WO2016099325A1

WO2016099325A1 - Method for generating thrust with a screw propeller, and a novel airfoil for the implementation thereof

Info

Publication number: WO2016099325A1
Application number: PCT/RU2015/000760
Authority: WO
Inventors: Джабраил Харунович БАЗИЕВ
Original assignee: Джабраил Харунович БАЗИЕВ
Priority date: 2013-12-19
Filing date: 2015-11-11
Publication date: 2016-06-23
Also published as: WO2015094022A1; WO2016099325A9; RU2013156481A

Abstract

Proposed are original airfoils that significantly enhance the aerodynamic qualities of screw propellers. The advantage of air and water vehicle propellers manufactured on the basis of the proposed airfoils with a sharp leading edge is that the entire oncoming flow is directed only at the trailing plane of the blades; the leading plane does not interact at all with the oncoming flow and is not subject to the kind of negative phenomena that affect traditional propellers, such as flutter, flow separation, wave drag, the generation of negative thrust and blade vibration, thus increasing the propeller thrust by two to three times in a blade tip speed range of υ=0.8М-2М.

Description

A method of forming thrust of a screw propulsion device and a new wing profile for its implementation.

The invention relates to shipbuilding and aircraft manufacturing, i.e. water and

air transport, for the construction of propellers and propellers with the possibility of their use on ships, helicopters and helicopters of any type and purpose.

A large series of classic screw propellers with

rounded front edge of the blades. The front plane of the tail rotor blade with such an edge has a negative angle of attack relative to the incoming flow to the plane of rotation (MN) similarly to the upper plane of the wing with a classic profile, also having

rounded leading edge separating the incoming flow and

directing it to the upper and lower planes [SM. Gorlin.

Experimental aerodynamics. M., Higher School, 1970, p. 371]. This feature of the propeller geometry imposes a propeller thrust limit on it. Classic propellers reach ultimate thrust at a rotational speed of the screw n = 2500-3000 rpm and an end speed of the blades υ = 1 M, and a further increase in the speed and speed of the blades

accompanied by a decrease in traction. It is the geometrical imperfection of the classical screw profile that has restrained and inhibits today the development of non-reactive air transport that exceeds jet

air transport several times in terms of economy and environmental friendliness, but inferior to it in speed due to the low efficiency of the screw.

The closest in technical essence to the claimed screw propulsion is a screw propulsion according to the application Ν ° 201 1 127563 for the grant of a patent of the Russian Federation “Screw propulsion”, taken as a prototype.

This mover contains a rotation axis mounted with

the possibility of rotation around it blades, each of which has a front and rear planes, a front sharp edge and a trailing edge, while the front plane of each blade has a straight, flat section.

The blade-sharp front edge of the blades cuts off the entire incoming flow and directs it entirely to the back plane (for helicopters, to the lower plane) of the blades. Due to this, a significant increase in thrust along the pressure (back) plane is achieved. Each front plane of the blade of the prototype screw has a straight section perpendicular to the axis of rotation of the screw and parallel to the plane of rotation of the screw (ΜΝ).

A positive quality of the prototype is the release of the front plane from interaction with the oncoming flow, which frees this the plane from the tear-off flow, from the flutter, the formation of reverse traction and wave resistance - insurmountable negative properties of the blades with

a classic profile having a blunt leading edge that directs most of the incoming flow to the front plane.

However, the prototype screw has a very large technical drawback, namely, that the front plane of each of its blades is completely excluded from the work on creating traction, since air rarefaction is not formed above it, since the angle between it and the plane of rotation of the screw, Y = 0 °.

The objective of the proposed technical solution is to increase the maximum thrust of screw propellers and their efficiency.

The problem is solved due to the fact that a screw propeller having a rotational axis, blades rotatably mounted around it, each of which has a front and rear planes, a front sharp edge and a trailing edge, while the front plane of each blade has a straight, flat section ( AB) which is located at a negative angle (Υ) to the plane of rotation of the screw (ΜΝ), while this angle can vary from Y1 = 0 ° to Υ2 = -45 °.

