CN109533311B

CN109533311B - High-performance ducted fan

Info

Publication number: CN109533311B
Application number: CN201811364053.6A
Authority: CN
Inventors: 仲唯贵; 张威; 刘衍涛
Original assignee: China Helicopter Research and Development Institute
Current assignee: China Helicopter Research and Development Institute
Priority date: 2018-11-16
Filing date: 2018-11-16
Publication date: 2021-02-26
Anticipated expiration: 2038-11-16
Also published as: CN109533311A

Abstract

The application provides a high performance duct fan, belong to aircraft aerodynamic design, the duct fan includes the duct, central fairing relative static with the duct, set up between duct and central fairing and respectively with duct and the fixed stator blade of central fairing, coaxial and the hub fairing that can rotate relatively of central fairing and set up a plurality of paddle fan on the hub fairing, the paddle fan has three region from the blade root to apex in proper order along the span direction, the torsion angle of paddle fan is invariable 7 ~ 9 in first region, the torsion angle of paddle fan is invariable 0 in the third region, the paddle fan torsion angle of second region between the terminal point of first region and the starting point of third region is linear change, D is paddle fan diameter. The geometrical optimization of the blade fan, the duct and the stator blade on the aspect of aerodynamics can be realized, the consumed power is reduced under the condition of generating the same lifting/pushing force, and the hovering performance can be obviously improved under the same pulling force.

Description

High-performance ducted fan

Technical Field

The application belongs to the field of aerodynamic design of aircrafts, and particularly relates to a high-performance ducted fan.

Background

The ducted fan is a common lift/thrust system of the aircraft, can generate unidirectional lift/thrust, and realizes vertical take-off and landing, balance and forward flight of the aircraft. Compared with lifting/thrust systems such as a rotor wing and a propeller, the ducted fan has the technical characteristics of convenience in maintenance, safety in use, compact structure, low noise level and the like, and is one of the main directions for improving the efficiency of the lifting/thrust system. On the basis of ensuring the ducted space and the structural space, the design of the ducted fan can be realized by comprehensively considering various factors such as aerodynamic performance, weight, maintainability and the like and through mutual coordination and comprehensive balance.

The ducted fan in the prior art has defects in mechanical properties, weight and the like, and also has an optimized space.

Disclosure of Invention

It is an object of the present application to provide a high performance ducted fan to solve or mitigate any of the above problems.

The technical scheme of the application is as follows: the ducted fan comprises a duct, a central fairing which is relatively static with the duct, stator blades which are arranged between the duct and the central fairing and are respectively fixed with the duct and the central fairing, a hub fairing which is coaxial with the central fairing and can rotate relatively and a plurality of blade fans which are arranged on the hub fairing, wherein the blade fans sequentially comprise three regions from a blade root to a blade tip along the spanwise direction, the torsion angle of each blade fan in a first region is 7-9 degrees, the torsion angle of each blade fan in a third region is 0 degree, the torsion angle of each blade fan in a second region between the terminal point of the first region and the starting point of the third region is changed linearly, and D is the diameter of each blade fan.

In one embodiment of the present application, the end point of the first region is 0.18D to 0.22D, the start point of the third region is 0.4D to 0.46D, and D is a blade fan diameter.

In this application embodiment, duct (1) is including consecutive lip, equal straight section and diffuser, wherein, the lip is the circular arc lines, equal straight section is the straight line parallel with the duct axis, the diffuser is the straight line that becomes to predetermine the diffusion angle with the rotation axis of paddle fan.

In an embodiment of the present application, the radius R of the arc line of the lip is 0.05D to 0.15D, the preset diffusion angle ψ of the diffuser is 8 ° to 12 °, the length L of the diffuser is greater than 0.5D, and D is the diameter of the blade fan.

In an embodiment of the present application, there is a gap δ between the blade fan and the duct, the gap δ being not more than 0.005D, D being the blade fan diameter.

In one embodiment of the present application, the airfoil thickness of the blade fan is constant 12.5% to 13.5% before the end point of the first region, and is 9% to 10% at the tip, and linearly changes along the blade span direction between the end point of the first region and the tip.

In one embodiment of the present application, the hub fairing and the center fairing are cylindrical structures having the same radius, and the radius is not less than 0.15D, D being the blade fan diameter.

In an embodiment of the present application, the number of the stator blades is the same as the number of the blades of the blade fan, and a gap between the stator blade and the blade fan is not greater than 0.1D, D being a diameter of the blade fan.

In one embodiment of the present application, the cross-section of the stator vane is angled with respect to the duct axis

The angle

The deflection direction of the duct is the direction that the axis of the duct points to the chord line of the stator blade, and the included angle

Is opposite to the direction of rotation of the blade fan.

