Large chord inlet guide vane blade structure

Abstract

This invention discloses a large chord length inlet guide vane structure, including a guide vane, which is a non-fan-shaped guide vane. The top of the guide vane is arc-shaped, and the bottom of the guide vane is a widened portion. The central angles at both ends of the widened portion are smaller than the central angle of the arc shape at the top of the guide vane. By providing a widened portion to the guide vane, this invention increases the chord length of the blade near the center, resulting in stronger pre-rotation capability, thus improving adjustment capability and energy saving capability. Furthermore, by further widening the guide vane at both ends through the widened portion, the adjustment capability of the blade can also be further increased.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, and in particular to a large chord length inlet guide vane structure. Background Technology

[0002] Currently, traditional inlet guide vanes, also known as petal-type regulating gates, are commonly used at the inlet of ventilation fans to regulate the flow and pressure of the fans. Their structural diagram is shown below. Figure 1 As shown, the actual object is as follows Figure 2 As shown, the system consists of guide vanes (1), flanges (2), and support rods (3). The connecting rod drives the vanes to rotate around their respective axes, changing the effective flow area of ​​the inlet guide vanes and altering the airflow direction, causing the airflow to swirl around the circumference. This swirling flow at the centrifugal fan impeller inlet is also called inlet pre-swirl. When the airflow pre-swirl direction is the same as the impeller rotation direction, it is called positive pre-swirl. According to Euler's equation, positive pre-swirl reduces the centrifugal fan's work capacity, causing a decrease in fan pressure. The inlet guide vane adjustment effect is actually achieved through the combined action of two factors: increased resistance due to decreased area and decreased centrifugal fan pressure due to increased pre-swirl. The pressure decrease generated by the airflow pre-swirl adjustment also reduces the centrifugal fan's power, making it an energy-saving adjustment method. This needs to be distinguished from adjustment methods that increase resistance (loss) (which are not energy-saving).

[0003] Conventional guide vanes have blades that are divided into equal circumferences. For example, a 9-blade guide vane has a central angle of 40° (30° for 12 blades, and so on). Figure 3 As shown, the blade chord length near the center is only a fraction of that at the outer edge. Due to the reduced radius, the blade chord length also decreases. The shorter the blade chord length, the weaker its ability to guide airflow, i.e., its pre-swirl capability, and consequently, its regulation and energy-saving capabilities. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to propose a large chord length inlet guide vane structure that increases the chord length of the blade, reduces its central angle, and enhances the blade's pre-rotation capability.

[0005] The technical solution of the present invention is as follows:

[0006] A large chord length inlet guide vane structure includes a guide vane, which is a non-fan-shaped guide vane. The top of the guide vane is arc-shaped, and the bottom of the guide vane is a widened portion. The central angles at the two ends of the widened portion are smaller than the central angles of the arc shape at the top of the guide vane.

[0007] Furthermore, the widened portion is preferably in the shape of an isosceles trapezoid.

[0008] Furthermore, the central angle of the arc at the top of the guide vane is 360° / n, where n is the number of guide vanes.

[0009] Furthermore, the central angle at both ends of the guide vane is preferably 360° / 2n, where n is the number of guide vanes.

[0010] Furthermore, the guide vanes are parallel to both ends and widened by 10%-40% in the horizontal direction.

[0011] The beneficial effects of this invention are as follows: By providing a widening section on the guide vane blade, the chord length of the blade near the center can be increased, resulting in a stronger pre-rotation capability, thus improving the adjustment capability and energy-saving capability. In addition, by further widening the guide vane blade at both ends through the widening section, the adjustment capability of the blade can also be further increased. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0013] Figure 1 This is a schematic diagram of a traditional imported guide vane structure;

[0014] Figure 2 This is a reference image of a traditional imported guide vane;

[0015] Figure 3 This is a schematic diagram of the shape of a traditional imported guide vane.

[0016] Figure 4 This is a schematic diagram of the shape of the large chord length inlet guide vane of the present invention;

[0017] Figure 5 This is a schematic diagram of the shape of another large chord length inlet guide vane of the present invention;

[0018] Figure 6 This is a schematic diagram of the airflow direction when the traditional inlet guide vane is closed;

[0019] Figure 7 This is a schematic diagram of the leakage airflow direction when the large chord length inlet guide vane of the present invention is closed;

[0020] In the diagram: 1-guide vane; 2-flange; 3-support rod; 4-widening section. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0023] Reference Figure 4 A large chord length inlet guide vane structure includes a guide vane 1, which is a non-fan-shaped guide vane. The top of the guide vane 1 is arc-shaped, and the bottom of the guide vane 1 is a widened portion 4. The central angles corresponding to the two ends of the widened portion 4 (i.e., the reverse extensions of the lines connecting the two ends of the widened portion 4 to the arc at the top) are smaller than the central angle of the arc at the top of the guide vane 1. The widened portion 4 is preferably an isosceles trapezoidal shape, which facilitates the installation and use of the guide vane 1 and also avoids the angle between its two sides being smaller than the central angle of the arc at the top of the guide vane 1. This results in a larger chord length at the bottom (which increases the chord length of the blade near the center), providing stronger pre-rotation capability, and thus improving adjustment capability and energy saving capability.

[0024] Figure 4 In the middle, the arc-shaped central angle at the top of the guide vane is 40°, corresponding to 9 guide vanes (similarly, it can also be 12 guide vanes or other numbers of guide vanes, i.e. n guide vanes, corresponding to a central angle of 360° / n). The central angle at both ends of the widened part 4 corresponding to the guide vane is preferably half of the central angle corresponding to the top arc, i.e., 20°.

[0025] Reference Figure 5 ,for Figure 4 The guide vane blades are improved by widening them horizontally by 10%-40% in the direction, parallel to both ends of the guide vane 1, meaning the chord length of the guide vane is greater than... Figure 4 Increase by another 10-40%.

[0026] When the conventional guide vane blades are closed, the direction of air leakage is as follows: Figure 6 As shown, in this application, because the blade chord length exceeds that of a traditional imported guide vane, the blade cannot achieve a full 90° closure like a traditional imported guide vane. Instead, it closes in an overlapping manner, with the blade angle less than 90° when closed. Figure 7 As shown, when closed, the blades overlap, which can also generate pre-rotation. The power of the centrifugal fan with the long chord length inlet guide vane is smaller than that with the traditional inlet guide vane.

[0027] In this application, the structures and connections not described in detail are all prior art, and their structures and principles are well known, so they will not be described in detail here.

[0028] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A large chord length inlet guide vane blade structure, comprising a guide vane, characterized in that: The guide vane is a non-fan-shaped guide vane, the top of the guide vane is an arc shape, and the bottom of the guide vane is a widened part, the central angles corresponding to the two ends of the widened part are smaller than the central angles of the arc shape at the top of the guide vane; The widened portion is in the shape of an isosceles trapezoid; The central arc angle at the top of the guide vane is 360° / n, where n is the number of guide vanes.

2. The large chord length inlet guide vane blade structure according to claim 1, characterized in that: The central angle at both ends of the guide vane is 360° / 2n, where n is the number of guide vanes.

3. The large chord length inlet guide vane blade structure according to claim 1, characterized in that: The guide vanes are parallel to both ends and widened horizontally by 10%-40%.

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