Cooling Device for Telemetry Module of Dynamic Stress Measurement of Low-Pressure Fan of Whole Turbofan Engine

Abstract

The present invention provides a cooling device for a telemetry module for measuring the dynamic stress of a low-pressure fan of a turbofan engine, comprising: an engine cowl, a through hole is opened at the center position of the front end thereof, and a tension bolt with a vent hole is arranged at the through hole; a gas collecting box is arranged inside, and the air inlet of the gas collecting box is communicated with the air outlet end of the tension bolt; the housing of the gas collecting box is sequentially connected to a first mounting seat and a second mounting seat to form a cooling gas collecting cavity; a plurality of impingement cooling holes are uniformly arranged along the circumference on the housing of the first mounting seat for enabling the cooling gas to form a jet impingement cooling on the transmitting device of the telemetry module through the impingement cooling holes; the housing of the second mounting seat is connected to a telemetry module receiving device adapter seat to form a telemetry cavity, and a plurality of cooling gas exhaust holes are uniformly opened along the circumference on the adapter seat; the cooled gas enters the telemetry cavity and then is discharged from the cooling gas exhaust holes. The present invention can ensure that the telemetry module does not exceed the limit temperature during the entire fan dynamic stress measurement test, so as to achieve the reliability and stability of the cooling scheme.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine design, and particularly to a cooling device for a telemetry module for measuring the dynamic stress of a low-pressure fan of an entire turbofan engine. Background Art

[0002] For aero-engines or gas turbines, the blade is one of the most important and fault-prone parts. Whether it is a compressor blade or a turbine blade, its structure and working environment are quite complex. Therefore, during the development process, it is necessary to measure the vibration stress of the blade to obtain the stable stress, resonance frequency, and resonance stress of the blade under the full-speed state, so as to evaluate the endurance and stress level of the blade under all working conditions. The fan blade is an important part of the aero-engine and is also a fault-prone part. To ensure the safe operation of the engine, usually during the engine design stage, a dynamic stress measurement and analysis test is carried out on the fan blade to evaluate and determine the allowable stress level and durability performance of the fan blade under all working conditions. Especially during the design and test stage of the aero-engine, the dynamic stress measurement of the fan blade is an important parameter for monitoring the safety of the aero-engine, and the safe and stable operation of the fan blade is an important guarantee for the reliability of the engine.

[0003] The dynamic stress measurement technology can truly reflect the deformation of the fan blade vibration during the test run, and is an important basis for ensuring the sufficient strength design of the engine fan blade. The basic principle of the fan blade vibration stress measurement is: paste a strain gauge on the blade surface. Under the working condition of the low-pressure turbine, use a lead wire to output the vibration signal to the test system through a slip ring electrical connector to directly obtain the vibration stress of the blade during rotation. Usually, the test working condition temperature of the low-pressure fan rotor does not exceed 200°C, so medium and normal temperature strain gauges are used for the dynamic stress measurement of the fan blade.

[0004] Due to the limitations of factors such as the complex working load of the low-pressure fan component, the interference of the high-pressure rotor component layout, and the spatial limitation of the low-pressure rotor structure, it is extremely difficult to design the test device and test lead installation structure for the dynamic stress measurement of the low-pressure fan blade in the entire machine state. Currently, the most common measurement method in engineering is to carry out a dynamic stress measurement test based on a remote sensing measurement system. However, during the entire dynamic stress measurement test process, the working temperature of the telemetry module is not allowed to exceed 80°C, which also poses strict requirements and severe challenges to the layout of the cooling system and the test device. During the dynamic stress measurement test process, once the telemetry module has an over-temperature fault, it usually causes the test to be interrupted, which will lead to a significant increase in the test cycle, and both the time cost and the economic cost will increase significantly.

