A high-temperature-resistant multi-spectral imaging endoscope for an aero-engine

Abstract

The application provides a high-temperature-resistant multi-spectrum imaging endoscope for an aero-engine, which comprises an endoscope heat insulation shell, a sapphire glass, a front section imaging lens, a front section compression ring, a front section partition ring, a front section lens barrel, a front section cement sheet, a middle section image transmission lens, a rear section cement sheet, a rear section lens barrel, a rear section partition ring, a rear section compression ring, a rear section image transmission lens and a light splitting prism group. The device uses an imaging system in the endoscope to collect two-dimensional spontaneous radiation signals of a flame in a combustion chamber, and can realize multi-spectrum imaging by adjusting the transmittance coefficient of the light splitting prism group. The device is the first of its kind at home and abroad, has the advantages of multi-spectrum imaging capability, high measurement stability and long service life, and can be applied to the field of combustion diagnosis.

Description

Technical Field

[0001] This invention relates to a high-temperature resistant multispectral imaging endoscope for aircraft engines, belonging to the field of combustion diagnostics. Background Technology

[0002] Aero engines are the power source of aircraft, often referred to as the heart of the plane. The combustion chamber, one of its three core components, functions between the compressor and turbine, converting the chemical energy of fuel into thermal energy. Its performance directly impacts the development level of aero engine technology and is a crucial aspect of aero engine research and development. With the rapid development of aero engine technology and the continuous improvement of thrust-to-weight ratio, the future development of combustion chambers will undoubtedly move towards higher fuel-to-air ratios, higher temperature rise, and higher heat capacity. Therefore, higher demands are placed on the precise measurement of the combustion chamber temperature field.

[0003] Currently, common combustion field temperature diagnostic methods are broadly classified into two categories: probe methods and optical methods. Probe methods include chromatography, thermocouple temperature measurement, and pneumatic temperature and velocity measurement; optical methods include absorption spectroscopy, emission spectroscopy, and scattering spectroscopy. Among these, probe methods are difficult to operate continuously in high-temperature environments and are point measurements, making it impossible to obtain high spatiotemporal resolution combustion chamber temperature fields in practical applications. Furthermore, absorption spectroscopy and scattering spectroscopy based on laser technology have excessively high requirements for equipment and operating environments, making them unsuitable for actual measurements in aero-engines. Emission spectroscopy utilizes the radiation signal from the flame itself within the combustion chamber for temperature measurement, offering advantages such as high signal-to-noise ratio and fine spatiotemporal resolution, and holds promise for application in aero-engine combustion chamber temperature measurement. Therefore, it is necessary to develop a high-temperature resistant multispectral imaging endoscope for aero-engine combustion chambers, combined with emission spectroscopy, to achieve precise measurement of the combustion chamber temperature field. Summary of the Invention

[0004] The technical problem to be solved:

[0005] The combustion chamber of an aircraft engine is characterized by high temperature, high pressure, and strong vibration. This requires endoscopes to meet requirements such as high temperature resistance, high pressure resistance, high stability, and durability. Simultaneously, emission spectroscopy requires the acquisition of multiple two-dimensional spectral signals from the flame, meaning the endoscope must also possess multispectral imaging capabilities. Careful design of the endoscope is necessary to simultaneously meet all these requirements.

[0006] The technical solution of this invention is as follows:

[0007] A high-temperature resistant multispectral imaging endoscope for aero-engines includes an endoscope heat shield, sapphire glass, a front imaging lens, a front retaining ring, a front spacer, a front endoscope barrel, a front cemented film, a middle image-transmitting lens, a rear cemented film, a rear endoscope barrel, a rear spacer, a rear retaining ring, a rear image-transmitting lens, and a beam splitter assembly. The endoscope heat shield is composed of a metal outer shell and internal heat-insulating material, enclosing the internal optical components. The sapphire glass is installed at the front end of the endoscope heat shield and connected to the front imaging lens via the front endoscope barrel. The front imaging lens is installed behind the sapphire glass and secured within the front endoscope barrel by the front retaining ring. The front retaining ring is installed within the front endoscope barrel to fix the front imaging lens. The front spacer is installed within the front endoscope barrel to adjust the spacing between the front imaging lenses. The front lens barrel is mounted on the back of the sapphire glass to constrain the internal optical elements. The front cemented plate is mounted after the front lens barrel to connect the middle image-transmitting lens and the front lens barrel. The middle image-transmitting lens is mounted after the front cemented plate to receive and transmit the image formed by radiation. The rear cemented plate is mounted to connect the middle image-transmitting lens and the rear lens barrel. The rear lens barrel is mounted after the rear cemented plate to constrain the internal optical elements. The rear spacer is mounted inside the rear lens barrel to adjust the spacing between the rear imaging lenses. The rear retaining ring is mounted inside the front lens barrel to fix the rear imaging lens. The rear image-transmitting lens is mounted inside the rear lens barrel and secured within it by the rear retaining ring. The beam-splitter assembly is mounted behind the rear image-transmitting lens to divide the image into multiple spectral channels.

[0008] The high-temperature resistant multispectral imaging endoscope for aero-engines described above has an endoscope heat insulation shell composed of a metal shell and internal heat insulation material, which can work for a long time under high temperature and high pressure, and protect the internal optical components; the internal front and rear barrels, pressure rings, rear spacers and adhesive sheets can keep the focal length and optical axis of the internal optical components stable under strong vibration environment.

[0009] The aforementioned high-temperature resistant multispectral imaging endoscope for aero-engines uses sapphire glass to provide an optical window for the front imaging lens, while also protecting the internal lens under high temperature and high pressure environments.

[0010] The aforementioned high-temperature resistant multispectral imaging endoscope for aero-engines features a front imaging lens with a diagonal viewing angle and a fixed focal length, forming a fixed-focus imaging system. The front imaging lens corrects transverse and on-axis chromatic aberration within the visible light range. To ensure the matching between the front fixed-focus system and the rear telecentric system, the image side of the front imaging lens is designed as a fixed-telecentric image side telecentric lens to acquire two-dimensional radiation signals from the flame.

[0011] The aforementioned high-temperature resistant multispectral imaging endoscope for aero-engines features a rear image transmission lens that is a dual-telecentric system for both object and image, with the image plane of the front optical path serving as the imaging object plane. The telecentric system has a fixed optical magnification and corrects transverse and on-axis chromatic aberration within the visible light range.

[0012] The high-temperature resistant multispectral imaging endoscope for aircraft engines has an adjustable transmittance coefficient for the beam splitter prism group, which splits light into multiple spectral channels as it passes through the prism group. Beneficial effects

[0013] The high-temperature resistant multispectral imaging endoscope for aero-engines provided by this invention enables multi-channel acquisition of spectral signals from the flame inside the combustion chamber of an aero-engine. Simultaneously, the endoscope employs a heat-insulating and vibration-resistant structure, allowing for stable operation within the combustion chamber for extended periods, significantly extending its service life. Multiple lenses within the endoscope enable two-dimensional imaging of the flame inside the combustion chamber, effectively increasing the amount of measurement data and improving temperature measurement accuracy. This device can also modify the transmittance of the beam-splitting prism group to perform two-dimensional imaging measurements of the spontaneous emission of the flame at different wavelengths. Attached Figure Description

[0014] Figure 1 : A schematic diagram of the system of the present invention.

[0015] Among them, 1-1 is the endoscope heat shield, 1-2 is sapphire glass, 1-3 is the front imaging lens, 1-4 is the front pressure ring, 1-5 is the front spacer, 1-6 is the front endoscope barrel, 1-7 is the front cemented sheet, 1-8 is the middle image transmission lens, 1-9 is the rear cemented sheet, 1-10 is the rear endoscope barrel, 1-11 is the rear spacer, 1-12 is the rear pressure ring, 1-13 is the rear image transmission lens, 1-14 is the beam splitter prism group, and 1-15 is the aero-engine combustion chamber. Detailed Implementation

[0016] The present invention will be further described below with reference to specific examples and accompanying drawings.

