airflow is collected by the volute and partially deflected in advance; meanwhile, the turning section is integrated into the volute, and the collecting section and the turning section are subjected to integrated curvature design, so that the deflection of the airflow direction to a specific direction in the volute is realized through a compact structure, a small size and a small flow loss.

2. The cross section of the through-flow rectangular section of the volute collecting section is continuously enlarged and simultaneously the through-flow rectangular section of the volute collecting section is along the three-dimensional volute molded line L₁Producing an axial offset such that the gas exiting the impeller in the volute has an axial velocity component when passing through the interior thereofGradually increasing; and the tapered turning section inhibits the flow separation at the inner side of the curve in the process of finally finishing the turning of the airflow, and reduces the flow loss in the deflection process of the airflow flowing direction.

3. Maximum axial offset, i.e. three-dimensional profile L, in the invention₁The distance between the axial position at the tail end and the front disc of the impeller is not more than 1/3 of the annular wall surface, namely the width B of the original volute, so that the working capacity of the impeller is prevented from being influenced by excessive blockage.

4. The invention controls the whole axial width of the volute within a certain range, relieves the gas flow in the volute, reduces the loss and avoids the overlarge whole volume of the volute.

Drawings

FIG. 1 is a schematic three-dimensional view of a turning scroll according to an embodiment of the present invention;

FIG. 2 is another perspective of FIG. 1;

FIG. 3 is a schematic diagram of two-dimensional profiles and three-dimensional profiles of a turning volute according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a three-dimensional profile design of a turning volute according to an embodiment of the present invention;

FIG. 5 is a schematic view of a turning volute turning section design according to an embodiment of the invention;

FIG. 6 is a schematic view of a key profile modeling process of a turning volute according to an embodiment of the present invention;

FIG. 7 is a schematic view of a turn-around volute with an impeller installed;

fig. 8 is a schematic view of the collection flow path in the turn volute with the impeller and motor installed.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein: 1-collection section, 2-turning section, 11-front helical surface, 12-rear helical surface, 13-ring wall surface, 14-arc straight volute tongue, 15-front arc wall surface, 16-rear arc wall surface, 17-motor installation surface, 21-large arc surface, 22-small arc surface, 23-ring wall side plane and 24-volute tongue side plane.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The centrifugal fan steering volute provided by the embodiment of the invention is as shown in fig. 1 and 2, the shape of the centrifugal fan steering volute is formed by enveloping a plurality of space curved surfaces, and the centrifugal fan steering volute comprises a collecting section 1 and a steering section 2, wherein the collecting section 1 and the steering section 2 are integrally formed and cannot be divided, and the centrifugal fan steering volute comprises:

the collecting section 1 is formed by enveloping a ring wall surface 13, a front spiral surface 11 and a rear spiral surface 12, wherein the lower edge of the ring wall surface 13 is provided with a molded lineDesigned to be formed by an upper edge pressing line Designed, B is the width of the ring wall surface 13; the front spiral surface 11 and the rear spiral surface 12 are both vertical to the annular wall surface 13, the front spiral surface 11 is connected with the lower side of the annular wall surface 13, the rear spiral surface 12 is connected with the upper side of the annular wall surface 13, one end of the front spiral surface 11 is an air inlet end, a round hole with the diameter larger than that of an impeller is arranged on the front spiral surface, the impeller is arranged in a volute, a current collector is arranged on the front spiral surface, and a motor mounting surface 17 is arranged in the middle area surrounded by the rear spiral surface 12 and used for mounting a motor; when in use, a centrifugal impeller is arranged in the volute, and an outlet surface of the impeller is positioned between the front spiral surface 11 and the rear spiral surface 12, so that the collecting section 1 and the outlet surface of the impeller jointly form a collecting flow channel (as shown in fig. 8, the cross section of the collecting flow channel is schematic); meanwhile, the front arc wall surface 15 and the rear arc wall surface 16 respectively seal gaps generated on the volute body due to axial displacement of the front spiral surface 11 and the rear spiral surface 12;

