CN113090390B - Precooling type engine air inlet channel with bypass flow path and design method - Google Patents
Precooling type engine air inlet channel with bypass flow path and design method Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
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- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
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- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/12—Cooling of plants
- F02C7/14—Cooling of plants of fluids in the plant, e.g. lubricant or fuel
- F02C7/141—Cooling of plants of fluids in the plant, e.g. lubricant or fuel of working fluid
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
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Abstract
The invention discloses an air inlet with a bypass flow path of a precooling engine, which comprises a central body, a lip cover, a fixed support plate, a precooler, a flow dividing partition plate, an air inlet shell and an actuating component, wherein the bypass flow path is arranged outside the precooler, so that the flow area of the precooler is effectively enlarged when the air inlet works under low Mach number, and the phenomenon that the air inlet is not started because the precooler forms a second throat channel is avoided; the invention also provides a design method suitable for the air inlet channel.
Description
Technical Field
The invention relates to the field of aircraft design, in particular to a precooling type engine air inlet with a bypass flow path.
Background
With the development of science and technology, the exploration and utilization of space by human beings are no longer limited to the earth orbit and the atmosphere, and the exploration of critical space with the height of 20-100km is started, so that the high-performance hypersonic aircraft is greatly required. The hypersonic aircraft refers to an aircraft which can cruise at the flight speed of more than 5 Mach numbers in the atmosphere, and has higher penetration prevention capability, stronger timely and high-precision hitting capability and wider flight envelope compared with the prior various stealth technologies. The power of the hypersonic aircraft is always the bottleneck of the development of the hypersonic aircraft, and the air inlet channel is one of the most important components of the power system of the hypersonic aircraft and is used for providing required air for the engine under various working conditions.
The precooling type engine is characterized in that the temperature of air flow at the inlet of the engine is reduced by means of heat exchange, jet flow and the like before the air flow enters the engine. The problem that incoming flow air is stagnated to be over high temperature when the engine works under the high Mach number is solved and improved. In recent years, a method of precooling incoming air by a micro-tube bundle type precooling heat exchanger represented by "SABRE" in the united kingdom has been effectively developed. In order to fully pre-cool the incoming air of the engine under the high-mach-number working condition before the incoming air enters the engine and not influence the pre-compression of the incoming air by the air inlet channel, the pre-cooler must be arranged behind the air inlet channel or in the diffuser section of the air inlet channel, which must influence the flow field in the air inlet channel.
The precooler is added in the diffusion section of the air inlet channel, so that the flight envelope of the air inlet channel can be effectively widened, and the performance of the air inlet channel in a high-speed flight state is greatly improved. However, under a low-speed working condition, the existence of the precooler reduces the effective flow area at the position, a second throat is possibly formed, the starting problem is brought to the air inlet channel, and particularly under a take-off state, the starting problem is more serious.
For this reason, a new technical solution is needed to solve the above technical problems.
Disclosure of Invention
In order to solve the problems, the invention provides an air inlet with a bypass flow path of a precooling type engine, which solves the technical problem that after a precooler is added in an expansion section of the air inlet, the precooler occupies the space in the expansion section to influence the flow field in the air inlet, and the starting capability and the pneumatic performance of the air inlet in a low-speed flight state are influenced.
The invention also provides a design method of the air inlet.
In order to achieve the above object, the technical solution that can be adopted by the air intake duct with bypass flow path of the precooling type engine and the design method provided by the invention is as follows:
an air inlet channel with a bypass flow path of a precooling engine comprises a hollow central body, a lip cover surrounding the central body, a shell extending backwards from the lip cover and also surrounding the central body, a main flow path, an expansion section and a precooler positioned in the main flow path; the main flow path is formed between the central body and the lip cover; the expansion section is formed between the central body and the outer shell and communicated with the main flow path; the method is characterized in that: a flow dividing partition plate positioned between the shell and the central body and an actuating component for driving the flow dividing partition plate to move back and forth are also arranged;
a bypass flow path is formed between the flow dividing partition plate and the shell, a connecting section which is also positioned in the shell is also arranged at the front end of the flow dividing partition plate, the precooler is completely positioned between the flow dividing partition plate and the central body, and when the flow dividing partition plate moves forwards to be in contact with the connecting section, the bypass flow path and the main flow path are closed; when the dividing partition plate moves backwards, the bypass flow path is communicated with the main flow path.
