A total temperature probe for optical fibers

Abstract

The application belongs to the technical field of optical fiber total temperature probe design, and particularly relates to an optical fiber total temperature probe, which collects optical signals in a high-temperature condition and a limited volume by using a high-temperature-resistant sapphire optical fiber, can effectively collect blackbody radiation energy, and low-lossly transfer the blackbody radiation energy to a low-temperature area for detection, the inner wall of a probe protection tube radiates optical signals, the sapphire optical fiber for receiving the optical signals is located at a relatively low-temperature position at the rear end of the probe, and non-contactly receives the blackbody radiation signals of the probe protection tube, so that the sapphire optical fiber can be prevented from directly contacting a highest-temperature area, and the upper limit of temperature measurement can be improved, in addition, in the structure of the optical fiber total temperature probe, the radiated optical signals have a fixed radiation source and propagate in a closed cavity, and measurement errors caused by environmental interference and emissivity deviation of a to-be-measured object in radiation temperature measurement can be effectively avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of optical fiber total temperature probe design, and specifically relates to an optical fiber total temperature probe. Background Art

[0002] The most common method for measuring aircraft engine temperature parameters is to use thermocouples in conjunction with a stagnation structure to form a total temperature sensor. With technological advancements, the exhaust gas temperature at the combustion chamber outlet of current aircraft engines has reached over 1800°C. In such harsh environments, total temperature measurement becomes significantly more difficult.

[0003] A metal thermocouple is used as the total temperature measurement probe of the temperature sensing element, which directly contacts the gas to measure the total temperature of the gas. The thermocouple wire is easily oxidized and fails under high temperature conditions, resulting in reduced measurement accuracy and poor reliability. At the same time, since the thermocouple generates a weak potential signal when measuring temperature, its anti-electromagnetic interference ability is poor, and it is difficult to meet the test requirements of the high-temperature total temperature of the gas at the outlet of the aircraft engine combustion chamber.

[0004] Special fiber optic sensors based on sapphire optical fibers are widely regarded as ultra-high temperature sensor solutions because they do not involve electrical properties, the material has stable optical properties under high-temperature conditions, good long-term temperature resistance, and high stability.

[0005] Currently, high-temperature sapphire fiber optic sensors are generally made by sputtering platinum coating on the end of a bare fiber rod to form a cylindrical blackbody cavity to sense the gas temperature. The end of the fiber optic sensor is exposed to the high-temperature gas. The blackbody radiation reflecting the gas temperature is repeatedly totally reflected on the inner surface of the sapphire rod and transmitted through the optical cable to the back-end detector to be converted into a temperature indication.

[0006] The current sapphire blackbody cavity fiber optic sensor is used to measure the total temperature at the outlet of an aircraft engine combustion chamber. Due to the sapphire rod's melting point of 2045°C, the upper temperature measurement limit is not high. At the same time, since the temperature sensing end is directly exposed to the high-temperature gas environment of the combustion chamber components, the radiation environment interference is relatively large. It is easily contaminated by carbon soot in the gas environment, which causes the blackbody cavity emissivity to change, resulting in a large error in the total temperature measurement.

[0007] Current sapphire blackbody cavity fiber optic sensors typically use direct contact measurements perpendicular to the high-temperature gas flow. This exposes the sapphire rod to the high-temperature gas environment. At high gas velocities, the temperature regeneration coefficient is low, resulting in significant error in the measured temperature velocity. Furthermore, radiation heat transfer between the ambient, low-temperature wall and the sensor probe introduces significant radiation error. The sensor's temperature-sensing tip also experiences significant thermal conductivity error due to the nonuniform temperature field at the combustion chamber's outlet and the cooling effect of the fiber optic sensor's support structure.