[0005] Therefore, the design of an efficient and reliable telemetry module cooling solution is an effective guarantee for the success of the dynamic stress measurement test. By innovatively designing the cooling solution, the stability of the telemetry module during the test can be ensured, thereby improving the success rate of the fan dynamic stress measurement test and the reliability of the data. Summary of the Invention

[0006] In view of this, an embodiment of the present application provides a cooling device for a telemetry module for measuring the dynamic stress of a low-pressure fan of a whole turbofan engine, so as to ensure that the telemetry module does not exceed the limit temperature during the entire fan dynamic stress measurement test, thereby achieving the reliability and stability of the cooling solution.

[0007] The embodiment of the present application provides the following technical solutions: A cooling device for a telemetry module for measuring the dynamic stress of a low-pressure fan of a whole turbofan engine, comprising:

[0008] An engine cowl, a through hole is opened at the center position of the front end of the engine cowl, a tension bolt is arranged at the through hole, and an air vent for introducing air is arranged on the tension bolt;

[0009] A gas collecting box is arranged inside the engine cowl. The gas collecting box is a rotary cavity structure. The air inlet of the gas collecting box is communicated with the outlet side of the air vent of the tension bolt for introducing cooling air into the gas collecting box. The housing of the gas collecting box is axially connected to a first mounting seat of a telemetry module receiving device and a second mounting seat of the telemetry module receiving device in sequence, and the inner cavity of the gas collecting box forms a cooling air collecting cavity;

[0010] A plurality of impingement cooling holes are uniformly arranged along the circumferential direction on the outer shell of the first mounting seat of the telemetry module receiving device, so that the cooling air entering the cooling air collecting cavity forms a jet impingement cooling on the telemetry module transmitting device through the impingement cooling holes. The housing of the second mounting seat of the telemetry module receiving device is axially connected to a telemetry module receiving device adapter seat and a front bearing chamber seal seat in sequence to form a telemetry chamber. A plurality of pressure regulating holes are uniformly opened along the circumferential direction on the telemetry module receiving device adapter seat. The cooled gas enters the telemetry chamber and then is discharged from the pressure regulating holes into the inner cavity of the cowl.

[0011] According to an embodiment of the present application, it further includes an air duct. A plurality of the air ducts are uniformly distributed along the circumferential direction at the front end of the gas collecting box, and the air inlet ends of the air ducts extend to the outside of the engine cowl to face the engine inlet air flow.

[0012] According to an embodiment of the present application, it further includes a cooling duct. The cooling duct is arranged at the center position of the front end of the first mounting seat of the telemetry module receiving device. A plurality of cold air return holes are evenly arranged circumferentially at a position close to the outlet end of the cooling duct; the inlet end of the cooling duct penetrates through the front end of the housing of the air collecting box and is threadedly connected to the outlet end of the ventilation hole of the tension bolt, for introducing the cooling air at the center position of the engine hood into the cooling duct to form a reflux impact cooling on the central area of the first mounting seat of the telemetry module receiving device. After the reflux impact cooling, the cooling air enters the cooling air collecting cavity through the cold air return holes.

[0013] According to an embodiment of the present application, a lip seal structure is installed inside the front bearing cavity seal seat through the cooperation of a snap ring structure and an annular gasket.

[0014] According to an embodiment of the present application, an intake frame is arranged in the inner cavity of the engine hood. A plurality of exhaust holes are evenly arranged circumferentially along the inner edge of the intake frame. The gas discharged from the pressure regulating hole and entering the inner cavity of the hood flows through the exhaust holes and then enters the front cavity of the first-stage fan disk.

[0015] According to an embodiment of the present application, the diameter D1 of the ventilation hole on the tension bolt is 10 mm - 25 mm;

[0016] The inner diameter D2 of the cooling duct is 1.22 * D1 - 2.15 * D1.

[0017] According to an embodiment of the present application, a set of the cold air return holes are respectively arranged at multiple different axial positions of the cooling duct, and each set of cold air return holes is evenly distributed circumferentially; the total area A3 of all the cold air return holes is 1.55 * A1 - 2.35 * A1, where A1 is the area of the ventilation hole on the tension bolt.