specifically, as shown in FIG. 3, the three-dimensional profileIs in a two-dimensional molded lineOn the basis of adding axial offsetThe method comprises the steps of forming, in which,in order to be the azimuth angle,the distance between the point on the molded line and the axis of the volute,is the azimuth angleAnd gradually increasing with azimuth, e.g.When the temperature of the water is higher than the set temperature,when the temperature of the water is higher than the set temperature,when the temperature of the water is higher than the set temperature,the cross-sectional area of the collecting flow channel is gradually increased;for axial offset, is azimuthAnd more particularly, the axial offsetIs a continuous monotone increasing function to ensure that the key geometrical profiles of the front spiral surface 11, the back spiral surface 12, the ring wall surface 13 and the like are all complete curved surfaces, and the profile line L₁The axial offset of the collecting channel gradually increases along with the increase of the azimuth angle, so that the collecting channel gradually offsets towards the opposite direction of the inlet; axial offsetThe rate of increase with azimuth angle cannot be reduced, i.e.To pairDerivative function ofThe continuous monotony is not reduced so as to ensure that key geometric molded surfaces such as the front spiral surface 11, the rear spiral surface 12, the annular wall surface 13 and the like are smooth curved surfaces, namely the curvature change of the curved surfaces has no sudden change; initial axial offsetMaximum axial offsetI.e. the three-dimensional profile L₁The axial position at the tip being spaced from the impeller front disk by no more than 1/3 of the width B of the annular wall surface 13, i.e.So as to avoid the influence of excessive blockage on the work capacity of the impeller; preferably, the polynomial representation is a multiple ofThe value of the coefficient k is obtained under the above-mentioned constraint conditions.

The turning section 2 is an elbow-shaped runner formed by enveloping a large arc surface 21, a small arc surface 22, a ring wall side plane 23 and a volute tongue side plane 24, the through-flow section of the runner is rectangular, wherein the large arc surface 21, the small arc surface 22 and the ring wall side plane 23 are respectively tangent to the tail ends of the front spiral surface 11, the rear spiral surface 12 and the ring wall surface 13, and the volute tongue side plane 24 is connected with the large arc surface 21 and the small arc surface 22 and is parallel to the ring wall side plane 23;

specifically, the large arc surface 21 and the small arc surface 22 are formed by the tangent plane of the end of the annular wall surface 13 and the three-dimensional line L₁The big and small sections of non-concentric arcs with tangent tail ends are obtained by stretching a distance W along the normal direction of the tangent plane to one side of the axis, namely the width of the rectangular section of the runner of the turning section 2 is W; the cross section area of the flow channel gradually shrinks along the flow direction, so that the separation of the airflow on the inner side of the curve (namely the small arc surface 22) is inhibited, and the flow loss of the airflow during turning is reduced; further, when the distance W is determined, the distance value of the minimum distance between the volute tongue side plane 24 and the axis is not larger than the radius of an impeller installed in the volute;

preferably, the overall axial width of the volute is H, and 1.5B < H <2.5B, since the curvature of the large arc surface 21 affects the flow state of the gas in the turning section 2, and an excessively small curvature radius will cause flow separation at the inner curve of the curve, and flow loss will be generated in the subsequent ventilation duct, and an excessively large curvature radius can relieve flow and reduce loss, but will cause an excessively large volute volume, and controlling the overall axial width of the volute within the above range can relieve gas flow in the volute and reduce loss, and at the same time, avoid the overall volume of the volute from being excessively large.

In addition, a circular arc straight volute tongue 14 is arranged between the annular wall surface 13 and the volute tongue side plane 24 and is obtained by rounding off at the intersection of the annular wall surface 13 and the volute tongue side plane 24.

When the spiral case works, an impeller is installed in the spiral case, airflow enters the impeller in the spiral case from one end of the front spiral face 11, the gas flows out of the impeller and enters the collecting section 1, the axial velocity component of the gas in the collecting section 1 is gradually increased, partial axial deflection is completed in advance and then enters the turning section 2, and finally the gas flows out of the turning section 2 through the guiding effect of the turning section 2 and flows to the designated direction.