[0008] In addition, when measuring the total temperature at the combustion chamber outlet, current aircraft engine total temperature probes mostly use ceramic-based materials as the probe's support rod load-bearing parts. During the test, they are constantly subjected to the erosion of high-temperature, high-speed combustion gas flow in the engine flow channel. At the same time, the nearby rotating blades also impose alternating loads on them. The ceramic-based material has poor toughness and thermal vibration resistance, and the ceramic-based support rod is not reliable. During processing and use, the root is prone to fracture and failure, threatening the safety of aircraft engine testing.

[0009] Currently, the internal sensors of total temperature measurement probes are mostly fixed packaging structures. High-temperature glue or cement is poured inside to fix the temperature sensing element to the supporting structure. It also plays a sealing role to prevent the high-temperature gas in the flow channel from leaking to the rear-end lead packaging part and causing ablation damage. However, this type of fixing and sealing structure will make it difficult to disassemble and replace the temperature sensing element, which is not conducive to the repair and maintenance of the temperature probe. At the same time, the high-temperature glue and cement will age after long-term use, and the sealing effect will be reduced or even fail, resulting in damage to the rear-end lead packaging part of the probe.

[0010] This application is proposed in view of the above-mentioned technical defects. Summary of the Invention

[0011] The purpose of the present application is to provide a fiber optic total temperature probe to overcome or alleviate at least one of the existing technical deficiencies.

[0012] The technical solution of this application is:

[0013] An optical fiber total temperature probe comprises an optical fiber total temperature probe, a compression nut, a mounting seat, a ceramic outer support, and a ceramic inner support;

[0014] The mounting base has a penetrating mounting hole;

[0015] The ceramic outer support is hollow inside, with an opening at the top of the root and a blocked front end of the tail;

[0016] The front end of the tail of the ceramic outer support is arranged through the mounting hole on the mounting seat, and the top end of the root is in the mounting hole and contacts with the 45° cone surface between the mounting holes;

[0017] The front end side wall of the rear end of the ceramic outer support member has an air inlet hole and an exhaust hole, wherein the air inlet hole is closer to the front end of the rear end than the exhaust hole; the diameter of the air inlet hole is larger than the diameter of the exhaust hole;

[0018] The ceramic inner support has a through inner hole and is arranged in the ceramic outer support. The top end is matched with the inner part of the ceramic outer support through a step structure. A second high-temperature ceramic fiber sealing pad is provided at the matching position of the step structure. The front end extends to the front of the exhaust hole on the side wall of the front end of the rear end of the ceramic outer support.

[0019] The fiber optic total temperature probe includes a fiber optic connector, a quartz fiber, an adapter, an inner tube, a sapphire fiber and a probe protection tube;

[0020] The probe protection tube is sealed at the front end, passes through the inner hole of the ceramic inner support, and extends into the front end of the tail of the ceramic outer support;

[0021] The front end of the sapphire optical fiber extends into the probe protection tube;

[0022] The inner tube is fixed between the probe protection tube and the sapphire optical fiber by high-temperature adhesive bonding;

[0023] The adapter is connected to the top of the probe protection tube;

[0024] The adapter seat has an adapter hole inside and an annular boss on the outer wall. The front end extends into the inner hole of the ceramic inner support and is matched with the inner hole of the ceramic inner support through a step structure. A first high-temperature ceramic fiber sealing pad is provided at the matching position of the step structure.

[0025] The rear end of the sapphire optical fiber extends into the adapter hole;

[0026] The front end of the quartz optical fiber extends into the adapter hole and connects to the back end of the sapphire optical fiber;

[0027] The optical fiber connector is connected to the rear end of the quartz optical fiber;

[0028] The compression nut is sleeved on the outer periphery of the adapter, is threadedly connected to the mounting hole of the mounting seat, is pressed on the annular boss, and cooperates with the annular boss through a step structure, and a sealing gasket is provided at the cooperation position of the step structure.

[0029] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, a threaded hole is formed on the side wall of the mounting seat for installing a locking screw;

[0030] A locking opening is provided on the side wall of the top end of the root of the ceramic outer support member, and a locking screw is inserted into the locking opening.

