Ventilation air intake system for turbofan engine core compartment

Abstract

The present invention relates to a ventilation air intake system (10) for a turbofan engine core cabin (4). The ventilation air intake system (10) comprises: an air intake pipe (1) allowing air flow to enter the core cabin (4); a ventilation air intake shell (2), the ventilation air intake shell (2) having an air intake end (2a) connected to the air intake pipe (1), an opposite end (2b) opposite to the air intake end (2a), and a central axis (X) passing through the air intake end (2a) and the opposite end (2b); and at least one exhaust grille (3) provided on the ventilation air intake shell (2). The cross-sectional area (S) of the ventilation air intake shell (2) taken on each plane perpendicular to the central axis (X) changes between the air intake end (2a) and the opposite end (2b) in a manner of first increasing and then decreasing. The present invention solves the problem that a ventilation cooling device cannot take into account both improving air intake uniformity and reducing total pressure loss, and helps to improve the ventilation and heat exchange efficiency in the core cabin.

Description

Technical Field

[0001] The present invention relates to a ventilation air intake system, and more particularly to a ventilation air intake system for a core cabin of a turbofan engine. Background Art

[0002] When the turbofan engine of a civil aircraft is running, a large amount of heat tends to accumulate in its core cabin. This heat causes the temperature inside the core cabin to rise through heat transfer activities such as radiation and convection. The high temperature inside the cabin can easily cause the system accessories to overheat, affecting their operational reliability and even posing a risk of fire. Therefore, it is necessary to equip the turbofan engine core cabin with a ventilation and cooling system.

[0003] In order to ensure that the airflow distribution in the core cabin is uniform and there is no dead zone in the flow to ensure good heat exchange in the core cabin, the innovative design of the ventilation and air intake system is extremely critical. However, due to the limitations of the ventilation and air intake systems in the core cabins of mainstream civil aircraft, the two goals of improving air intake uniformity and reducing total pressure loss are often not achieved at the same time.

[0004] For example, Figure 1 A commonly used ventilation air intake system 10A for a turbofan engine core compartment is schematically shown. Figure 1 As shown, it can be seen that the ventilation and air intake system 10A is roughly in the shape of a hollow cylinder, and its cross-section is basically constant along the entire length direction of the ventilation and air intake system 10A. In other words, the cross-sectional area of ​​the ventilation and air intake system 10A taken on each plane perpendicular to its central axis X does not change between the air intake end and the exhaust end of the ventilation and air intake system 10A. Therefore, this type of ventilation and air intake system is also known as a "straight-through air intake system" in the industry, which ensures that the air intake volume of the ventilation and cooling airflow in the core cabin is always sufficient, and the flow rate along the radial direction of the core cabin is relatively fast, and the local cooling effect near the air inlet position is obvious. However, compared with the radial distribution, the circumferential distribution uniformity of the airflow is poor, and the overall cooling effect is not ideal.

[0005] Figure 2 Another commonly used ventilation air intake system 10B for a turbofan engine core compartment is schematically shown. Figure 2 As shown, the ventilation intake system 10B is Figure 1 The straight-through air intake system 10A shown in the figure has been improved by blocking the exhaust end of the ventilation air intake system 10B and opening a plurality of parallel strip grilles 3B on the side wall of the cylinder, thereby changing the "straight-through air intake system" into a "straight-barrel grille air intake system". Figure 2In the example shown, eight strip grilles 3B are evenly arranged along the circumferential direction of the cylinder side wall, and each grille 3B extends parallel to the central axis X of the ventilation and air intake system 10B, and its length is substantially half of the length of the cylinder. In this way, the cooling airflow can only flow out from each grille 3B along the circumferential direction, which improves the airflow uniformity to a certain extent. However, in the ventilation and air intake system 10B, the external flow will directly impact the closed exhaust end, which inevitably pays the price of total pressure loss, reduces the overall flow capacity of the cooling airflow in the core cabin, and cannot be applied to areas where local heat accumulation exists and centralized cooling is required.

