A complete optical fiber lead structure, assembly method and measurement system for measuring temperature and vibration stress of turbine rotor blades

Abstract

The present invention discloses a complete optical fiber lead structure, assembly method and measurement system for measuring temperature and vibration stress of turbine rotor blades, and relates to the technical field of temperature and vibration stress testing. The optical fiber lead structure includes a rotor lead structure section, a smooth ring positioning and switching structure section and a stator lead structure section. The rotor lead structure section includes a blade-disk rear transition structure, a disk-inner shaft transition structure and an inner shaft lead channel; the smooth ring positioning and switching structure section includes a front shaft end nut belt rotation structure and a stator positioning structure; the stator lead structure section leads the optical fiber to the outer wall of the engine based on a hollow support plate. The assembly method of the invention includes the steps of optical fiber laying, lead connection, smooth ring positioning and assembly, stator lead lead and complete machine debugging. The present invention solves the problems of limited radial and axial dimensions of the engine rotor, uncoordinated deformation of the rotor and stator, and smooth transition of the optical fiber lead surface, and improves the survival rate of the optical fiber lead of the entire engine.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber installation in the temperature and vibration stress test of the rotor blade of an aero-engine, relates to the application and wiring of the optical fiber sensing technology in the aero-engine test, and particularly relates to a complete optical fiber lead structure, an assembly method and a measurement system for measuring the temperature and vibration stress of the turbine rotor blade. While making full use of the configuration of the original air intake casing and the front shaft end nut of the engine, reliable positioning of the smooth ring is achieved, the problems of limited radial and axial dimensions of the engine rotor, uncoordinated deformation of the rotor and stator, and smooth transition of the optical fiber lead surface are solved, and the survival rate of the optical fiber lead of the complete engine is improved. Background Art

[0002] As the core power unit of aircraft, the working environment of its key parts is very harsh, including multiple harsh conditions such as high temperature, high pressure, high-speed rotation and strong vibration. In particular, the turbine components are often in a working state of high temperature (up to nearly 2000℃), high pressure (tens of atmospheres) and high-speed rotation (speed can reach tens of thousands of revolutions per minute). Such a complex working environment not only places strict requirements on the materials, structure and manufacturing process of the turbine rotor blades, but also poses extremely high challenges to the temperature measurement and vibration stress testing of the blades. In addition, the operation of turbine components involves strong interaction and coupling between multiple disciplines such as aerodynamics, thermal power, structure, strength, and materials, resulting in the inability to fully predict and evaluate the operating state of the turbine rotor by relying solely on theoretical calculations or numerical simulations. Therefore, in order to ensure the reliable operation of the turbine rotor in a complex environment, its performance, function, strength and reliability must be fully corrected and verified through actual test runs. For example, the turbine temperature field directly determines the strength and service life of the component materials, but its distribution is affected by many factors such as gas temperature, flow state, blade cooling structure, etc. Similarly, the vibration stress of the turbine blades is also closely related to the actual working state of the whole machine. Currently, only by relying on the vibration stress measurement of the whole machine (or the core machine that can reflect the working environment of the whole machine) can a more accurate vibration stress value be obtained.

[0003] In traditional turbine rotor testing technology, temperature measurement mainly relies on thermocouples, while vibration stress measurement mainly uses strain gauges. However, for the temperature and vibration stress measurement of small aircraft engine turbine rotor blades, these traditional methods have many technical difficulties: first, the harsh working environment, including high temperature, high speed, rich oil, etc.; second, the limited structural space, resulting in small lead space and poor reliability of test lead signal transmission; finally, the installation space of traditional thermocouples and strain gauges is small, and it is difficult to arrange cables at multiple measurement points, making it difficult to achieve comprehensive measurement of blade temperature field and vibration stress field.

[0004] Fiber optic sensors, especially those based on fiber Bragg gratings, can be serially engraved on an optical fiber in batches according to the designed spacing, so that multiple temperature and vibration stress measurement points can be arranged on a single blade. The filaments are thin and light in mass, making it easier to achieve multi-point field measurement than traditional thermocouples and strain gauges, which makes it possible to measure the temperature field and vibration stress field of the blade in a refined manner. However, optical fiber is very brittle and easily fails once it is bent. Secondly, in a complex structure such as a turbine blade, the deformation incoordination caused by the relative motion between the rotor and the stator and the complex flow field environment in the rotating system (such as oil mist and impact airflow) further increase the measurement challenges. How to achieve the layout and protection of optical fiber and the reliable transmission of signals also puts higher requirements on the optical fiber leads.

[0005] In summary, the application of optical fiber sensors in the measurement of temperature and vibration stress of turbine rotor blades of small aircraft engines has significant potential. Its high sensitivity, multi-point capability and anti-electromagnetic interference characteristics can effectively supplement the shortcomings of traditional technologies. However, how to comprehensively consider the structural space and optical fiber lead requirements of small aircraft engines, design a complete optical fiber lead structure suitable for turbine rotor blade temperature and vibration stress measurement, and make it meet the special requirements of optical fiber lead and ensure the long-term reliable operation of the measurement system, so as to achieve accurate and reliable measurement of blade temperature and vibration stress, and provide key data support for the design, optimization and condition monitoring of turbine blades, is still a key technical problem that needs to be solved urgently. Summary of the invention

[0006] 1. Purpose of the invention

[0007] In view of the above technical defects existing in the prior art, the present invention provides a complete optical fiber lead structure, assembly method and measurement system for measuring temperature and vibration stress of turbine rotor blades, including a rotor lead structure, a smooth ring positioning and switching structure and a stator lead structure. The rotor lead structure realizes a smooth lead transition from the turbine rotor blade flow channel-turbine disc cavity-shaft to the smooth ring rotor. The smooth ring positioning and switching structure realizes reliable positioning and switching of the smooth ring, ensures stable collection and output of the test signal, and the stator lead structure realizes the lead from the smooth ring stator to the outer wall of the engine casing, thereby completing the whole machine lead in the engine. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades in the present invention is compact, the lead transition is smooth, and the original structure configuration of the engine is fully utilized. It is practically applicable to engine rotors with limited radial and axial dimensions, and can avoid the test hidden dangers caused by the uncoordinated axial deformation of the engine rotor and stator, and reduce the failure rate of optical fiber and smooth ring. It has the advantages of simple structure, easy installation, maintenance and replacement, and has broad application prospects for aviation engines.

