A focusing structure for an aviation engine radiation pyrometer

Abstract

The present invention provides a focusing structure for an aero-engine radiation pyrometer, which comprises a focusing structure control module, an optical tube and a focusing structure fixing seat. The advantages of the focusing structure of the aero-engine radiation pyrometer are as follows: it can receive the infrared radiation at different curved surface positions of the turbine blade, accurately adjust its focal length, and eliminate the measurement error caused by the change of object distance. Moreover, the device is small in size, has a wide application range, a large focal length adjustment range for infrared radiation, strong anti-interference ability, can accurately measure the temperature at various positions of the turbine blade, and the measured temperature of the turbine blade can provide important data support for the research of aero-engines.

Description

Technical Field

[0001] The present invention relates to a focusing structure, specifically a focusing structure for a radiation pyrometer of an aero-engine. Background Art

[0002] At present, non-contact radiation temperature measurement technology is widely used in the temperature measurement of aero-engine turbine blades, which is the future development trend of temperature measurement technology in this field. When this technology works, it neither interferes with the surface temperature of the target nor the surrounding medium, and has obvious advantages for some rotating objects, high-speed moving objects or objects with strong corrosion. The principle of the radiation pyrometer is based on the corresponding relationship between the thermal radiation of an object and its temperature, such as brightness temperature measurement, etc. However, currently during the temperature measurement process of the radiation pyrometer, the surface of the object to be measured is not a standard plane. Especially, the surface of a turbine rotor is an irregular curved surface, which makes it inconvenient and ineffective for the radiation pyrometer to accurately and quickly measure the radiation light with various different focal lengths. Therefore, there is an urgent need for a focusing structure that can adjust the light focal length to a specified focal length, accurately adjust the focal lengths of different positions on the curved surface of the turbine blade, and then accurately receive the infrared radiation, so that it can transmit the data to a photodetector through an optical fiber, and the data is processed by an industrial control computer to obtain the final measured temperature, providing support for the accurate temperature measurement of the radiation pyrometer. Summary of the Invention

[0003] The main technical problem to be solved by the present invention is to provide a focusing structure for a radiation pyrometer of an aero-engine, so as to solve the problem of low temperature measurement accuracy caused by the mismatch of the infrared radiation focal length during the temperature measurement of the current radiation pyrometer of an aero-engine.

[0004] To solve the above technical problems, a technical solution adopted by the present invention is: a focusing structure for a radiation pyrometer of an aero-engine, the focusing structure comprising: a control module, an optical tube and a fixed seat, wherein the control module and the optical tube are both fixed on the fixed seat;

[0005] The control module comprises: a support seat, a motor control module, and a convex lens adjustment module. The motor control module and the convex lens adjustment module are both installed on the support seat, and the support seat is installed on the fixed seat; the motor control module comprises: a motor, an output gear, and a motor controller. The output gear is arranged on the output shaft of the motor, and the motor controller is arranged at the tail of the motor;

[0006] The lens adjustment module includes: a lens barrel, a limit tube, and a rotating tube. The lens barrel includes: a mounting tube, a lens, and a lens retaining ring. The lens is disposed inside the mounting tube. A boss is provided inside the mounting tube to cooperate with the lens retaining ring to fix the lens. Screw holes are provided on the side of the mounting tube for installing guide screws. The limit tube includes: a head and a body. The head is tubular, and a moving through slot is provided on the side wall in the axial direction. The diameter of the head is larger than that of the body, and mounting platforms are provided on both sides of the head for installing limit sensors. The rotating tube includes a rotating cylinder and a rotating gear. The rotating gear is disposed at one end of the rotating cylinder, and a limit groove is provided at the other end of the rotating barrel. A spiral through slot is provided on the side of the rotating cylinder. The lens barrel is located inside the limit tube, and the limit tube is located inside the rotating tube. The guide screws installed on the side of the lens barrel are simultaneously located in the moving through slot of the limit tube and the spiral through slot of the rotating tube. The rotating gear of the rotating tube meshes with the output gear of the electrode control module. The rotation of the output gear drives the rotation of the rotating gear, thereby rotating the rotating cylinder. The guide screws slide relative to each other in the spiral groove and the limit groove, so that the lens barrel moves back and forth. The limit sensor has an elastically movable limit protrusion, which is equivalent to a limit switch. When the protrusion is located in the limit groove of the rotating tube, a sensing signal is sent to stop the motor from rotating.