[0006] For this reason, a large number of designs that replace the above-mentioned ventilation and air intake systems 10A and 10B have also appeared in the industry. For example, in the Chinese patent application CN102135035A entitled "Turbine Aircraft Propulsion Device" filed by Airbus Operations Ltd. on January 26, 2011, a propeller and a turbine cooling device are disclosed. The high-temperature airflow is cooled by heat exchange with external cold air in a cooler arranged in the nacelle. The propeller includes at least one air pulse to draw high-temperature and high-pressure air to an air duct arranged between the inner and outer walls of the nacelle, and is cooled through the first and second surfaces of the cooler. The cooling device is a group of fins parallel to the airflow direction to enhance heat exchange.

[0007] In Chinese patent application CN102139764A entitled “Cooling device for aircraft propulsion system” also filed by Airbus Operations Ltd. on January 26, 2011, a volumetric cooling device is disclosed, which is arranged in an air duct to provide a high-pressure jet for the propulsion system to introduce high-pressure air into the air duct arranged between the outer wall and the inner wall of the nacelle.

[0008] However, the above design requires special manufacturing of fins, air ducts or other cooling devices to enhance the cooling effect, including but not limited to an air guide assembly consisting of an air diffuser and an air distributor, an air flow adjustment assembly capable of adjusting the amount of air flow entering the core cabin through the air inlet, a ventilation circulation assembly capable of reusing the cooling air flow of the fan cabin and reintroducing it into the core cabin, a heat transfer assembly that allows the heat exchange fluid to flow in the circulation pipeline and absorb heat in the nacelle and release heat in the air inlet cabin, etc. However, the manufacturing cost of these components is relatively high compared to the above ventilation and air intake system, and their economic efficiency is not ideal.

[0009] Therefore, it is necessary to design a low-cost ventilation and air intake system for the core cabin of a turbofan engine that can achieve both the goals of improving air intake uniformity and reducing total pressure loss. Summary of the invention

[0010] The object of the present invention is to provide a ventilation and air intake system which can improve the ventilation and heat exchange efficiency in a core compartment of a turbofan engine at a relatively low cost.

[0011] A first aspect of the present invention relates to a ventilation air intake system for a turbofan engine core compartment, comprising:

[0012] the air intake ducts that allow airflow into the core module;

[0013] a ventilated air intake housing having an air intake end communicating with the air intake pipe, an opposite end opposite to the air intake end, and a central axis passing through the air intake end and the opposite end; and

[0014] At least one exhaust grille provided on the ventilation air intake housing,

[0015] The cross-sectional area of ​​the ventilation air intake housing taken on each plane perpendicular to the central axis changes between the air intake end and the opposite end in a manner of first increasing and then decreasing.

[0016] Compared with the "straight-through air intake system" in the prior art, the cooling gas is evenly distributed in the core cabin through the grille after being rectified by the shell, so that the airflow is evenly developed along the circumference, radial and axial directions inside the core cabin. Compared with the "straight-barrel grille air intake system" in the prior art, the irregular spherical shell profile first forms a gradually expanding structure on the airflow path, so that the incoming flow slowly decelerates and expands along the central axis, which weakens the impact on the bottom surface to a certain extent and significantly reduces the total pressure loss.

[0017] On the other hand, the curved wall gradually induces flow separation, and the separated gas is driven by the high pressure inside the spherical shell and ejected directly through the grille. As a result, the irregular spherical shell grille intake mode reduces the sensitivity to the flow field distortion of the external air inlet, which helps to achieve efficient cooling and heat exchange.

[0018] Preferably, the ventilation air intake shell can be composed of a cross-sectional expansion section and a cross-sectional contraction section, wherein the cross-sectional area of ​​the cross-sectional expansion section increases monotonically along the direction from the air intake end to the opposite end, and the cross-sectional area of ​​the cross-sectional contraction section decreases monotonically along the direction from the air intake end to the opposite end.

[0019] More preferably, the cross-sectional area of ​​the cross-sectional expansion section increases monotonically at a first ratio along the direction from the air inlet end to the opposite end, and the cross-sectional area of ​​the cross-sectional contraction section decreases monotonically at a second ratio along the direction from the air inlet end to the opposite end, wherein the first ratio may be equal to the second ratio.