Furthermore, the shunting partition plate is in a sleeve shape, and a sliding groove is formed in the shell; a chute cover plate connected with the actuating part and a fixed support plate penetrating through the chute are covered on the outer side of the shell; the outer end of the fixed support plate is connected with the chute cover plate, and the inner end of the fixed support plate is connected with the shunting partition plate.
Further, the precooler includes a plurality of annular tube bundles disposed about the central body and having a cooling liquid flowing therein.
Furthermore, a central body fixing support plate is also arranged; the central body is fixedly connected with the outer shell through a central body fixing support plate; a cooling liquid input device, a cooling liquid output device, a cooling liquid input channel and a cooling liquid output channel are fixed on the outer side of the shell, the cooling liquid input device and the cooling liquid output device are communicated with each other, and the cooling liquid input channel extends from the cooling liquid input device into the central body fixing support plate, then continues to extend from the central body and enters the expansion section to be communicated with the precooler; the cooling liquid output channel extends from the cooling liquid output device to the central body fixing support plate, then extends from the central body continuously and enters the expansion section to be communicated with the precooler; the cooling liquid input device, the cooling liquid input channel, the precooler, the cooling liquid output channel and the cooling liquid output device form a loop; the precooler includes a plurality of annular tube bundles disposed about the central body and having a cooling liquid flowing therein.
Further, when the flight Mach number of the aircraft is lower than the flow path conversion Mach number Mt of the air inlet channel, the flow dividing partition plate is moved backwards to enable the bypass flow path to be communicated with the main flow path; when the flight Mach number of the aircraft is higher than the conversion Mach number Mt of the air inlet channel, the flow dividing partition plate is moved backwards to close the bypass channel and the expansion section. .
Has the advantages that: the technical scheme of the air inlet provided by the invention realizes the layout of adding the adjustable bypass flow path in the axisymmetric air inlet, and avoids the starting problem of the traditional precooling type axisymmetric air inlet under the low-speed condition. Specifically, when the air inlet channel is in a low-speed flight state or a ground takeoff state, the air inflow entering the air inlet channel from the main flow path is large, and the expansion section occupies a space occupied by the precooler, so that the starting capacity of the air inlet channel is influenced. Therefore, the inlet of the bypass flow path is communicated with the main flow path of the air inlet channel, so that the flow area of the expansion section at the position of the precooler is effectively enlarged when the air inlet channel works under the low Mach number, the phenomenon that the air inlet channel is not started due to the fact that the precooler forms a second throat is avoided, and the starting performance and the starting capacity of the air inlet channel under the working condition of the low Mach number are improved. And when the air inlet channel is in a high-speed state, the air flow in the air inlet channel needs to be cooled, the bypass flow path is closed, and the air flow needs to pass through the space where the precooler is located so as to play a precooling effect brought by the precooler, so that the problem that the incoming air is stagnated to an excessively high temperature when the engine works under a high Mach number is solved.