[0031] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the entire mounting base is made of a high-temperature alloy material;

[0032] The outer wall of the mounting seat has a mounting edge and can be mounted on the receiver by bolts;

[0033] The mounting seat is provided with a mounting gasket which is made of relatively soft metal material and is located between the mounting edge and the receiver.

[0034] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the ceramic outer support member and the ceramic inner support member are tightly connected by high-temperature resistant ceramic fibers;

[0035] The air inlet and exhaust holes on the ceramic outer support are circular, and the air inlet openings are 45°

[0036] Chamfer.

[0037] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the ceramic outer support is reinforced near the root of the mounting seat and transitions to the exhaust hole position on the front end side wall of the tail at a certain cone angle.

[0038] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the probe protection tube is made of metal iridium;

[0039] The ratio of the length of the portion of the probe protection tube extending into the front end of the tail of the ceramic outer support to the diameter is greater than 10.

[0040] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the inner tube is a ceramic tube.

[0041] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the adapter is connected to the top end of the probe protection tube by bonding or welding.

[0042] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, the front end of the quartz optical fiber and the rear end of the sapphire optical fiber are fused in the transition hole, and the fusion joint is sealed and protected.

[0043] According to at least one embodiment of the present application, in the above-mentioned optical fiber total temperature probe, a high-temperature spring washer is provided on the outer periphery of the adapter;

[0044] The high-temperature spring washer is located between the annular boss and the top end of the ceramic outer support member.

[0045] This application has at least the following beneficial technical effects:

[0046] Provided is a fiber optic total temperature probe that uses high-temperature resistant sapphire optical fiber to collect optical signals under high-temperature conditions and in a limited volume. The probe can effectively collect blackbody radiation energy and transmit it to a low-temperature area with low loss for detection. The inner wall of the probe protection tube radiates optical signals. The sapphire optical fiber that receives the optical signal is designed to be located at a relatively low-temperature position at the rear end of the probe. The blackbody radiation signal of the probe protection tube is received non-contact, which prevents the sapphire optical fiber from direct contact with the highest-temperature area and improves the upper limit of temperature measurement. In addition, in the fiber optic total temperature probe structure, the radiated optical signal has a fixed radiation source and propagates in a closed cavity, which can effectively avoid measurement errors caused by environmental interference and emissivity offset of the object to be measured during radiation temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of an optical fiber total temperature probe provided in an embodiment of the present application;

[0048] Figure 2 is a schematic diagram of a mounting base provided in an embodiment of the present application;

[0049] Figure 3 is a schematic diagram of a ceramic outer support provided in an embodiment of the present application;

[0050] Figure 4 Schematic diagram of an optical fiber total temperature probe provided in an embodiment of the present application;

[0051] Figure 5 Schematic diagram of the variation of the blackbody radiation spectrum with temperature provided in the embodiment of the present application;

[0052] in:

[0053] 1-Fiber optic total temperature probe; 2-Compression nut; 3-Sealing gasket; 4-High-temperature spring washer; 5-Locking screw; 6-Mounting seat; 7-Mounting gasket; 8-First high-temperature ceramic fiber sealing gasket; 9-Ceramic outer support; 10-Second high-temperature ceramic fiber sealing gasket; 11-Ceramic inner support;

[0054] 1-1-Fiber optic connector; 1-2-Quartz fiber; 1-3-Adapter; 1-4-Inner tube; 1-5-Sapphire fiber; 1-6-Probe protection tube.

[0055] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be understood as limiting this application. DETAILED DESCRIPTION

[0056] To make the technical solution and its advantages of this application more clear, the technical solution of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only some of the embodiments of this application and are only used to explain this application, not to limit this application. It should be noted that for ease of description, only the parts relevant to this application are shown in the accompanying drawings, and other relevant parts can refer to the general design.