[0008] (II) Technical solution

[0009] In order to achieve the purpose of the invention and solve the technical problems, the present invention adopts the following technical solutions:

[0010] The first invention object of the present invention is to provide a complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades, which is used to realize the layout, protection and reliable signal transmission of optical fiber leads in the temperature and vibration stress measurement system of small aircraft engine turbine rotor blades, and at least includes a rotor lead structure section, a smooth ring positioning and switching structure section and a stator lead structure section, specifically:

[0011] The rotor lead structure section is used to lead the sensor optical fiber from the surface of the turbine blade to the smooth ring rotor at the front end of the turbine rotor shaft, and includes a blade-disk rear transition structure, a disk rear-shaft inner transition structure and an inner shaft lead channel, wherein:

[0012] The blade-disk rear transition structure at least includes a blade-disk rear transition inclined hole and a disk rear lead groove, wherein: the blade-disk rear transition inclined hole extends backward from the turbine blade root to the rear end face of the disk, and the disk rear lead groove passes through the dynamic balancing boss on the rear end face of the disk and extends radially, and is used to guide the optical fiber to smoothly transition from the blade root and the rear end face of the disk to the central hub area of ​​the rear end face of the disk in sequence;

[0013] The rear-disk-inside-shaft transition structure at least includes a ball nut and a locking piece, wherein: the ball nut is arranged on the central hub on the rear end face of the wheel disc, and its outer wall is designed as a spherical arc surface structure with the same outer diameter as the central hub, and a through hole connected to the inner lead-in channel of the shaft is arranged in the center; the locking piece has the same outer diameter as the ball nut, is arranged between the ball nut and the central hub, and a lead-in groove is arranged on the outer edge; the optical fiber led out from the rear-disk lead-in groove smoothly transitions to the inner lead-in channel of the shaft through the locking piece lead-in groove and the central through hole of the ball nut;

[0014] The in-shaft lead-in channel is a hollow channel disposed inside the turbine rotor shaft and axially penetrated, and is used to accommodate and protect the optical fiber and guide it from the rear end of the shaft to the front end of the shaft;

[0015] The smooth ring positioning and switching structure section is used to realize reliable transmission of optical fiber signals from the rotor to the stator, and includes a smooth ring rotor switching structure and a smooth ring stator positioning structure, wherein:

[0016] The smooth ring rotor transfer structure is designed based on the front shaft end nut of the turbine rotor shaft, and a belt rotation structure in the form of a groove or a slot is arranged on the front shaft end nut. The smooth ring rotor is coaxially installed in the front end inner cavity of the lead wire channel in the shaft, and a smooth ring shift fork is arranged to be embedded in the belt rotation structure to achieve synchronous rotation with the turbine rotor, and an axial gap is reserved between the shift fork and the rear end surface of the belt rotation structure to avoid collision and damage caused by uncoordinated axial deformation of the engine rotor and stator;

[0017] The smooth ring stator positioning structure is arranged in the inner casing of the straight section of the engine air intake casing, and includes a plurality of positioning bosses arranged on the inner wall of the inner casing and circumferentially discretely evenly distributed, for realizing radial and axial positioning of the smooth ring stator, the inner cylindrical surface of the boss cooperates with the outer cylindrical surface of the smooth ring stator to realize radial positioning, and the rear end surface of the boss fits with the end surface of the smooth ring stator to realize axial positioning;

[0018] The stator lead structure section is formed as an intake casing lead channel based on the hollow support plate between the inner casing and the outer casing of the engine intake casing, which is used to lead the optical fiber from the smooth ring stator through the internal cavity of the hollow support plate to the outer wall of the intake casing.

[0019] The second invention object of the present invention is to provide an assembly method of the complete optical fiber lead structure for measuring the temperature and vibration stress of the turbine rotor blades, which at least comprises the following steps:

[0020] SS1. Installation and layout of fiber optic sensors:

[0021] Arranging optical fiber sensors on the surface or internal measuring points of turbine rotor blades, wherein the optical fiber sensors include optical fiber grating sensors for temperature measurement and optical fiber sensors for stress measurement;

[0022] SS2. Assembly of rotor lead structure segment:

[0023] The blade-disk rear transition structure, the disk rear-shaft transition structure and the shaft lead-in channel are installed in sequence: first, the optical fiber is passed through the blade-disk rear transition inclined hole to be led out from the root of the turbine blade to the rear end face of the disk; then the optical fiber is laid out along the lead-in groove behind the disk to the central hub position; a locking piece with a lead-in groove and a ball nut with a central through hole are sequentially assembled on the central hub at the rear end face of the disk, so that the optical fiber smoothly transitions along the lead-in groove of the locking piece and the central through hole of the ball nut; finally, the optical fiber is passed through the shaft lead-in channel of the turbine rotor shaft to be led out from the rear end of the shaft to the front end of the shaft, and during the laying process, the optical fiber is ensured to be arranged loosely to adapt to the axial expansion and dynamic deformation during the operation of the engine;

[0024] SS3. Installation of smooth ring adapter structure:

[0025] A front shaft end nut with a groove or slotted belt-rotating structure is installed at the front end of the turbine rotor shaft, the smooth ring rotor is coaxially installed in the front end inner cavity of the shaft inner lead-in channel, the smooth ring shift fork is adjusted to be embedded in the belt-rotating structure, and a prescribed axial gap is reserved between the shift fork and the rear end surface of the belt-rotating structure; the optical fiber is guided from the shaft inner lead-in channel to the signal input end of the smooth ring rotor, and the optical fiber signal is transferred to the smooth ring stator through the smooth ring rotor;

[0026] SS4. Positioning and fixing of smooth ring stator:

[0027] The smooth ring stator is installed on the inner casing of the straight section of the engine air intake casing through the positioning boss, so that its outer cylindrical surface and the inner cylindrical surface of the boss are radially positioned and matched, and the axial position of the smooth ring stator is adjusted so that its end face and the rear end face of the boss are axially positioned and fitted; the smooth ring stator is fixed on the positioning boss by screws to ensure that the smooth ring stator is firmly installed;

[0028] SS5. Layout of stator lead structure:

[0029] Separate the intake cone section and the straight section of the intake casing for easy operation and observation, and lead the optical fiber from the smooth ring stator to the outer wall of the intake casing through the hollow support plate between the inner and outer casings; check and confirm that the bending radius of the optical fiber at each turning point meets the requirements and there is no kink or extrusion; set a sealing structure at the inlet and outlet of the hollow support plate to prevent oil mist, airflow or foreign matter from entering the channel;

[0030] SS6. Machine assembly and debugging stage:

[0031] The intake cone section is connected or welded to the straight section of the intake casing through flange bolts and the coaxiality is ensured to complete the assembly of the entire fiber optic lead in the engine under test; the fiber optic lead structure is inspected and debugged as a whole, including the integrity test of the fiber optic signal, the rotational stability test of the smooth ring switching structure, and the layout status of the optical fiber in the shaft channel, to ensure the smooth layout of the fiber optic lead, stable signal transmission and the firmness of the assembly of each component.

[0032] The third inventive object of the present invention is to provide a turbine rotor blade temperature and vibration stress measurement system, including the above-mentioned turbine rotor blade temperature and vibration stress measurement complete optical fiber lead-in structure of the present invention.

[0033] (III) Technical Effect

[0034] Compared with the prior art, the whole machine optical fiber lead structure, assembly method and measurement system for measuring temperature and vibration stress of turbine rotor blades of the present invention have the following beneficial and significant technical effects:

[0035] (1) The whole machine optical fiber lead structure of the present invention can realize the firm connection of the smooth ring by setting a smooth ring stator positioning structure in the air intake casing. The structure can realize the reliable radial and axial positioning of the smooth ring stator through multiple positioning bosses on the inner wall of the air intake casing, meeting the requirements of reliable tight connection of the smooth ring, and has the functions of smooth ring and whole machine vibration and ensuring stable signal transmission, solving the problem that the smooth ring is difficult to install on the rotor due to the size limitation of the engine rotor, and at the same time ensuring the coordination of the smooth ring and the whole machine vibration, enhancing the stability of signal transmission, and ensuring the long-term reliable operation of the optical fiber lead system in high speed and complex vibration environment.

[0036] (2) The smooth ring rotor transfer structure of the present invention adopts a belt-rotating structure set on the front shaft end nut, which can not only drive the smooth ring rotor and the turbine rotor to rotate synchronously, but also take into account the axial deformation coordination design through the design of reserved axial clearance, thereby avoiding axial collision between the engine rotor and the smooth ring rotor under working conditions, and effectively eliminating the risk of damage to the smooth ring caused by the uncoordinated axial deformation of the rotor and stator, ensuring the reliable operation of the smooth ring and improving the reliability and durability of the measurement system.

[0037] (3) The turbine lead structure and ball nut and locking plate lead structure of the present invention include the blade-disk rear transition inclined hole, the disk rear lead groove, the locking plate lead groove, the ball nut center through hole and the shaft lead channel, etc., which can realize the smooth lead-in of the optical fiber from the turbine blade-turbine disk cavity-shaft, minimize the bending radius and the number of bending times of the optical fiber, and reduce the optical fiber bending failure rate.

[0038] (4) The in-shaft lead structure of the present invention arranges the optical fiber lead in an axially through hollow channel inside the rotor shaft by drilling holes inside the shaft for lead-in, thereby reducing the impact of harsh environments such as oil mist and airflow on the outer wall, reducing the possibility of external contamination and physical damage to the optical fiber, and improving the optical fiber survival rate, thereby enhancing the protection effect of the optical fiber and the reliability of the measurement signal.

[0039] (5) The fiber optic lead structure of the present invention is designed with minimal modification based on the original engine component configuration. It has a simple and compact structure and is easy to install, maintain and replace. It has strong engineering practicality and promotion value and can be widely used in the field of temperature and vibration stress testing of aircraft engines, gas turbines and other rotating machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein:

[0041] Figure 1 The figure shows a schematic diagram of the structure of the whole optical fiber lead wire for measuring the temperature and vibration stress of the turbine rotor blade according to an embodiment of the present invention;

[0042] Figure 2 The figure shows a schematic diagram of the turbine blade-disk rear lead structure in an embodiment of the present invention;

[0043] Figure 3 The figure shows a schematic diagram of the blade-disk-ball nut and lock piece lead structure in an embodiment of the present invention;

[0044] Figure 4 The figure shows a cross-sectional schematic diagram of the in-shaft lead channel in an embodiment of the present invention;

[0045] Figure 5 The figure shows a schematic cross-sectional view of a smooth ring structure in an embodiment of the present invention;

[0046] Figure 6 The figure is a schematic diagram of the structure of the front axle end nut in an embodiment of the present invention;

[0047] Figure 7 Shown is a schematic diagram of a cross section of an air intake casing (excluding a hollow support plate) in an embodiment of the present invention;

[0048] Figure 8 The figure shows a schematic diagram of a straight section of an air intake casing in an embodiment of the present invention;

[0049] Fig. 9 The figure shows a schematic diagram of positioning and installing a smooth ring in an air intake casing in an embodiment of the present invention;

[0050] Fig.10 The figure shows the relative positions of the smooth ring and the hollow support plate in the embodiment of the present invention;

[0051] Fig.11 The figure shows the speed of the tested engine changing with time according to the embodiment of the present invention;

[0052] Fig.12 Shown is a diagram of the central wavelength signal of each measuring point changing with time according to an embodiment of the present invention;

[0053] Fig.13 The figure shows an assembly flow chart of the complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades in an embodiment of the present invention.

