A current collector based on multi-segment sinusoidal curves and applications thereof

Abstract

The application belongs to the technical field of current collectors, and discloses a current collector based on a multi-segment sinusoidal curve and application thereof.The busbar of the current collector is composed of n segments of sinusoidal curves; wherein the n segments of sinusoidal curves are sequentially composed of sinusoidal curves with the domain [(i-1)pi, i pi] from the first segment to the nth segment, the amplitudes of the n segments of sinusoidal curves are sequentially reduced, n is an odd number from 3 to 9, and i sequentially takes integral values from 1 to n; wherein the highest point of the waveform of the first segment of sinusoidal curve faces the inner side of the current collector pipeline.The current collector prepared by the application has the beneficial effects of reducing the flow impact loss, weakening the separated flow of the front disc of the impeller, and improving the axial uniformity of the airflow at the inlet of the impeller.The parameterized control of the multi-segment waveform can realize the variable design of the busbar structure of the current collector, and the adjustment of the corresponding control parameters can provide the design scheme of the waveform line current collector busbar for centrifugal fans with different structures and sizes.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of flow collectors, and more particularly relates to a flow collector based on a multi-segment sinusoidal curve and application thereof. BACKGROUND

[0002] A centrifugal fan is a fluid machine that relies on input mechanical energy to improve the pressure of gas and transport it, and is widely used in the fields of environmental ventilation, air conditioning, and range hood. The centrifugal fan mainly includes three parts: an impeller, a volute, and a flow collector. As one of the core components of the performance of the centrifugal fan, the flow collector functions to guide the gas to the impeller and establish a uniform velocity field and pressure field in the front section of the inlet of the fan, so as to improve the efficiency of the fan.

[0003] Due to the special inlet mode of the centrifugal fan, the airflow needs to be quickly converted from axial to radial, and a relatively obvious separation flow region appears near the front disc of the impeller, resulting in relatively serious flow loss. The structure of the flow collector has an important influence on the separation flow phenomenon at the inlet. Although there are various flow collector structures at present, such as cylindrical, conical, single and double circular arc collector, there are still many problems. For example, under the existing flow collector structure, there is still a clear separation flow phenomenon and a low-speed flow region near the front disc of the impeller of the centrifugal fan, which limits the further improvement of the performance of the fan; the flow direction of the airflow at the inlet of the centrifugal fan changes greatly, and the current flow collector structure has few designs considering flow direction control; the traditional flow collector design method is difficult to parameterize the adjustment of the inner surface structure, which limits the flow control effect at the inlet of the centrifugal fan. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a flow collector based on a multi-segment sinusoidal curve and application thereof.

[0005] The generatrix of the flow collector provided by the present application is based on the bionic design of the front edge protrusion structure of the fin limb of the beluga whale, and is composed of n segments of sinusoidal curves; wherein the n segments of sinusoidal curves are sequentially composed of sinusoidal curves with a domain of [(i-1)π, iπ] from the first segment to the nth segment, the amplitudes of the n segments of sinusoidal curves sequentially decrease from the first segment to the nth segment, and the highest point of the waveform of the first segment of sinusoidal curve is directed towards the inside of the flow collector pipeline. The generatrix structure of the flow collector disclosed in the present application weakens the flow separation near the front disc of the centrifugal fan impeller, improves the work capacity of the blades of the front disc of the impeller, and improves the aerodynamic performance of the fan. Moreover, the present application realizes the variable design of the generatrix structure of the flow collector based on the parameterized control of the multi-segment sinusoidal curve, and can provide an adaptive waveform flow collector generatrix design scheme for centrifugal fans of different structures and sizes by adjusting the corresponding control parameters.

[0006] In the first aspect of the present application, a multi-segment sinusoidal current collector is disclosed, the busbar of the current collector is composed of n segments of sinusoidal curves; wherein the n segments of sinusoidal curves are composed of sinusoidal curves with the domain [(i-1)π, iπ] from the first segment to the nth segment, the amplitudes of the n segments of sinusoidal curves decrease from the first segment to the nth segment, n is an odd number of 3-9, i is an integer value from 1 to n; wherein the highest point of the first segment of sinusoidal curve waveform is towards the inside of the current collector pipeline.