[0018] According to an embodiment of the present application, the inner diameter D4 of the air guiding pipe is 0.75 * D1 - 0.95 * D1, and the number of the air guiding pipes is determined according to the maximum cooling air flow required for each working condition of the whole machine fan dynamic stress measurement test.

[0019] According to an embodiment of the present application, the aspect ratio L / D5 of the impact cooling hole is 3.2 - 7.5, and the diameter D5 of the impact cooling hole is 0.6 mm - 2.5 mm; a set of the impact cooling holes are respectively arranged at multiple different radius positions of the outer shell of the first mounting seat of the telemetry module receiving device, and each set of impact cooling holes is evenly arranged circumferentially; the total area A5 of all the impact cooling holes is 0.7 * A - 0.95 * A, where A is the sum of the total flow areas of several air guiding pipes and the area of the ventilation hole on the tension bolt.

[0020] According to an embodiment of the present application, the total area A6 of multiple said pressure regulating holes is 0.65*A5 - 2.25*A5, where A5 is the total area of said impact cooling holes; the total area A7 of multiple said exhaust holes is 3.5*A6 - 15.0*A6.

[0021] The objective of the present invention is to provide a telemetry cooling solution for dynamic stress measurement, specifically relating to a cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of a turbofan engine as a whole, so as to ensure that the telemetry module does not exceed the limit temperature during the entire fan dynamic stress measurement test, thereby achieving the reliability and stability of the cooling solution. The present invention ensures the reliability of the telemetry module cooling solution through an innovative design of the air system cooling flow path, specifically as follows: By introducing air from the central area of the engine inlet cowl, relying on the pressure difference between the total pressure of the air flow at the cowl inlet and the static pressure at the root of the outlet of the engine inlet strut, the cooling air is driven into the telemetry cavity for impact cooling, taking away the heat generated by the telemetry module itself and the heat rise due to wind resistance, so as to ensure that the telemetry module does not exceed the limit temperature during the entire fan dynamic stress measurement test, which is beneficial to ensuring the stability of the telemetry module test system during the test, thereby improving the test success rate and the reliability of the data.

[0022] Compared with the conventional cooling solution for the telemetry module of the fan dynamic stress measurement, the solution provided by the present invention, on the one hand, does not require the test bench to provide additional cooling air, nor does it require additional air intake pipes; on the other hand, the modification of the existing structure of the engine during testing is small, which will not cause high processing costs, and at the same time, the assembly difficulty and complexity are relatively low.

[0023] The solution provided by the present invention has the characteristics of high cooling reliability, low cost, and small assembly difficulty, and can be widely applied to the dynamic stress test of other types of aeroengines. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a two-dimensional structural schematic diagram of the cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of a turbofan engine as a whole in the embodiment of the present invention;

[0026] Figure 2 It is a partial enlarged structural schematic diagram of the cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of a turbofan engine as a whole in the embodiment of the present invention;

[0027] Figure 3It is a schematic diagram of the air cooling flow path of the cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine in the embodiment of the present invention;

[0028] Among them, 1 - tension bolt, 2 - engine cowl, 3 - ventilation hole, 4 - air intake pipe, 5 - air collecting box, 6 - first mounting seat of the telemetry module receiving device, 7 - second mounting seat of the telemetry module receiving device, 8 - adapter seat of the telemetry module receiving device, 9 - pressure regulating hole, 10 - cold air return hole, 11 - cooling air collecting cavity, 12 - impact cooling hole, 13 - telemetry cavity, 14 - inner cavity of the cowl, 15 - lip seal structure, 16 - front bearing cavity seal seat, 17 - front cavity of the first stage disk of the fan, 18 - front rim clearance of the first stage disk of the fan, 19 - engine intake strut, 20 - snap ring structure, 21 - telemetry module receiving device, 22 - telemetry module transmitting device, 23 - intake frame, 24 - low-pressure drive shaft of the engine, 25 - annular gasket, 26 - mounting seat of the #1 pivot bearing, 27 - exhaust hole, 28 - adjustment bracket, 29 - mounting seat of the telemetry module transmitting device; 30 - front bearing cavity; 31 - #1 pivot bearing. Specific embodiments