[0057] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should have the usual meanings understood by those skilled in the art in the field to which this application belongs. The words indicating orientation used in the description of this application are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application means that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0058] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0059] A fiber optic total temperature probe, such as Figure 1 As shown, it includes an optical fiber total temperature probe 1, a compression nut 2, a sealing gasket 3, a high-temperature spring washer 4, a locking screw 5, a mounting seat 6, a mounting gasket 7, a first high-temperature ceramic fiber sealing gasket 8, a ceramic outer support 9, a second high-temperature ceramic fiber sealing gasket 10, and a ceramic inner support 11.

[0060] The mounting seat 6 is made of high temperature alloy material as a whole. Figure 2 As shown, there is a through mounting hole. The side wall of the mounting seat 6 is provided with a threaded hole for installing the locking screw 5.

[0061] The outer wall of the mounting seat 6 has a mounting edge and can be mounted on the receiver by bolts.

[0062] The mounting gasket 7 is made of a relatively soft metal material and is sleeved on the outer periphery of the mounting seat 6, located between the mounting edge and the casing, and can play a role in vibration reduction and sealing.

[0063] The ceramic outer support 9 and the ceramic inner support 11 are combined into a double-layer load-bearing support rod, which can withstand the erosion of high-temperature combustion gas in the flow channel inside the casing. The ceramic outer support 9 and the ceramic inner support 11 are designed to be tightly connected using high-temperature resistant ceramic fibers.

[0064] Ceramic outer support 9 such as Figure 3 As shown, the overall conical structure is hollow, with an open base and a sealed tail. The tail end of the ceramic outer support 9 passes through the mounting hole in the mounting seat 6 and extends into the casing, where it comes into contact with the high-temperature combustion gas. The root end is located in the mounting hole, where it engages with the 45-degree tapered surface between the mounting holes.

[0065] The side wall of the front end of the rear end of the ceramic outer support 9 has an air inlet and an exhaust hole, wherein the air inlet is closer to the front end of the rear end than the exhaust hole. The air inlet and exhaust holes are circular. This ensures that the high-temperature gas flow rate from the air inlet into the ceramic outer support 9 is reduced to below M0.2. The air inlet orifice is chamfered at 45°, which can expand the insensitive angle range of the temperature test and improve the accuracy of temperature measurement.

[0066] The ceramic outer support 9 is reinforced near the root of the mounting seat 6, and transitions to the exhaust hole position on the front end side wall of the tail at a certain cone angle, close to the center of the flow channel in the casing.

[0067] A locking hole is provided on the top side wall of the root of the ceramic outer support 9, and the locking screw 5 is inserted into the locking hole to lock and limit the ceramic outer support 9 to prevent the ceramic outer support 9 from circumferential rotation and axial movement during use.

[0068] The ceramic inner support 11 has a penetrating inner hole and is arranged in the ceramic outer support 9. The top end is matched with the ceramic outer support 9 through a step structure. A second high-temperature ceramic fiber sealing pad 10 is provided at the matching position of the step structure, and the front end extends to the front of the exhaust hole on the front side wall of the rear end of the ceramic outer support 9.

[0069] Fiber optic total temperature probe 1 Figure 4 As shown, it is mainly composed of an optical fiber connector 1-1, a quartz optical fiber 1-2, an adapter 1-3, an inner tube 1-4, a sapphire optical fiber 1-5 and a probe protection tube 1-6.

[0070] The probe protection tube 1-6 is sealed at the front end, passes through the inner hole of the ceramic inner support 11, and extends into the front end of the rear end of the ceramic outer support 9. The ratio of the length of the portion of the probe protection tube 1-6 extending into the front end of the rear end of the ceramic outer support 9 to the diameter is greater than 10.

[0071] Probe protection tube 1-6 is made of iridium metal and comes into direct contact with the high-temperature gas. The high-temperature gas entering the front end of the rear end of the ceramic outer support member 9 stagnates at the front end of the probe protection tube 1-6. At this point, the temperature at the front end of the probe protection tube 1-6 matches the total stagnation temperature of the high-temperature gas. The interior of the probe protection tube 1-6 emits a blackbody radiation signal at this temperature, which is unaffected by the external high-temperature gas environment.