[0007] As a preferred embodiment of the present application, the function of the sinusoidal curve is y=A1sinx to y=A n sinx from the first segment to the nth segment.

[0008] As a preferred embodiment of the present application, the amplitude of the function of the sinusoidal curve gradually decreases from A1 to A n in the range of [0.2, 2].

[0009] As a preferred embodiment of the present application, the amplitude of the function of the nth segment of sinusoidal curve A n is in the range of [0.2, 0.3].

[0010] As a preferred embodiment of the present application, the amplitude variation control parameter T m of the sinusoidal curve is A m / A m+1 , T m is in the range of [1.2, 1.6]. The value of m is an integer in the range of [1, n-1].

[0011] As a preferred embodiment of the present application, the function origin corresponding to the first segment of sinusoidal curve waveform is any point on the inlet radial cross-sectional profile line of the current collector.

[0012] As a preferred embodiment of the present application, the angle between the x-axis of the n segments of sinusoidal curves and the axis of the current collector is 0-60°.

[0013] In the second aspect of the present application, a centrifugal fan is provided, which has the multi-segment sinusoidal current collector provided in the first aspect of the present application.

[0014] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0015] (1) The busbar of the current collector of the application is spliced by n segments of sinusoidal curves, the n segments of sinusoidal curves are sequentially composed according to the definition domain of [(i-1)pi, i pi] from the first segment to the nth segment, the amplitudes of the n segments of sinusoidal curves are sequentially reduced, and the overall waveform line with sequentially reduced amplitudes is formed. After determining that the highest point of the waveform of the first segment of sinusoidal curve is directed to the inner side of the current collector pipeline, the shape and position of the waveform curve are determined. The busbar of the current collector is based on the bionic design of the convex structure of the front edge of the fin limb of the beluga whale, and the beneficial effects of reducing the impact loss of the incoming flow, weakening the separated flow of the front disc of the impeller and improving the axial uniformity of the inlet airflow of the impeller are achieved.

[0016] (2) The busbar of the current collector of the application is a waveform line with sequentially reduced amplitudes, and the waveform line is composed of n segments of sinusoidal curves, especially y=A1 sinx to y=A n sinx from the first segment to the nth segment. Based on the function expression of the curve, by adjusting the corresponding parameters of the waveform line, including the number of segments of the waveform line, the amplitude change control parameter and the function amplitude of the sinusoidal curve, the structure of the current collector can be flexibly designed.

[0017] (3) The application realizes the flow direction angle control of the outflow of the current collector by limiting the outflow angle formed by the tangent line at the connection between the tail end of the current collector and the volute and the main flow direction, so as to better reduce the separated flow near the front disc, thereby improving the flow state at the inlet of the fan.

[0018] (4) The busbar of the current collector of the application is based on the function expression of the curve, especially by controlling the amplitude change of the ith segment and the i+1th segment, the waveform of all curves is kept to change at the same frequency in half a period, further improving the controllability and flexibility of the design.

[0019] (5) The application further determines the spatial position of the busbar of the current collector by determining the angle between the busbar of the current collector and the axis, providing an optional scheme for the controllable design of the busbar of the current collector. Especially based on the specific position setting of any point on the inlet radial cross-sectional profile line of the current collector, when the angle between the busbar of the current collector and the axis is 0-60°, the busbar of the current collector is flexibly designed by the flexible application of various parameters in the curve function.

[0020] (6) Further, the design of the collector of the present application can be adaptively adjusted according to the air inlet conditions of centrifugal fans of different structural types, improving the flexibility of the structural design of the collector. Specifically, after the inlet pipe diameter and the volute inlet diameter are determined, the starting point and the ending point of the collector are determined, and after the amplitude of the last wave structure is limited, the angle is also limited. The higher the amplitude of the last wave structure, the smaller the angle between the outflow direction and the axial direction. The actual outflow angle of the collector is determined according to the actual sizes of the specific inlet pipe diameter and the volute inlet diameter, so for different structural inlet pipe diameters and volute inlet diameters of the collector, the outflow angle of the collector is controlled by adjusting the amplitude of the last wave structure, so as to provide an adaptive optimal solution according to different structural parameters of the centrifugal fan.