[0029] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. The technical solutions of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figures 1 - 3 shown, the embodiment of the present invention provides a cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine, including:

[0032] The engine cowl 2, a through hole is opened at the center position of the front end of the engine cowl 2, a tension bolt 1 is arranged at the through hole, and a ventilation hole 3 for air intake is arranged on the tension bolt 1;

[0033] A gas collecting box 5 is arranged inside the engine hood 2. The gas collecting box 5 has a rotary cavity structure. The air inlet of the gas collecting box 5 is communicated with the outlet side of the ventilation hole 3 of the tension bolt 1 for introducing cooling gas into the gas collecting box 5. The housing of the gas collecting box 5 is axially connected with a first mounting seat 6 of a telemetry module receiving device and a second mounting seat 7 of the telemetry module receiving device in sequence. The inner cavity of the gas collecting box 5 forms a cooling gas collecting cavity 11. Among them, the first mounting seat 6 of the telemetry module receiving device and the second mounting seat 7 of the telemetry module receiving device are used for mounting the telemetry module receiving device 21.

[0034] A plurality of impact cooling holes 12 are uniformly arranged on the outer shell of the first mounting seat 6 of the telemetry module receiving device in the circumferential direction, so that the cooling gas entering the cooling gas collecting cavity 11 forms a jet impact cooling on the telemetry module transmitting device 22 through the impact cooling holes 12. The housing of the second mounting seat 7 of the telemetry module receiving device is axially connected with a telemetry module receiving device adapter seat 8 and a front bearing cavity sealing seat 16 in sequence to form a telemetry cavity 13. A plurality of pressure regulating holes 9 are uniformly arranged on the telemetry module receiving device adapter seat 8 in the circumferential direction. The cooled gas enters the telemetry cavity 13 and then is discharged from the pressure regulating holes 9 into the hood inner cavity 14. Among them, the telemetry module transmitting device 22 is rotatable and is connected to an adjusting bracket 28 and a telemetry module transmitting device mounting seat 29 through a bolt assembly. The telemetry module transmitting device mounting seat 29 is connected to the engine low-pressure drive shaft 24 through a transmission spline structure.

[0035] In one embodiment, an air guide pipe 4 is further included. A plurality of the air guide pipes 4 are uniformly distributed along the circumference at the front end of the gas collecting box 5, and the air inlet ends of the air guide pipes 4 extend to the outside of the engine hood 2.

[0036] During specific implementation, a certain number of through holes are evenly distributed along the circumference of the engine hood 2 to cooperate with a plurality of the same air guide pipes 4 evenly distributed along the circumference at the front end of the gas collecting box 5 to pass through, so as to form a cooling channel.

[0037] In another embodiment, a cooling duct is further included. The cooling duct is arranged at the center position of the front end of the first mounting seat 6 of the telemetry module receiving device. A plurality of cold air return holes 10 are uniformly arranged along the circumference at a position close to the outlet end of the cooling duct. The air inlet end of the cooling duct penetrates through the front end of the housing of the gas collecting box 5 and is threadedly connected to the outlet end of the ventilation hole 3 of the tension bolt 1, so as to introduce the cooling gas at the center position of the engine hood 2 into the cooling duct to form a return impact cooling on the central area of the first mounting seat 6 of the telemetry module receiving device. After the return impact cooling, the cooling gas enters the cooling gas collecting cavity 11 through the cold air return holes 10. The telemetry module receiving device 21 is mounted on the first mounting seat 6 of the telemetry module receiving device.