In an embodiment of the present application, the included angle

The distribution is as follows:

wherein, a is-342.9D-50, b is 285.7D +83.3, c is-85.7D-37.5, D is 17.1D +4.2, e is-0.23D-0.2,

in the formula: r is variable, R is blade fan radius, D is blade fan diameter.

The high-performance ducted fan can achieve geometric optimization of the blade fan, the duct and the stator blades in pneumatic, consumed power is reduced under the condition that the same lifting/pushing force is generated, and hovering performance can be remarkably improved under the same pulling force.

Drawings

In order to more clearly illustrate the technical solutions provided by the present application, the following briefly introduces the accompanying drawings. It is to be expressly understood that the drawings described below are only illustrative of some embodiments of the invention.

FIG. 1 is a cross-sectional view of a high performance ducted fan and parameter definitions according to the present application;

FIG. 2 is a schematic view of a high performance ducted fan configuration of the present application;

FIG. 3 is a cross-sectional twist angle distribution schematic of a fan blade of the present application;

FIG. 4 is a cross-sectional thickness profile schematic of a fan blade of the present application;

FIG. 5 is a cross-sectional schematic view of a fan blade of the present application;

FIG. 6 is a schematic view of a stator section angle distribution of the present application;

FIG. 7 is a performance comparison of a ducted fan of the present application with a conventional ducted fan.

Reference numerals:

1-duct, 11-lip, 12-equal straight section, 13-diffusion section;

2-a blade fan;

3-a rotor hub fairing;

4-a central fairing;

5-stator vanes;

6-duct axis.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.

In the description of the present application, the terms "central," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like refer to orientations or positional relationships illustrated in the drawings, which are used for convenience in describing the present application and to simplify the description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the scope of the present application.

In order to solve the problems that in the prior art, the ducted fan consumes lower power and improves the aerodynamic efficiency of the ducted fan under the condition of generating the same lift/thrust by optimizing the geometric shape of the ducted fan and integrating the geometric parameters and layout of the ducted fan, the blades and the stator.

As shown in fig. 1 and 2, the high-performance ducted fan of the present application includes: the rotor comprises a non-rotating duct 1, a plurality of blade fans 2 arranged coaxially with the duct 1, a hub fairing 3 rotating together with the blade fans 2 and wrapping the hub, a fixed central fairing 4 and a plurality of stator blades 5 of which the outer ends are connected with the duct 1 and the inner ends are connected with the central fairing 4.

As shown in fig. 3, in the optimization of the high-performance ducted fan, the optimization for the blade fan 2 includes: the blade fan 2 is sequentially provided with three regions from a blade root to a blade tip along the spanwise direction, the torsion angle of the blade fan in the first region is constantly 7-9 degrees, the torsion angle of the blade fan in the third region is constantly 0 degree, the torsion angle of the blade fan in the second region between the end point of the first region and the starting point of the third region is linearly changed, and D is the diameter of the blade fan. The radial direction in the drawing is the same as the direction indicated by the spanwise direction in the present application, but the radial position zero in the drawing generally indicates the position of the axis of the hub fairing 4, and the blade root of the blade fan 2 is generally spaced from the axis of the hub fairing 4, so that the position of about 0.15 in the radial position in the drawing is the blade root of the blade fan 2 in the present application.

In the present application, further optimization of the above blade fan 2 includes: the end point of the first zone is located in the interval 0.18D to 0.22D, shown as 0.2D, and the start point of the third zone is located in the interval 0.4D to 0.46D, shown as 0.45D, D being the blade fan diameter.

In the present application, the structure of duct 1 is optimized:

1) the inner wall of the duct 1 is formed by sequentially connecting a lip 11, an equal straight section 12 and a diffuser section 13, wherein the lip 11 is an arc line, the equal straight section 12 is a straight line parallel to the rotation center (duct axis 6), and the diffuser section 13 is a straight line forming a certain diffusion angle with the rotation axis of the blade fan 2;

2) as shown in fig. 2, the clearance δ between the blade fan 2 and the duct 1 is not more than 0.005D, the arc radius R of the lip 11 is located between 0.005D and 0.15D, the optimal scheme is close to 0.1D, the diffusion angle ψ of the diffuser 13 is located between 8 ° and 12 °, the optimal scheme is close to 10 °, the length L of the diffuser 13 is not less than 0.5D, the optimal scheme is close to 0.5D, D is the diameter of the blade fan, and the best aerodynamic efficiency of the duct can be realized by the combination of the geometrical shapes;

3) as shown in fig. 3, the blade fan 2 is connected to the hub enclosed in the hub fairing 3, and the twist angle of the blade fan varies non-linearly as a whole, and is about 8 ° at a position close to 0.2D, about 0 ° at a position close to 0.45D, and varies linearly between 0.2D and 0.45D, and remains constant from 0.45D to the tip twist angle.