[0020] Regarding the exhaust grilles, a plurality of exhaust grilles may be formed on the ventilation air intake housing, and the exhaust grilles are evenly distributed on the ventilation air intake housing around the central axis.

[0021] Preferably, a total of eight exhaust grilles may be formed on the ventilation air intake housing.

[0022] Preferably, the exhaust grille may be formed on a cross-sectional expansion section and / or a cross-sectional contraction section of the ventilation air intake housing.

[0023] More preferably, the length of the exhaust grille may be half or more than half of the length of the ventilation air intake housing along the central axis thereof.

[0024] The second aspect of the present invention relates to a turbofan engine core module, in which at least one ventilation air intake system as described in the first aspect of the present invention is arranged upstream of the air intake of the core module, wherein the cooling airflow enters the ventilation air intake shell through an air intake pipe, is radially discharged into the core module through an exhaust grille, and is finally discharged from the core module from the annular gap at the nozzle end located downstream of the core module.

[0025] Preferably, the air intake duct may be fixedly connected to the core compartment wall surface.

[0026] A third aspect of the present invention relates to an aircraft equipped with a turbofan engine core module as described in the second aspect of the present invention.

[0027] The ventilation and air intake system for a turbofan engine core module according to the present invention can obtain the following advantages: the ventilation and air intake system expands and induces separation of the cooling airflow entering the core module through a spherical shell grid rectification system, thereby satisfying the ventilation and cooling air intake volume and promoting the cooling gas to be evenly distributed in the core module to achieve an efficient cooling and heat exchange process, thereby solving the problem of the existing air intake system being unable to take into account both improving the air intake uniformity and reducing the total pressure loss at a lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to further illustrate the technical effect of the ventilation and air intake system for a turbofan engine core compartment according to the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, wherein:

[0029] Figure 1 It is a schematic diagram of a ventilation air intake system for a turbofan engine core compartment in the prior art;

[0030] Figure 2 It is a schematic diagram of another ventilation air intake system for a turbofan engine core compartment in the prior art;

[0031] Figure 3 is a three-dimensional diagram of a ventilation and air intake system for a turbofan engine core compartment according to the present invention, the diagram being viewed from an oblique upper position;

[0032] Figure 4is a front view of a ventilation and air intake system for a turbofan engine core compartment according to the present invention, wherein arrows are used to indicate the flow path of cooling airflow through the ventilation and air intake system;

[0033] Figure 5 yes Figure 3 A top view of a ventilation intake system for a turbofan engine core compartment is shown;

[0034] Figure 6 yes Figure 3 A bottom view of a ventilation intake system for a turbofan engine core compartment is shown; and

[0035] Figure 7 Yes Figure 3 The diagram shows a ventilation intake system installed in a turbofan engine core module, with arrows indicating the flow path of the cooling airflow through the core module.

[0036] Reference numerals

[0037] 1 Intake pipe

[0038] 2 Ventilation air intake housing

[0039] 2-1 Cross-sectional expansion section

[0040] 2-2 Cross-sectional contraction section

[0041] 2a Inlet side

[0042] 2b Opposite end

[0043] 3.3B Exhaust grille

[0044] 4 Core Module

[0045] 5 Core compartment wall

[0046] 6 Nozzle end annular gap

[0047] 10, 10A, 10B Ventilation and air intake system

[0048] X center axis

[0049] S Cross-sectional area

[0050] F Flow Path DETAILED DESCRIPTION

[0051] The structure, cooling process and effect of the ventilation and air intake system for a turbofan engine core compartment according to the present invention are described below with reference to the accompanying drawings.

[0052] It should be clear that the embodiments described in this specification only cover some embodiments of the present invention, not all embodiments. Based on the embodiments recorded in the specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The terms "including" and "having" in the specification and claims of the present invention and the above-mentioned accompanying drawings and any variations thereof are intended to cover non-exclusive inclusions. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0054] Based on the same understanding of orientation, in the description of the present invention, the orientation or position relationship indicated by terms such as "length", "upstream", "downstream", "top", "bottom", "front" and "back" are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0055] Figures 3 to 6 They are respectively a stereoscopic view, a front view, a top view and a bottom view of the ventilation and air intake system 10 according to the present invention.