[0038] During specific implementation, the end of the cooling duct connected to the air inlet of the air collecting box 5 extends into the interior of the air collecting box 5, and a plurality of cold air return holes 10 are uniformly arranged in the circumferential direction of the extended part. The total flow area of the plurality of cold air return holes 10 should be large enough to ensure that there is no throttling phenomenon; the other end of the cooling duct is internally provided with threads for connecting with the tension bolt 1.

[0039] In a preferred embodiment, a set of the cold air return holes 10 are respectively arranged at a plurality of different axial positions of the cooling duct, and each set of cold air return holes 10 is uniformly distributed in the circumferential direction; the total area A3 of all the cold air return holes 10 is 1.55*A1 - 2.35*A1, where A1 is the area of the ventilation hole 3 on the tension bolt 1.

[0040] Preferably, the air collecting box 5, the first mounting seat 6 of the telemetry module receiving device, and the second mounting seat 7 of the telemetry module receiving device are axially positioned and connected by bolt connection to form a cooling air collecting cavity 11.

[0041] In this embodiment, the functions of the tension bolt 1 are as follows: (1) The tension bolt connects the engine hood and the cooling duct together; (2) A ventilation hole is provided in the center of the tension bolt, so that the cooling air at the center of the hood enters the interior of the cooling duct and has a cooling effect on the first mounting seat of the telemetry module receiving device.

[0042] In this embodiment, an air inlet frame 23 is provided in the inner cavity of the engine hood 2. The cooling air enters the cooling air collecting cavity 11 through the ventilation hole 3 on the tension bolt 1 and the air guiding pipe 4, and through a plurality of impact cooling holes 12, the cooling air forms a strong jet impact cooling on the telemetry module transmitting device 22 from the cooling air collecting cavity 11 through the arrayed impact cooling holes 12, thereby effectively reducing the temperature of the telemetry module; then, the cooling air flow enters the telemetry cavity 13 and then flows out from a plurality of pressure regulating holes 9 on the adapter seat 8 of the telemetry module receiving device; the gas discharged from the pressure regulating holes 9 enters the inner cavity 14 of the hood, and a plurality of exhaust holes 27 are uniformly arranged in the circumferential direction along the inner side mounting edge of the air inlet frame 23. The gas in the inner cavity 14 of the hood then flows into the front cavity 17 of the first-stage fan disk through the exhaust holes 27 and is discharged from the front wheel rim gap 18 of the first-stage fan disk on the outer shell of the front cavity 17 of the first-stage fan disk.

[0043] Preferably, in this embodiment, the total flow area of ​​the pressure regulating hole 9 should be appropriate to ensure that the telemetry cavity can establish a certain cavity pressure to provide appropriate pressure for the sealing of the 1# fulcrum bearing 31; preferably, the inner side of the front bearing cavity sealing seat 16 is equipped with a lip-type sealing structure through a retaining ring structure 20 and an annular gasket 25, and the lip-type sealing structure cooperates with the outer ring surface of the low-pressure drive shaft to form a contact dynamic seal, that is, the front seal of the 1# fulcrum bearing 31, and the 1# fulcrum bearing 31 is fixed on the 1# fulcrum bearing mounting seat 26; preferably, the minimum pressure bearing capacity of the lip-shaped sealing structure is ±20kPa to adapt to the pressure changes in the telemetry cavity under different working conditions during the dynamic stress measurement test, and provide reliable guarantee for the lubricating oil seal of the front bearing cavity 30.

[0044] Preferably, exhaust holes of sufficient area are arranged on the mounting edges of the frame of the turbofan engine air intake support plate 19 and the front axle cavity seat to ensure that the static pressure of the inner cavity 14 of the cap cover is almost the same as the static pressure of the front cavity 17 of the fan first-stage disk, so as to drive the cooling air into the telemetry cavity 13 for impact cooling by relying on the pressure difference between the total airflow pressure at the inlet of the cap cover and the airflow static pressure at the outlet root of the engine air intake support plate 19, and take away the heat generated by the telemetry module itself and the heat caused by the wind resistance temperature rise, thereby ensuring that the telemetry module does not exceed the limit temperature during the entire fan dynamic stress measurement test, which is beneficial to ensure the stability of the telemetry module test system during the test, thereby improving the test success rate and the reliability of the data.