[0007] The outer diameter of the head of the limit tube is 25 mm, the outer diameter of the body is 20 mm, and the inner diameter is 17 mm. There are two rectangular planes on both sides of the head, and two circular holes are provided on the planes for installing limit sensors in cooperation. The diameter of the lens barrel is 17 mm, the diameter of the lens is 10 mm, and the diameter of the lens retaining ring is 14 mm. Two lens barrel guide screws with a diameter of 3 mm are provided on both sides of the lens barrel to fix the relative position of the lens barrel. Driven by the rotating gear, the lens barrel moves back and forth along the rotation path of the convex lens barrel guide screw and prevents improper position offset during the movement of the lens barrel. The outer diameter of the rotating tube is 25 mm, the diameter of the rear-end gear is 28 mm, and the inner diameter is 21 mm. Two long spiral through slots with a gap of 3 mm and a length of 22 mm are provided along the side wall as the relative displacement path of the guide screws when the convex lens barrel moves back and forth. Two limit grooves are symmetrically provided on both sides of the front end. The limit grooves are composed of three rectangular surfaces, with an included angle of 135 degrees between each two, a width of 2 mm, a side wall length of 2.8 mm, and a bottom length of 4 mm. When the convex lens barrel moves to the maximum position back and forth, the limit switch of the limit sensor pops out into the limit groove. At this time, the limit sensor transmits a signal to the motor control module to control the rotation of the motor gear to stop.

[0008] The light tube includes: a housing, a push rod, and a reflector. The end of the housing has a window, and a reflector is provided inside the end of the housing. The reflector faces the window. The push rod is disposed outside the housing, and the push rod is connected to the reflector to adjust the angle of the reflector. The push rod is controlled by an additional control system.

[0009] The beneficial effects of the present invention are as follows: it can accurately receive the infrared radiation at different positions on the surface of the turbine blade, adjust its focal length with a wide adjustment range, strong anti-interference ability, and the device is small in size and has a wide application range. The infrared radiation after adjusting the focal length can process data through the corresponding equipment of the terminal, providing important support for the research of aeroengines. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an assembly effect diagram of the focusing structure;

[0011] Figure 2 It is a schematic diagram of the light pipe;

[0012] Figure 3 It is a schematic diagram of the fixed seat;

[0013] Figure 4 It is a schematic diagram of the control module;

[0014] Figure 5 It is a schematic diagram of the limit pipe;

[0015] Figure 6 It is a schematic diagram of the lens barrel;

[0016] Figure 7 It is a schematic diagram of the lens adjustment module;

[0017] Figure 8 It is a schematic diagram of the rotating pipe structure;

[0018] Figure 9 It is a schematic diagram of the radiation temperature measurement light focusing temperature measurement process;

[0019] Figure 10 It is a schematic diagram of the principle of adjusting the radiation focal length.

[0020] In the figure, 1. Control module; 2. Fixed seat; 3. Light pipe; 4. Push rod; 5. Installation position of the light pipe mirror; 6. Convex lens adjustment module; 7. Motor; 8. Support seat; 9. Moving through groove; 10. Lens retaining ring; 11. Lens; 12. Screw hole; 13. Guide screw; 14. Limit sensor; 15. Rotating gear; 16. Spiral through groove; 17. Limit groove; 18. Photoelectric sensor housing. DETAILED DESCRIPTION OF THE INVENTION

