Blade, Fan and Aircraft Environmental Control System

Abstract

The present application provides a blade, a fan and an aircraft environmental control system. The blade includes a trailing edge (1), a leading edge (2), a rear edge (3) and a blade tip (4). On any airfoil section of the blade, the line connecting the leading edge point of the leading edge (2) and the trailing edge point of the rear edge (3) is the chord line, the length of the chord line is the chord length, and the distance between the position with the maximum airfoil thickness of the airfoil section and the leading edge point occupies 30% - 40% of the entire chord length. According to the blade of the present application, the fan can be modified from itself, an airfoil pre-compression part of the fan can be increased, the shock loss can be weakened, and the isentropic efficiency of the fan can be improved.

Description

Technical Field

[0001] This application relates to the technical field of aircraft air conditioning, and specifically relates to a blade, a fan, and an aircraft environmental control system. Background Art

[0002] Currently, the power of the mainstream aircraft cabin air conditioner comes from the bleed air of the aircraft engine. The high-temperature and high-pressure gas discharged from the engine enters the refrigeration pack unit. Specifically, after the expansion wheel, it drives the compression wheel and the ram fan to operate. The expansion wheel is mainly used to provide power and generate a low-temperature air flow. The compression wheel is mainly used to increase the pressure of the low-pressure air outside the aircraft at high altitude, and at the same time, there is a temperature increase effect. The main purpose of the ram fan is to perform heat exchange for the heat exchanger.

[0003] The ram fan mostly uses a conventional airfoil, which has problems of low efficiency and high shaft work. The high shaft work of the fan requires increasing the opening of the turbine inlet and increasing the turbine power to meet the system design capacity. As a result, the fuel consumption of the aircraft will increase.

[0004] Therefore, considering the transformation of the turbine from the perspective of improving the fan shaft work, although it can improve the fan shaft work, it will also lead to an increase in aircraft fuel consumption and a reduction in the aircraft's cruising range. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this application is to provide a blade, a fan, and an aircraft environmental control system, which can be transformed from the fan itself, increase the pre-compression part of the fan airfoil, weaken the shock loss, and improve the isentropic efficiency of the fan.

[0006] To solve the above problems, this application provides a blade, including a trailing edge, a leading edge, a rear edge, and a blade tip. On any airfoil section of the blade, the line connecting the leading edge point of the leading edge and the trailing edge point of the trailing edge is the chord line, the length of the chord line is the chord length, and the distance between the position with the maximum airfoil thickness of the airfoil section and the leading edge point occupies 30% - 40% of the entire chord length.

[0007] Preferably, the midline of the airfoil section is defined as the airfoil camber line. The maximum curvature of the airfoil camber line from the leading edge point to the position with the maximum airfoil thickness is C1max, and the maximum curvature of the airfoil camber line from the position with the maximum airfoil thickness to the trailing edge point is C2min, and C1max < C2min.

[0008] Preferably, the midline of the airfoil section is defined as the airfoil camber line. Taking the plane where the airfoil section is located as a two-dimensional plane, taking the straight line where the chord line is located as the X-axis, taking the trailing edge point of the chord line as the O point, the distance between each point on the chord line and the O point is X, the height of the airfoil camber line is Y, and the chord length of the chord line is L. In the range of 0 - L, the difference between the Y values of the upper and lower surfaces of the airfoil section corresponding to any X is the airfoil thickness δ. A coordinate system is established with the direction of the leading edge point as the positive direction, and the distribution curve of the airfoil camber line satisfies the following formula:

[0009] Y / L = -0.042841527389776(X / L) 4 +0.23736049237894(X / L) 3 -0.396413722036336(X / L) 2 +0.202008278313312(X / L).

[0010] Preferably, the airfoil thickness satisfies:

[0011] When X / L is in the range of [0, 0.05], δ / L = -12.6534096068(X / L) 2 +1.3833469536(X / L).