[0054] Description of reference numerals:

[0055] Optical fiber 100, blade-disk rear transition structure 10, blade-disk rear transition inclined hole 11, disk rear lead groove 12, ball nut 20, ball nut center through hole 21, locking plate 30, locking plate lead groove 31, shaft lead channel 40, shaft lead channel front section 41, shaft lead channel rear section 42, smooth ring 50, smooth ring rotor 51, smooth ring stator 52, smooth ring fork 53, radial positioning surface 54, axial positioning surface 55, first screw hole 56, front shaft end nut 60, groove 61, air intake casing 70, outer casing 71, hollow support plate 72, inner casing 73, straight section 731, air intake cone section 732, positioning boss 74, second screw hole 75. DETAILED DESCRIPTION

[0056] The present invention aims to provide a complete optical fiber lead structure, assembly method and measurement system for measuring temperature and vibration stress of turbine rotor blades, so as to solve the problems of limited radial and axial dimensions of engine rotors, uncoordinated deformation of rotors and stators, and smooth transition of optical fiber lead surfaces, and improve the survival rate of the complete optical fiber lead of the engine. In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the embodiment of the present invention. The described embodiments are part of the embodiments of the present invention, not all of the embodiments, and the described embodiments are exemplary and are intended to be used to explain the present invention, and cannot be understood as limiting the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Example 1: Complete optical fiber lead structure and measurement system

[0058] According to one embodiment of the present invention, the complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades of the present invention is used to realize the layout, protection and reliable transmission of optical fiber leads in the temperature and vibration stress measurement system of turbine rotor blades of small aircraft engines. The schematic diagram of the structure is shown in FIG. Figure 1 As shown, the engine under test can be, for example, a small single-shaft turbojet engine, which includes, in order from the measuring point to the outside of the engine, the following optical fiber lead-in sequence: blade-disk rear transition structure 10, ball nut 20 and lock piece 30 and shaft lead-in channel 40 (the three constitute the rotor lead-in structure section); smooth ring 50, front shaft end nut 60 (a smooth ring rotor transition structure) and air intake casing 70 (including a smooth ring stator positioning structure and a stator lead-in structure). The above-mentioned whole machine optical fiber lead-in structure can be divided into a rotor lead-in structure section, a smooth ring positioning and transition structure section and a stator lead-in structure section, wherein:

[0059] The rotor lead structure section is used to lead the sensor optical fiber from the turbine blade surface to the smooth ring rotor at the front end of the turbine rotor shaft, and includes a blade-disk rear transition structure 10, a disk rear-shaft internal transition structure and an internal shaft lead channel 40 in sequence, wherein: the blade-disk rear transition structure 10, in addition to the inherent blade body surface, rim surface and disk rear end surface of the measured turbine rotor, mainly includes a blade-disk rear transition inclined hole 11 from the rim to the disk rear end surface and a disk rear lead groove 12 at the dynamic balance boss on the disk rear end surface, such as Figure 2 As shown, smooth routing of the optical fiber from the blade body, blade root to the rear end surface of the turbine disk is achieved.

[0060] Preferably, the inclination angle of the blade-disk rear transition inclined hole 11 is determined according to the installation angle of the turbine blade, the geometric structure of the wheel disk, and the relative position between the blade root and the rear end face of the wheel disk, and the setting of the inclination angle should ensure that the bending radius of the optical fiber when transitioning from the blade root to the rear end face of the wheel disk is not less than the minimum bending radius allowed by the optical fiber, so as to avoid the failure of the optical fiber due to excessive bending. In addition, the depth and width of the rear lead groove 12 of the disk are determined according to the optical fiber diameter and the number of wirings, the inner wall of the groove is polished, and the groove extends from the dynamic balance boss on the rear end face of the wheel disk to the center hub direction, so as to ensure the smooth transition of the optical fiber 100 from the outer edge of the wheel disk to the center area of ​​the rear end face of the wheel disk.

[0061] The disc rear-shaft transition structure of the embodiment of the present invention includes at least a ball nut 20 and a locking plate 30, wherein: the outer diameter of the ball nut 20 is the same as the outer diameter of the center hub on the rear end face of the turbine disc, and is threadedly fixed on the center hub on the rear end face of the disc. Its outer wall is designed as a spherical arc surface structure with the same outer diameter as the center hub, and a ball nut center through hole 21 connected to the lead wire channel in the shaft is provided in the center. At the same time, a pair of planes are cut on the outer wall surface of the ball nut 20 to facilitate the application of assembly tightening torque. The locking plate 30 is arranged between the ball nut 20 and the center hub, and its outer edge is partially cut to form a locking plate lead wire groove 31, so as to ensure that the lead wire area maintains the same outer diameter as the rear end face of the turbine disc and the ball nut, such as Figure 3 The optical fiber 100 is smoothly guided from the rear end of the turbine disc to the rear end of the shaft through the ball nut 20 and the ball nut center through hole 21 of the locking piece 30 and the locking piece lead groove 31.

[0062] Preferably, the spherical outer wall of the ball nut 20 is the same as the outer diameter of the central hub, and its surface roughness is not greater than Ra0.8. The inner wall of the central through hole 21 of the ball nut is polished, and a circular arc transition structure is designed at least at the entrance of the through hole to ensure smooth transition of the optical fiber at the turning point. The depth and width of the locking plate lead groove 31 are determined according to the optical fiber diameter and the number of wirings. The inner wall of the groove is polished and aligned with the rear lead groove in the circumferential direction to ensure that the optical fiber led out from the rear lead groove 12 of the disk smoothly transitions from the locking plate lead groove 31 and the central through hole 21 of the ball nut to the lead channel in the shaft.