This installation angle Υ, in combination with a sharp leading edge of the profile, leads to the formation of a shadow area (ACD) along the entire front contour of the propeller blade, in which such negative aerodynamic effects as flow separation, flutter and the accompanying vibration of the blade, wave resistance and negative traction, which are integral properties of screws with a classic profile, which is proved by tests of two screws in Ryazan 10/28/2014 (table 1, Figs. 1 and 2). At the same time, a deeper rarefaction is formed in the shadow region (ACD) than on the front plane of the blade with a classical profile (Table 1).

Propeller blades can be mounted in variable pitch. However, if the optimal value of the negative angle along the front plane is determined in advance, then the blades can be installed without a variable pitch, and the screw can be made monoblock.

The preferred profiles for propeller blades are the following three options:

1) The profile profile of the rear plane of the blade connecting the sharp front edge with the trailing edge is made by a segment (AC, Figure 2).

2) The profile profile of the rear plane of the blade connecting the leading sharp edge with the trailing edge is made by a smooth convex straight line (AC, Figure 1).

3) A symmetric profile in which the straight sections of the upper and lower circuits (AC1) and (BC), Fig.Z, are parallel to each other.

The blades with the proposed profiles can have a height (h) of projection of the pressure surface onto a plane parallel to the axis of rotation of the screw and perpendicular to the plane of its rotation and the outer chord of the blade constant along the entire length of the blade or they can be variable. But more options for the formation of propeller thrust (for water transport) are given by the variable (h) and the variable chord along the length of the blade.

The use of the new wing profile introduces the following

advantages of screw propellers:

1. The interaction of the front plane of the blades with the incoming flow is completely eliminated, which leads to the formation of high

rarefaction over this plane.

2. The entire incoming flow is directed to the rear (lower — for helicopters), pressure plane, which leads to an increase in the velocity head on this plane.

3. The blades are completely freed from tear-off flow, from flutter and wave resistance. In this case, the blades are completely

exempt from vibration and noise and the formation of negative traction, inherent disadvantages of the blades with a classic profile.

The rotor blades with a new wing profile are devoid of twist,

characteristic of the blades with a blunt leading edge, but have

installation angle on the front plane. The purpose of the installation angle is to translate the front plane of the blade into the shadow of the oncoming flow, giving it a negative angle of attack (y, Figs. 1,2, 3) relative to the plane of rotation of the screw (MN). Such geometry, combined with the fact that a sharp leading edge deprives the front plane of interaction with the incoming flow, creates the conditions for the formation of a deeper vacuum on this plane than the classical profile. In this case, the front plane of the blade, with the Baziev profile, enters the formation of rarefaction even at a minimum angle (= -i °) and increases the degree of rarefaction, both as the angle (y) increases, and as the rotor speed and the circular speed of the blades increase up to υ = 2M-3M.

The invention is illustrated by drawings, in which:

- in FIG. 1 shows a variant of the profile of the blade, where the lower contour is formed by a smooth curve.

- in FIG. 2 shows a variant of the profile of the blade, where the lower contour

represented by a straight line segment connecting the front and rear edges.

- in FIG. Figure 3 shows a wing profile in which the straight sections of the upper (ACi) and lower (BD) contours are parallel to each other. This option is best for the wing of large aircraft.

- in FIG. 4 shows a propeller for water transport with the blade profile shown in FIG. 2.

When using screws with new profiles, in addition to the above advantages, it is additionally achieved that:

1. For a screw with new profiles, there is no limit to the speed and limit of thrust attained in the absence of restriction, due to engine power and strength characteristics of the screw.

2. The diameters of the rotors for helicopters, with the proposed

profiles, can be reduced to 2-4 meters with a simultaneous increase in the frequency of rotation transmitted to the screw shaft to n = 2000-4000 rpm and a significant simplification of the group of gearboxes.