[0012] Preferably, the airfoil thickness satisfies:

[0013] When X / L is in the range of (0.05, 0.95], δ / L = 0.1177824124(X / L) 5 -0.6657562588(X / L) 4 +0.7814026682(X / L) 3 -0.4132020692(X / L) 2 +0.1625958224(X / L) + 0.0299876166.

[0014] Preferably, the airfoil thickness satisfies:

[0015] When X / L is in the range of (0.95, 1.0], δ / L = -0.6510933512(X / L) 2 +0.6530338642(X / L).

[0016] Preferably, the chord length of the airfoil is L, the airfoil thickness is δ, and the relative thickness of the airfoil section Along the span direction, the relative thickness of each airfoil section decreases.

[0017] Preferably, the midline of the airfoil section is defined as the airfoil camber line, and the airfoil camber line is a curve segment.

[0018] Preferably, the midline of the airfoil section is defined as the airfoil camber line, and the airfoil camber line is a combination of a curve segment and a straight line segment. The straight line segment is located at the leading edge of the airfoil section, and the intersection point of the straight line segment and the curve segment is P. The distance between point P and the leading edge point m is Pm, and 0 < Pm / L ≤ 0.3.

[0019] Preferably, the leading edge of the airfoil section is wedge-shaped.

[0020] According to another aspect of the present application, a fan is provided, including a hub and blades. The blades are the above-mentioned blades, and the blades are mounted on the hub, and a plurality of blades are evenly distributed along the circumferential direction of the hub.

[0021] Preferably, the number of blades is 9.

[0022] According to another aspect of the present application, an aircraft environmental control system is provided, including a compressor, an expander and a fan arranged coaxially. The fan is the above-mentioned fan, and the expander provides power for the rotation of the compressor and the fan.

[0023] The blade provided by the present application includes a trailing edge, a leading edge, a rear edge and a blade tip. On any airfoil section of the blade, the line connecting the leading edge point of the leading edge and the trailing edge point of the trailing edge is the chord line, the length of the chord line is the chord length, and the distance between the position where the maximum airfoil thickness of the airfoil section is located and the leading edge point occupies 30% - 40% of the entire chord length. In the embodiment of the present application, the structure of the fan blade is modified, and the position of the maximum airfoil thickness on the chord line is adjusted, so that the position of the maximum airfoil thickness on the chord line is shifted backward relative to the existing fan blade, thereby optimizing the fan airfoil, increasing the pre-compression part of the fan airfoil, weakening the shock loss in the transonic flow, improving the isentropic efficiency of the fan, reducing the required fan shaft work, so that there is no need to modify the turbine, and the heat exchange requirement of the fan can be met by modifying the fan blade itself, and further the working temperature of the heat exchanger can be reduced, the service life of the components can be improved, and at the same time, the aircraft's compensatory fuel consumption can be reduced, and the aircraft's endurance can be increased. Description of the Drawings

[0024] Figure 1 Is a three-dimensional structure schematic diagram of a fan according to an embodiment of the present application;

[0025] Figure 2 Is a schematic diagram of the blade element level of a fan according to an embodiment of the present application;

[0026] Figure 3 Is a blade airfoil structure diagram of a fan according to an embodiment of the present application;

[0027] Figure 4 Is a schematic diagram of the blade airfoil parameters of a fan according to an embodiment of the present application;

[0028] Figure 5 Is a schematic diagram of the blade airfoil parameters of a fan according to an embodiment of the present application;

[0029] Figure 6 Is a distribution diagram of the blade airfoil camber line of a fan according to an embodiment of the present application;

[0030] Figure 7 Is a distribution diagram of the blade airfoil thickness of a fan according to an embodiment of the present application;

[0031] Figure 8Fluid velocity distribution diagram of a conventional airfoil fan for a related technology embodiment;

[0032] Figure 9 Fluid velocity distribution diagram of a fan using the blade of the embodiment of the present application.