[0063] The in-shaft lead-in channel 40 is designed as follows Figure 4The hollow shaft shown is a hollow channel arranged inside the engine rotor shaft and axially penetrated, which is used to accommodate and protect the optical fiber and guide it from the rear end of the shaft to the front end of the shaft. Preferably, the inner diameter of the front section 41 of the lead-in channel in the shaft is larger than the inner diameter of the rear section 42, wherein the inner diameter of the front section is 7-10 mm, ensuring that the smooth ring rotor and the inner wall of the shaft form a clearance fit in the working state, and the inner diameter of the rear section is 5-7 mm, which takes into account the requirements of processing, lead assembly and strength. At the same time, the inner wall of the channel is preferably polished and a circular arc transition structure is designed at the diameter change. At the same time, the optical fiber is laid out in a loose arrangement in the channel to ensure that the optical fiber can adapt to the thermal expansion and dynamic deformation of the rotor shaft when the engine is running. The lead-in channel 40 in the shaft realizes smooth lead-in from the rear end face of the shaft to the smooth ring rotor. At this point, the lead-in from the turbine rotor blade measuring point to the smooth ring rotor is completed.

[0064] Preferably, the rotor lead structure segment of the embodiment of the present invention further includes a blade surface lead channel, which is a microgroove channel arranged on the surface of the turbine blade for laying sensor optical fiber. The laying path of the microgroove channel is optimized according to the blade profile and / or measuring point distribution, and the bottom and side walls of the microgroove are polished to reduce wear on the optical fiber.

[0065] In the whole machine optical fiber lead layout structure of the embodiment of the present invention, the smooth ring positioning and transition structure section is used to realize the reliable transmission of optical fiber signals from the rotor to the stator, including the smooth ring rotor transition structure and the smooth ring stator positioning structure. The smooth ring 50 includes two parts, the smooth ring rotor 51 and the smooth ring stator 52, which can be rotors and stators to each other. Considering the small radial size of the rotor of the tested engine and the narrow axial space at the front end, the side with the small radial size of the smooth ring is selected as the smooth ring rotor, so that most of the length of the smooth ring rotor can be assembled into the engine shaft, and at the same time, it is convenient to realize the smooth ring positioning and transition structure design with less modification. The smooth ring structure is as follows Figure 5 As shown, the right frame is the smooth ring rotor part, which can drive the smooth ring to rotate synchronously with the test rotor through the upper and lower smooth ring forks 53. The left frame is the smooth ring stator part, which includes radial / axial positioning surfaces and three screw connections evenly distributed in the circumference. The engine turbine rotor blade test signal is converted into a stator signal output after passing through the smooth ring, and reliable connection and positioning must be ensured.

[0066] The smooth ring rotor transfer structure in the embodiment of the invention is based on the original configuration of the engine front shaft end nut, and a belt rotation structure is designed on the front shaft end nut 60 to realize the synchronous rotation of the smooth ring rotor driven by the engine rotor. The structure is as follows: Figure 6The upper and lower grooves 61 shown in the figure, when assembled, the upper and lower two smooth ring forks 53 of the smooth ring rotor 51 are embedded in the grooves 61 as the belt rotating structure, which can also be a card slot or other similar structure, so that the engine rotor can drive the smooth ring fork 53 to rotate in the circumferential direction under the working state. After assembly, the smooth ring fork 53 is 1.5mm away from the rear end surface of the groove 61. This reserved amount fully considers the forward displacement of the engine rotor relative to the stator when the engine is in the working state, and avoids the smooth ring being hit by the engine rotor and failing under the working state. At this point, the smooth ring rotor is transferred.

[0067] As a further preference, the smooth ring rotor and the front shaft end nut are matched at the belt-rotating structure with a fork and groove interlocking design, the width of the fork matches the groove width of the belt-rotating structure, and the axial reserved gap between the fork and the rear end face of the belt-rotating structure is 1.5-2.0mm. The gap is precisely designed according to the axial deformation characteristics of the engine's rotor and stator to avoid collision and damage caused by the uncoordinated axial deformation of the rotor and stator when the engine is working.

[0068] In the smooth ring stator positioning structure of the embodiment of the present invention, the smooth ring stator 52 is firmly and reliably connected to three circumferentially discrete uniformly distributed positioning bosses on the inner side of the inner casing 73 in the straight section of the air intake casing 70. The air intake casing 70 is divided into an air intake cone section and a straight section. Correspondingly, its inner casing 73 is also divided into an air intake cone section 732 and a straight section 731. Figure 7 As shown in the figure, the straight section of the air intake casing 70 includes, from outside to inside, the outer casing 71 of the original configuration of the engine air intake casing, three hollow support plates 72 evenly distributed in the circumferential direction, and the inner casing 73, as well as three circumferentially discrete and evenly distributed positioning bosses 74 designed for the connection and positioning needs of the test smooth ring, as shown in FIG. Figure 8 As shown. The inner cylindrical surface of the positioning boss 74 cooperates with the radial positioning surface 54 of the smooth ring stator to achieve radial positioning of the smooth ring stator; the rear end surface of the positioning boss 74 fits closely with the axial positioning surface 55 of the smooth ring stator to achieve axial positioning, as shown in FIG. Fig. 9 The rear end surface of the positioning boss 74 is evenly distributed with three second screw holes 75 (as shown in FIG. Figure 8 As shown in FIG. 1 ), the smooth ring stator is also provided with three first screw holes 56 (as shown in FIG. Figure 5 As shown in the figure, the smooth ring stator and the engine air intake casing can be fastened by 3 M2 screws. The smooth ring is firmly connected and the radial and axial positioning are reliable, thus avoiding the problems of large vibration, unstable test signal and smooth ring failure caused by unreliable connection and positioning of the smooth ring when the engine is working. At this point, the positioning and transfer of the smooth ring stator are completed.

[0069] As a further preference, in the smooth ring stator positioning structure, the number of positioning bosses 74 is set to 3 to 6, and the circumferentially uniformly distributed intervals are optimized according to the working environment and vibration characteristics of the engine to ensure the radial and axial positioning accuracy of the smooth ring stator 52, while providing sufficient space for the lead-in operation of the optical fiber; and a threaded hole is provided on the rear end face of each positioning boss 74, and the smooth ring stator is fixed on the positioning boss by screws.

