CN113184167B - Coaxial equidirectional propeller with variable phase difference - Google Patents
Coaxial equidirectional propeller with variable phase difference Download PDFInfo
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- CN113184167B CN113184167B CN202110566354.2A CN202110566354A CN113184167B CN 113184167 B CN113184167 B CN 113184167B CN 202110566354 A CN202110566354 A CN 202110566354A CN 113184167 B CN113184167 B CN 113184167B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
- B64C11/46—Arrangements of, or constructional features peculiar to, multiple propellers
- B64C11/48—Units of two or more coaxial propellers
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Abstract
The invention discloses a coaxial equidirectional propeller with variable phase difference, which is characterized in that two propellers with coincident rotating shafts are arranged in front and back along the thrust direction of the propellers, the propeller comprises a front propeller, a propeller rotating shaft, a sliding sleeve and a rear propeller, the rotating directions of the two propellers are the same, and the rear propeller and the front propeller have a certain phase difference to ensure that the rear propeller and the front propeller are far away from a wake flow helicoid of the front propeller. In the actual operation process, if the forward ratio changes to cause the wake flow spiral surface to approach the rear propeller, the rear propeller adjusts the phase difference formed by the rear propeller and the front propeller through the forward and backward movement of the sleeve, so that the rear propeller can still be positioned outside the wake flow area of the front propeller. The invention thus reduces the adverse aerodynamic interference and aerodynamic noise of the coaxial propeller system.
Description
Technical Field
The invention belongs to the technical field of aircraft propulsion device design, and particularly relates to a coaxial equidirectional propeller with variable phase difference.
Background
In the case of a limited maximum diameter of the propeller, the most important means of increasing the thrust of the propeller is to increase the rotor wing area, i.e. to increase the rotor solidity. The rotor solidity can be increased by two methods of increasing the chord length of the blades and increasing the number of the blades. Like the three decades old, the propeller fighter aircraft mainly uses two-blade and three-blade propellers, typical examples are Yi-16 (two blades), La-9 (three blades), etc. However, in the end of the 40 s, four-bladed propellers became increasingly mainstream, such as Ki-84, P-51, and the like.
In view of the reduced propeller efficiency after rotor solidity above a certain range, coaxial counter-rotor solutions have been proposed. The rotating shafts of the two propellers of the coaxial reverse-propeller propulsion device are overlapped in space, but the rotating planes of the blades of the coaxial reverse-propeller propulsion device have certain position difference along the direction of the rotating shafts, the rotor solidity of the front propeller and the rotor solidity of the rear propeller are both in a medium level, the rotating directions are opposite to each other, and the scheme ensures that the rotor solidity of the two propellers does not break through the upper limit of the optimal range in a form of staggering the front propeller and the rear propeller. Typical aircraft using coaxial contra-rotating propellers are russian diagram-95M, the westerland "flying dragon" propeller fighter, uk, etc.
For the single propeller solution, although increasing rotor solidity can increase the thrust of the single propeller propulsion device, this method also increases the adverse aerodynamic interference between the individual blades of the propeller, so that the aerodynamic efficiency of the propeller is continuously reduced with the increase of thrust. For the coaxial counter-rotor scheme, the scheme can ensure that the two propellers are both in a better rotor solidity, but because the rotation directions of the two propellers are opposite, the propeller at the rear continuously passes through the wake flow of the propeller at the front, which can generate a complex and periodic dynamic adverse aerodynamic interference, so that the overall aerodynamic efficiency of the coaxial counter-rotor propulsion device is lowered. The aerodynamic efficiency of the propellers determines the thrust power ratio of the aircraft, and the decrease of the aerodynamic efficiency means that the engine power required by the propellers is increased and the fuel consumption rate is increased under the same thrust, which can shorten the range of the propeller aircraft. The undesirable aerodynamic interference of the coaxially counter-rotating propeller is periodic and therefore continues to produce significant aerodynamic noise. This noise can result in reduced comfort for the aircraft crew and poor concealment of the aircraft. Such as Russian-95M bombers, the coaxial contra-rotating propeller generates a noise of up to 130 dB, which can be heard clearly even under water.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a coaxial propeller capable of further weakening the adverse aerodynamic interference caused by increasing the propeller thrust, and the specific technical scheme of the coaxial propeller is as follows:
a coaxial equidirectional propeller with variable phase difference comprises a front propeller, a propeller rotating shaft, a sliding sleeve and a rear propeller; wherein,
the propeller rotating shaft penetrates through the front propeller and is rigidly and fixedly connected with the front propeller;
the propeller rotating shaft penetrates through the rear propeller but is not in direct contact with the rear propeller;
a through hole for the sliding sleeve to pass through is formed in the rear propeller; the outer side of the sliding sleeve is provided with an inclined external thread, and the inner wall of the through hole of the rear propeller is provided with an inclined internal thread matched with the through hole;
by controlling the axial movement of the sliding sleeve, the phase angle of the rotating rear propeller is changed, and further the phase difference between the rear propeller and the front propeller is changed, and the rear propeller does not contact with the wake flow of the front propeller under various forward ratios.