[0033] The reference numerals are indicated as:

[0034] 1, trailing edge; 2, leading edge; 3, rear edge; 4, blade tip; 5, airfoil camber line; 6, curved segment; 7, straight segment; 8, hub; 9, compressor; 10, expander; 11, fan. Detailed implementation manners

[0035] Referring to Figures 1 to 7 As shown, according to the embodiment of the present application, the blade includes a trailing edge 1, a leading edge 2, a rear edge 3 and a blade tip 4. On any airfoil section of the blade, the line connecting the leading edge point of the leading edge 2 and the trailing edge point of the rear edge 3 is the chord line, the length of the chord line is the chord length, and the distance between the position where the maximum airfoil thickness of the airfoil section is located and the leading edge point occupies 30% - 40% of the entire chord length. Preferably, the distance between the position where the maximum airfoil thickness of the airfoil section is located and the leading edge point occupies 35% - 40% of the entire chord length. Wherein the leading edge point refers to the foremost point of the airfoil section, and the trailing edge point refers to the rearmost point of the airfoil section.

[0036] For the fan blade in the related technology, the distance between the position of the maximum airfoil thickness on the chord line and the leading edge point generally occupies 10% - 20% of the entire chord length. This airfoil structure makes the pre-compression part of the fan blade smaller, and the path of the air flow through the pre-compression part of the fan blade is shorter. Therefore, during the transonic flow process, it is easy to cause the shock wave intensity to be too large, resulting in a large shock wave loss for the air flow, reducing the isentropic efficiency of the fan, and further leading to too high fan shaft work, which cannot meet the system design requirements.

[0037] The embodiment of the present application has modified the structure of the fan blade, adjusted the position of the maximum airfoil thickness on the chord line, so that the distance between the position of the maximum airfoil thickness on the chord line and the leading edge point occupies 30% - 40% of the entire chord length, which is significantly shifted backward compared with the fan blade in the related technology. It can optimize the fan airfoil, greatly increase the pre-compression part of the fan airfoil, weaken the shock wave loss in the transonic flow, improve the isentropic efficiency of the fan, reduce the fan shaft work, so that there is no need to modify the turbine, and the heat exchange requirement of the fan can be met by modifying the fan blade itself. Furthermore, it can reduce the working temperature of the heat exchanger, improve the component life, and at the same time reduce the aircraft's compensatory fuel consumption and increase the aircraft's endurance mileage.

[0038] In addition, setting the position of the maximum airfoil thickness at a position where the distance from the leading edge point occupies 30% - 40% of the entire chord length can also better control the flow pattern of the air flow, reduce the separation of the boundary layer air flow, and improve the blade efficiency.

[0039] After the structure of the blade itself is modified and the fan efficiency is improved, the system design requirements can be met by the fan itself, without the need to modify other parts of the aircraft environmental control system to improve the fan efficiency. Therefore, the factors to be considered in the modification process of other components are also reduced, the design difficulty and processing cost of related components are reduced, and the service life of related components is increased.

[0040] Combined with Figure 2 As shown, a circle is drawn with the distance between any point between the trailing edge 1 of the blade hub and the tip 4 of the blade and the central axis of the blade hub as the radius, and the circle extends axially along the hub to form a cylindrical surface. The intersection line of the cylindrical surface and the blade surface is called the elementary stage, that is Figure 2 the S curve in , and the surface formed by the intersection of the cylindrical surface and the blade is unfolded circumferentially into a two-dimensional planar airfoil. This two-dimensional planar airfoil is the blade airfoil of the present application, also known as the airfoil section or blade section.

[0041] In one embodiment, multiple circles are drawn in the plane where the airfoil section is located, so that the circles are tangent to the upper and lower profiles of the airfoil section. Starting from the leading edge point of the airfoil, passing through the centers of each circle, and finally connecting to the trailing edge point of the airfoil. This connection line is the median line of the airfoil section, and the median line of the airfoil section is defined as the airfoil backbone line 5. The maximum curvature of the airfoil backbone line 5 from the leading edge point to the position where the airfoil thickness is the largest is C1max, and the maximum curvature of the airfoil backbone line 5 from the position where the airfoil thickness is the largest to the trailing edge point is C2min, and C1max < C2min.