The technical scheme adopted by the design method of the air inlet provided by the invention is as follows: the method comprises the following steps:
(1) the determination of the bypass flow path opening area and the flow area includes:
(1a) firstly, determining the flow area of the installation position of an expansion section precooler of an air inlet channel, and determining the opening and closing of a bypass flow path and the opening area of the bypass flow path by comparing the flow area with the throat area of the air inlet channel in different flight states;
(1b) determining the minimum flow area of the bypass flow path after the opening areas of the bypass flow path in different flight states are obtained according to the step (1 a); (ii) a
(2) The bypass flow path is designed according to the basic configuration, and comprises:
(2a) the flow dividing partition plate is tightly attached to a connecting section (13) of the air inlet casing (11) and the air inlet lip cover (2) when the bypass flow path is closed, and the molded line of the flow dividing partition plate on the main flow path side is smoothly and excessively connected with the molded line on the inner side of the lip cover;
(2b) the air inlet channel shell (11) and the air inlet channel lip cover (2) are fixedly connected through a connecting section (12) behind the central body fixing support plate (3), and the connecting section (12) and the axial direction have a certain deflection angle gamma;
(2c) determining the deflection angle gamma of the connecting section by means of simulating the characteristics of the flow field structure of the connecting section in the step (2b) at different deflection angles gamma and the loss of the bypass flow path through computational fluid mechanics simulation software so as to enable the total pressure recovery coefficient of the bypass flow path to be not less than 0.9 under different opening areas;
(2d) designing the molded lines at the inner side of the flow dividing partition plate at the inner side of the bypass flow path by means of computational fluid dynamics simulation software so that the total pressure recovery coefficient of the bypass flow path under different opening areas is not less than 0.9;
(2e) designing the molded line at the inner side of the air inlet casing at the outer side of the bypass flow path by means of computational fluid dynamics simulation software so that the total pressure recovery coefficient of the bypass flow path is not less than 0.9 under different opening areas, and when the bypass flow path and the main flow path are merged and mixed, the total pressure recovery coefficient is not less than 0.9;
(3) the determination of the bypass flow path installation position includes:
the installation position of the bypass flow path is mainly determined by the installation position of the flow dividing partition plate, and the simulation of the flow dividing partition plate at different radial and axial installation positions is carried out by means of computational fluid dynamics simulation software so that the total pressure recovery coefficient of the bypass flow path at different opening areas is not less than 0.9.
Further, the opening and closing of the bypass flow path in step (1a) is determined by the following factors:
when A is1-Aprecooler>α·AthroatWhile bypassingClosing the flow path;
when A is1-Aprecooler<α·AthroatWhen the bypass flow path is opened.
Wherein A is1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe frontal area of the precooler, AthroatThe area of the air inlet channel is taken as the area of the air inlet channel, and the value of alpha is 1.5 in consideration of the total pressure loss of the air flow from the air inlet channel to the precooler; and A isprecooler＝N·AsingleWherein N is the number of layers of the precooler in the radial direction, AsingleThe windward area of the single precooler tube bundle.
Further, the bypass flow path opening area determined in step (1a) is determined by the following factors:
AL＝β·(α·Athroat-A1+Aprecooler)
wherein A isLOpening area of bypass flow path, AthroatIs the area of the throat of the air inlet, A1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe value range of beta is 1.5-3.0 for the windward area of the precooler.
Further, the opening area of the bypass flow path is determined by the translational distance of the dividing partition along the axial direction, and the translational distance of the dividing partition is determined by the following formula:
L＝AL/D
wherein L is the translation distance of the flow dividing partition, ALThe bypass flow path opening area, and D the outside diameter of the expansion section; determining the minimum flow area value of a bypass flow path:
AH＝θ·(α·Athroat-A1+Aprecooler)
wherein A isHIs the minimum flow area of the bypass flow path, AthroatIs the area of the throat of the air inlet, A1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe value range of theta is 1.2-2.5 for the windward area of the precooler and for the consideration of the through-flow capacity and the total pressure recovery performance of the bypass flow path.
Further, the steps of calculating the fluid mechanics simulation method in the steps (2c), (2d) and (2e) are as follows: firstly, establishing a connecting section (12) between an air inlet duct shell (11) with a specific deflection angle and an air inlet duct lip cover (2), establishing molded lines of inner and outer side wall surfaces of a bypass flow path with specific molded lines, and simulating the through-flow capacity and total pressure recovery performance of the bypass flow path under the corresponding connecting section deflection angle gamma and the molded lines of the inner and outer sides by a computational fluid dynamics method;
the computational fluid dynamics simulation method in the step (3) comprises the following steps: firstly, establishing a shunt partition plate model with specific axial and radial installation positions, and then simulating the total pressure loss and the flow resistance of a bypass flow path at the corresponding shunt partition plate installation position by a computational fluid dynamics method; under different air inlet channel flight conditions; in the axial mounting position; when the splitter plate has the maximum moving distance L, the front edge of the splitter plate is opposite to the front edge of the outermost precooler tube bundle; less than 5R, where R is the diameter of a single precooler tube bundle; in the radial installation position, the distance between the front edge of the wall surface at the main flow path side of the flow dividing partition plate and the tube bundle of the outermost precooler; less than 5R, where R is the diameter of a single precooler tube bundle
The design method provided by the invention can adapt to a wider flight speed range and provides the most appropriate working mode for the wide-speed-range engine, so that the pneumatic performance of the air inlet channel at high and low speeds is considered, the wide-speed-range engine can effectively work in a wider flight envelope, and the design method has the advantages of small windward area, compact layout, large internal available volume ratio and the like.