[0072] The front end of the sapphire optical fiber 1-5 extends into the probe protection tube 1-6 and can receive blackbody radiation signals.

[0073] The inner tube 1-4 is a ceramic tube, which is fixed between the probe protection tube 1-6 and the sapphire optical fiber 1-5 by high-temperature adhesive bonding. It supports and limits the sapphire optical fiber 1-5 and ensures the stability of the sapphire optical fiber 1-5 when receiving blackbody radiation signals.

[0074] The adapter 1-3 is attached to the top of the probe protection tube 1-6 by bonding or welding, and is used to secure the optical fiber total temperature probe 1. The adapter 1-3 has an internal adapter hole and an annular boss on its outer wall. The front end of the adapter 1-3 extends into the inner hole of the ceramic inner support 11, where it engages with the inner hole of the ceramic inner support 11 via a stepped structure. A first high-temperature ceramic fiber sealing gasket 8 is positioned at the mating point of this stepped structure. The rear end of the sapphire optical fiber 1-5 extends into the adapter hole.

[0075] The front end of quartz fiber 1-2 extends into the adapter hole and is fused to the rear end of sapphire fiber 1-5. The fusion splice is sealed and protected. The blackbody radiation signal received by the front end of sapphire fiber 1-5 is transmitted to the rear end of quartz fiber 1-2 in the lower temperature region. The two fibers are coupled together through fusion splicing or other methods.

[0076] The optical fiber connector 1-1 is connected to the rear end of the quartz optical fiber 1-2.

[0077] The compression nut 2 is sleeved on the outer periphery of the adapter 1-3, threadedly connected to the mounting hole of the mounting seat 6, pressed on the annular boss, and matched with the annular boss through a step structure, and a sealing gasket 3 is provided at the matching position of the step structure.

[0078] The high-temperature spring washer 4 is sleeved on the outer periphery of the adapter 1-3, located between the annular boss and the top of the ceramic outer support 9. It can play a buffering and vibration reduction role when the clamping nut 2 compresses the optical fiber total temperature probe 1. At the same time, it can also adjust the thread pre-tightening force of the clamping nut 2 to prevent the clamping nut 2 from loosening due to vibration during use.

[0079] In the optical fiber total temperature probe disclosed in the above embodiment, four movable sealing structures are designed, namely, the 45° conical surface seal between the ceramic outer support 9 and the mounting seat 6, the ceramic inner support 11 and the optical fiber total temperature probe 1 will be sealed with a first high-temperature ceramic fiber sealing gasket 8, the ceramic inner support 11 and the ceramic outer support 9 will be sealed with a second high-temperature ceramic fiber sealing gasket 10, and the optical fiber total temperature probe 1 and the clamping nut 2 will be sealed with a sealing gasket 3. After the clamping nut 2 is tightened, the four movable sealing structures can be pressed by force to ensure that the high-temperature gas will not leak. At the same time, the setting of the four movable sealing structures facilitates the replacement of the optical fiber total temperature probe 1.

[0080] The fiber optic total temperature probe 1 is a key temperature-sensing component of the fiber optic total temperature probe and must be securely fixed during use. Tightening the compression nut 2 applies a compressive force to the fiber optic total temperature probe 1, which then transmits this compressive force to the ceramic inner support 11 and ceramic outer support 9. This ensures that all internal components of the fiber optic total temperature probe are securely connected to the mounting base 6, securing the fiber optic total temperature probe 1. This fixed structure allows for flexible replacement of the fiber optic total temperature probe 1, resulting in higher reliability and cost-effectiveness.

