CN209972778U - Small-sized propeller - Google Patents
Small-sized propeller Download PDFInfo
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- CN209972778U CN209972778U CN201920440325.XU CN201920440325U CN209972778U CN 209972778 U CN209972778 U CN 209972778U CN 201920440325 U CN201920440325 U CN 201920440325U CN 209972778 U CN209972778 U CN 209972778U
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Abstract
The utility model provides a small propeller, which comprises two identical blades, wherein one blade is obtained by rotating the other blade for 180 degrees around a rotating shaft; each blade consists of an upper surface and a lower surface; from the root to the tip, the upper surface curved surface is convex from the front edge to the rear edge; from the root to 50% of the radius, the lower surface curve is convex; from 50% of radius to the tip, the lower surface curved surface is convex downwards at 10% of the chord length of the front edge, and is concave inwards from 10% of the chord length to the rear edge, and the concave degree is gradually increased from 50% of radius to the tip; the chord length of the blade gradually increases from the rotating shaft to 50 percent of the radius; the chord length gradually decreases from 50% of the radius to the blade tip; the maximum chord length is at 50% of the radius with a chord length of 15% of the radius and the minimum chord length is at the tip with a chord length of 6% of the radius. The utility model provides a small-size screw, its coefficient of tension, power coefficient, efficiency of hovering all have detailed improvement, and pneumatic efficiency obtains obviously improving.
Description
Technical Field
The invention belongs to the technical field of aerospace, and particularly relates to a small propeller.
Background
The multi-rotor unmanned aerial vehicle plays an important role in industrial and agricultural production and daily life of people. The aircraft generates a pulling force vertical to a rotating plane by driving the propellers to rotate through the motor, and actions of hovering, flying ahead, ascending and the like of the aircraft are realized by adjusting the pulling force values of different propellers. The tension and the torque of the propeller are important input conditions of a flight control system and two main technical indexes of the aerodynamic shape design of the blade, because the magnitude of the tension and the torque determines the aerodynamic efficiency of the propeller, which is a key factor of the cruising time of an aircraft.
Therefore, how to improve the aerodynamic performance of the propeller is a challenge to be studied.
Disclosure of Invention
Compared with the existing propeller, the small propeller has the advantages that the tension coefficient, the power coefficient and the hovering efficiency are improved in detail, and the pneumatic efficiency is obviously improved.
The technical scheme adopted by the invention is as follows: the invention provides a small propeller, which comprises two identical blades, wherein one blade is obtained by rotating the other blade for 180 degrees around a rotating shaft;
each blade consists of an upper surface and a lower surface; from the root to the tip, the upper surface curved surface is convex from the front edge to the rear edge; from the root to 50% of the radius, the lower surface curve is convex;
the relative thickness of the blade is gradually reduced from the rotating shaft to the blade tip; the maximum relative thickness is 30%, the relative thickness at 50% radius is 8.67%, the relative thickness at 60% radius is 7.07%, the relative thickness at 70% radius is 6.87%, the relative thickness at 80% radius is 6.04%, the relative thickness at 90% radius is 4.55%, and the relative thickness of the tip is 2.07%.
Preferably, the relative thickness and the section torsion angle gradually decrease from the root to the tip, and the section chord length increases and then decreases.
Preferably, the trailing edge of the blade has a relative thickness, and the relative thickness tapers from a 50% radius to the tip.
Preferably, from 50% of radius to the tip, the lower surface curved surface is convex downwards at 10% of the chord length of the front edge, and is concave inwards from 10% of the chord length to the rear edge, and the concave degree is gradually increased from 50% of radius to the tip;
the chord length of the blade gradually increases from the rotating shaft to 50 percent of the radius; the chord length gradually decreases from 50% of the radius to the blade tip; the maximum chord length is at 50% of the radius with a chord length of 15% of the radius and the minimum chord length is at the tip with a chord length of 6% of the radius.
Preferably, the twist angle of the blade section is gradually reduced from the root to the tip, the twist angle of the blade root is 40 degrees, the twist angle at 50% radius is 22.5 degrees, and the twist angle of the blade tip is 11 degrees.