Further, the phase variation amount of the rear propeller is:
in the formula: and delta theta is the phase variation of the rear propeller, delta x is the axial movement distance of the sliding sleeve, alpha is the thread inclination angle of the sliding sleeve, and R is the section radius of the sliding sleeve.
Furthermore, the coaxial equidirectional propeller further comprises two propeller limiters which are rigidly and fixedly connected with the propeller rotating shaft, and the propeller limiters are provided with channels passing through the sliding sleeve.
Further, the coaxial equidirectional propeller also comprises three plane bearings and a sleeve control ring, wherein,
two sides of the rear propeller are respectively provided with the plane bearing and the propeller limiter in sequence from near to far, and coordinate limiting of the rear propeller is completed in a matching way;
the axial outside of sliding sleeve sets gradually one the flat face bearing with sleeve control circle, owing to there is one the flat face bearing, sliding sleeve's rotation can't transmit for sleeve control circle, both possess the independence on the rotational motion.
Furthermore, protruding edges are arranged on the left side and the right side of the cylindrical surface of the propeller rotating shaft, and a sliding pair is formed by the protruding edges and the grooves in the sliding sleeve, so that the sliding sleeve can move on the propeller rotating shaft only along the axial direction.
The invention has the beneficial effects that:
1. according to the coaxial propeller propulsion system, the sleeve capable of adjusting the phase of the rear propeller is added, so that the rear propeller of the coaxial equidirectional propeller has the capability of avoiding the wake flow of the front propeller under various working conditions, the pneumatic efficiency of the coaxial propeller propulsion system is improved, and the pneumatic noise is reduced.
2. Compared with the scheme of a single propeller with high rotor solidity, the invention has larger distance between the blades and is beneficial to reducing the unfavorable aerodynamic interference between the blades; compared with a coaxial counter-rotating propeller scheme, the invention has the advantages that the adverse aerodynamic interference is relatively small and the efficiency is higher because the rear propeller does not need to pass through the wake flow.
Drawings
In order to illustrate embodiments of the present invention or technical solutions in the prior art more clearly, the drawings which are needed in the embodiments will be briefly described below, so that the features and advantages of the present invention can be understood more clearly by referring to the drawings, which are schematic and should not be construed as limiting the present invention in any way, and for a person skilled in the art, other drawings can be obtained on the basis of these drawings without any inventive effort. Wherein:
FIG. 1 is an isometric view of the device of the present invention;
FIG. 2 is a front view of the apparatus of the present invention;
FIG. 3 is a side view of the apparatus of the present invention;
FIG. 4 is a top view of the apparatus of the present invention;
FIG. 5(a) is a cross-sectional view of the apparatus of the present invention in a front plane through the centerline of the shaft;
FIG. 5(b) is a cross-sectional view of the device of the present invention in a side plane through the centerline of the shaft;
FIG. 6 is a schematic disassembled view of the components of the apparatus of the present invention;
FIG. 7 is a schematic side view of the working principle of the device of the present invention, wherein (a) is a schematic view showing the relative relationship between the front and rear propellers before the phase difference is changed, and (b) is a schematic view showing the relative relationship between the front and rear propellers after the phase difference is changed;
fig. 8 is a schematic top view of the working principle of the device of the present invention, wherein (a) is a schematic diagram of the relative relationship between the front propeller and the rear propeller before the phase difference is changed, and (b) is a schematic diagram of the relative relationship between the front propeller and the rear propeller after the phase difference is changed.
The reference numbers illustrate:
1-a front propeller; 2-propeller shaft; 3-a sliding sleeve; 4-propeller limiter; 5-a planar bearing; 6-rear propeller; 7-sleeve control ring.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.