[0042] In the embodiment of the present application, the airfoil backbone line 5 is divided into two parts from the position where the airfoil thickness is the largest. The first part is the leading edge part, and the second part is the middle and trailing edge parts, and the maximum curvature of the first part is less than the minimum curvature of the second part, so as to distinguish on both sides of the position where the airfoil thickness is the largest by using the curvature of the airfoil backbone line 5. By reducing the curvature of the airfoil backbone line 5 on the leading edge side, the pre-compression section of the airfoil leading edge is improved, the shock wave intensity is weakened, and the isentropic efficiency of the blade is increased.

[0043] Combined with Figure 4 As shown, in one embodiment, the median line of the airfoil section is defined as the airfoil backbone line 5. Taking the plane where the airfoil section is located as the two-dimensional plane, the straight line where the chord is located as the X axis, the trailing edge point of the chord as the O point, the distance between each point on the chord and the O point as X, the height of the airfoil backbone line 5 as Y, and the chord length of the chord as L. In the range of 0 to L, the difference between the Y values of the upper and lower surfaces of the airfoil section corresponding to X is taken as the airfoil thickness δ corresponding to X. A coordinate system is established with the direction of the leading edge point as the positive direction. The distribution curve of the airfoil backbone line 5 satisfies the following formula:

[0044] Y / L = -0.042841527389776(X / L) 4+0.23736049237894(X / L) 3 -0.396413722036336(X / L) 2 +0.202008278313312(X / L).

[0045] Through the above formula, the airfoil camber line can be optimized, and the curvature change of the airfoil camber line can be reasonably set, so as to effectively reduce the leading edge work and improve the isentropic efficiency of the blade.

[0046] Table 1

[0047]

[0048] As can be seen from Table 1, after adopting the airfoil camber line of the embodiment of the present application, compared with the fan adopting the conventional airfoil, under the same rotational speed and static pressure conditions, the power is reduced by 13.0%, and the efficiency is increased by 4.5%. Therefore, the shaft work required by the fan is greatly reduced, the efficiency is significantly improved, and the performance of the fan is effectively improved.

[0049] In one embodiment, the airfoil thickness satisfies:

[0050] When X / L is in the range of [0, 0.05], δ / L = -12.6534096068(X / L) 2 +1.3833469536(X / L).

[0051] In one embodiment, the airfoil thickness satisfies:

[0052] When X / L is in the range of (0.05, 0.95], δ / L = 0.1177824124(X / L) 5 -0.6657562588(X / L) 4 +0.7814026682(X / L) 3 -0.4132020692(X / L) 2 +0.1625958224(X / L)+0.0299876166.

[0053] In one embodiment, the airfoil thickness satisfies:

[0054] When X / L is in the range of (0.95, 1.0], δ / L = -0.6510933512(X / L) 2 +0.6530338642(X / L).

[0055] In one embodiment, the chord length of the airfoil is L, the airfoil thickness is δ, and the relative thickness of the airfoil section Along the spanwise direction, the relative thickness of each airfoil section decreases, which can reduce the root stress of the blade and ensure the strength of the wind turbine blade. The spanwise direction is from the trailing edge 1 to the tip 4 of the blade.

[0056] Table 2

[0057]

[0058] As can be seen from Table 2, when the same airfoil backbone line is adopted and the airfoil thickness distribution of the embodiment of the present application is used, compared with the fan using the conventional airfoil, under the same rotational speed and static pressure conditions, the power is reduced by 7.0% and the efficiency is increased by 3.6%. Therefore, the shaft work required by the fan is significantly reduced, the efficiency is significantly improved, and the performance of the fan is effectively improved.

[0059] In one embodiment, the midline of the airfoil section is defined as the airfoil backbone line 5, and the airfoil backbone line 5 is a curve segment 6 or a combination of curve segment 6 and curve segment 6.