[0081] When measuring the total temperature at the outlet of an aircraft engine combustion chamber using the optical fiber total temperature probe disclosed in the above-mentioned embodiment, the mounting edge on the mounting seat 6 can be connected to the casing with bolts for fixation. The mounting seat 6 and the front end of its ceramic outer support 9 extend into the flow channel through the measuring hole opened on the casing. The high-temperature combustion gas can enter from the windward side from the air inlet hole on the ceramic outer support 9, stop at the front end of the optical fiber total temperature probe 1, and be discharged from the exhaust hole on the leeward side of the ceramic outer support 9. The front end temperature of the optical fiber total temperature probe 1 is the stagnation temperature of the high-temperature combustion gas, that is, the total temperature of the high-temperature combustion gas at the outlet of the aircraft engine combustion chamber.

[0082] Aircraft engine internal flow temperature measurement typically refers specifically to total internal flow temperature. The total airflow temperature, T*, consists of two components: static temperature (T) and dynamic temperature (Tv). The static temperature (T) represents the kinetic energy of the free motion of gas molecules, while the dynamic temperature (Tv) represents the kinetic energy of their directional motion. To ensure that the sensor surface temperature more closely approximates the total airflow temperature, the total temperature probe incorporates a stagnation structure. This stagnation acts both within the stagnation cavity and on the sensor end face, significantly reducing flow velocity. This converts the kinetic energy of the airflow into heat, raising the temperature within the probe. Neglecting heat dissipation, the temperature at the sensor tip represents the total airflow temperature.

[0083] According to the radiation principle, all objects with temperature will continuously emit thermal radiation to the outside world, and it will be expressed in the form of electromagnetic waves. According to Planck's formula, the radiation energy per unit wavelength interval of a specific wavelength emitted by a black body per unit area in all directions of the hemispherical space per unit time is Where λ is the radiation wavelength of the object, T is the absolute temperature of the object, C1=3.7418×10 －16 Wm 2 、C 2 =1.4388×10 －2 mk are the first and second radiation constants respectively.

[0084] The variation of blackbody radiation spectrum with temperature, such as Figure 5 As shown in Figure 2, the energy characteristics of blackbody radiation within a certain wavelength band are modulated by temperature. This characteristic also applies to real objects. Based on this characteristic, the corresponding temperature information can be obtained by measuring the characteristic signal of the target object's radiation energy and demodulating it.

[0085] The optical fiber total temperature probe disclosed in the above embodiment uses a high-temperature resistant sapphire optical fiber 1-5 to collect optical signals under high temperature conditions and in a limited volume. It can effectively collect blackbody radiation energy and transmit it to the low-temperature area with low loss for detection. The inner wall of the probe protection tube 1-6 will radiate optical signals. The sapphire optical fiber 1-5 that receives the optical signal is designed to be located at a relatively low temperature position at the rear end of the probe. The blackbody radiation signal of the probe protection tube 1-6 is received non-contact, which can prevent the sapphire optical fiber 1-5 from direct contact with the highest temperature area and improve the upper limit of temperature measurement. In addition, in the optical fiber total temperature probe structure disclosed in the above embodiment, the radiated optical signal has a fixed radiation source and propagates in a closed cavity, which can effectively avoid measurement errors caused by environmental interference and emissivity offset of the object to be measured in radiation temperature measurement.

[0086] In the optical fiber total temperature probe disclosed in the above embodiment, the ceramic outer support 9 is designed to have a front end side wall at the rear end. The flow rate of the high-temperature gas entering the front end of the tail of the ceramic outer support 9 can be reduced to below M0.2, which can effectively reduce the speed error of the temperature measurement of the optical fiber total temperature probe 1, and the front end of the tail of the ceramic outer support 9 can effectively shield the radiation interference of the low-temperature wall of the surrounding environment on the optical fiber total temperature probe 1 therein, reduce the temperature difference between the optical fiber total temperature probe 1 and the wall it "sees", and reduce the temperature measurement error caused by radiation heat exchange. In addition, the optical fiber total temperature probe 1 is parallel to the flow direction of the gas in the shielding cavity formed at the front end of the tail of the ceramic outer support 9. According to the principle of infinite length pivot heat conduction, the ratio of the length to the diameter of the optical fiber total temperature probe 1 in the shielding cavity is designed to be greater than 10, and the convective heat transfer area and thermal conductivity resistance of the optical fiber total temperature probe 1 are increased. The optical fiber total temperature probe 1 in the shielding cavity will be uniformly heated by the high-temperature gas, and the temperature at the internal support base will be closer to the temperature of the temperature sensing area at the front end of the probe, so as to reduce the thermal conduction error.