Drawings
Fig. 1 is a sectional view of the intake bypass passage in the present invention when it is open.
Fig. 2 is a sectional view of the intake bypass passage in the present invention when closed.
Fig. 3 is a partially enlarged view of fig. 1.
Fig. 4 is a partially enlarged view of fig. 2.
Fig. 5 is a three-dimensional view of the fixing support plate, the chute cover and other parts of the flow dividing partition plate of the bypass flow path of the intake duct according to the present invention.
FIG. 6 shows the deflection angle of the connecting section under parametric study in the design method of the present inventionDegree gamma, bypass flow passage opening area ALAnd a bypass flow passage flow area AHSchematic representation of (a).
Detailed Description
The technical scheme provided by the invention is explained in detail in the following with the accompanying drawings.
Referring to fig. 1 and 2, a bypass flow path intake of a precooling engine includes a hollow central body 1, a lip cover 2, a central body fixing support plate 3, an actuating member 4, a splitter plate assembly 5, an air bleed system 9, a precooler 10, an intake housing 11, and a connecting section 12. The actuating element 4 can be driven hydraulically or by an electric motor.
The central body 1 is fixedly connected with the air inlet housing 11 through a central body fixing support plate 3, and the flow dividing partition plate 501 is sleeved outside the precooler 10 as an inner cylinder.
The actuating component 4 is arranged outside the air inlet casing 11 along the axis and is connected with a chute cover plate 503, the chute cover plate 503 is fixedly connected with a fixed support plate 502 of the dividing partition plate, and the fixed support plate 502 of the dividing partition plate is fixedly connected with the dividing partition plate 501.
As shown in fig. 2, fig. 3, and fig. 6, a cooling liquid input device 1301, a cooling liquid output device 1302, a cooling liquid input channel, and a cooling liquid output channel are fixed outside the housing, the cooling liquid input device 1301 and the cooling liquid output device 1302 are communicated with each other, and the cooling liquid input channel extends from the cooling liquid input device 1301 into the central body fixing support plate 3, and then extends from the central body 1 and enters the expansion section to communicate with the precooler 10. The coolant outlet passage extends from the coolant outlet 1302 into the central body mounting plate 3, and then continues from the central body 1 and into the expanded section to communicate with the precooler 10. The cooling liquid inlet 1301, the cooling liquid inlet channel, the precooler 10, the cooling liquid outlet channel and the cooling liquid outlet 1302 form a loop.
The dividing wall 501 is located inside the inlet casing 11. An annular bypass flow path 8 is formed between the flow dividing partition 501 and the air inlet casing 11, and the inlet of the bypass flow path 8 is arranged at the upstream of the precooler 10; an annular main flow path 6 is formed between the central body 1 and the lip shroud 2. The main flow path 6 is inside the flow dividing partition 501, and the main flow path 6 and the bypass flow path 8 join downstream of the flow dividing partition 501, and the flow path cross section gradually changes from annular to circular.
The dividing wall 501 is driven by the actuating member to move between a first position and a second position, so that the internal structure of the intake duct can be adjusted. Specifically, when the dividing partition 501 is at the first position, the dividing partition does not contact the connecting section 12, the inlet of the bypass flow path 8 is communicated with the main flow path 6 of the intake duct, the bypass flow path is completely opened at this time, the intake duct is in a low-speed flight state or a ground takeoff state, and the flow path conversion mach number M for the flight speed smaller than that of the intake duct is usedt(Mt<2) The state of time.
When the dividing septum 501 is in the second position, the dividing septum contacts the connecting segment and closes off the inlet of the bypass flow path. At the moment, only the main flow path works, and the air inlet channel is in a high-speed flight state and is used for switching the flow path with the flight speed larger than the flow path of the air inlet channel to the Mach number Mt(Mt>2) The state of time.