The invention provides a propeller which rotates coaxially in the same direction, namely, a propeller with two rotating shafts coincident with each other is arranged in front of and behind the propeller in the thrust direction. Considering that the change of the advancing ratio of the propeller can cause the change of the distribution rule of the wake flow of the front propeller in the space, for the common coaxial same-direction rotating propeller scheme, the phase difference of the front propeller and the rear propeller is not variable, and the rear propeller is continuously positioned in the wake flow of the front propeller after the advancing ratio of the propeller reaches a certain value. Therefore, the coaxial homodromous propeller with fixed phase difference cannot avoid the problem that the efficiency of the propeller is reduced under a specific forward ratio. The invention designs a sleeve capable of independently adjusting the phase angle of the rear propeller. In the actual operation process, if the forward ratio changes to cause the wake spiral surface to approach the rear propeller, the rear propeller adjusts the phase difference formed by the rear propeller and the front propeller through the axial movement of the sleeve, so that the rear propeller can still be positioned outside the wake area of the front propeller, and the adverse aerodynamic interference and the aerodynamic noise of the coaxial propeller system are reduced.
As shown in fig. 1-4, a coaxial equidirectional propeller with variable phase difference comprises a front propeller 1, a propeller rotating shaft 2, a sliding sleeve 3 and a rear propeller 6; wherein,
the propeller rotating shaft 2 penetrates through the front propeller 1 and is rigidly and fixedly connected with the front propeller 1;
the propeller rotating shaft 2 penetrates through the rear propeller 6 but is not in direct contact with the rear propeller 6;
a through hole for the sliding sleeve 3 to pass through is formed in the rear propeller 6; the outer side of the sliding sleeve 3 is provided with an inclined external thread, and the inner wall of the through hole of the rear propeller 6 is provided with an inclined internal thread matched with the through hole;
by controlling the axial movement of the sliding sleeve 3, the phase angle of the rotating rear propeller 6 is changed, and further the phase difference between the rear propeller 6 and the front propeller 1 is changed, so that the rear propeller 6 does not contact with the wake of the front propeller 1 at any forward speed.
The coaxial equidirectional propeller also comprises two propeller limiters 4 which are rigidly connected with the propeller rotating shaft 2, the propeller limiters 4 are provided with channels passing through the sliding sleeve 3, and the sliding sleeve 3 can ensure that the sliding sleeve passes through the propeller limiters 4 on the premise of not colliding with the propeller limiters 4;
the coaxial co-rotating propeller further comprises three flat bearings 5 and a sleeve control ring 7, wherein,
two sides of the rear propeller 6 are respectively provided with a plane bearing 5 and a propeller limiter 4 from near to far in sequence, and coordinate limitation of the rear propeller 6 is completed in a matching way; because the plane bearing 5 is arranged between the propeller limiter 4 and the rear propeller 6, the rotary motion of the propeller rotating shaft 2 cannot be directly transmitted to the rear propeller 6, and therefore the rear propeller 6 and the front propeller 1 do not have strict synchronization property on the rotary motion, and the phase difference adjusting function is favorably realized;
the axial outside of the sliding sleeve 3 is provided with a plane bearing 5 and a sleeve control ring 7 in sequence, and the rotation of the sliding sleeve 3 cannot be transmitted to the sleeve control ring 7 due to the existence of the plane bearing 5, and the two have independence on the rotation motion.
As shown in fig. 5 and 6, the left and right sides of the cylindrical surface of the propeller rotating shaft 2 are provided with protruding ribs, and the protruding ribs and the grooves inside the sliding sleeve 3 form sliding pairs, so that the sliding sleeve 3 can move only on the propeller rotating shaft 2 along the axial direction.
The outer side of the sliding sleeve 3 is provided with an inclined external thread, the inner side of the rear propeller 6 is provided with an inclined internal thread matched with the inclined external thread, the sliding sleeve 3 is matched with the rear propeller 6 through the inclined thread, and when the sliding sleeve 3 slides on the propeller rotating shaft 2 along the axial direction, the rear propeller 6 rotates relative to the axis of the propeller rotating shaft 2 due to the inclined thread matching. Because the sliding sleeve 3 is connected with the propeller rotating shaft 2 through the sliding pair along the axial direction, the sliding sleeve 3 and the propeller rotating shaft 2 cannot move relatively in the circumferential direction, so that the sliding sleeve 3 is synchronous with the propeller rotating shaft 2 at any moment in the rotating motion, and the sliding sleeve 3 can transmit the rotating motion of the propeller rotating shaft 2 outwards. The sliding sleeve 3 is connected with a sleeve control ring 7 through a plane bearing 5, and in the rotating process of the whole propeller system, the sliding sleeve 3 is pushed by the translation sleeve control ring 7 to change the phase difference of the rear propeller 6 relative to the propeller rotating shaft 2 and the front propeller 1. The mechanism of the invention realizes the function of changing the phase difference of the front and the rear blades of the coaxial equidirectional propeller.