[0021] (7) On the basis of the present application, when the invention is limited to n=1 or 2, i.e. a single half-cycle sinusoidal curve or a two-segment spliced half-cycle sinusoidal curve, by controlling the adjustment of the parameter T value, a certain degree of similarity replacement can be achieved for the single-double circular arc bus structure (refer to the patent application file No. 202110041341.3). The present application has obvious advantages over the single-double circular arc bus collector in that it can control the parameters of the overall structure of the collector bus and flexibly adjust the outflow angle of the collector. This is because the present application uses the bionic design of the front edge of the fin limb of the beluga whale to design the collector bus by using multiple sinusoidal curves, which can reduce the flow impact at this point, adjust the speed and angle of the inlet flow in the front disc area of the impeller, and improve the work capability of the front disc blades.

[0022] In summary, the collector of the present application realizes the variable design of the collector bus structure by controlling the multiple sinusoidal curves, and the flow separation in the front disc of the centrifugal fan impeller is weakened by using the bionic collector structure in the present application, the work capability of the blades is improved, and the aerodynamic performance of the fan is improved. At the same time, the present application realizes the parameterization adjustment of the collector structure of different centrifugal fans by setting different control parameters, providing multiple solutions for the flow control in the inlet area of the centrifugal fan. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The structural schematic diagram of the centrifugal fan for the embodiment of the present application is shown;

[0024] Figure 2 The structural diagram of the collector for the embodiment of the present application is shown;

[0025] Figure 3 The schematic diagram of the collector bus for the embodiment of the present application is shown;

[0026] Figure 4 The cross-sectional view of the collector for the embodiment of the present application is shown;

[0027] Figure 5 is a two-dimensional graph formed based on a 5-segment sinusoidal function curve in Embodiment 1 of the present application;

[0028] Figure 6 is a total pressure efficiency-flow rate curve graph of a centrifugal fan in Embodiment 1 of the present application; wherein C1 is a collector with a straight busbar, and C2 is a collector with a wave-shaped structure designed based on a 5-segment sinusoidal curve in Embodiment 1;

[0029] Figure 7 is a radial cross-sectional velocity nephogram in Embodiment 1 of the present application; wherein C1 is a collector with a straight busbar, and C2 is a collector with a wave-shaped structure designed based on a 5-segment sinusoidal curve in Embodiment 1;

[0030] Figure 8 is a two-dimensional graph formed based on a 9-segment sinusoidal function curve in Embodiment 2 of the present application;

[0031] Figure 9 is a total pressure efficiency-flow rate curve graph of a centrifugal fan in Embodiment 2 of the present application; wherein C1 is a collector with a straight busbar, and C3 is a collector with a wave-shaped structure designed based on a 9-segment sinusoidal curve in Embodiment 2;

[0032] Figure 10 is a radial cross-sectional velocity nephogram in Embodiment 2 of the present application; wherein C1 is a collector with a straight busbar, and C2 is a collector with a wave-shaped structure designed based on a 9-segment sinusoidal curve in Embodiment 1. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0034] In the present application, unless otherwise specified and limited, when terms such as "provided", "connected", "linked" appear, these terms should be understood in a broad sense, for example, can be fixedly connected, detachably connected or integrally connected; can be directly connected or connected through one or more intermediate media. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. For the direction words appearing in the present application, in order to better explain the characteristics of the features and the relationship between the features, it should be understood that when the display direction of the present application changes, the characteristics of the features and the relationship between the features also change accordingly. Therefore, the direction words do not constitute an absolute limitation on the characteristics of the features and the relationship between the features in space, but only have a relative limiting effect.

[0035] As Figure 1 The structure diagram of a centrifugal fan is shown in the embodiment of the present application. The centrifugal fan comprises three parts of an impeller, a volute and a collector. The collector is connected to the inlet of the volute of the centrifugal fan, and its function is to guide the gas to the impeller, and to establish a uniform velocity field and pressure field in the inlet area of the fan, so as to improve the efficiency of the fan. As Figure 2 The structure diagram of a collector is shown in the embodiment of the present application.