The specific steps of designing an air inlet with a bypass flow path of a precooling type engine by adopting the design method of the invention are described below.
(1) The determination of the bypass flow path opening area and the flow area includes:
(1a) firstly, determining the flow area of the installation position of the air inlet expanding section precooler, and determining the opening and closing of a bypass flow path according to the following formula:
when A is1-Aprecooler>α·AthroatWhen the bypass flow path is closed;
when A is1-Aprecooler<α·AthroatWhen the bypass flow path is opened.
Wherein A is1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe frontal area of the precooler, AthroatThe value of alpha is 1.5 considering the total pressure loss from the throat to the precooler. And A isprecooler＝N·AsingleWherein N is the number of layers of the precooler in the radial direction, AsingleThe windward area of the single precooler tube bundle.
After determining that the bypass flow path is open, the bypass flow path open area is given by the following equation:
AL＝β·(α·Athroat-A1+Aprecooler)
wherein A isLOpening area of bypass flow path, AthroatIs the area of the throat of the air inlet, A1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe value range of beta is 1.5-3.0 for the windward area of the precooler in consideration of the separation and total pressure loss of the airflow from the main flow path to the bypass flow path.
(1b) After the opening areas of the bypass flow path in different flight states are obtained according to the step (1a), in order to ensure that the bypass flow path has enough through-flow capacity in different flight states of the air inlet channel, the minimum flow area of the bypass flow path is given by the following formula:
AH＝θ·(α·Athroat-A1+Aprecooler)
wherein A isLOpening area of bypass flow path, AthroatIs the area of the throat of the air inlet, A1Is the flow area of the expansion section of the air inlet passage, AprecoolerIn order to take account of the through-flow capacity and the total pressure recovery performance of the bypass flow path, the value range of theta is 1.2-2.5 for the windward area of the precooler.
(2) Basic configuration design of bypass flow path
(2a) The shunting baffle is clung to the connecting section of the air inlet casing and the air inlet lip cover when the bypass flow path is closed, and the molded lines of the shunting baffle on the side of the main flow path are smoothly connected with the molded lines on the inner side of the lip cover excessively.
(2b) The air inlet channel shell and the air inlet channel lip are fixedly connected through a connecting section behind the central body fixing support plate, and the connecting section and the axial direction have a certain deflection angle gamma.
(2c) And (3) simulating the characteristics of the flow field structure of the connecting section in the step (2b) at different deflection angles gamma and the loss of the bypass flow path by means of a computational fluid mechanics method, and determining that the deflection angle gamma of the connecting section is between 10 and 45 degrees in order to ensure that the bypass flow path has smaller total pressure loss at different opening areas.
(2d) The molded lines on the inner side of the flow dividing partition plate on the inner side of the bypass flow path are designed by means of a computational fluid dynamics method, so that the bypass flow path is ensured to have smaller total pressure loss under different opening areas.
(2e) The molded line of the inner side of the air inlet casing on the outer side of the bypass flow path is designed by means of a computational fluid dynamics method, so that the bypass flow path has smaller total pressure loss under different opening areas, and has smaller mixing loss after the bypass flow path is converged with the main flow path.
(3) Determination of bypass flow path installation position
The installation position of the bypass flow path is mainly determined by the installation position of the shunt partition plate, the simulation of the shunt partition plate at different radial and axial installation positions is carried out by means of a computational fluid dynamics method, and in order to ensure that the bypass flow path has smaller total pressure loss and flow resistance under different opening areas, the installation position of the shunt partition plate is determined as follows:
in the axial installation position, when the diversion baffle plate has the maximum moving distance L in the most openable area of the bypass flow path, namely the diversion baffle plate, the relative position of the front edge of the diversion baffle plate and the front edge of the outermost precooler tube bundle is less than 5R, wherein R is the diameter of a single precooler tube bundle; in the radial installation position, the distance between the front edge of the wall surface at the main flow path side of the flow dividing partition plate and the tube bundle of the outermost precooler is less than 5R, wherein R is the diameter of the single tube bundle of the precooler.
The invention embodies a number of methods and approaches to this solution and the foregoing is only a preferred embodiment of the invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention. All the components not specified in the present embodiment can be realized by the prior art.