[0021] The motor control module can be connected to the drive module through a flexible cable. By controlling the drive of the motor through a program, the rotation of the gear is controlled, and further the purpose of controlling the forward and backward stepping of the convex lens is achieved. The lens adjustment module is fixedly connected to the motor control module through screws and a metal frame. Its rotating gear is closely fitted with the output gear of the motor control module. The rotating gear of the lens adjustment module can be driven by the output gear of the motor control module to rotate. A lens is installed inside the lens adjustment module. The lens can be controlled by the rotation of the gear to move forward and backward to achieve the purpose of adjusting the focal length. Two limit sensors are installed at the front end of the lens adjustment module. The lead wires drawn from them are connected to the motor control module and cooperate with the front groove of the lens barrel rotation control structure of the lens adjustment module to adjust the motor control module, preventing damage to the internal gears of the motor control module or damage caused by the movement of the lens barrel beyond the normal range. There is an optical fiber interface at the rear end of the lens adjustment module, which can be connected to an optical fiber to output the infrared radiation after focusing.

[0022] The overall shape of the light pipe is a cylinder. There is a hole at its front end, and a mirror with adjustable angle is installed inside. There is an optical path pipe inside the light pipe that can transmit radiant light, and can stably transmit the infrared radiation received by the mirror to the front end of the convex lens of the focusing structure control module. A push rod is provided above the light pipe. The push rod is connected to the mirror at the front end of the light pipe through a movable structure. The angle of the mirror can be controlled by pushing and pulling the push rod to receive the infrared radiation at different positions of the turbine blade.

[0023] The focusing structure fixing seat is a cuboid, with regular oval holes and circular holes inside. The fixing seat can be closely connected to the small seat at the bottom of the focusing structure control module through screws and nuts to maintain the stability and accuracy of infrared radiation transmission, avoid light transmission deviation caused by shaking, and reduce the error of focal length adjustment.

[0024] The overall schematic diagram of radiation temperature measurement and focusing temperature measurement is as Figure 9 shown, including a temperature measurement system composed of a photodetector, an industrial control computer and an optical fiber, and the focusing structure of this radiation pyrometer. In this experiment, the focal length of the radiant light is adjusted by moving the lens back and forth, and the temperature value of the high-temperature turbine blade is measured by the radiation calibration method. The principle of adjusting the focal length is as Figure 10As shown, Figure (a) shows that the optical tube mirror 5 receives the infrared radiation at the position of the turbine blade P1 at an angle a. Figure (b) shows that the optical tube mirror 5 receives the infrared radiation at the position of the turbine blade P2 at an angle b. Figure (c) shows the schematic diagram of the principle of the focusing structure control module 1 adjusting the focal length. The dashed line (I) represents the schematic diagram of the optical path focusing end face before the infrared radiation of the turbine blade at the P2 position in Figure (b) is focused by the focusing structure control module 1. The dashed line (II) represents the schematic diagram of the actual optical fiber end face. L1 represents the difference in distance between the two. P1 represents the schematic diagram of the optical path in the focusing structure control module 1 shown in Figure (a). P2(1) represents the schematic diagram of the optical path before focusing shown in Figure (b). P2(2) represents the schematic diagram of the optical path after being focused by the focusing structure control module 1 shown in Figure (b). As shown in Figure (a), when the optical tube mirror 5 is at an angle a, it receives the infrared radiation at the position of the turbine blade P1. The infrared radiation is reflected by the optical tube mirror 5 and transmitted in the optical path channel inside the optical tube in the horizontal direction shown in the figure. As shown by P1 in Figure (c), the radiation light is refracted by the lens and converges to the optical fiber end face (II). At this time, the focal length of the infrared radiation light matches the position of the convex lens in the focusing structure control module 1, and the infrared radiation can be converged to the optical fiber transmission without moving the convex lens. As shown in Figure (b), when the optical tube mirror 5 swings to an angle b, it receives the infrared radiation at the position of the turbine blade P2. The infrared radiation is reflected by the optical tube mirror 5 and transmitted in the optical path channel inside the optical tube in the horizontal direction shown in the figure. As shown by P2(1) in Figure (c), after the radiation light is refracted by the convex lens at the same position as P1, the focused end face (I) does not overlap with the actual optical fiber end face (II), indicating that the radiation light cannot be correctly converged into the optical fiber for transmission. Therefore, focusing work is required. As shown by P2(2) in Figure (c), the convex lens is stepped by a distance L1 through the motor control module 7. At this time, the infrared radiation can just be converged to the actual optical fiber end face (II) after being refracted by the lens, meeting the requirements, and the focusing work is completed. The radiation calibration method means aligning the photodetector with the center of the reference blackbody furnace. When the blackbody furnace is heated to temperature T1 and the heating is stopped, after stabilizing for 30 minutes, record the voltage amplitude of the industrial control computer at this time as V1. When the blackbody furnace is heated to temperature T2 again and the heating is stopped, after stabilizing for 30 minutes, record the voltage amplitude of the industrial control computer at this time as V2. Repeat this operation N times to obtain N groups of data of temperature and voltage amplitude. Then, a voltage-temperature curve can be fitted therefrom. Transmit the infrared radiation at a certain position of the turbine blade by the focusing structure to the photodetector through the optical fiber. The data is processed by the photodetector and transmitted to the industrial control computer to obtain the corresponding voltage amplitude V at this time. By comparing the function expression analyzed from the voltage-temperature curve obtained by calibrating the blackbody furnace above, the temperature value corresponding to this V value can be obtained as T.Therefore, the infrared radiation of the turbine blade at a certain temperature is received by the light pipe mirror 5 and the stepping displacement of the convex lens is adjusted by using the focusing structure, so that the infrared radiation is accurately converged to the end face of the optical fiber. Then the infrared radiation is transmitted through the optical fiber to the photodetector for data processing, and finally transmitted to the industrial control computer to obtain the voltage value at this time. Then, the temperature value corresponding to this voltage value is calculated through the function expression obtained by the above radiation calibration method, and the target temperature value corresponding to the infrared radiation at this voltage value can be obtained.