3. Reducing the diameter of the screws leads to a decrease in the mass of the screws by several times, a reduction in the radius of the center of gravity of the blades by several times and a reduction in the inertia of the screw by several times.

4. The share of the payload of helicopters equipped with small diameter screws (2-4 m) with a Baziev profile rotating in the frequency range n = 2000 - 4000 rpm, will reach 55-60% of the take-off weight of the helicopter.

5. The thrust of screws with a Baziev profile is proportional to the speed of the blades and can continuously increase, as the rotational speed increases and the end speed of the blades increases, up to υ = 2 M - M, while for screws with a classical profile there is a technical limit to the thrust growth associated with the beginning of the formation of negative (reverse) thrust already at the end speed of the blades υ = 0.64, the value of which continuously increases and at υ = \ Μ the thrust of the screw reaches the maximum force, and then the negative thrust of the screw becomes more than the direct thrust.

Test results of two single propellers with

Baziev’s profile and classic profile

1. The screw with a classic profile: k = 2 - the number of blades,

D = 1700 mm - screw diameter,

B] = 64 mm - end chord of the blade,

B ₂ = 140 mm - the middle chord,

B ₃ = 125 mm - chord at the butt,

b = 109.667 mm - the average value of the chord,

L = 785 mm - the length of the working part of the blade,

5 ₁ = 2L · L = 0, 172177 m ² - the working area of the screw,

mi = 3.6 kg - screw mass.

2. Baziev screw: k = 2 - the number of blades,

D = 1700 mm - screw diameter,

b— 88 mm — chord of the blade,

L = 795 mm - the length of the working part of the blade,

5 ₂ = 2b · L = 0, 13992 m - the working area of the screw,

t ₂ = 2.3 kg - the mass of the screw.

Both screws are made according to the drawings of Baziev D.Kh. the company "Finish - 2", the city of Kazan.

For the manufacture of a test bench for propellers, an automobile engine with a rated power of w = 409 l / s = 300819.5 W and a maximum crankshaft speed of p = 6000 rpm was used. A stand was built on the basis of this engine according to the method of the outstanding aircraft designer B.N. St. George's. The stand was made by N.V. mechanical laboratory Peshkova, Ryazan. We are ready to hold a demonstration of the operation of both screws to everyone, but so far only in Ryazan.

To measure the thrust of the screws, as a function of the frequency of their rotation, an electronic dynamometer of the DEP 1 -1 D-10R2 brand was used. The rotation frequency was fixed by the standard tachometer of the engine itself, and the frequency was controlled using the gas pedal. The tests were conducted on October 28, 2014 in Ryazan, with the participation of 7 people, five of them are employees of the laboratory that made the stand. The results obtained are summarized (in the table Ν ° 1) and presented graphically (figures 5-6).

These experimental data characterize not only screws, but also wings with corresponding profiles. In view of the fact that the blades with the Baziev profile are devoid of the twist characteristic of the blades with the classical profile, they are miniature wings with the same profile. therefore the aerodynamic features of the Baziev propeller established in this study can be correctly transferred to the wing with the Baziev profile, naturally - in the stationary test mode.

The first application for a fundamentally new wing profile was submitted by me to Rospatent (then it was called differently) on October 5, 1980, but then I did not have the opportunity to bring the application to the patent. Creating a bench for testing a new wing profile on a rotating mini-wing has cost me a lot of effort over the past 5 years, but it was worth it, because the data obtained on this stand completely confirmed the theoretically expected result: the most perfect wing profile was found, which significantly increases propeller thrust and wing lift.