[0070] The stator lead structure of the embodiment of the present invention is based on the hollow support plate 72 between the inner casing and the outer casing of the engine intake casing to form an intake casing lead channel. The optical fiber 100 of the smooth ring stator 52 will pass through the discrete position of the positioning boss 74 and pass along the hollow support plate structure of the intake casing. Fig.10 As shown, the outer casing of the engine air intake casing is led out. So far, the whole machine optical fiber lead-in for measuring the temperature and vibration stress of the turbine rotor blades is completed.

[0071] In the whole machine optical fiber lead-in structure for measuring temperature and vibration stress of turbine rotor blades of the present invention, according to the temperature limit of the use of the smooth ring, the smooth ring positioning and transition structure is designed between the engine air intake casing and the rotor front shaft end with lower temperature; based on the original air intake casing configuration of the engine, the smooth ring stator positioning structure is designed to take into account the radial and axial positioning structure of the smooth ring stator, solving the problem that it is difficult to position the smooth ring rotor due to the limited radial size of small-sized rotors, while taking into account the lead-in design of the smooth ring stator; based on the original front shaft end nut configuration of the engine, the smooth ring rotor transition structure is designed to have a belt-rotating structure that drives the smooth ring rotor to rotate in a circumferential direction, solving the problem of the axial size of the smooth ring when installing it, and at the same time, in order to solve the problem of the reduced axial gap between the front shaft end nut belt-rotating structure and the smooth ring rotor caused by the uncoordinated axial deformation of the rotor and stator during the operation of the engine, a suitable axial gap is reserved and designed between the front shaft end nut belt-rotating structure and the smooth ring rotor, thereby avoiding the situation where the engine rotor and the smooth ring rotor are in axial contact under working conditions to generate excessive axial force that damages the slip ring.

[0072] The rotor lead structure includes a turbine rotor lead modification structure, a ball nut and a lock lead structure between the turbine rotor and the rear shaft end, and an inner shaft lead structure. The turbine rotor lead modification structure is designed with an inclined hole structure from the wheel rim flow channel to the rear end face of the wheel disc, which can achieve a smooth transition lead from the blade to the wheel disc, reduce the bending of the brittle optical fiber, and reduce the optical fiber failure rate.

[0073] Through the above-mentioned structural design, the complete optical fiber lead-in structure of the present invention can realize multi-point deployment of optical fiber measuring points and stable transmission of signals under the high temperature and high-speed rotation conditions of the turbine rotor blades of a small aircraft engine, solving the problems of limited space, uneven optical fiber wiring, and uncoordinated deformation of rotors and stators of traditional measurement methods in high temperature environments. At the same time, it improves the survival rate of the optical fiber and the reliability of the measurement signal, and has the characteristics of compact structure and easy installation and maintenance.

[0074] On the basis of the whole machine optical fiber lead structure for measuring the temperature and vibration stress of the turbine rotor blades provided in the embodiment of the present invention, the present invention also provides a turbine rotor blade temperature and vibration stress measurement system including the whole machine optical fiber lead structure, the system includes the optical fiber measurement point layout on the turbine rotor blades, the optical fiber signal acquisition device and the data processing unit, which can realize high-precision and real-time monitoring of the temperature and vibration stress of the turbine blades during the operation of the small aircraft engine. During the operation of the system, the optical fiber sensor is laid in the key area of ​​the turbine blade according to the preset layout scheme, and the optical fiber lead is used to pass through the blade-disk rear transition structure, the disk rear-shaft transition structure and the shaft lead channel in sequence, and finally transmit the optical fiber signal to the smooth ring rotor located at the front shaft end of the engine. The optical fiber signal is transferred between the smooth ring rotor and the smooth ring stator to achieve stable transmission from the rotor part to the stator part, and is further guided to the engine external signal acquisition device along the hollow support plate of the air intake casing through the stator lead structure.

[0075] The whole machine optical fiber lead structure for measuring turbine rotor blade temperature and vibration stress in this embodiment has been effectively verified through testing. Under the whole machine optical fiber lead structure in this embodiment, the measured test signal can achieve stable output, such as Fig.11 and Fig.12 shown.

[0076] Fig.11 The figure shows the time-varying speed of the tested engine according to the embodiment of the present invention. The figure reflects the speed change of the engine during the test, wherein the engine speed starts from a stationary state, undergoes acceleration, steady-state operation, and re-speeding stages, and can reach up to 20,000 r / min. Through the speed change data, the working stability of the optical fiber lead structure provided by the present invention under different speed conditions can be verified, and the temperature and vibration stress response characteristics can be analyzed.

[0077] Fig.12The central wavelength signal diagram of each measuring point over time in an embodiment of the present invention is shown. The diagram shows the change of the central wavelength of the fiber Bragg grating at different measuring points during the operation of the engine. The wavelength of each measuring point shows different response trends with the change of the engine speed, reflecting the change of the blade surface temperature and vibration stress. The curve of the central wavelength change over time of measuring points 1 to 7 shows that at each stage of the engine speed change, the wavelength signals of different measuring points can clearly show the real-time change trend of temperature and stress, verifying the reliability and accuracy of the measurement system of the present invention.

[0078] In addition, this measurement system can be combined with the engine status monitoring and health management system to use the measured temperature and vibration stress data for real-time analysis and prediction, provide early fault warning, optimize the engine operation strategy, and improve the overall engine operation safety and economy.

[0079] Example 2: Complete optical fiber lead assembly solution

[0080] The design of the whole machine lead structure in the embodiment 1 of the present invention fully considers the feasibility of the whole machine optical fiber lead assembly, and its matching whole machine optical fiber lead assembly scheme is as follows: Fig.13 As shown, the specific steps include:

[0081] SS1. Installation and layout of fiber optic sensors:

[0082] First, fiber optic sensors are laid on the surface or inside of turbine rotor blades. The fiber optic sensors include fiber grating sensors for temperature measurement and fiber optic sensors for stress measurement. During the fiber optic laying process, it is necessary to ensure that it fits tightly with the blade surface. The layout of the microgroove channel should ensure a smooth transition of the fiber optic in the blade root area, and reserve sufficient fiber length for subsequent fusion and connection.