4) As shown in fig. 4, the section thickness of the blade fan 2 is about 12.5% to 13.5% at a position near 0.2D (i.e., the end point of the first region), 13% as shown, about 9% to 10% at the tip, and 10% as shown, and varies linearly between 0.2D and the tip along the blade span direction;

5) the propeller hub fairing 3 and the central fairing 4 are cylindrical structures and have the same radius which is not less than 0.15D, and D is the diameter of the blade fan;

6) as shown in fig. 5, the stator blade 5 has a fixed multi-blade structure, the number of the blades is the same as that of the blade fan 2, the outer end of each blade of the blade fan 2 is connected with the duct 1, the inner end of each blade is connected with the central fairing 4, the gap M between the stator blade 5 and the blade fan 2 is not more than 0.1D, and D is the diameter of the blade fan.

7) Referring to fig. 6, the cross section of the stator blade 5 forms an angle phi with the duct axis 6, and the direction of the angle phi is opposite to the rotation direction of the blade fan 2, which is defined as the positive direction, to improve the aerodynamic performance of the duct. In the present application, the included angle between the section of the non-constant stator blade 2 and the duct axis 6 is defined, and the included angle is distributed according to the following formula:

wherein, a is-342.9D-50, b is 285.7D +83.3, c is-85.7D-37.5, D is 17.1D +4.2, e is-0.23D-0.2;

in the formula, R is a variable, R is a blade fan radius, and D is a blade fan diameter.

The high-performance ducted fan of this application is through the geometric parameters and the overall arrangement of comprehensive optimization duct 1, paddle fan 2 and stator blade 5 etc. showing the performance that has promoted the ducted fan.

To verify the performance of the high performance ducted fan of the present application, the effectiveness of the present application was verified by comparing the hover performance of the high performance ducted fan of the present application with a conventional 10 blade ducted fan employing the NACA23012 airfoil.

The hovering performance FM of the ducted fan is defined by the following formula:

wherein T is total tension of the ducted fan, P is fan power, rho is air density, and S is fan area.

By contrast, the high performance ducted fan of the present application can improve hover performance by over 6% at the same pull force as a conventional ducted fan, as shown in fig. 7.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A high performance ducted fan, characterized in that the ducted fan comprises a duct (1), a central fairing (4) relatively stationary with the duct (1), stator blades (5) arranged between the duct (1) and the central fairing (4) and respectively fixed with the duct (1) and the central fairing (4), a hub fairing (3) coaxial with the central fairing (4) and capable of relatively rotating, and a plurality of blade fans (2) arranged on the hub fairing (3);

the duct (1) comprises a lip (11), an equal straight section (12) and a diffusion section (13) which are sequentially connected, wherein the lip (11) is an arc line, and the radius R of the arc line₁0.05D-0.15D, the equal straight section (12) is a straight line parallel to the ducted axis (6), the diffusion section (13) is a straight line forming a diffusion angle psi of 8-12 degrees with the rotating shaft of the blade fan (2), the length L of the diffusion section (13) is not less than 0.5D, and a gap delta of not more than 0.005D is formed between the blade fan (2) and the ducted channel (1);

the blade fan (2) is sequentially provided with three regions from a blade root to a blade tip along the spanwise direction, the torsion angle of the blade fan in the first region is constantly 7-9 degrees, the torsion angle of the blade fan in the third region is constantly 0 degree, the torsion angle of the blade fan in the second region between the terminal point of the first region and the starting point of the third region is linearly changed, the terminal point of the first region is 0.18D-0.22D, the starting point of the third region is 0.4D-0.46D, and D is the diameter of the blade fan.

2. The high performance ducted fan in accordance with claim 1 wherein the airfoil thickness of the blade fan (2) is constant 12.5% -13.5% before the end of the first region, 9% -10% at the tip, and varies linearly along the blade span direction between the end of the first region and the tip.

3. The high performance ducted fan in accordance with claim 1 wherein the rotor hub fairing (3) and the center fairing (4) are cylindrical structures having the same radius and the radius is not less than 0.15D.

4. The high performance ducted fan in accordance with claim 1, characterized in that the number of blades of the stator blade (5) is the same as the number of blades of the blade fan (2), and the clearance between the stator blade (5) and the blade fan (2) is not more than 0.1D.

5. The method of claim 1High performance ducted fan, characterised in that the cross section of the stator blades (5) has an angle with the duct axis (6)

The angle

The deflection direction of the duct is the direction that the duct axis (6) points to the chord line of the stator blade (5), and the included angle is

Is opposite to the direction of rotation of the blade fan (2).

6. The high performance ducted fan in accordance with claim 5 wherein said included angle

The distribution is as follows:

in the formula: r is a variable and R is the blade fan radius.