For a coaxial twin screw arrangement, the forward propeller will form a helicoidal shaped wake shear layer behind it, as shown in figure 7. Due to the viscosity, the gas velocity inside the wake shear layer is low, and the aerodynamic efficiency of the rear propeller will be reduced when the rear propeller passes through the wake shear layer. For the coaxial reverse propeller, because the steering is different, the rear propeller is supposed to periodically pass through the wake flow shear layer of the front propeller, so that the pneumatic problem caused by the wake flow shear layer cannot be avoided on the coaxial reverse propeller; for a coaxial co-rotating propeller, when the forward ratio reaches a certain value, the wake shear layer will still contact the aft propeller.
The proposal provided by the invention enables the coaxial equidirectional propeller to have the function of adjusting the front and rear phase difference, and the sliding sleeve 3 is axially moved by pushing the sleeve control ring 7 forwards and backwards, so as to change the phase angle of the rotating rear propeller 6 and change the phase difference between the rear propeller 6 and the front propeller 1. The specific formula is as follows:
in the formula: Δ θ is the amount of phase change of the rear propeller 6, Δ x is the axial movement distance of the sliding sleeve 3, α is the thread pitch angle of the sliding sleeve 3, and R is the cross-sectional radius of the sliding sleeve 3. As shown in fig. 7 and 8, the propeller phase differences corresponding to (a) and (b) are different, and the propeller phase difference is changed forward and backward, so that the rear propeller 6 does not contact with the wake flow of the front propeller 1 under various forward ratios, and the aerodynamic efficiency of the whole propeller system is improved.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. 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 (5)
1. The coaxial equidirectional propeller with variable phase difference is characterized by comprising a front propeller (1), a propeller rotating shaft (2), a sliding sleeve (3) and a rear propeller (6); wherein,
the propeller rotating shaft (2) penetrates through the front propeller (1) and is rigidly and fixedly connected with the front propeller (1);
the propeller rotating shaft (2) penetrates through the rear propeller (6) but is not in direct contact with the rear propeller (6);
a through hole for the sliding sleeve (3) to pass through is formed in the rear propeller (6); the outer side of the sliding sleeve (3) is provided with an inclined external thread, and the inner wall of the through hole of the rear propeller (6) is provided with an inclined internal thread matched with the through hole;
by controlling the axial movement of the sliding sleeve (3), the phase angle of the rotating rear propeller (6) is changed, and further the phase difference between the rear propeller (6) and the front propeller (1) is changed, and the rear propeller (6) does not contact with the wake flow of the front propeller (1) under various forward ratios.
2. A variable phase difference coaxial homodyne propeller according to claim 1, characterized in that the phase change of the rear propeller (6) is:
in the formula: delta theta is the phase variation of the rear propeller (6), Delta x is the axial movement distance of the sliding sleeve (3), alpha is the thread inclination angle of the sliding sleeve (3), and R is the section radius of the sliding sleeve (3).
3. Coaxial equidirectional propeller with variable phase difference according to claim 1 or 2, characterized in that it further comprises two propeller stops (4) rigidly fixed to the propeller shaft (2), said propeller stops (4) being provided with a passage through the sliding sleeve (3).
4. A variable phase difference co-axial co-rotating propeller according to claim 3, further comprising three flat bearings (5) and a sleeve control ring (7), wherein,
the two sides of the rear propeller (6) are respectively provided with the plane bearing (5) and the propeller limiter (4) from near to far in sequence, and coordinate limiting of the rear propeller (6) is completed in a matching manner;
the axial outside of sliding sleeve (3) sets gradually one flat bearing (5) with sleeve control circle (7), owing to there is one flat bearing (5), the rotatory unable transmission of sliding sleeve (3) is for sleeve control circle (7), and both possess the independence on the rotational motion.
5. Coaxial equidirectional propeller with variable phase difference according to claim 1 or 2, characterized in that the left and right sides of the cylindrical surface of the propeller shaft (2) are provided with raised ribs which form sliding pairs with grooves inside the sliding sleeve (3) so that the sliding sleeve (3) can move axially only on the propeller shaft (2).
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US5054998A (en) * | 1988-09-30 | 1991-10-08 | The Boeing Company, Inc. | Thrust reversing system for counter rotating propellers |
US20090026310A1 (en) * | 2007-07-23 | 2009-01-29 | Linn Romeo S | Variable pitch anti torque coaxial counter rotation bi-prop rotor |
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CN110422318B (en) * | 2019-07-10 | 2022-07-19 | 沈阳航空航天大学 | Coaxial contra-rotating propeller with self-adaptive variable axial spacing |
CN111332462B (en) * | 2020-02-24 | 2021-08-03 | 北京理工大学 | Portable small-sized cylinder type coaxial reverse-propeller three-blade rotor type unmanned aerial vehicle |
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