[0083] SS2. Assembly of rotor lead structure segment:

[0084] The blade-disk rear transition structure, the disk rear-shaft transition structure, and the shaft lead channel are installed in sequence. The specific steps are as follows: pass the optical fiber through the blade-disk rear transition inclined hole to lead it from the root of the turbine blade to the rear end face of the disk; lay the optical fiber along the lead groove behind the disk to make it smoothly transition to the center hub area at the rear end of the disk; install the locking piece with the lead groove and the ball nut with the center through hole on the center hub at the rear end face of the disk in sequence to ensure that the optical fiber smoothly transitions to the shaft lead channel along the locking piece lead groove and the center through hole of the ball nut; the optical fiber passes through the shaft channel from the rear end of the shaft and is finally guided to the front end of the shaft, and the optical fiber is ensured to be in a relaxed state during the laying process to adapt to the thermal expansion and dynamic deformation during engine operation.

[0085] SS3. Installation of smooth ring adapter structure:

[0086] A front shaft end nut with a groove or slotted rotating structure is installed at the front end of the engine shaft; the smooth ring rotor is coaxially installed in the front end inner cavity of the lead-in channel in the shaft, and the smooth ring fork is adjusted to embed the rotating structure of the front shaft end nut to realize synchronous rotation of the rotor; ensure that an appropriate axial gap is reserved between the smooth ring fork and the rear end face of the rotating structure to avoid axial deformation under the working state of the engine and damage to the optical fiber.

[0087] SS4. Positioning and fixing of smooth ring stator:

[0088] Install the smooth ring stator to the circumferentially discrete and uniformly distributed positioning boss on the inner casing of the straight section of the intake casing, ensuring that its outer cylindrical surface and the inner cylindrical surface of the boss are radially positioned. Axial positioning is achieved by adjusting the end face of the smooth ring stator to make it fit closely with the rear end face of the positioning boss. Use screws to firmly fix the smooth ring stator to ensure the stability of the smooth ring stator during engine operation.

[0089] SS5. Layout of stator lead structure:

[0090] When installing the straight section of the intake casing, the intake cone section is separated from the straight section for easy operation and observation. The optical fiber is led out from the smooth ring stator to the outer wall of the engine casing through the hollow support plate between the inner and outer casings. During the laying process, check the bending radius of the optical fiber to avoid exceeding the minimum bending radius allowed by the optical fiber, and ensure that there is no kink or extrusion during the laying process. Set up sealing structures at the entrance and exit of the hollow support plate to prevent oil mist, airflow or foreign matter from entering the optical fiber channel and affecting the signal transmission quality.

[0091] SS6. Machine assembly and debugging stage:

[0092] Complete the fiber optic fusion splicing at the rear end of the engine shaft, and do the corresponding packaging and protection. When assembling the straight section of the intake casing, since the intake cone section has not yet been assembled, the smooth ring rotor fork is accurately installed into the front shaft end nut with rotation structure under visual conditions to avoid blind installation and improve assembly accuracy. Weld the intake cone section of the intake casing, assemble the tail nozzle, and complete the fiber optic lead layout of the entire engine. Perform a comprehensive inspection of the fiber optic lead system, including fiber optic signal integrity testing, rotational stability testing of the smooth ring switching structure, and fiber optic layout status inspection to ensure the stability and reliability of the optical fiber under various working conditions.

[0093] The above-mentioned assembly method provided in this embodiment 2 fully considers the assembly convenience of the engine and the long-term reliability of the optical fiber on the basis of ensuring smooth optical fiber layout and stable signal transmission, and is suitable for temperature and vibration stress measurement in various high-temperature, high-speed and high-vibration environments.

[0094] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different. Any equivalent or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades, comprising a rotor lead structure section, a smooth ring positioning and switching structure section and a stator lead structure section, characterized in that: The rotor lead structure section is used to realize the smooth transition of the optical fiber from the surface of the turbine blade to the smooth ring rotor at the front end of the turbine rotor shaft, and includes a blade-disk rear transition structure, a disk rear-shaft inner transition structure and an inner shaft lead channel, wherein: The blade-disk rear transition structure at least includes a blade-disk rear transition inclined hole and a disk rear lead groove, wherein the blade-disk rear transition inclined hole extends backward from the turbine blade root to the rear end face of the disk, and the disk rear lead groove passes through the dynamic balance boss on the rear end face of the disk and extends radially; The disc rear-shaft inner transition structure at least includes a ball nut and a locking plate. The ball nut is arranged on the central hub on the rear end face of the wheel disc, and its outer wall is designed as a spherical arc surface structure with the same outer diameter as the central hub, and a through hole connected to the lead wire channel in the shaft is arranged in the center; the locking plate has the same outer diameter as the ball nut, is arranged between the ball nut and the central hub, and a lead wire groove is arranged on the outer edge; The in-shaft lead-in channel is a hollow channel disposed inside the turbine rotor shaft and axially penetrated, and is used to accommodate and protect the optical fiber and guide it from the rear end of the shaft to the front end of the shaft; The smooth ring positioning and switching structure section is used to realize reliable transmission of optical fiber signals from the rotor to the stator, and includes a smooth ring rotor switching structure and a smooth ring stator positioning structure, wherein: The smooth ring rotor transfer structure is designed based on the front shaft end nut of the turbine rotor shaft, and a belt rotation structure in the form of a groove or a slot is arranged on the front shaft end nut. The smooth ring rotor is coaxially installed in the front end inner cavity of the lead wire channel in the shaft, and the smooth ring fork is arranged to be embedded in the belt rotation structure to achieve synchronous rotation with the turbine rotor shaft, and an axial gap is reserved between the fork and the rear end surface of the belt rotation structure; The smooth ring stator positioning structure is arranged in the inner casing of the straight section of the engine air intake casing, and includes a plurality of positioning bosses arranged on the inner wall of the inner casing and circumferentially discretely evenly distributed, for realizing radial and axial positioning of the smooth ring stator, the inner cylindrical surface of the boss cooperates with the outer cylindrical surface of the smooth ring stator to realize radial positioning, and the rear end surface of the boss fits with the end surface of the smooth ring stator to realize axial positioning; The stator lead structure section is formed as an intake casing lead channel based on the hollow support plate between the inner casing and the outer casing of the engine intake casing, and is used to lead the optical fiber from the smooth ring stator through the internal cavity of the hollow support plate to the outer wall of the intake casing.

2. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The rotor lead structure segment also includes a blade surface lead channel, which is a microgroove channel arranged on the surface of the turbine blade for laying out the sensor optical fiber. The laying path of the microgroove channel is optimized according to the blade profile and / or the measurement point distribution, and the bottom and side walls of the microgroove are polished.

3. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The inclination angle of the blade-disk rear transition inclined hole is determined based on the installation angle of the turbine blade, the geometric structure of the disk, and the relative position of the blade root and the rear end face of the disk, and the setting of the inclination angle should ensure that the bending radius of the optical fiber when transitioning from the blade root to the rear end face of the disk is not less than the minimum bending radius allowed by the optical fiber.

4. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The depth and width of the lead groove behind the disk are determined according to the optical fiber diameter and the number of wirings. The inner wall of the groove is polished, and the groove extends from the dynamic balancing boss on the rear end surface of the wheel disk toward the central hub to ensure a smooth transition of the optical fiber from the outer edge of the wheel disk to the central area.

5. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The spherical outer wall of the ball nut is the same as the outer diameter of the central hub, and its surface roughness is not greater than Ra 0.

8. The inner wall of the central through hole is polished, and an arc transition structure is designed at least at the entrance of the through hole; the depth and width of the locking plate lead groove are determined according to the optical fiber diameter and the number of wirings. The inner wall of the groove is polished and aligned with the lead groove behind the disk in the circumferential direction.

6. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The inner diameter of the front section of the in-shaft lead-in channel is larger than that of the rear section, wherein the inner diameter of the front section is 7-10 mm, which is used to ensure that the smooth ring rotor and the inner wall of the shaft form a clearance fit under working conditions, and the inner diameter of the rear section is 5-7 mm. The inner wall of the channel is polished and a circular arc transition structure is designed at the diameter change point. At the same time, the optical fiber is laid out in the channel in a loose arrangement.

7. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The smooth ring rotor and the belt-rotating structure of the front shaft end nut are matched with a fork and groove interlocking design, the width of the fork matches the groove width of the belt-rotating structure, and the axial reserved gap between the fork and the rear end face of the belt-rotating structure is 1.5-2.0mm.

8. The complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to claim 1, characterized in that: The number of positioning bosses in the smooth ring stator positioning structure is set to 3 to 6, and the circumferentially evenly distributed spacing is optimized according to the working environment and vibration characteristics of the engine; and a threaded hole is provided on the rear end surface of each positioning boss, and the smooth ring stator is fixed on the positioning boss by screws.

9. An assembly method of the complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades according to any one of claims 1 to 8, characterized in that: At least the following steps are included: SS1. Installation and layout of optical fiber sensors: optical fiber sensors are laid out on the surface or internal measuring points of turbine rotor blades. The optical fiber sensors include optical fiber grating sensors for temperature measurement and optical fiber sensors for stress measurement. SS2. Assembly of the rotor lead structure: Pass the optical fiber through the blade-disk rear transition inclined hole to lead it out from the root of the turbine blade to the rear end face of the disk; lay the optical fiber along the lead groove behind the disk to the center hub position; assemble the locking piece with the lead groove and the ball nut with the center through hole on the center hub of the rear end face of the disk in sequence, so that the optical fiber smoothly transitions along the lead groove of the locking piece and the center through hole of the ball nut; pass the optical fiber through the inner lead channel of the turbine rotor shaft to lead it out from the rear end of the shaft to the front end of the shaft, and ensure that the optical fiber is loosely arranged during the laying process to adapt to the axial expansion and dynamic deformation during the operation of the engine; SS3. Installation of the smooth ring transfer structure: Install the front shaft end nut with a groove or slotted belt transfer structure at the front end of the turbine rotor shaft, coaxially install the smooth ring rotor in the front end inner cavity of the shaft inner lead channel, adjust the smooth ring shift fork to embed it into the belt transfer structure, and ensure that the specified axial gap is reserved between the shift fork and the rear end surface of the belt transfer structure; guide the optical fiber from the shaft inner lead channel to the signal input end of the smooth ring rotor, and transfer the optical fiber signal to the smooth ring stator through the smooth ring rotor; SS4. Positioning and fixing of smooth ring stator: install the smooth ring stator on the inner casing of the straight section of the engine intake casing through the positioning boss, so that its outer cylindrical surface and the inner cylindrical surface of the boss are radially positioned and matched, adjust the axial position of the smooth ring stator, so that its end face and the rear end face of the boss are axially positioned and fitted; fix the smooth ring stator on the positioning boss with screws; SS5. Layout of stator lead structure: Separate the intake cone section and the straight section of the intake casing for easy operation and observation, and lead the optical fiber from the smooth ring stator to the outer wall of the intake casing through the hollow support plate between the inner and outer casings; Check and confirm that the bending radius of the optical fiber at each turning point meets the requirements and there is no kink or extrusion; Set up sealing structures at the inlet and outlet of the hollow support plate; SS6. Whole machine assembly and debugging stage: The intake cone section is connected or welded to the straight section of the intake casing by flange bolts and the coaxiality is ensured to complete the assembly of the whole machine fiber optic lead wire in the tested engine; the fiber optic lead wire structure is tested and debugged as a whole machine, including the integrity test of the fiber optic signal, the rotation stability test of the smooth ring switching structure and the layout status of the fiber optic in the shaft channel to ensure the smooth layout of the fiber optic lead wire, stable signal transmission and the firmness of the assembly of each component.

10. A turbine rotor blade temperature and vibration stress measurement system, characterized in that: A complete optical fiber lead structure for measuring temperature and vibration stress of turbine rotor blades comprising any one of claims 1 to 8.

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