The volute and its design process are described in detail below with a specific embodiment:

the conventional common molded line of the fan volute is a two-dimensional curve which can be expressed as polar coordinatesAs shown by the dotted line in fig. 3, it can be spiral lines or processed curves in various forms, and the design method thereof is described in various books, and is not described herein again; here, the two-dimensional volute profileOn the basis of adding axial offsetForming three-dimensional volute profileAs shown in solid lines in fig. 3; wherein the axial offsetAbout an azimuth angleThe function of (1) is a 4 th-order polynomial curve, monotonically increases and the corresponding derivative function is continuously monotonically non-decreasing, and has an initial valueThe maximum axial offset is 1/3 of the original volute width (i.e. the width of the annular wall surface 13) B, i.e. the maximum axial offset is

As shown in fig. 4, curveThe first molded line is translated along the axial direction by a distance B to obtain a second molded lineThen passes through the end of the first profilePoint a and point B at the end of the second profile, making a tangent plane S1 at the end of the annular wall, it is apparent that S1 is perpendicular to the XOY plane;

FIG. 5 is a schematic diagram of making a key turning circle of the turning section 2 on the S1 plane, passing through the first profile L₁Along a first profile L₁At a distance R from₃Find the center point O₃(ii) a With O₃Drawing a circular arc through the point A as the center of a circleO₃The angle of C is determined according to the designed outlet direction, the air flow in this embodiment flows along the axis, therefore O₃C is vertical to the axial direction; through a second profile line L'₃End point B of₃C intersects with O₄Make a small arcIt is clear that R₃The size of the volute determines the overall thickness H of the volute, wherein H is 2B;

FIG. 6 is a process of shaping each molded surface of the volute, and the arc segments are formedStretching a distance W towards one side of the shaft along the normal direction of the tangent plane S1 to obtain a large arc surface 21 and a small arc surface 22, wherein the obtained four endpoints are respectively marked as A ', B', C 'and D', and the planes ABDC and A 'B' D 'C' are respectively a ring wall side plane 23 and a volute tongue side plane 24; the distance between B' and the volute shaft is R_sSelecting W value to make R_s≤R₂，R₂Is the radius of the impeller mounted in the volute;

in operation, the flow enters the deflecting segment 2 from the section ABB 'A' and exits from the CDD 'C' due to the arcAndnon-concentric, length-wise CD<AB, according toThe turning section 2 designed by the method has a tendency to gradually shrink along the flow direction.

In the first profile L₁And a second molding line L₁' Upper division azimuth angleCorresponding point A_nAnd B_nSelecting a point B_n' let line segment B_nB_nPerpendicular to A_n B_nAnd is perpendicular to the second molded line L₁' at B_nTangent line at point, and satisfies point B_n' distance from axis equals R_s(ii) a In the same way, point A can be determined_n' position, then rectangle A_nB_nB_n’A_n' that is, the present embodiment provides a volute in azimuthThe flow cross section of the upper part can be sequentially made into a flow cross section rectangle corresponding to each azimuth angle. It can be seen that the cross-sectional area of the volute flow-through rectangular section at different azimuth angles is continuously enlarged and simultaneously the cross-sectional area is continuously enlarged along the three-dimensional volute molded line L₁The axial offset is gradually generated so that the axial velocity component generated by the gas flowing out of the impeller when passing therethrough is gradually increased. Segment A_nA_n’，B_nB_n’，A_nB_nRespectively along the three-dimensional volute molded lines L₁Or L₁Scanning to obtain a front spiral surface 11, a rear spiral surface 12 and a circular wall surface 13 of a key three-dimensional profile enveloping a collecting section 1;

will have different azimuth anglesCorresponding B_n' Point-to-point connection obtains line L₂In the above manner, point B_n' distance to axis constant R_sThus L is₂Projected axially downward to a certain depth to obtain a radius R_sCircle L of₂' (as shown in FIG. 2), mixing L₂And L₂' obtaining a rear arc wall surface 16 as the upper and lower edges; circle L₂' enclosing into a circular plane is a motorA mounting surface 17 on which a hole is opened for mounting and fixing the motor; one side of the front spiral surface 11 is provided with a round hole for installing the impeller in the volute, and the front arc wall surface 15 is used for sealing a gap which is formed on the volute body by the front spiral surface 11 in the axial direction and is staggered; a circular arc straight volute tongue 14 is arranged between the ring wall surface 13 and the volute tongue side plane 24 and is obtained by rounding off at the intersection of the ring wall surface 13 and the volute tongue side plane 24 with a certain radius; thereby completing the overall design of the turning volute, which is a perspective view of the turning volute provided with the impeller and the current collector as shown in fig. 7.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.