[0087] Applying the optical fiber total temperature probe disclosed in the above embodiment to measure the total temperature at the outlet of an aircraft engine combustion chamber can effectively suppress velocity error, radiation error, and thermal conductivity error, thereby reducing the impact of these three errors on the accuracy of total temperature measurement.

[0088] In the optical fiber total temperature probe disclosed in the above embodiment, the sapphire optical fiber 1-5 inside the optical fiber total temperature probe 1 receives the thermal radiation energy of the part of the probe that contacts the high-temperature gas, and then demodulates the gas stagnation temperature, so as to perform contact measurement of the total temperature of the high-temperature and high-speed gas at the outlet of the aircraft engine combustion chamber. This can solve the problems of existing temperature measurement methods that are susceptible to environmental interference, poor reliability and low accuracy, and can effectively avoid measurement errors caused by the emissivity offset of the object to be measured in traditional radiation temperature measurement.

[0089] In the optical fiber total temperature probe disclosed in the above embodiment, the shielding cavity formed at the front end of the tail of the ceramic outer support 9 can shield the radiation interference of the low-temperature wall of the surrounding environment, reduce the temperature measurement error caused by the radiation heat exchange, and reduce the high-temperature gas flow rate at the temperature sensing end of the optical fiber total temperature probe 1 by designing the area of ​​the air inlet and outlet holes. The optical fiber total temperature probe 1 is parallel to the flow direction of the high-temperature gas in the shielding cavity. The optical fiber total temperature probe 1 will be uniformly heated by the gas in the shielding cavity, and the surface temperature is close to uniform, which can reduce the influence of the cooling effect of the root of the supporting structure of the optical fiber total temperature probe 1 and reduce the thermal conductivity error.

[0090] In the optical fiber total temperature probe disclosed in the above embodiment, a ceramic outer support member 9 and a ceramic inner support member 11 are combined into a double-layer load-bearing support rod to form a double-layer composite ceramic support structure. The inner and outer layer support rods are tightly connected by high-temperature resistant ceramic fibers, which can reduce the impact load of the high-temperature gas flow and the alternating load applied by the rotating blades, and improve the rigidity and vibration resistance of the support structure. In addition, if the inner and outer layer support rods and seals under this structure are damaged, they can be replaced separately, which is economical.

[0091] In the optical fiber total temperature probe disclosed in the above embodiment, a reliable internal sealing and fixing structure is designed to prevent leakage of high-temperature gas and avoid ablation of the probe tail packaging part. At the same time, this structure can also ensure that the optical fiber total temperature probe 1 inside the probe is reliably fixed and flexibly replaced, with high reliability and economy.