[0025] Step 1: Fix the small seat 8 of the focusing structure control module and the fixing seat 2 of the focusing structure control module by screws and nuts to maintain the stability of light transmission.

[0026] Step 2: Fix the light pipe 3 and the fixing seat 2 of the focusing structure control module by screws and nuts. There is a fixed distance between the lens at the rear end of the light pipe and the convex lens lens 11. The final assembly effect diagram is as Figure 1 shown.

[0027] Step 3: Debug the relevant parameters of the photodetector to ensure that the photodetector can stably measure the radiation energy of the infrared radiation and process the data and transmit it to the industrial control computer.

[0028] Step 4: Adjust the light pipe mirror 5 to different angles to receive the infrared radiation at different positions of the turbine blade. It is transmitted to the focusing structure control module 1 through the internal optical path pipeline of the light pipe 3. Through the program control of the motor control module 7, the convex lens is displaced step by step forward and backward through the gear power structure until the infrared radiation is refracted and converged to the end face of the optical fiber through the convex lens and transmitted through the optical fiber. Record the angle of the light pipe mirror 5 at this time as a;

[0029] Step 5: Sweep the light pipe mirror 5 again to make it reach an angle recorded as b. At this time, the light pipe mirror 5 receives the infrared radiation at another position of the turbine blade. This infrared radiation is reflected by the light pipe mirror 5 and transmitted to the focusing structure control module 1 through the internal optical path pipeline of the light pipe 3. Through the program control of the motor control module 7, the convex lens is displaced step by step forward and backward through the gear power structure until the infrared radiation is refracted and converged to the end face of the optical fiber through the convex lens and transmitted through the optical fiber. Then the focusing work of the infrared radiation light when the angle of the light pipe mirror 5 is b is completed.

[0030] Step 6: Connect both ends of the optical fiber to the optical fiber interface at the rear end of the focusing structure control module 1 and the photodetector. After the voltage amplitude displayed on the industrial control computer is stable, record the voltage amplitude at this time as V1.

[0031] Step 7: Align the furnace opening of the blackbody furnace with the photodetector, measure the voltage-temperature curve through the radiation calibration method and obtain the function expression. The optical tube mirror 5 at the front end of the swing-scanning optical tube 3 receives the infrared radiation from different positions of the turbine blade through the optical tube mirror 5. After focusing through the focusing structure control module 1, the infrared radiation is stably transmitted to the photodetector through the optical fiber. Substitute the voltage amplitude displayed on the industrial control computer at this time into the above function expression, calculate the corresponding temperature value at this amplitude, and this temperature value is the temperature value at a certain position of the turbine blade.