[0017] A high-temperature resistant multispectral imaging endoscope for aircraft engines, with each component conforming to the attached... Figure 1 Assemble the structure shown, and the endoscope is attached. Figure 1 Insert it into the combustion chamber 1-15 of the aircraft engine in the direction shown.

[0018] A high-temperature resistant multispectral imaging endoscope for aircraft engines includes an endoscope heat shield 1-1, sapphire glass 1-2, a front imaging lens 1-3, a front retaining ring 1-4, a front spacer 1-5, a front endoscope barrel 1-6, a front cemented sheet 1-7, a middle image transmission lens 1-8, a rear cemented sheet 1-9, a rear endoscope barrel 1-10, a rear spacer 1-11, a rear retaining ring 1-12, a rear image transmission lens 1-13, and a beam splitter prism group 1-14. The endoscope heat shield 1-1 is composed of a metal outer shell and... The internal heat insulation material encloses the internal optical components. Sapphire glass 1-2 is installed at the front end of the endoscope's heat insulation shell 1-1 and connected to the front imaging lens 1-3 via the front endpiece barrel 1-6. The front imaging lens 1-3 is installed behind the sapphire glass 1-2 and secured within the front endpiece barrel 1-6 by a front retaining ring 1-4. The front retaining ring 1-4 is installed within the front endpiece barrel 1-6 to fix the front imaging lens 1-3. A front spacer 1-5 is installed within the front endpiece barrel 1-6 to adjust the front imaging. Lens 1-3 spacing; Front lens barrel 1-6 is mounted behind sapphire glass 1-2 to constrain the internal optical elements of the front section; Front cemented sheet 1-7 is mounted after the front lens barrel 1-6 to connect the middle image-transmitting lens 1-8 and the front lens barrel 1-6; Middle image-transmitting lens 1-8 is mounted after the front cemented section to receive and transmit the image formed by radiation; Rear cemented sheet 1-9 is mounted to connect the middle image-transmitting lens 1-8 and the rear lens barrel 1-10; Rear lens barrel 1-10 is mounted on the rear cemented section. Following the plates 1-9, the rear section internal optical elements are constrained; the rear section spacer 1-11 is installed inside the rear section lens barrel 1-10 to adjust the spacing between the rear section imaging lenses; the rear section retaining ring 1-12 is installed inside the front section lens barrel 1-6 to fix the rear section imaging lens; the rear section image transmission lens 1-13 is installed inside the rear section lens barrel 1-10 and is secured within the rear section lens barrel 1-10 by the rear section retaining ring 1-12; the beam splitter prism group 1-14 is installed behind the rear section image transmission lens 1-13 to divide the image into multiple spectral channels.

[0019] A high-temperature resistant multispectral imaging endoscope for aero-engines, wherein the endoscope heat insulation shell 1-1, composed of a metal shell and internal heat insulation material, can work for a long time under high temperature and high pressure, and protect the internal optical components; the internal front and rear barrel sections 1-10, pressure ring, rear spacer and adhesive sheet can keep the focal length and optical axis of the internal optical components stable under strong vibration environment.

[0020] A high-temperature resistant multispectral imaging endoscope for aircraft engines uses sapphire glass 1-2 to provide an optical window for the front imaging lens 1-3, while protecting the internal lens under high temperature and high pressure environments.

[0021] A high-temperature resistant multispectral imaging endoscope for aero-engines includes a front imaging lens 1-3 with a diagonal viewing angle and a fixed focal length, forming a fixed-focus imaging system. The front imaging lens 1-3 corrects transverse chromatic aberration and on-axis chromatic aberration within the visible light range. To ensure the matching between the front fixed-focus system and the rear telecentric system, the image side of the front imaging lens 1-3 is designed as an image side telecentric lens with a fixed telecentricity to acquire two-dimensional radiation signals from flames.

[0022] A high-temperature resistant multispectral imaging endoscope for aero-engines, wherein the rear image transmission lenses 1-13 form a dual-telecentric system for the object and image, and the image plane of the front optical path is the imaging object plane; the optical magnification of the telecentric system is fixed, and it corrects transverse chromatic aberration and on-axis chromatic aberration in the visible light range.