[0045] In one embodiment, the diameter D1 of the vent hole on the tightening bolt is 10 mm-25 mm; the inner diameter D2 of the cooling duct is 1.22*D1-2.15*D1.

[0046] In one embodiment, the inner diameter D4 of the air duct is 0.75*D1-0.95*D1, and the number of the air ducts is determined according to the maximum cooling air flow required for each working condition of the whole machine fan dynamic stress measurement test.

[0047] In one embodiment, the aspect ratio L / D5 of the impact cooling hole is 3.2-7.5, and the diameter D5 of the impact cooling hole is 0.6mm-2.5mm; a group of the impact cooling holes is respectively arranged at multiple different radial positions of the outer shell of the first mounting seat of the telemetry module receiving device, and the impact cooling holes of each group are evenly arranged along the circumferential direction; the total area A5 of all the impact cooling holes is 0.7*A-0.95*A, where A is the sum of the total flow area of ​​several of the air ducts and the ventilation hole area on the tightening bolt.

[0048] In one embodiment, the total area A6 of the plurality of pressure regulating holes is 0.65*A5 - 2.25*A5, where A5 is the total area of the impingement cooling holes; the total area A7 of the plurality of exhaust holes is 3.5*A6 - 15.0*A6.

[0049] In the embodiment of the present invention, by providing the air inlet pipe and the cooling duct that meet the above geometric dimension requirements, two cooling air flow paths are respectively formed to draw air from the central area of the engine cowl inlet at the same time; by providing the cold air return holes that meet the above geometric dimension requirements, the mixing loss when the two parts of cooling air enter the air collecting cavity can be reasonably controlled; by providing the impingement cooling holes that meet the above geometric dimension requirements, the cold air flow path can be more effectively organized to achieve a "double" high-efficiency cooling effect on the left side and the outer side of the first mounting seat housing of the telemetry module receiving device; by providing the pressure regulating holes that meet the above geometric dimension requirements, the cavity pressure fluctuation range of the telemetry cavity under different working conditions during the dynamic stress measurement test can be reasonably controlled, providing a reliable guarantee for the sliding seal of the front bearing cavity. In summary, the present invention mainly utilizes the pressure difference between the total pressure of the air flow at the cowl inlet and the static pressure of the air flow at the root of the outlet of the zero-stage guide vane of the fan to construct a pressure difference self-driven telemetry module cooling device, which does not require additional cooling air to be drawn from the test bench. While achieving stable cooling of the telemetry module under various test conditions, it can also provide reliable sliding seal for the front bearing cavity of the engine.

[0050] The above is only the specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A cooling device for a telemetry module for measuring the dynamic stress of a low-pressure fan of a turbofan engine as a whole, characterized in that, Comprising: An engine hood, a through hole is opened at the center position of the front end of the engine hood, a tension bolt is arranged at the through hole, and an air vent hole for air intake is arranged on the tension bolt; A gas collecting box is arranged inside the engine hood. The gas collecting box is of a rotary cavity structure. The air inlet of the gas collecting box is communicated with the air outlet side of the air vent hole of the tension bolt for introducing cooling air into the gas collecting box. The housing of the gas collecting box is axially connected with a first mounting seat of a telemetry module receiving device and a second mounting seat of the telemetry module receiving device in sequence, and a cooling air collecting cavity is formed inside the gas collecting box; A plurality of impact cooling holes are uniformly arranged on the outer side housing of the first mounting seat of the telemetry module receiving device in the circumferential direction, so that the cooling air entering the cooling air collecting cavity forms a jet impact cooling on the telemetry module transmitting device through the impact cooling holes. The housing of the second mounting seat of the telemetry module receiving device is axially connected with a telemetry module receiving device adapter seat and a front bearing cavity sealing seat in sequence to form a telemetry cavity. A plurality of pressure regulating holes are uniformly opened on the telemetry module receiving device adapter seat in the circumferential direction. The cooled gas enters the telemetry cavity and then is discharged from the pressure regulating holes into the inner cavity of the hood.