Preferably, the profile airfoil at a blade radial position of 50%, 60%, 70%, 80%, 90%, 100% has the following characteristics:
50% position: the maximum thickness of the airfoil is 8.67%, and the maximum thickness position is located at 0.2395 chord lengths;
60% position: the maximum thickness of the airfoil is 7.07 percent, and the maximum thickness position is located at 0.2125 chord lengths;
70% position: the maximum thickness of the airfoil is 6.87%, and the maximum thickness position is located at the chord length of 0.20;
80% position: the maximum thickness of the airfoil is 6.04%, and the maximum thickness position is located at 0.1770 chord length;
90% position: the maximum thickness of the airfoil is 4.55%, and the maximum thickness position is located at 0.1230 chord lengths;
100% position: the maximum thickness of the airfoil is 2.07%, and the maximum thickness position is located at 0.0615 chord length.
The invention has the beneficial effects that:
1. compared with the existing propeller, the small propeller provided by the invention has the advantages that the tension coefficient, the power coefficient and the hovering efficiency are improved in detail, and the pneumatic efficiency is obviously improved.
2. Compared with the prior propeller NR640 with the same diameter, the propeller of the invention has higher aerodynamic efficiency: more pulling force is generated with the same motor power consumed, or less motor power is consumed with the same pulling force.
Drawings
FIG. 1 is a schematic representation of the prior art three-dimensional profile of the propeller NR640 of a UIUU;
FIG. 2 is a schematic view of a prior art propeller NR640 cross-section airfoil of a UIUU;
FIG. 3 is a schematic view of a cross-sectional airfoil (leaf element) force of a propeller according to an embodiment of the present invention;
FIG. 4 is a schematic representation of the aerodynamic profile of a small propeller (the aerodynamic profile does not include a hub) provided by embodiments of the present invention;
FIG. 5 is a schematic view of a curved shape of a blade in a propeller according to an embodiment of the present invention;
fig. 6 is a schematic diagram comparing the airfoil shape of radial positions of a small propeller with the airfoil shape of a propeller NR640 provided by the embodiment of the invention.
Reference numerals: 1-a hub; 2-three-dimensional propeller blades; 3-airfoil profile; 4-rotation plane; 5-50% of the blade radial position; 6-60% of the blade radial position; 7-70% of the blade radial position; 8-80% of the blade radial position; 9-90% of the blade radial position; 10-100% of the blade radial position; 11-blade tip; 12-root of oar; 13-a first paddle; 14-a second paddle; 15-a rotating shaft; 16-a leading edge; 17-the trailing edge;
Detailed Description
For a better understanding of the technology by those skilled in the art, reference should be made to the drawings and to the accompanying detailed description, in which the invention is described in further detail.
The overall dimension of the propeller provided by the embodiment of the invention is consistent with that of the existing NR 640: blade diameter 0.23m (9 inches), blade cross-sectional shape from center pivot to 50% radial position is consistent with NR 640: the profile shape takes a low Reynolds number propeller profile Clark-Y profile as a reference, the relative thickness and the profile torsion angle are gradually reduced from the root to the tip, and the profile chord length is increased and then reduced. However, the propeller blade provided by the embodiment of the present invention is obviously different from NR640 from a 50% radial position to a 100% radial position, as shown in fig. 6, and experiments prove that a good beneficial effect is obtained.
Compared with the existing NR640 propeller, the tension coefficient and hovering efficiency of the propeller are obviously improved.
An embodiment of the present invention provides a small propeller, which includes two blades, as shown in fig. 4, the two blades have the same shape, and one of the two blades is obtained by rotating the other blade 180 degrees around a rotation axis. Each blade is composed of an upper surface and a lower surface. From the root to the tip, the upper surface curved surface is convex from the front edge to the rear edge; from the root to 50% of the radius, the lower surface curve is convex, but flatter than the upper surface; from 50% radius to the blade tip, the lower surface curved surface shows the downward convex shape at about 10% chord length of leading edge, is concave shape from 10% chord length to trailing edge, and the degree of indent, from 50% radius to blade tip increase gradually. The profile characteristics improve the camber of each section of the paddle, increase the lift coefficient of each section and further play a role in increasing the tension coefficient of the paddle.