Claims

1. A focusing structure for an aviation engine radiation pyrometer, the focusing structure comprising: A control module, a light tube and a fixing base, wherein the control module and the light tube are both fixed on the fixing base; The control module includes: a support base, a motor control module, and a convex lens adjustment module. The motor control module and the convex lens adjustment module are both installed on the support base, and the support base is installed on the fixing base. The motor control module includes: a motor, an output gear, and a motor controller. The output gear is arranged on the output shaft of the motor, and the motor controller is arranged at the tail of the motor; The convex lens adjustment module includes: a lens barrel, a limit tube, and a rotating tube. The lens barrel includes: a mounting tube, a lens, and a lens retaining ring. The lens is arranged inside the mounting tube. There is a boss inside the mounting tube to cooperate with the lens retaining ring to fix the lens. There are screw holes on the side of the mounting tube for installing guiding screws. The limit tube includes: a head and a body. The head is tubular, and there is a moving through groove along the axis direction on the side wall. The diameter of the head is larger than that of the body, and there are mounting platforms on both sides of the head for installing limit sensors. The rotating tube includes a rotating cylinder and a rotating gear. The rotating gear is arranged at one end of the rotating cylinder, and there is a limit groove at the other end of the rotating cylinder. There is a spiral through groove on the side of the rotating cylinder. The lens barrel is located inside the limit tube, and the limit tube is located inside the rotating tube. The guiding screws installed on the side of the lens barrel are simultaneously located in the moving through groove of the limit tube and the spiral through groove of the rotating tube. The rotating gear of the rotating tube meshes with the output gear of the motor control module. The rotation of the output gear drives the rotation of the rotating gear, so that the rotating cylinder rotates, and the guiding screws slide relative to each other in the spiral groove and the limit groove, so that the lens barrel moves back and forth. There is an elastically movable limit protrusion on the limit sensor, which is equivalent to a limit switch. When the limit protrusion is located in the limit groove of the rotating tube, a sensing signal is sent to stop the motor from rotating.

2. The focusing structure for an aviation engine radiation pyrometer according to claim 1, characterized in that The outer diameter of the head of the limit tube is 25mm, the outer diameter of the body is 20mm, the inner diameter is 17mm. There are two rectangular planes on both sides of the head, and there are two circular holes on the rectangular planes for installing limit sensors in cooperation. The diameter of the mounting tube is 17mm, the diameter of the lens is 10mm, and the diameter of the lens retaining ring is 14mm. There are two guiding screws with a diameter of 3mm on both sides of the mounting tube. Driven by the rotating gear, the lens barrel moves back and forth along the rotation path of the guiding screws, and prevents the lens barrel from being misaligned during the movement. The outer diameter of the rotating cylinder is 25mm, the outer diameter of the rotating gear is 28mm, and the inner diameter is 21mm. There are two spiral through grooves with a gap of 3mm and a length of 22mm along the side wall as the relative displacement path of the guiding screws when the lens barrel moves back and forth. There are two symmetric limit grooves on both sides of the front end. The limit grooves are composed of three rectangular surfaces, and the included angles between two adjacent surfaces are 135 degrees, and the widths are all 2mm. The length of the side wall of the limit groove is 2.8mm, and the length of the bottom is 4mm. When the lens barrel moves back and forth to the maximum position, the limit protrusion of the limit sensor pops out into the limit groove. At this time, the limit sensor transmits a signal to the motor control module to control the motor to stop rotating.

3. The focusing structure for an aviation engine radiation pyrometer according to claim 1, characterized in that The light tube includes: a housing, a push rod, and a reflector. The end of the housing is provided with a window, and the reflector is arranged inside the end of the housing, facing the window. The push rod is arranged outside the housing, and the push rod is connected to the reflector to adjust the angle of the reflector.

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