[0056] like Figure 3 and 4 As shown, the ventilation air intake system 10 for the core module 4 of a turbofan engine according to the present invention includes: an air intake duct 1 that allows air flow to enter the core module 4; a ventilation air intake shell 2, the ventilation air intake shell 2 having an air intake end 2a connected to the air intake duct 1, an opposite end 2b opposite to the air intake end 2a, and a central axis X passing through the air intake end 2a and the opposite end 2b; and at least one exhaust grille 3 opened in the ventilation air intake shell 2.

[0057] like Figure 3 As shown, the air intake pipe 1 is composed of a substantially cylindrical sleeve or similar component, and is fixed to the core cabin wall surface 5 of the core cabin 4 by connection means such as welding, riveting, adhesives, etc. The air intake pipe 1 has a first end and a second end opposite to each other, wherein the first end is connected to an air source (not shown in the figure) supplying air to the core cabin 4, and the second end is connected to the ventilation air intake shell 2 to allow the air flow to enter the ventilation air intake shell 2 and then enter the core cabin 4 along the flow path F indicated by the arrow in the figure.

[0058] In a preferred embodiment, the air intake pipe 1 may also be composed of a square tube. Such a variation should be easy to think of for a person skilled in the art, and therefore should also fall within the protection scope of the present invention.

[0059] The ventilation air intake housing 2 has a central axis X that passes through the housing 2 and is parallel to the flow path F that just enters the housing 2. For example, when the air intake pipe 1 is located directly above the top of the ventilation air intake housing 2, the central axis X extends in the vertical direction. Figure 3 The two points where the central axis X passes through the shell 2 are defined as the centers of the inlet end 2a and the opposite end 2b of the shell 2, wherein the inlet end 2a of the shell 2 is connected to the second end of the inlet pipe 1, and the opposite end 2b of the shell 2 is closed.

[0060] See also Figure 4 It can be seen that the middle cross section is marked by a dotted line inside the housing 2, and the middle cross section is perpendicular to the central axis X, and its cross-sectional area is S. As is well known, countless cross sections perpendicular to the central axis X can be obtained along the central axis X of the ventilation and air intake housing 2, and the areas S of these cross sections will change accordingly based on the shape change of the ventilation and air intake housing 2.

[0061] In the present application, the ventilation air intake housing 2 is designed to have the following shape, namely: the cross-sectional area S of the housing 2 taken on each plane perpendicular to the central axis X changes between the air intake end 2a and the opposite end 2b of the housing 2 in a manner of first increasing and then decreasing.

[0062] Still Figure 3 and 4 Taking the ventilation air intake shell 2 shown in the figure as an example, the ventilation air intake shell 2 shown in the figure has a spherical shape. In this case, the cross-sectional area of ​​the shell 2 perpendicular to the central axis X at the air intake end 2a and the opposite end 2b is the minimum value, and the cross-sectional area of ​​the shell 2 perpendicular to the central axis X passing through its sphere center (that is, the area S of the middle cross section) is the maximum value. The first half shell or upper half shell of the shell 2 between the air intake end 2a and the middle cross section is defined as the cross-sectional expansion section 2-1 of the shell 2, and the second half shell or lower half shell of the shell 2 between the middle cross section and the opposite end 2b is defined as the cross-sectional contraction section 2-2. In other words, the ventilation air intake shell 2 is composed of the cross-sectional expansion section 2-1 and the cross-sectional contraction section 2-2.