The relative thickness of the blade is gradually reduced from the rotating shaft to the blade tip; the maximum relative thickness is 30%, the relative thickness at 50% radius is 8.67%, the relative thickness at 60% radius is 7.07%, the relative thickness at 70% radius is 6.87%, the relative thickness at 80% radius is 6.04%, the relative thickness at 90% radius is 4.55%, and the relative thickness of the tip is 2.07%. The torsion angle of the blade section is gradually reduced from the root to the blade tip, the torsion angle of the blade root is 40 degrees, the torsion angle at the 50 percent radius is 22.5 degrees, and the torsion angle of the blade tip is 11 degrees. The relative thickness of the section from the blade root to the blade tip can ensure the strength and rigidity of the structure and inhibit the resistance coefficient of the section of the outer section, thereby inhibiting the torque coefficient of the blade.
The trailing edge of the blade has a relative thickness, and the relative thickness gradually decreases from a 50% radius to the tip. The chord length of the blade gradually increases from the rotating shaft to 50 percent of the radius; the chord length gradually decreases from 50% of the radius to the blade tip; the maximum chord length is at 50% of the radius with a chord length of 15% of the radius and the minimum chord length is at the tip with a chord length of 6% of the radius.
The cross-sectional profile of the propeller blade of the embodiment of the present invention at 50%, 60%, 70%, 80%, 90%, 100% radial position has the following features:
50% position: the maximum thickness of the airfoil is 8.67%, the maximum thickness position is located at 0.2395 chord length, and the geometrical coordinate (x, y) expressions of the upper surface and the lower surface of the airfoil are respectively as follows:
the upper surface of the airfoil:
airfoil lower surface:
the coefficients are as follows:
Au,0＝0.152655,Au,1＝0.425461,Au,2＝-0.163914,Au,3＝1.190867,Au,4＝-1.097427
Au,5＝2.094674，Au,6＝-1.246325，Au,7＝1.481334，Au,8＝-0.090386，Au,9＝0.574920，Au,10＝0.385483
Al,0＝-0.130539,Al,1＝0.06895,Al,2＝-0.024549,Al,3＝0.093360,Al,4＝0.301629
Al,5＝-0.045437，Al,6＝0.103491，Al,7＝0.334922，Al,8＝0.098178，Al,9＝0.244832，Al,10＝0.182890
60% position: the maximum thickness of the airfoil is 7.07%, the maximum thickness position is located at 0.2125 chord length, and the geometrical coordinate (x, y) expressions of the upper surface and the lower surface of the airfoil are respectively as follows:
the upper surface of the airfoil:
airfoil lower surface:
the coefficients are as follows:
Au,0＝0.134306,Au,1＝0.427156,Au,2＝-0.182180,Au,3＝1.158585,Au,4＝-0.984807
Au,5＝1.851305，Au,6＝-1.036964，Au,7＝1.279719，Au,8＝-0.030759，Au,9＝0.509214，Au,10＝0.358182
Al,0＝-0.111891,Al,1＝0.120356,Al,2＝-0.043038,Al,3＝0.227367,Al,4＝0.205828
Al,5＝0.099386，Al,6＝0.044842，Al,7＝0.406770，Al,8＝0.114971，Al,9＝0.270654，Al,10＝0.196961
70% position: the maximum thickness of the airfoil is 6.87%, the maximum thickness position is located at the chord length of 0.20, and the geometrical coordinate (x, y) expressions of the upper surface and the lower surface of the airfoil are respectively as follows:
the upper surface of the airfoil:
airfoil lower surface:
the coefficients are as follows:
Au,0＝0.128423,Au,1＝0.453256,Au,2＝-0.212088,Au,3＝1.196303,Au,4＝-0.959491
Au,5＝1.718774，Au,6＝-0.953750，Au,7＝1.182584，Au,8＝-0.071382，Au,9＝0.464090，Au,10＝0.299464
Al,0＝-0.117286,Al,1＝0.158370,Al,2＝-0.106667,Al,3＝0.373278,Al,4＝0.046426
Al,5＝0.211088，Al,6＝0.003169，Al,7＝0.423350，Al,8＝0.089246，Al,9＝0.260095，Al,10＝0.173089
80% position: the maximum thickness of the airfoil is 6.04%, the maximum thickness position is located at 0.1770 chord length, and the geometrical coordinate (x, y) expressions of the upper surface and the lower surface of the airfoil are respectively as follows:
the upper surface of the airfoil:
airfoil lower surface:
the coefficients are as follows:
Au,0＝0.128171,Au,1＝0.424357,Au,2＝-0.183163,Au,3＝1.060051,Au,4＝-0.766158
Au,5＝1.396571，Au,6＝-0.727121，Au,7＝0.972472，Au,8＝-0.049234，Au,9＝0.391837，Au,10＝0.248007
Al,0＝-0.104653,Al,1＝0.154068,Al,2＝-0.061138,Al,3＝0.290147,Al,4＝0.209649
Al,5＝-0.025255，Al,6＝0.236628，Al,7＝0.240151，Al,8＝0.134606，Al,9＝0.208060，Al,10＝0.141050
90% position: the maximum thickness of the airfoil is 4.55%, the maximum thickness position is located at 0.1230 chord length, and the geometrical coordinate (x, y) expressions of the upper surface and the lower surface of the airfoil are respectively as follows:
the upper surface of the airfoil:
airfoil lower surface:
the coefficients are as follows:
Au,0＝0.112687,Au,1＝0.363011,Au,2＝-0.186421,Au,3＝0.908302,Au,4＝-0.656793
Au,5＝1.132545，Au,6＝-0.573745，Au,7＝0.765489，Au,8＝-0.042525，Au,9＝0.307268，Au,10＝0.193787
Al,0＝-0.092962,Al,1＝0.153907,Al,2＝-0.052851,Al,3＝0.263846,Al,4＝0.266642
Al,5＝-0.178655，Al,6＝0.413754，Al,7＝0.028554，Al,8＝0.176092，Al,9＝0.133850，Al,10＝0.103037
100% position: the maximum thickness of the airfoil is 2.07%, the maximum thickness position is located at the chord length of 0.0615, and the geometrical coordinate (x, y) expressions of the upper surface and the lower surface of the airfoil are respectively as follows:
the upper surface of the airfoil:
airfoil lower surface:
the coefficients are as follows:
Au,0＝0.073514,Au,1＝0.193734,Au,2＝-0.121582,Au,3＝0.500704,Au,4＝-0.340172
Au,5＝0.587201，Au,6＝-0.235181，Au,7＝0.372227，Au,8＝0.023512，Au,9＝0.171377Au,10＝0.143392
Al,0＝-0.053941,Al,1＝0.116787,Al,2＝-0.005766，Al,3＝0.172813,Al,4＝0.308408
Al,5＝-0.300532，Al,6＝0.561680，Al,7＝-0.261820，Al,8＝0.240156，Al,9＝0.016343，Al,10＝0.070061
the following are experimental data:
the propeller of the embodiment of the invention is compared and tested with the prior propeller NR640 in an experiment as follows:
the parameter of the aerodynamic characteristics of the propeller is mainly the coefficient of tension CTTorque coefficient CMPower coefficient CPHover efficiency FM, etc., whose expressions are:
wherein T is the pulling force generated by the propeller, M is the torque around the rotating shaft generated by the propeller, and P is the power generated by the propeller; rho∞Is the incoming air density, R is the propeller radius, and Ω is the rotational angular velocity (rad/s) of the propeller.