[0060] In one embodiment, the midline of the airfoil section is defined as the airfoil backbone line 5, and the airfoil backbone line 5 is a combination of a curve segment 6 and a straight line segment 7. The straight line segment 7 is located at the leading edge 2 of the airfoil section. The intersection point of the straight line segment 7 and the curve segment 6 is P, and the distance between point P and the leading edge point m is Pm, where 0 < Pm / L ≤ 0.3. By setting the airfoil backbone line as a combination of the curve segment 6 and the straight line segment 7 and controlling the length of the straight line segment 7, the purpose of enhancing the pre-compression part can also be effectively achieved, and the isentropic efficiency of the blade can be improved.

[0061] In one embodiment, both the leading edge and the trailing edge of the airfoil section are wedge-shaped. The wedge-shaped structure at the leading edge is used to reduce the shock wave intensity, weaken the shock wave loss, and improve the fan efficiency. The wedge-shaped structure at the trailing edge can weaken the boundary layer flow separation, thereby improving the flow efficiency.

[0062] Combined with reference to Figure 8 and Figure 9 As shown, compared with the fan using the conventional airfoil in the related art, the air flow velocity efficiency of the blade of the embodiment of the present application is significantly improved.

[0063] Combined with reference to Figure 1 As shown, according to the embodiment of the present application, the fan includes a hub 8 and blades. The blades are the above-mentioned blades, and the blades are installed on the hub 8. Multiple blades are evenly distributed along the circumferential direction of the hub 8.

[0064] In one embodiment, the number of blades is 9. In other embodiments, the number of blades can also be selected according to needs.

[0065] In one embodiment, the mass flow rate, pressure ratio, power, and efficiency of the wind turbine blade with a conventional airfoil and the wind turbine blade of the embodiment of the present application are tested at a rotational speed of 68,000 RPM under different static pressure conditions, and the following data can be obtained:

[0066]

[0067]

[0068]

[0069] Among them, Table 3 shows the characteristic data of the wind turbine blade with a conventional airfoil in the related art, and Table 4 shows the characteristic data of the wind turbine blade of the embodiment of the present application.

[0070] From the comparison between Table 3 and Table 4, it can be seen that under the static pressure condition of 1500 Pa, compared with the wind turbine blade in the related art, the mass flow rate of the wind turbine blade of the embodiment of the present application is increased by 26.6%, the pressure ratio is increased by 0.2%, the power is reduced by 7.4%, and the isentropic efficiency is increased by 15.5%; under the static pressure condition of 2500 Pa, compared with the wind turbine blade in the related art, the mass flow rate of the wind turbine blade of the embodiment of the present application is increased by 25.1%, the pressure ratio is increased by 0.5%, the power is reduced by 6.4%, and the isentropic efficiency is increased by 17.3%; under the static pressure condition of 5480 Pa, compared with the wind turbine blade in the related art, the mass flow rate of the wind turbine blade of the embodiment of the present application is increased by -1.4%, the pressure ratio is increased by -1.1%, the power is reduced by 24.8%, and the isentropic efficiency is increased by 7.6%; under the static pressure condition of 7500 Pa, compared with the wind turbine blade in the related art, the mass flow rate of the wind turbine blade of the embodiment of the present application is increased by -1.9%, the pressure ratio is increased by -1.2%, the power is reduced by 22.8%, and the isentropic efficiency is increased by 6.7%.

[0071] From the above comparison, it can be seen that after using the blade of the embodiment of the present application, compared with the wind turbine blade in the related art, the power is significantly reduced and the isentropic efficiency is significantly increased. Especially under the static pressure condition of 5480 Pa at the design operating point, the power reduction reaches 24.8% and the isentropic efficiency improvement reaches 7.6%, and the comprehensive performance is significantly improved.

[0072] In one embodiment, the aircraft environmental control system includes a compressor 9, an expander 10, and a fan 11 arranged coaxially. The fan 11 is the above-mentioned fan, and the expander 10 provides power for the rotation of the compressor 9 and the fan 11.