[0063] It can be seen that, in the case where the ventilation air intake housing 2 is a sphere, the cross-sectional area S of the cross-sectional expansion section 2-1 increases monotonically from the air intake end 2a to the middle cross-sectional area along the central axis X, and the cross-sectional area of ​​the cross-sectional contraction section 2-2 decreases monotonically from the middle cross-sectional area to the opposite end 2b along the central axis X. If the rate at which the cross-sectional area of ​​the cross-sectional expansion section 2-1 increases monotonically is set as a first ratio, and the rate at which the cross-sectional area of ​​the cross-sectional contraction section 2-2 decreases monotonically is set as a second ratio, it is obvious to those skilled in the art that the first ratio is equal to the second ratio.

[0064] However, a person skilled in the art may also modify the shape of the ventilation air intake housing 2, as long as the cross-sectional area S of the housing 2 taken on each plane perpendicular to the central axis X changes between the air intake end 2a and the opposite end 2b of the housing 2 in a manner of first increasing and then decreasing. For example, the ventilation air intake housing 2 may be designed to be an elliptical shape, or the ventilation air intake housing 2 may be designed to be a shape formed by splicing two bell mouths or a plurality of step portions. Such modifications should be easy to think of for a person skilled in the art, and therefore should also fall within the scope of protection of the present invention.

[0065] A person skilled in the art may also adjust the first ratio and the second ratio so that they are not equal to each other. For example, the first ratio may be set to be greater than the second ratio. In this case, the rate at which the cross-sectional area of ​​the cross-sectional expansion section 2-1 increases monotonically will be greater than the rate at which the cross-sectional area of ​​the cross-sectional contraction section 2-2 decreases monotonically. Such a variation should be easy to imagine for a person skilled in the art, and therefore should also fall within the scope of protection of the present invention.

[0066] Figure 5 and 6 The top view and bottom view of the ventilation and air intake system 10 according to the present invention are shown in FIG. 1 , in which a plurality of exhaust grilles 3 are formed on the ventilation and air intake housing 2. The exhaust grilles 3 are evenly distributed on the ventilation and air intake housing 2 around the central axis X of the housing 2. Figure 5 and 6 In the example shown, a total of eight exhaust grilles 3 are formed on the ventilation air intake housing 2, and these exhaust grilles 3 extend on at least a portion of at least one of the cross-sectional expansion section 2-1 and the cross-sectional contraction section 2-2 of the ventilation air intake housing 2. For example, the exhaust grille 3 can be designed to extend only on the cross-sectional contraction section 2-2, or to extend the same length on the cross-sectional expansion section 2-1 and the cross-sectional contraction section 2-2.

[0067] from Figure 5It can be seen from FIG. 1 that the length of the exhaust grille 3 distributed in the cross-sectional expansion section 2-1 exceeds half or more of the length of the cross-sectional expansion section 2-1 along its central axis X. Figure 5 It can be seen that the length of the exhaust grille 3 distributed in the cross-sectional contraction section 2-2 exceeds half or more of the length of the cross-sectional contraction section 2-2 along its central axis X. In other words, the total length of the exhaust grille 3 is half or more of the length of the ventilation air intake housing 2 along its central axis X.

[0068] Ordinary technicians in this field can also make various changes and improvements to the number, size, distribution pattern, etc. of the exhaust grilles. Such modifications should be easy to think of for ordinary technicians in this field, and therefore should also fall within the scope of protection of the present invention.

[0069] Figure 7 The figure shows a ventilation air intake system 10 installed in the turbofan engine core module 4. It can be seen that a pair of ventilation air intake systems 10 are arranged upstream of the air intake of the core module 4, and these ventilation air intake systems 10 are arranged in pairs at the top and bottom of the core module 4. Of course, multiple pairs of ventilation air intake systems 10 can be installed according to the situation, or only one ventilation air intake system 10 can be installed.

[0070] It can be seen that the upstream end of the air intake pipe 1 of the ventilation air intake shell 2 is fixedly connected to the core cabin wall 5, and the cooling airflow introduced from the outer duct first enters the shell 2 through the air intake pipe 1 for rectification, and then is radially discharged to the surrounding space through the exhaust grille 3.

[0071] The cooling gas is sucked by the pressure difference between upstream and downstream. Figure 7 The arrow track marked in the middle flows toward the downstream of the core cabin 4, and uses convection heat exchange to absorb the heat in the core cabin 4. The heated cooling gas is finally discharged from the annular gap 6 at the end of the nozzle, completing the ventilation cooling heat exchange process.