The propeller of the embodiment of the invention has the advantages that the tension coefficient is 0.103152, the power coefficient is 0.043964, the hovering efficiency is 0.6012, the hovering efficiency is 8.13% higher than that of a reference propeller, and the aerodynamic efficiency is obviously improved. The effectiveness of the method was thus verified, see table 1. Fig. 4 shows a three-dimensional shape of a propeller according to an embodiment of the present invention. Fig. 5 shows a grid plane formed by connecting all coordinate points on a blade.
TABLE 1 aerodynamic parameter comparison of design propeller to propeller NR640
Fig. 6 shows the comparison of the airfoil shape of the propeller from 50% to 100% radial position with the airfoil shape of the propeller NR640, and it is seen that the propeller blade of the embodiment of the invention is thinner and has more camber, so that a larger pulling force coefficient is generated, and the hovering efficiency is improved.
The (x, y) coordinate points for 50%, 60%, 70%, 80%, 90%, 100% radial positions of the propellers of an embodiment of the invention are given below:
the present invention is not limited to the embodiments, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A small propeller is characterized in that the propeller comprises two identical blades, wherein one blade is obtained by rotating the other blade for 180 degrees around a rotating shaft;
each blade consists of an upper surface and a lower surface; from the root to the tip, the upper surface curved surface is convex from the front edge to the rear edge; from the root to 50% of the radius, the lower surface curve is convex;
the relative thickness of the blade is gradually reduced from the rotating shaft to the blade tip; the maximum relative thickness is 30%, the relative thickness at 50% radius is 8.67%, the relative thickness at 60% radius is 7.07%, the relative thickness at 70% radius is 6.87%, the relative thickness at 80% radius is 6.04%, the relative thickness at 90% radius is 4.55%, and the relative thickness of the tip is 2.07%.
2. The propeller of claim 1 wherein the relative thickness, the cross-sectional twist angle, decreases progressively from the root to the tip, and the cross-sectional chord length increases and then decreases.
3. The propeller of claim 1 wherein the trailing edge of the blade has a relative thickness and the relative thickness tapers from a 50% radius to the tip.
4. The propeller of claim 1, wherein the lower surface curved surface is convex downward at 10% of the chord length of the front edge from 50% of the radius to the tip, and concave inward at 10% of the chord length to the rear edge, and the degree of concavity is gradually increased from 50% of the radius to the tip;
the chord length of the blade gradually increases from the rotating shaft to 50 percent of the radius; the chord length gradually decreases from 50% of the radius to the blade tip; the maximum chord length is at 50% of the radius with a chord length of 15% of the radius and the minimum chord length is at the tip with a chord length of 6% of the radius.
5. The propeller as claimed in claim 1, wherein the twist angle of the blade profile decreases from the root to the tip, the twist angle of the blade root is 40 °, the twist angle at 50% radius is 22.5 °, and the twist angle of the tip is 11 °.
6. The propeller of claim 1 wherein the cross-sectional airfoil profile at the blade radial position of 50%, 60%, 70%, 80%, 90%, 100% has the following characteristics:
50% position: the maximum thickness of the airfoil is 8.67%, and the maximum thickness position is located at the chord length of 0.2395;
60% position: the maximum thickness of the airfoil is 7.07%, and the maximum thickness position is located at the chord length of 0.2125;
70% position: the maximum thickness of the airfoil is 6.87%, and the maximum thickness position is located at the chord length of 0.20;
80% position: the maximum thickness of the airfoil is 6.04%, and the maximum thickness position is located at the chord length of 0.1770;
90% position: the maximum thickness of the airfoil is 4.55%, and the maximum thickness position is located at the chord length of 0.1230;
100% position: the maximum thickness of the airfoil is 2.07%, and the maximum thickness location is at 0.0615 chord length.
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| CN201920440325.XU CN209972778U (en) | 2019-04-03 | 2019-04-03 | Small-sized propeller |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920440325.XU CN209972778U (en) | 2019-04-03 | 2019-04-03 | Small-sized propeller |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110015417A (en) * | 2019-04-03 | 2019-07-16 | 中南大学 | A kind of small propeller |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110015417A (en) * | 2019-04-03 | 2019-07-16 | 中南大学 | A kind of small propeller |
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