Table 1

Propeller thrust and vacuum on the front plane of the blades

N p Screw Classic Baziev Screw

n / a rpm Positive Negative Degree Positive Negative Degree of thrust, thrust, vacuum, thrust, thrust, vacuum, N N Pa N N Pa

1 2 3 4 5 6 7

1 1200 747.160 0.00 -3529.80 777.046 0.00 -2567.12

2 1500 1225.888 0.00 -6417.80 1158.098 0.00 -4813.35

3 1800 1718.468 0.00 -9305.81 1811.863 0.00 -7701.36

4 2100 2506.430 0.00 -13798.27 2301.253 0.00 -11712.48

5 2,400 3,389.322 0.00 -18611.62 2997.979 0.00 -16044.51

6 2700 4322.541 -213.892 -25029.42 3877.760 0.00 -20536.96

7 3000 5061.406 -614.939 -30484.54 5080.688 0.00 -27275.65

8 3300 5578.589 -1283.352 -34335.23 6119.240 0.00 -34977.01

9 3550 5883.885 -2031.974 -35939.68 7218.928 0.00 -43320.15

Power of screws and their efficiency.

1. The screw with a classic profile: g, = 0, 388056L * - the radius of the center of mass of the blade,

W _l = m, - r, ² - nl I π = 35741.608285m - power consumed by the screw,

W _g = 248351.3855m is the total engine power developed at a shaft speed of n ₉ = 3550 rpm.

= _ coefficient of useful

screw action. In hypersonic mode will decrease.

2. Baziev screw: g ₂ = 0, 393l / - the radius of the center of mass of the blade,

W ₂ = t ₂ - r ₂ -

I n = 23420, 4045m - power consumed by the screw, at a frequency of n ₉ ,

^ ₌ W ₉ - W _{2 =} 224930.9815m ₌ ^ _9056965098 4 _ the efficiency of the screw in subsonic mode. In hypersonic mode will grow. Findings for screws resulting from test results.

1. A stand made in Ryazan corresponds to the technical specifications and allowed accurate measurements of the dynamic properties of both screws.

2. For a screw with a classic profile, when the end speed on the blades and = 0.64 (2700 rpm) is reached, the formation of negative thrust on the rear plane of the blades begins (the test was carried out in the mode of a pushing screw).

3. Negative thrust continuously increases with increasing speed at the ends of the blades. At u = 0.95, it already amounts to 34.52% of the total thrust of the screw. From the graph of the dependence of the thrust of the screw on the speed of the blades it follows that at the speed of the blades υ> Ш the proportion of negative thrust will be 50% or more of the total thrust of the screw. In our experience, the power of the power plant was not enough to bring the rotational speed of the propellers to n - 4000 rpm, at which hypersonic speed at the ends of the blades (356 m / s = 1,075 M) would be achieved.

4. For a screw with a Baziev profile, in contrast to a screw with a classical profile, negative thrust is not formed even at υ = 0.95. Moreover, it will not form even at hypersonic speeds of the blades, since a new wing profile cuts off the incoming flow from the rear plane of the blades (pusher propeller mode). 5. Up to the blade speed υ = 0.8, the Baziyev’s screw is inferior to the classical propeller in terms of traction, but when υ = 0.8 is reached, the Baziev’s propeller thrust curve intersects the thrust curve of the classic propeller, and at υ = 0.95 it develops thrust superior to the thrust of the classical propeller screw in n _} = 1.226898 times, while it has a smaller working area in n ₂ = 1.23 times, taking into account which the superiority of the Baziev screw is = 1.509 times.

6. From the nature of the graph it follows that the traction curve for the Baziev screw is represented by a parabola branch directed to the hypersound region, and this is a breakthrough to hypersonic speeds of screw planes and high speeds of helicopters (up to 750 km / h), with the diameter of their screws 2-4 m

7. Conducted theoretical studies based on the results obtained in this experiment, showed that the new wing profile, there are great prospects.

Here are the calculations made under the assumption: the strength of the test screw with the Baziev profile is quite high and it can be untwisted up to n = 8500 rpm.

a) o, = l, 6A = 529.28 l </ s; n, = 6000 rpm.