[0072] In the above ventilation and heat exchange mechanism, the upstream and downstream pressure difference of the core cabin 4 determines the overall flow capacity, and the uniformity of the upstream gas is also the key to the overall airflow distribution of the cabin. The grille 3 set on the shell 2 cools the gas by expanding and rectifying it, and makes it diffuse and densely distributed in the upstream area of ​​the core cabin 4 in time, ensuring the initial uniformity of the robustness of the subsequent suction process, which helps to achieve efficient ventilation and heat exchange in the core cabin.

[0073] Although the structure and working principle of the ventilation and air intake system for the core compartment of a turbofan engine according to the present invention are described above in combination with the preferred embodiments and the accompanying drawings, it should be recognized by those skilled in the art that the above examples are only for illustration and cannot be used as limitations of the present invention. Therefore, the present invention can be modified and varied within the spirit of the claims, and these modifications and variations will fall within the scope required by the claims of the present invention.

Claims

1. A ventilation air intake system (10) for a turbofan engine core compartment (4), comprising: An air intake pipe (1) allowing airflow to enter the core module (4); a ventilation air intake housing (2), the ventilation air intake housing (2) having an air intake end (2a) in communication with the air intake pipe (1), an opposite end (2b) opposite to the air intake end (2a), and a central axis (X) passing through the air intake end (2a) and the opposite end (2b); and A plurality of exhaust grilles (3) are provided on the ventilation air intake housing (2), the exhaust grilles (3) being evenly distributed on the ventilation air intake housing (2) around the central axis (X), and the cross-sectional area (S) of the ventilation air intake housing (2) taken on each plane perpendicular to the central axis (X) changes between the air intake end (2a) and the opposite end (2b) in a manner of first increasing and then decreasing.

2. The ventilation air intake system (10) according to claim 1, characterized in that: The ventilation air intake housing (2) is composed of a cross-sectional expansion section (2-1) and a cross-sectional contraction section (2-2), wherein the cross-sectional area of ​​the cross-sectional expansion section (2-1) increases monotonically along the direction from the air intake end (2a) to the opposite end (2b), and the cross-sectional area of ​​the cross-sectional contraction section (2-2) decreases monotonically along the direction from the air intake end (2a) to the opposite end (2b).

3. The ventilation air intake system (10) according to claim 2, characterized in that: The cross-sectional area of ​​the cross-sectional expansion section (2-1) increases monotonically at a first ratio along the direction from the air inlet end (2a) to the opposite end (2b), and the cross-sectional area of ​​the cross-sectional contraction section (2-2) decreases monotonically at a second ratio along the direction from the air inlet end (2a) to the opposite end (2b), wherein the first ratio is equal to the second ratio.

4. The ventilation air intake system (10) according to claim 1, characterized in that: A total of eight exhaust grilles (3) are formed on the ventilation air intake housing (2).

5. The ventilation air intake system (10) according to claim 1 or 4, characterized in that: The exhaust grille (3) is formed on the cross-sectional expansion section (2-1) and / or the cross-sectional contraction section (2-2) of the ventilation air intake housing (2).

6. The ventilation air intake system (10) according to claim 1, characterized in that: The length of the exhaust grille (3) is half or more than half of the length of the ventilation air intake housing (2) along its central axis (X).

7. A turbofan engine core module (4), wherein at least one ventilation air intake system (10) according to any one of claims 1 to 6 is arranged upstream of the air intake of the core module (4), wherein: The cooling airflow enters the ventilation air intake shell (2) through the air intake pipe (1), is then radially discharged into the core module (4) through the exhaust grille (3), and finally is discharged from the core module (4) through the nozzle end annular gap (6) located downstream of the core module (4).

8. The turbofan engine core cabin (4) according to claim 7, characterized in that: The air intake pipe (1) is fixedly connected to the core cabin wall surface (5).

9. An aircraft, equipped with a turbofan engine core module (4) as claimed in claim 8.

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