[0023] A high-temperature resistant multispectral imaging endoscope for aircraft engines, wherein the transmittance coefficient of the beam splitting prism group 1-14 is adjustable, and the light is split into multiple spectral channels as it passes through the prism group.

[0024] The endoscope heat shield 1-1 is inserted into the combustion chamber 1-15 of the aircraft engine. Sapphire glass 1-2 is installed at the front end of the endoscope heat shield 1-1. Spontaneous radiation from the flame enters the front endpiece tube 1-6 through the sapphire glass 1-2, and completes the first image through the front imaging lens 1-3. Then, it enters the rear endpiece tube 1-10 through the middle image transmission lens 1-8, and after a second image through the rear image transmission lens 1-13, it reaches the beam splitter prism group 1-14, where it completes multispectral channel two-dimensional imaging.

Claims

1. A high-temperature resistant multispectral imaging endoscope for aero-engines, comprising an endoscope heat shield, sapphire glass, a front imaging lens, a front retaining ring, a front spacer, a front endpiece tube, a front cemented sheet, a middle image-transmitting lens, a rear cemented sheet, a rear endpiece tube, a rear spacer, a rear retaining ring, a rear image-transmitting lens, and a beam splitter assembly; characterized in that: The endoscope heat shield consists of a metal outer shell and internal heat insulation material, enclosing the internal optical components. Sapphire glass is mounted at the front end of the heat shield and connected to the front imaging lens via the front endpiece tube. The front imaging lens is mounted behind the sapphire glass and secured within the front endpiece tube by a front retaining ring. The front retaining ring is installed inside the front endpiece tube to fix the front imaging lens. A front spacer is installed inside the front endpiece tube to adjust the spacing between the front imaging lenses. The front endpiece tube is mounted behind the sapphire glass to constrain the internal optical components. A front cemented plate is installed after the front endpiece tube to connect the middle image transmission lens and the front endpiece tube. The middle image-transmitting lens is installed after the front cemented section and is used to receive and transmit the image formed by radiation. The rear cemented section is installed to connect the middle image-transmitting lens and the rear lens barrel. The rear lens barrel is installed after the rear cemented section and is used to constrain the internal optical elements of the rear section. The rear spacer is installed inside the rear lens barrel and is used to adjust the spacing of the rear imaging lenses. The rear retaining ring is installed inside the front lens barrel and is used to fix the rear imaging lens. The rear image-transmitting lens is installed inside the rear lens barrel and is secured inside the rear lens barrel by the rear retaining ring. The beam splitter prism group is installed behind the rear image-transmitting lens and divides the image into multiple spectral channels. The front imaging lens is a fixed-focus imaging system with a diagonal viewing angle and a fixed focal length. The front imaging lens corrects the transverse chromatic aberration and on-axis chromatic aberration in the visible light range. To ensure the matching between the front fixed-focus system and the rear telecentric system, the image side of the front imaging lens is designed as an image side telecentric lens with a fixed telecentricity to collect the two-dimensional radiation signal of the flame. The rear image transmission lens is a telecentric system with the image plane of the front optical path as the imaging object plane; the optical magnification of the telecentric system is a fixed value, and it corrects transverse chromatic aberration and on-axis chromatic aberration in the visible light range.

2. The high-temperature resistant multispectral imaging endoscope for aero-engines according to claim 1, characterized in that: The endoscope's heat insulation shell, composed of a metal outer shell and internal heat insulation material, protects the internal optical components. The internal front and rear sections of the endoscope barrel, pressure ring, rear spacer, and adhesive sheet can keep the focal length and optical axis of the internal optical components stable even under vibration.

3. The high-temperature resistant multispectral imaging endoscope for aero-engines according to claim 1, characterized in that: Sapphire glass is used to provide an optical window for the front imaging lens while protecting the internal lenses.

4. A high-temperature resistant multispectral imaging endoscope for aero-engines according to claim 1, characterized in that: The transmittance of the beam splitter prism group is adjustable, so that light is split into multiple spectral channels as it passes through the prism group.

Images