AP _t = 18315, b6H <s - excess voltage on the front plane of the blades (push propeller mode),

AR ₂ = -103007, TbPa - rarefaction on the rear plane, on which the dynamic vacuum is reached, i.e. pressure is zero!

F _i = (Δ /> -AP ₂ ) -S ₂ = 121323.42Я / l * ² -0.13992 - 16975.57Я- thrust of the screw.

b) υ ₂ = 2, \ M = 694, 68l <lc П ₂ = 8297 rpm.

Δ / ⁵ , = 21368, 878I <s - excess pressure of the front plane,

AR ₂ = -131780,878 Ya- high pressure on the rear plane of the blades, pressure is less than zero!

F ₂ = (Δ, -AP ₂ ) -S ₂ = 21563, 4I - thrust of the screw.

F _s = F ₂ / S ₂ = 154112,35Я / l * ² - specific load on the working area of the screw. For comparison, I bring the same parameter for the Mi-8 helicopter.

F _s = 12000kg -gs = 4707.192J and ² - specific load on the screw in the hover mode.

7718 Q? 8 m

F n ₉ ) = F ₄ IS, =: = 51593.253 // / l / ² - specific load of the screw

* ⁹ 0.13992.w ²

Bazieva really received on the test. It exceeds the load of the screw-

8 n = 10.96 times! It should be borne in mind that this parameter is the most objective characteristic of the degree of propeller and wing efficiency.

T. about. the high efficiency of the Baziev screw, first installed theoretically (in 1980), has now received experimental confirmation.

The thrust of this screw continuously grows as the speed of the blades increases, which means that a hypersonic screw is created, freed from tear-off flow around the flutter and the vibration accompanying it, from wave resistance and the formation of negative thrust. Summing up the above, we can consider the following requirements for patentability of the proposed method of forming thrust of a screw and device for its implementation to be fulfilled.

1. The analysis of the prior art (this is my 3 screw application) showed that the claimed combination of essential features set forth in the claims is not known. This allows us to conclude that it meets the criterion of "novelty", since for the first time a combination of a sharp front edge with a setting negative angle (Y) along the front plane of the blade is proposed, which frees the screw from all the negative properties of the classical profile.

2. The claimed technical solution does not follow explicitly from the prior art. Therefore, the claimed solution meets the criterion of "inventive step".

3. Based on the results obtained, when testing two screws with different profiles, we can conclude that the claimed method of forming propeller and propeller thrust and devices for its implementation can be implemented in practice with the achievement of the specified technical solution. Therefore, they meet the criterion of "industrial applicability".

1. D.Kh. Baziev. Fundamentals of a unified theory of physics. M., Pedagogy, 1994, 640 pp.

2. D.Kh. Baziev. RF patent for the invention of a new wing profile N "2461492 of September 20, 2012.

Description of the drawings.

FFiigg..11 .. PPrrooffiill sseechcheenniiyaya llooppaassttii ss oossttrrooyy ppeerreeddnneeyy kkrroommkkooyy ,, ,, ppeerreeddnneeyy pplloosskkoossttyuyu bboollshshaayaya chchaasstt kkoottoorrooyy vvyyppoollnneennaa oottrreezzkkoomm pprryayammooyy ((AABB)) ,, ppeerreehhooddyayaschschiimm centuries ppllaavvnnuuyuyu kkrriivvuuyuyu ((VVSS)) ss oobbrraazzoovvaanniieemm zzaaddnneeyy oossttrrooyy kkrroommkkii centuries ttoochchkkee ssooeeddiinneenniiyaya ss nniiizhzhnniimm kkoontntuurroomm prproffiffiillaya ((AACC)) ,, vyvyppollnenennnymm ppllaavvnoyoy kkrriivvoyoy .. LLini iyaya MMNN - pplloosskkoosstt vvrraaschscheenniiyaya vviinnttaa ,, oottnnoossiitteellnnoo kkoottoorrooyy vveerrhhnniiyy // kkoonnttuurr uussttaannaavvlliivvaayuyutt ppoodd oottrriitstsaatteellnnyymm uugglloomm ^{(((($$ "")} ) .. DDCC == hh - vvyyssoottaa

prproeektsktsii nnaappapporrnoyoy ppooveververkhkhnostii llooppaasststiya nnaa pplloosskkoostst ,,, paarraallyleellnuyu Oossii vrarashchenshenniya vvininttaa ..