Claims (10)
1. A precooling type engine intake duct with a bypass flow path comprises a hollow central body (1), a lip cover (2) surrounding the central body, a shell (11) extending backwards from the lip cover and also surrounding the central body, a main flow path, an expansion section and a precooler (10) positioned in the main flow path; the main flow path is formed between the central body and the lip cover; the expansion section is formed between the central body and the outer shell and communicated with the main flow path; the method is characterized in that: a flow dividing partition plate (501) positioned between the shell and the central body and an actuating component (4) for driving the flow dividing partition plate (501) to move back and forth are also arranged;
a bypass flow path (8) is formed between the flow dividing partition plate and the shell, a connecting section (12) which is also positioned in the shell is also arranged at the front end of the flow dividing partition plate, the precooler (10) is completely positioned between the flow dividing partition plate and the central body, and when the flow dividing partition plate moves forwards to be in contact with the connecting section, the bypass flow path and the main flow path are closed; when the dividing partition plate moves backwards, the bypass flow path is communicated with the main flow path.
2. The air scoop according to claim 1, wherein: the flow dividing partition plate (501) is in a sleeve shape, and a sliding groove (504) is formed in the shell; the outer side of the shell is covered with a chute cover plate (503) connected with the actuating component and a fixed support plate (502) penetrating through the chute (504); the outer end of the fixed support plate is connected with the chute cover plate, and the inner end of the fixed support plate is connected with the shunting partition plate (501).
3. The intake duct with a bypass flow path of a precooling engine according to claim 2, wherein: the precooler includes a plurality of annular tube bundles disposed about the central body and having a cooling liquid flowing therein.
4. The intake duct with a bypass flow path of a precooling engine according to claim 3, wherein: a central body fixing support plate (3) is also arranged; the central body (1) is fixedly connected with the shell (11) through a central body fixing support plate (3); a cooling liquid input device (1301), a cooling liquid output device (1302), a cooling liquid input channel and a cooling liquid output channel are fixed on the outer side of the shell, the cooling liquid input device (1301) and the cooling liquid output device (1302) are communicated with each other, and the cooling liquid input channel extends from the cooling liquid input device to the central body fixing support plate (3), then extends from the central body continuously and enters the expansion section to be communicated with the precooler (10); the cooling liquid output channel extends from the cooling liquid output device to the central body fixing support plate (3), then extends from the central body continuously and enters the expansion section to be communicated with the precooler (10); the cooling liquid input device, the cooling liquid input channel, the precooler, the cooling liquid output channel and the cooling liquid output device form a loop.
5. The intake duct according to any one of claims 1 to 4, wherein: when the flight Mach number of the aircraft is lower than the flow path conversion Mach number Mt of the air inlet channel, the flow dividing partition plate is moved backwards to enable the bypass flow path to be communicated with the main flow path; when the flight Mach number of the aircraft is higher than the conversion Mach number Mt of the air inlet channel, the flow dividing partition plate is moved backwards to close the bypass channel and the expansion section.
6. A design method of the intake duct according to any one of claims 1 to 5, comprising the steps of:
(1) the determination of the bypass flow path opening area and the flow area includes:
(1a) firstly, determining the flow area of the installation position of an expansion section precooler of an air inlet channel, and determining the opening and closing of a bypass flow path and the opening area of the bypass flow path by comparing the flow area with the throat area of the air inlet channel in different flight states;
(1b) determining the minimum flow area of the bypass flow path after the opening areas of the bypass flow path in different flight states are obtained according to the step (1 a);
(2) the bypass flow path is designed according to the basic configuration, and comprises:
(2a) the flow dividing partition plate is tightly attached to a connecting section (13) of the air inlet casing (11) and the air inlet lip cover (2) when the bypass flow path is closed, and the molded line of the flow dividing partition plate on the main flow path side is smoothly and excessively connected with the molded line on the inner side of the lip cover;
(2b) the air inlet channel shell (11) and the air inlet channel lip cover (2) are fixedly connected through a connecting section (12) behind the central body fixing support plate (3), and the connecting section (12) and the axial direction have a certain deflection angle gamma;
(2c) determining the deflection angle gamma of the connecting section by means of simulating the characteristics of the flow field structure of the connecting section in the step (2b) at different deflection angles gamma and the loss of the bypass flow path through computational fluid mechanics simulation software so as to enable the total pressure recovery coefficient of the bypass flow path to be not less than 0.9 under different opening areas;
(2d) designing the molded lines at the inner side of the flow dividing partition plate at the inner side of the bypass flow path by means of computational fluid dynamics simulation software so as to enable the bypass flow path to be under different opening areas;
(2e) designing the molded line at the inner side of the air inlet casing at the outer side of the bypass flow path by means of computational fluid dynamics simulation software so that the total pressure recovery coefficient of the bypass flow path is not less than 0.9 under different opening areas, and when the bypass flow path and the main flow path are merged and mixed, the total pressure recovery coefficient is not less than 0.9;
(3) the determination of the bypass flow path installation position includes:
the installation position of the bypass flow path is mainly determined by the installation position of the flow dividing partition plate, and the simulation of the flow dividing partition plate at different radial and axial installation positions is carried out by means of computational fluid dynamics simulation software so that the total pressure recovery coefficient of the bypass flow path at different opening areas is not less than 0.9.