[0036] In the embodiment of the present application, the design method of the collector based on the multi-segment sinusoidal curve is as follows:

[0037] Design of the two-dimensional curve of the collector busbar:

[0038] Determine the function expression of each segment of the sinusoidal curve, for example, y=A1 sinx to y=A n sinx in turn, and the overall waveform line is the collection of the segmented functions expressed by the sinusoidal curve. Set the number of segments of the waveform line and the amplitude variation parameter, set the amplitude of the curve function, and generate the two-dimensional curve of the waveform line.

[0039] Design of the two-dimensional shape of the collector busbar:

[0040] Set the origin of the collector busbar, taking any point on the radial cross-sectional profile line of the inlet of the collector as the origin; set the angle between the x-axis of the sinusoidal curve and the axis of the collector, and the y-axis direction is perpendicular to the x-axis and points to the inside of the pipeline of the collector; set the highest point of the waveform of the first segment of the sinusoidal curve to point to the inside of the pipeline of the collector, and design the two-dimensional curve of the waveform line as the two-dimensional shape of the collector busbar of the centrifugal fan. As Figure 3 The two-dimensional shape of the collector busbar is shown in the embodiment of the present application, wherein the angle α between the x-axis of the collector busbar and the axis of the collector (the main flow direction of the inlet pipeline) is 0-60°, and R is the radius of the inlet pipeline.

[0041] Design of the three-dimensional structure of the collector:

[0042] According to the proportion of the x-axis length of the two-dimensional shape of the collector busbar to the actual length of the collector busbar, the overall waveform line is reduced or enlarged based on the origin; design the surface of the shell of the collector to obtain the collector with the waveform line having the amplitude decreasing in turn.

[0043] In the actual method implementation, the overall waveform line is directly reduced or enlarged based on the origin, and the shape of the overall waveform line remains unchanged. The basic principle is still to be according to the proportion of the x-axis length of the two-dimensional shape to the actual length of the collector busbar.

[0044] The aforementioned collector can adapt to centrifugal fans of different structures, and specific optimization and adaptation can be achieved through the parameters expressed by the above function. In the embodiments of this invention, centrifugal fans of models 11-62 are uniformly used as the test objects for the collector in this embodiment.

[0045] The above-mentioned design method for current collectors can be based on computer programs or combined with automated equipment for design and fabrication.

[0046] like Figure 3 The cross-sectional view of the current collector shown in this invention illustrates that the inner surface structure of the current collector is a busbar. In embodiments of the invention, this busbar structure is located on the inner surface of the current collector, while its outer surface can be designed as a smooth straight surface or an adaptive waveform design to suit the actual application of the current collector. The busbar of the current collector is a waveform line composed of multiple sine curves with successively decreasing amplitudes, and the outer surface of the current collector is designed as a smooth surface, while its interior is hollow.

[0047] In the embodiments of the present invention, specifically corresponding to scheme C1 in the following embodiments, scheme C1 is a current collector structure with a straight busbar serving only as a reference for establishing the two-dimensional reference system in this design method, i.e., a conventional conical current collector. Therefore, in scheme C1, the spatial position of the busbar of the straight current collector is the same as that of the current collector of this application, differing only in the busbar itself.

[0048] The following are specific examples:

[0049] Example 1

[0050] Scheme C2: Five consecutive sine function curves with domains defined as [(i-1)π, iπ] (i takes the values ​​1, 2, 3, 4, and 5 in sequence) are spliced ​​together to form the collector bus.

[0051] The amplitude variation control parameter T of the above collector bus is set to 1.6; the amplitude A5 of the last waveform is set to 0.2, then A1, A2, A3, and A4 are set to 1.31, 0.82, 0.51, and 0.32 respectively.

[0052] Specific curves are as follows Figure 4 As shown, the actual dimensions of the waveform lines are then adjusted according to the aforementioned method to generate a two-dimensional diagram of the waveform structure on the inner surface of the collector.