2. The cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine according to claim 1, characterized in that An air guiding pipe is further included. A plurality of the air guiding pipes are uniformly distributed along the circumference at the front end of the gas collecting box. The air inlet end of the air guiding pipe extends to the outside of the engine hood to face the engine inlet air flow.

3. The cooling device for the telemetry module for measuring the dynamic stress of the low-pressure fan of the whole turbofan engine according to claim 2, wherein, A cooling conduit is further included. The cooling conduit is arranged at the center position of the front end of the first mounting seat of the telemetry module receiving device. A plurality of cold air return holes are uniformly arranged along the circumference at a position close to the outlet end of the cooling conduit. The air inlet end of the cooling conduit penetrates through the front end of the housing of the gas collecting box and is threadedly connected with the air outlet end of the air vent hole of the tension bolt for introducing the cooling air at the center position of the engine hood into the cooling conduit to form a return impact cooling on the central area of the first mounting seat of the telemetry module receiving device. After the return impact cooling, the cooling air enters the cooling air collecting cavity through the cold air return holes.

4. The cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine according to claim 1, characterized in that, A lip seal structure is installed inside the front bearing cavity sealing seat through the cooperation of a snap ring structure and an annular gasket.

5. The cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine according to claim 1, characterized in that, An air intake frame is arranged inside the inner cavity of the engine hood. A plurality of exhaust holes are uniformly arranged along the circumference on the inner mounting edge of the air intake frame. The gas discharged from the pressure regulating holes and entering the inner cavity of the hood flows through the exhaust holes and then enters the front cavity of the first-stage fan disk.

6. The cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine according to claim 3, characterized in that, The diameter D1 of the air vent hole on the tension bolt is 10 mm - 25 mm; The inner diameter D2 of the cooling conduit is 1.22*D1 - 2.15*D1.

7. The cooling device for the telemetry module of the dynamic stress measurement of the low-pressure fan of the whole turbofan engine according to claim 6, characterized in that, A group of the cold air return holes are respectively arranged at a plurality of different axial positions of the cooling conduit, and each group of cold air return holes is uniformly distributed along the circumference; the total area A3 of all the cold air return holes is 1.55*A1 - 2.35*A1, where A1 is the area of the air vent hole on the tension bolt.

8. The cooling device for the telemetry module for measuring the dynamic stress of the low-pressure fan of the whole turbofan engine according to claim 6, characterized in that, The inner diameter D4 of the air guiding pipe is 0.75*D1 - 0.95*D1, and the number of the air guiding pipes is determined according to the maximum cooling air flow required for each working condition of the whole machine fan dynamic stress measurement test.

9. The cooling device for the telemetry module for measuring the dynamic stress of the low-pressure fan of the whole turbofan engine according to claim 2, characterized in that The aspect ratio L / D5 of the impingement cooling holes is 3.2 - 7.5, and the diameter D5 of the impingement cooling holes is 0.6 mm - 2.5 mm; a set of the impingement cooling holes are respectively arranged at multiple different radius positions on the outer shell of the first mounting seat of the telemetry module receiving device, and the impingement cooling holes in each group are uniformly arranged circumferentially; the total area A5 of all the impingement cooling holes is 0.7*A - 0.95*A, where A is the sum of the total flow areas of several of the air guide pipes and the ventilation hole areas on the tension bolts.

10. The cooling device for the telemetry module for measuring the dynamic stress of the low-pressure fan of the whole turbofan engine according to claim 5, characterized in that, The total area A6 of the multiple pressure regulating holes is 0.65*A5 - 2.25*A5, where A5 is the total area of the impingement cooling holes; the total area A7 of the multiple exhaust holes is 3.5*A6 - 15.0*A6.

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