[0092] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. An optical fiber total temperature probe, characterized in that: It comprises an optical fiber total temperature probe (1), a compression nut (2), a mounting base (6), a ceramic outer support (9), and a ceramic inner support (11); The mounting seat (6) has a through mounting hole; The ceramic outer support member (9) is hollow inside, with an opening at the top end of the root and a blocked front end of the tail; The front end of the tail of the ceramic outer support (9) passes through the mounting hole on the mounting seat (6), and the top end of the root is located in the mounting hole and is in contact with the 45° conical surface between the mounting holes; The ceramic outer support member (9) has an air inlet and an exhaust hole on its rear front end side wall, wherein the air inlet is closer to the rear front end than the exhaust hole; the diameter of the air inlet is larger than the diameter of the exhaust hole; The ceramic inner support member (11) has a through inner hole and is arranged in the ceramic outer support member (9). The top end is matched with the ceramic outer support member (9) through a step structure. A second high-temperature ceramic fiber sealing pad (10) is provided at the matching position of the step structure. The front end extends to the front of the exhaust hole on the side wall of the rear end of the ceramic outer support member (9). The optical fiber total temperature probe (1) comprises an optical fiber connector (1-1), a quartz optical fiber (1-2), an adapter (1-3), an inner tube (1-4), a sapphire optical fiber (1-5) and a probe protection tube (1-6); The probe protection tube (1-6) is sealed at the front end, passes through the inner hole of the ceramic inner support (11), and extends into the front end of the tail of the ceramic outer support (9); The front end of the sapphire optical fiber (1-5) extends into the probe protection tube (1-6); The inner tube (1-4) is fixed between the probe protection tube (1-6) and the sapphire optical fiber (1-5) by means of high-temperature adhesive bonding; The adapter (1-3) is connected to the top of the probe protection tube (1-6); The adapter seat (1-3) has an adapter hole inside and an annular boss on its outer wall. The front end extends into the inner hole of the ceramic inner support (11) and is matched with the inner hole of the ceramic inner support (11) via a step structure. A first high-temperature ceramic fiber sealing pad (8) is provided at the matching position of the step structure. The rear end of the sapphire optical fiber (1-5) extends into the adapter hole; The front end of the quartz optical fiber (1-2) extends into the transfer hole and is connected to the rear end of the sapphire optical fiber (1-5); The optical fiber connector (1-1) is connected to the rear end of the quartz optical fiber (1-2); The compression nut (2) is sleeved on the outer periphery of the adapter seat (1-3), is threadedly connected to the mounting hole of the mounting seat (6), is pressed against the annular boss, and is matched with the annular boss via a step structure. A sealing gasket (3) is provided at the matching position of the step structure.

2. The optical fiber total temperature probe according to claim 1, characterized in that: The side wall of the mounting seat (6) is provided with a threaded hole for mounting a locking screw (5); A locking opening is provided on the top side wall of the root of the ceramic outer support member (9), and a locking screw (5) is inserted into the locking opening.

3. The optical fiber total temperature probe according to claim 2, characterized in that: The mounting seat (6) is entirely made of high-temperature alloy material; The outer wall of the mounting seat (6) has a mounting edge and can be mounted on the receiver by bolts; The mounting seat (6) is sleeved with a mounting gasket (7), which is made of relatively soft metal material and is located between the mounting edge and the casing.

4. The optical fiber total temperature probe according to claim 3, characterized in that: The ceramic outer support member (9) and the ceramic inner support member (11) are tightly connected by high-temperature resistant ceramic fibers; The air inlet and the air outlet on the ceramic outer support (9) are circular, and the opening of the air inlet is chamfered at 45 degrees.

5. The optical fiber total temperature probe according to claim 4, characterized in that: The ceramic outer support member (9) is reinforced near the root of the mounting seat (6) and transitions to the exhaust hole position on the front end side wall of the tail at a certain cone angle.

6. The optical fiber total temperature probe according to claim 5, characterized in that: The probe protection tube (1-6) is made of metal iridium; The ratio of the length of the portion of the probe protection tube (1-6) extending into the front end of the tail of the ceramic outer support (9) to the diameter is greater than 10.

7. The optical fiber total temperature probe according to claim 6, characterized in that: The inner pipe parts (1-4) are ceramic pipes.

8. The optical fiber total temperature probe according to claim 7, characterized in that: The adapter (1-3) is connected to the top of the probe protection tube (1-6) by bonding or welding.

9. The optical fiber total temperature probe according to claim 8, characterized in that: The front end of the quartz optical fiber (1-2) and the rear end of the sapphire optical fiber (1-5) are fused in the transfer hole, and the fusion joint is sealed for protection.

10. The optical fiber total temperature probe according to claim 9, characterized in that: The outer periphery of the adapter seat (1-3) is provided with a high-temperature spring washer (4); The high-temperature spring washer (4) is located between the annular boss and the top end of the ceramic outer support (9).

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