[0053] A centrifugal fan of model 11-62 was selected as the test object in this embodiment. Computational fluid dynamics (CFD) numerical simulation was used to compare the overall performance of the conical collector (C1) and the biomimetic waveform structure collector (C2) composed of five sine curve segments (as described in this embodiment), both mounted on the same centrifugal fan, and to analyze the internal flow field. Figure 5It can be seen that the centrifugal fan (C2 scheme) with the flow concentrator of the embodiment has an enlarged high-efficiency operating condition interval and the highest total pressure efficiency is increased by about 1.65% compared with the flow concentrator (C1 scheme) without the wave structure on the inner surface.

[0054] Figure 6 is the radial section cloud diagram of 80% blade height (close to the impeller front disc) under the condition that the flow rate is 8496 m 3 / h. It can be seen that the high flow rate area of the outflow of the impeller front disc blade of the C2 scheme is larger, and the outflow speed of the top blade is obviously increased, which means that the bionic design of the inner surface structure of the flow concentrator increases the work capacity of the impeller front disc blade to a certain extent and improves the uniformity of the impeller outflow.

[0055] Embodiment 2

[0056] Nine continuous domains [(i-1)π, iπ] (i is 1, 2, 3, 4, 5, 6, 7, 8, 9 in turn) are intercepted respectively, and the sinusoidal function curves are spliced as the flow concentrator generatrix.

[0057] The amplitude variation control parameter T of the above flow concentrator generatrix is set as 1.2, the amplitude A9 of the last wave is set as 0.3, and A1-A8 are 1.29, 1.07, 0.90, 0.75, 0.62, 0.52, 0.43, 0.36 respectively. The specific curve is shown in Figure 7 .

[0058] A centrifugal fan of model 11-62 is selected as the test object of the embodiment, and the whole machine multi-condition performance test and internal flow analysis are performed on the centrifugal fan with the conical flow concentrator (C1) and the flow concentrator (C3) with the bionic curve as the generatrix in the embodiment. Figure 8 The flow rate-total pressure efficiency curve of the whole machine of the C1 and C3 schemes is shown in the figure, and it can be seen that the highest total pressure efficiency of the centrifugal fan (C3 scheme) with the flow concentrator designed in the embodiment is increased by about 1.75% compared with the C1 scheme.

[0059] Figure 9 is the radial section cloud diagram of 80% blade height (close to the impeller front disc) under the condition that the flow rate is 8496 m 3 / h. It can be seen that after increasing the number of spliced sinusoidal curve segments, the area of the high flow rate zone of the annular region between the impeller outlet and the volute near the impeller front disc of the C3 scheme is larger than that of the C1, and the uniformity of the outflow speed of each blade is obviously improved, which further proves that the bionic design of the inner surface structure of the flow concentrator improves the work capacity of the impeller front disc blade, and also means that the separation flow near the inlet of the centrifugal fan is weakened, so as to improve the aerodynamic efficiency of the fan.

[0060] It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the application should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. A current collector based on a multi-segment sine curve, characterized in that, The busbar of the current collector is composed of n sine curve segments; wherein the n sine curve segments, from the 1st segment to the nth segment, are sequentially defined according to the domain [(i-1)]. i The sine curve is composed of the following: the function of the sine curve from the 1st segment to the nth segment is y=A1sinx to y=A n sinx, the amplitude of the n-sine curve from the 1st segment to the nth segment is from A1 to A... n The value is gradually decreased within the range of [0.2, 2], and the amplitude variation control parameter of the sine curve is T. m =A m / A m+1 T m The value range is [1.2, 1.6], where n is an odd number from 3 to 9, i is rounded up to the nearest integer from 1 to n, and m is an integer from [1, n-1]. The highest point of the first sine curve waveform faces the inside of the collector pipe.

2. The current collector based on a multi-segment sine curve according to claim 1, characterized in that, The amplitude A of the function of the nth sine curve n The value range is [0.2, 0.3].

3. The current collector based on a multi-segment sine curve according to claim 1, characterized in that, The origin of the function corresponding to the first sine curve waveform is any point on the radial cross-sectional profile of the inlet of the collector.

4. The current collector based on a multi-segment sine curve according to claim 1, characterized in that, in, The angle between the x-axis of the n-sine curve and the axis of the current collector is 0-60°.

5. A centrifugal fan, characterized in that, A current collector based on a multi-segment sine curve as described in any one of claims 1-4.

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