A fan blade with a trailing edge serrated structure

Abstract

A fan blade with a trailing edge serration structure includes an impeller, which comprises a hub and several blades. The outer contour of the blade consists of a root edge, a leading edge, a top edge, and a trailing edge. The trailing edge, near the top edge, has several serrations formed thereon. The pitch of the serrations on the trailing edge gradually increases from the root to the tip of the blade, and the depth of the gullets between the serrations gradually increases from the root to the tip of the blade. The valleys between the serrations are arc-shaped, and the radius of the arc of the valleys between the serrations gradually increases from the root to the tip of the blade. The serrations designed on the fan blades have gradually increasing tooth profiles. The serration structure can effectively improve fan performance and reduce fan noise.

Description

Technical field:

[0001] The present invention relates to the technical field of fan blades, and more particularly to a fan blade provided with a trailing edge serration structure. Background technology:

[0002] At the trailing edge of a blade, due to the separation of airflow, a large number of flow vortices (eddies) are generally generated in the separation zone. The presence of these eddies will affect the aerodynamic characteristics of the fan blade (increased drag, reduced lift), thereby affecting fan performance (air volume, air pressure, power, and efficiency). Therefore, a certain number of serrations of appropriate size and shape are arranged at the trailing edge of the blade. The favorable vortices generated by the serrations are used to actively interfere with the vortices in the main flow field at the trailing edge of the blade. If the two vortices are in opposite directions, they will weaken or even cancel out the vortices in the main flow field at the trailing edge of the blade, thereby effectively controlling the trailing edge vortex and improving fan performance. This is the principle and effect of active flow interference of the trailing edge pitch. Trailing edge serrations have long been successfully used in the aviation field, primarily on the trailing edge of aircraft engine nacelles. By actively interfering with the vortices, they effectively control the flow field of the engine exhaust jet, thereby reducing the vortices and eddies in the engine exhaust jet, ultimately achieving the goal of controlling and reducing aerodynamic noise.

[0003] At present, some fan blades have serrations on their trailing edges to improve fan performance and reduce noise. However, the serrations on the trailing edges of existing blades are generally of equal size and cover the entire trailing edge of the blade. In order to further improve fan performance, it is necessary to study the serration structure on fan blades. Summary of the invention:

[0004] The purpose of the present invention is to address the deficiencies of the prior art and to provide a fan blade with a trailing edge serration structure. The serration structure on the fan blade can effectively improve the performance of the fan and effectively reduce the noise of the fan.

[0005] A fan blade with a trailing edge serration structure includes an impeller, which is composed of a hub and a plurality of blades. The outer contour edge of the blade is composed of a blade root edge, a leading blade edge, a blade top edge and a blade trailing edge. A plurality of serrations are formed on the edge of the blade trailing edge close to the blade top edge. The pitch of the serrations on the blade trailing edge gradually increases from the blade root to the blade tip, the tooth groove depth between the serrations gradually increases from the blade root to the blade tip, the tooth valleys between the serrations are arc-shaped, and the arc radius of the tooth valleys between the serrations gradually increases from the blade root to the blade tip.

[0006] Preferably, the geometric shape of the serrations on the blade satisfies the following equation:

[0007] y=(p1+p3*x+p5*x^2+p7*x^3+p9*x^4+p11*x^5+p13*x^6+p15*x^7) / (1+p 2*x+p4*x^2+p6*x^3+p8*x^4+p10*x^5+p12*x^6+p14*x^7+p16*x^8); where:

[0008] p1=0.1268;

[0009] p2 = -7.1159;

[0010] p3 = -0.6437;

[0011] p4=16.1764;

[0012] p5=0.4981;

[0013] p6=-7.2463;

[0014] p7=1.8876;

[0015] p8 = -13.9493;

[0016] p9=-2.21089;

[0017] p10=1.5409;

[0018] p11=-1.5758;

[0019] p12=13.9021;

[0020] p13=-1.1542;

[0021] p14=9.5881;

[0022] p15=5.2072;

[0023] p16=-12.2496.

[0024] Preferably, the length of the trailing edge of the blade occupied by the serrations on the blade is between 3 / 20 and 4 / 20 of the length of the trailing edge of the blade.

[0025] Preferably, the tooth pitch of the saw teeth on the trailing edge of the blade is the distance between the tooth tips of the saw teeth, and the tooth tips of the saw teeth are in an arc shape; the tooth valley between the saw teeth is the bottom of the tooth groove between the saw teeth.

[0026] Preferably, the angle between the inner walls on both sides of the tooth grooves between the serrations on the blade is an acute angle.

[0027] The beneficial effects of the present invention are:

[0028] It designs serrations with gradually increasing tooth shapes on the fan blades. The serration structure can effectively improve the performance of the fan and effectively reduce the noise of the fan. Description of the drawings:

[0029] Figure 1 It is a schematic structural diagram of the side view of the present invention;

[0030] Figure 2 It is a structural schematic diagram of the present invention;

[0031] Figure 3 for Figure 2 A partial enlarged schematic diagram of point A in the middle;

[0032] Figure 4 A data table showing tests on existing conventional fan blades with uniformly sized serrations;

[0033] Figure 5 The graph is a test graph of a conventional fan blade with uniform-sized serrations.

[0034] Figure 6 A data table showing the fan blade test results of the present invention;

[0035] Figure 7 This is a curve chart of the fan blade test of the present invention.