7. The design method according to claim 6, wherein: the opening and closing of the bypass flow path in step (1a) is determined by the following factors:
when A is1-Aprecooler＞α·AthroatWhen the bypass flow path is closed;
when A is1-Aprecooler＜α·AthroatWhen the bypass flow path is opened;
wherein A is1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe frontal area of the precooler, AthroatThe area of the air inlet channel is taken as the area of the air inlet channel, and the value of alpha is 1.5 in consideration of the total pressure loss of the air flow from the air inlet channel to the precooler; and A isprecooler＝N·AsingleWherein N is the number of layers of the precooler in the radial direction, AsingleThe windward area of the single precooler tube bundle.
8. The design method according to claim 7, wherein: the bypass flow path opening area determined in step (1a) is determined by the following factors:
AL＝β·(α·Athroat-A1+Aprecooler)
wherein A isLOpening area of bypass flow path, AthroatIs the area of the throat of the air inlet, A1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe value range of beta is 1.5-3.0 for the windward area of the precooler.
9. The design method according to claim 8, wherein: the open area of the bypass flow path is determined by the distance of translation of the dividing wall in the axial direction, which is determined by the following equation:
L＝AL/D
wherein L is the translation distance of the flow dividing partition, ALThe bypass flow path opening area, and D the outside diameter of the expansion section; determining the minimum flow area value of a bypass flow path:
AH＝θ·(α·Athroat-A1+Aprecooler)
wherein A isHIs the minimum flow area of the bypass flow path, AthroatIs the area of the throat of the air inlet, A1Is the flow area of the expansion section of the air inlet passage, AprecoolerThe value range of theta is 1.2-2.5 for the windward area of the precooler and for the consideration of the through-flow capacity and the total pressure recovery performance of the bypass flow path.
10. The design method according to claim 6, wherein: the computational fluid dynamics simulation method in the steps (2c), (2d) and (2e) comprises the following steps: firstly, establishing a connecting section (12) between an air inlet duct shell (11) with a specific deflection angle and an air inlet duct lip cover (2), establishing molded lines of inner and outer side wall surfaces of a bypass flow path with specific molded lines, and simulating the through-flow capacity and total pressure recovery performance of the bypass flow path under the corresponding connecting section deflection angle gamma and the molded lines of the inner and outer sides by a computational fluid dynamics method;
the computational fluid dynamics simulation method in the step (3) comprises the following steps: firstly, establishing a shunt partition plate model with specific axial and radial installation positions, and then simulating the total pressure loss and the flow resistance of a bypass flow path at the corresponding shunt partition plate installation position by a computational fluid dynamics method; under different air inlet channel flight conditions, when the diversion partition plate has the maximum moving distance L at the axial installation position, the relative position of the front edge of the diversion partition plate and the front edge of the outermost precooler tube bundle is less than 5R, wherein R is the diameter of a single precooler tube bundle; in the radial installation position, the distance between the front edge of the wall surface at the main flow path side of the flow dividing partition plate and the tube bundle of the outermost precooler is less than 5R, wherein R is the diameter of the single tube bundle of the precooler.
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