[0073] Those skilled in the art can easily understand that, on the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0074] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the technical principle of the present application, several improvements and variations can also be made, and these improvements and variations should also be regarded as within the protection scope of the present application.

Claims

1. A blade, characterized in that, It includes a trailing edge (1), a leading edge (2), a rear edge (3) and a blade tip (4). On any airfoil section of the blade, the line connecting the leading edge point of the leading edge (2) and the trailing edge point of the trailing edge (3) is the chord line, the length of the chord line is the chord length, and the distance between the position with the maximum airfoil thickness of the airfoil section and the leading edge point occupies 30% - 40% of the entire chord length; Define the midline of the airfoil section as the airfoil camber line (5). Taking the plane where the airfoil section is located as a two-dimensional plane, the straight line where the chord line is located as the X-axis, the trailing edge point of the chord line as the O point, the distance between each point on the chord line and the O point as X, the height of the airfoil camber line (5) as Y, and the chord length of the chord line as L. In the range of 0 - L, take the difference between the Y values of the upper and lower surfaces of the airfoil section corresponding to X as the airfoil thickness δ. Establish a coordinate system with the direction where the leading edge point is located as the positive direction. The distribution curve of the airfoil camber line (5) satisfies the following formula: Y / L = -0.042841527389776(X / L) 4 +0.23736049237894(X / L) 3 - 0.396413722036336(X / L) 2 +0.202008278313312(X / L).

2. The blade according to claim 1, characterized in that, Define the midline of the airfoil section as the airfoil camber line (5). The maximum curvature of the airfoil camber line (5) from the leading edge point to the position with the maximum airfoil thickness is C1max, and the maximum curvature of the airfoil camber line (5) from the position with the maximum airfoil thickness to the trailing edge point is C2min, and C1max < C2min.

3. The blade according to claim 1, characterized in that, The airfoil thickness satisfies: When X / L is in the range of [0, 0.05], δ / L = -12.6534096068(X / L) 2 + 1.3833469536(X / L).

4. The blade according to claim 1, characterized in that, The airfoil thickness satisfies: When X / L is within the range of (0.05, 0.95], δ / L = 0.1177824124(X / L) 5 - 0.6657562588(X / L) 4 + 0.7814026682(X / L) 3 - 0.4132020692(X / L) 2 + 0.1625958224(X / L)+ 0.0299876166。 5. The blade according to claim 1, characterized in that, The airfoil thickness satisfies: When X / L is in the range of (0.95, 1.0], δ / L = -0.6510933512(X / L) 2 + 0.6530338642(X / L).

6. The blade according to claim 1, characterized in that, The chord length of the chord line is L, the airfoil thickness is δ, and the relative thickness c of the airfoil section = δmax / L. Along the span direction, the relative thickness of each airfoil section decreases.

7. The blade according to claim 1, characterized in that, Define the midline of the airfoil section as the airfoil camber line (5), and the airfoil camber line (5) is a curve segment (6).

8. The blade according to claim 1, characterized in that, Define the midline of the airfoil section as the airfoil camber line (5), and the airfoil camber line (5) is a combination of a curve segment (6) and a straight line segment (7). The straight line segment (7) is located at the leading edge (2) of the airfoil section, and the intersection point of the straight line segment (7) and the curve segment (6) is P. The distance between point P and the leading edge point m is Pm, and 0 < Pm / L ≤ 0.

3.

9. The blade according to any one of claims 1 to 8, characterized in that, The leading edge of the airfoil section is wedge-shaped.

10. A fan, comprising a hub (8) and blades, characterized in that, The blade is the blade according to any one of claims 1 to 9, and the blade is installed on the hub (8), and a plurality of the blades are evenly distributed along the circumferential direction of the hub (8).

11. The fan according to claim 10, characterized in that, The number of the blades is 9.

12. An aircraft environmental control system, comprising a compressor (9), an expander (10) and a fan (11) arranged coaxially, and the fan (11) is the fan according to claim 10 or 11.

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