FFiigg..22 .. PPrrooffiill sseechcheenniiyaya llooppaassttii ss bboolleeee oossttrrooyy ppeerreeddnneeyy kkrroommkkooyy ,, oobbrraazzoovvaannnnooyy mmaallyymm uugglloomm rraasskhhoozhzhddeenniiyaya vveerrhhnneeggoo uu nniizhzhnneeggoo kkoonnttuurroovv ((ββ)) .. NNiizhzhnniiyy kkoonnttuurr ((AACC)) vvyyppoollnneenn oottrreezzkkoomm pprryayammooyy .. VVeerrhhnniiyy kkoonnttuurr uussttaannoovvlleenn // ppoodd oottrriitstsaatteellnnyymm

kk pplloosskkoststii vvrarashchischenniyaiya vviintntaa ((ΜΜΝΝ)) ..

DC = h. This option is best for propellers.

Fig.Z. The sectional profile of the blade, in which the rectilinear sections of the upper (ACi) and lower (BD) contours are parallel to each other. This option is best for the wing of heavy aircraft, while the upper circuit is set at a negative angle to the longitudinal axis of the aircraft, as indicated in figure 3. (ADi) = b is the outer chord of the section, (AD) is the inner chord.

Figure 4. General view of the propeller with blades made with the proposed profile according to figure 2.

Figure 5. Traction graph of two screws obtained in the test and summarized in table 1.

6. Schedule thrust screws at a prospective speed of rotation n = 6000 rpm

Claims

Claim.

1. A method of forming a thrust of a screw propeller having a rotation axis and blades mounted on it, each of which has a front sharp edge like a knife and a trailing edge, while the front plane of each blade has a straight, flat section, characterized in that the sharp leading edge of the blade cuts off the entire incident flow and directs it to the rear (pressure) plane, freeing the front plane from interacting with it, while a straight section of the front plane is set at a negative angle (y) to the plane and rotating the screw (MN).

2. The wing profile for implementing the method according to claim 1, the blade is made with a profile B-1, characterized in that its rear contour is performed by a straight line segment (AC) connecting the front and rear edges, and a straight section of the upper contour (AB) is set under a negative angle (γ) to the plane of rotation of the screw (ΜΝ), while the installation angle (γ) determines the formation of a shadow region (ACD) along the entire front contour, in which such negative aerodynamic effects as a separated flow of the stream, flutter and related yuschaya him vibration vane, the wave resistance and the formation of a negative thrust in the front plane.

3. The wing profile for implementing the method according to claim 1, make a blade with a profile B-2, characterized in that its sharp front edge is connected to the trailing edge of the smooth curve (AC), and the straight section of the front contour (AB) is set at a negative angle (γ) to the plane of rotation of the screw (ΜΝ), while the installation angle (γ) forms the formation of the shadow region (ACD) along the entire front contour, in which such negative aerodynamic effects as the separated flow of the stream, flutter and the accompanying vibration cannot form I am of the blade, and the characteristic impedance of a negative pull on the front of the blade plane.

4. The wing profile B-1 for implementing the method according to claim 1, characterized in that the height (h) of the projection of the pressure surface of the blade onto a plane parallel to the axis of rotation of the screw and the chord of the blade is constant along the length of the blade.

5. The wing profile B-2 for implementing the method according to claim 1, characterized in that the height (h) of the projection of the pressure plane of the blade onto a plane parallel to the axis of rotation of the screw and chord is variable along the length of the blade.

SUBSTITUTE SHEET (RULE 26)