[0036] In the figure: 1, hub; 2, blade; 21, blade root edge; 22, leading blade edge; 23, blade top edge; 24, blade trailing edge; 241, serration; d, tooth pitch; r, arc radius of tooth valley. Specific implementation method:

[0037] Example: See Figures 1 to 3 As shown, a fan blade with a trailing edge serration structure includes an impeller, which is composed of a hub 1 and a plurality of blades 2. The outer contour edge of the blade 2 is composed of a blade root edge 21, a leading blade edge 22, a blade top edge 23 and a blade trailing edge 24. A plurality of serrations 241 are formed on the edge of the blade trailing edge 24 close to the blade top edge 23. The tooth pitch d of the serrations 241 on the blade trailing edge 24 gradually increases from the blade root to the blade tip, the tooth groove depth between the serrations 241 gradually increases from the blade root to the blade tip of the blade 2, the tooth valley between the serrations 241 is arc-shaped, and the arc radius r of the tooth valley between the serrations 241 gradually increases from the blade root to the blade tip of the blade 2.

[0038] Preferably, the geometric shape of the serrations 241 on the blade 2 satisfies the following equation:

[0039] y=(p1+p3*x+p5*x^2+p7*x^3+p9*x^4+p11*x^5+p13*x^6+p15*x^7) / (1+p 2*x+p4*x^2+p6*x^3+p8*x^4+p10*x^5+p12*x^6+p14*x^7+p16*x^8); where:

[0040] p1=0.1268;

[0041] p2 = -7.1159;

[0042] p3 = -0.6437;

[0043] p4=16.1764;

[0044] p5=0.4981;

[0045] p6=-7.2463;

[0046] p7=1.8876;

[0047] p8 = -13.9493;

[0048] p9=-2.21089;

[0049] p10=1.5409;

[0050] p11=-1.5758;

[0051] p12=13.9021;

[0052] p13=-1.1542;

[0053] p14=9.5881;

[0054] p15=5.2072;

[0055] p16=-12.2496;

[0056] Preferably, the length of the blade trailing edge 24 occupied by the serrations 241 on the blade 2 is between 3 / 20 and 4 / 20 of the length of the blade trailing edge 24 .

[0057] Preferably, the blade 2 is provided with five serrations 241 .

[0058] Preferably, the tooth pitch d of the serrations 241 on the blade trailing edge 24 is the distance between the tooth tips of the serrations 241 , and the tooth tips of the serrations 241 are arc-shaped; the tooth valleys between the serrations 241 are the bottoms of the tooth grooves between the serrations 241 .

[0059] Preferably, the angle between the inner walls on both sides of the tooth grooves between the serrations 241 on the blade 2 is an acute angle.

[0060] Working Principle: The present invention is provided with a fan blade having a trailing edge serrated structure. Based on the research on the serrated structure, a plurality of serrations 241 with gradually increasing tooth pitch d, tooth groove depth, and tooth valley arc radius r are designed on the trailing edge 24 of the blade 2. The design equations for the geometric structure of the serrations 241 of this structure are proposed. The serrations 241 of this structure can effectively improve the performance of the fan and effectively reduce the noise of the fan.

[0061] In order to verify the technical effect achieved by the fan blade of the present invention, a conventional fan blade with the same structural dimensions but provided with uniformly sized serrations and covered with blade trailing edges 24 and a fan blade of the present invention were tested under the same operating conditions.

[0062] The data chart of conventional fan blade test is as follows Figure 4 、 5 As shown, the data chart of the fan blade test of the present invention is as follows Figure 6 、 7 As shown, according to the comparison of data charts, the fan blades can effectively improve the efficiency of the fan and effectively reduce the noise.

[0063] The embodiments are intended to illustrate the present invention and are not intended to limit the present invention. Any person skilled in the art may modify the embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be as set forth in the claims of the present invention.

Claims

1. A fan blade with a trailing edge serration structure, comprising an impeller, the impeller comprising a hub (1) and a plurality of blades (2), the outer contour edge of the blade (2) comprising a blade root edge (21), a leading blade edge (22), a blade top edge (23) and a blade trailing edge (24), characterized in that: A plurality of saw teeth (241) are formed on the edge of the trailing edge (24) close to the top edge (23) of the blade, the tooth pitch (d) of the saw teeth (241) on the trailing edge (24) gradually increases from the root of the blade (2) to the tip of the blade, the tooth groove depth between the saw teeth (241) gradually increases from the root of the blade (2) to the tip of the blade, the tooth valley between the saw teeth (241) is in an arc shape, and the arc radius (r) of the tooth valley between the saw teeth (241) gradually increases from the root of the blade (2) to the tip of the blade; The geometric shape of the serrations (241) on the blade (2) satisfies the following equation: y=(p1+p3*x+p5*x^2+p7*x^3+p9*x^4+p11*x^5+p13*x^6+p15*x^7) / (1+p 2*x+p4*x^2+p6*x^3+p8*x^4+p10*x^5+p12*x^6+p14*x^7+p16*x^8); where: p1=0.1268； p2=-7.1159； p3=-0.6437； p4=16.1764； p5=0.4981； p6=-7.2463； p7=1.8876； p8=-13.9493； p9=-2.21089； p10=1.5409； p11=-1.5758； p12=13.9021； p13=-1.1542； p14=9.5881； p15=5.2072； p16=-12.2496； The length of the blade (2) occupied by the saw teeth (241) on the blade (2) is between 3 / 20 and 4 / 20 of the length of the blade trailing edge (24).

2. The fan blade with a trailing edge serration structure according to claim 1, characterized in that: The tooth pitch (d) of the saw teeth (241) on the blade trailing edge (24) is the distance between the tooth tips of the saw teeth (241), and the tooth tips of the saw teeth (241) are in an arc shape; the tooth valleys between the saw teeth (241) are the bottoms of the tooth grooves between the saw teeth (241).

3. The fan blade with a trailing edge serration structure according to claim 1, characterized in that: The included angle between the inner walls on both sides of the tooth grooves between the saw teeth (241) on the blade (2) is an acute angle.

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