A fluid transient temperature sensor based on the FP principle

Abstract

The application relates to a fluid transient temperature sensor based on an FP principle and belongs to the field of optical temperature sensing; one end of a 99 corundum ceramic pipe is overlapped on a 316 stainless steel metal seat, a fiber collimator is coaxially arranged in the inner cavity of the end of the 99 corundum ceramic pipe; a 99 corundum adapter is connected with the other end of the 99 corundum ceramic pipe; a transparent reflecting sheet is vertically arranged in the inner cavity of the 99 corundum adapter, and the transparent reflecting sheet is axially perpendicular to the 99 corundum ceramic pipe; fluid holes are uniformly arranged on the outer wall of the 99 corundum adapter in the circumferential direction, and the positions of the fluid holes correspond to the positions of the transparent reflecting sheet; one end of the fiber collimator, which is stretched out of the 99 corundum ceramic pipe, is connected with a circulator through a cable; the circulator is connected with a wide-spectrum light source and a demodulation terminal through optical fibers; the application improves the temperature resistance degree and the upper limit of temperature measurement of the overall structure, has a long service life, and does not have the service life attenuation problem under the conditions that the application is not damaged by the outside world and the temperature sensing element is kept clean.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of optical temperature sensing, and relates to a fluid transient temperature sensor based on the FP principle. BACKGROUND

[0002] Temperature is an important physical parameter, and temperature measurement is widely used in state evaluation of vehicles, aircrafts, pipelines and many other devices, and is of great significance to device design and operation monitoring. In some special scenarios, such as the temperature field in the fluid flow channel of an aircraft engine, the temperatures of different temperature measuring points may not be consistent, and the temperature changes rapidly. If the fluid temperature at a certain point can be measured quickly, it will be of great significance to the working state confirmation and health monitoring of the engine.

[0003] In special application conditions, such as the combustion chamber pipeline of an aviation or aerospace engine, the fluid temperature can reach thousands of degrees Celsius. Therefore, how to measure the fluid temperature at a specific point in the ultra-high temperature range has become an urgent solution in engineering. At the same time, the response speed of the temperature sensor will directly affect the health monitoring ability of the flow channel, and the highest airflow speed of this part may reach 1-2 Mach.

[0004] At present, in special working conditions, fluid temperature measurement is usually carried out by using special thermocouples. Thermocouple temperature measurement belongs to electrical temperature measurement, which is easy to be disturbed in a strong electromagnetic environment. The optical anti-electromagnetic interference characteristic is unmatched by electricity, and the thermocouple is usually corroded by high-temperature environment, resulting in heat loss and the need for regular replacement. SUMMARY

[0005] The technical problem solved by the application is to overcome the shortcomings of the prior art and provide a fluid transient temperature sensor based on the FP principle, which improves the overall temperature resistance and temperature measurement upper limit, has a long service life, and does not have the problem of service life decay under the condition of not being damaged by the outside world and keeping the temperature sensing element clean.

[0006] The technical solution of the application is:

[0007] A fluid transient temperature sensor based on the FP principle, comprising a transparent reflector, a 99 corundum adapter, a 99 corundum ceramic tube, a 316 stainless steel metal seat, a fiber collimator, a circulator, a wide-spectrum light source and a demodulation terminal.

[0008] The 316 stainless steel metal seat is horizontally placed; the 99 corundum ceramic tube is axially and horizontally placed, and one end of the 99 corundum ceramic tube is overlapped on the 316 stainless steel metal seat, and the optical fiber collimator is coaxially arranged in the inner cavity of the end of the 99 corundum ceramic tube; the 99 corundum adapter is connected with the other end of the 99 corundum ceramic tube; the transparent reflection sheet is vertically arranged in the inner cavity of the 99 corundum adapter, and the transparent reflection sheet is axially perpendicular to the 99 corundum ceramic tube; the fluid holes are uniformly arranged on the outer wall of the 99 corundum adapter in the circumferential direction, and the positions of the fluid holes correspond to the positions of the transparent reflection sheet; one end of the optical fiber collimator extending out of the 99 corundum ceramic tube is connected with the circulator through a cable; the circulator is connected with the wide-spectrum light source and the demodulation terminal through optical fibers.

[0009] In the above-mentioned fluid transient temperature sensor based on the FP principle, the working process of the fluid transient temperature sensor is as follows:

[0010] The wide-spectrum light source emits a divergent light signal to the circulator; the circulator switches the transmission direction of the divergent light signal to transmission to the collimator; the collimator converts the divergent light signal into a collimated light signal and sends the collimated light signal to the transparent reflection sheet along the axial direction of the 99 corundum ceramic tube;

[0011] The external fluid to be measured enters the inner cavity of the 99 corundum adapter through the fluid hole and contacts the transparent reflection sheet, thereby transmitting the temperature to the transparent reflection sheet; the transparent reflection sheet deforms after being heated; the transparent reflection sheet receives the collimated light signal transmitted by the collimator and reflects it; the collimator receives the reflected light and transmits it to the circulator; the circulator switches the transmission direction of the reflected light to transmission to the demodulation terminal; the demodulation terminal demodulates the temperature of the external fluid to be measured.

[0012] In the above-mentioned fluid transient temperature sensor based on the FP principle, the transparent reflection sheet is a temperature-sensing element; the transparent reflection sheet is made of transparent materials such as quartz, single-crystal silicon carbide or single-crystal aluminum oxide.

[0013] In the above-mentioned fluid transient temperature sensor based on the FP principle, the top surface and the bottom surface of the transparent reflection sheet are both provided with FP cavities, i.e., both of them reflect the incoming collimated light signal; after the transparent reflection sheet is deformed after being heated, there is an optical path difference between the reflected light of the top surface and the reflected light of the bottom surface.

[0014] In the above-mentioned fluid transient temperature sensor based on the FP principle, the collimator transmits the reflected light of the top surface and the reflected light of the bottom surface of the transparent reflection sheet to the demodulation terminal through the circulator; the demodulation terminal obtains the amount of deformation of the transparent reflection sheet according to the optical path difference of the two reflected lights, and obtains the temperature of the external fluid to be measured according to the known curve of the deformation amount of the transparent reflection sheet and the temperature.

[0015] In the above-mentioned fluid transient temperature sensor based on the FP principle, the transparent reflective sheet is bonded in a dot coating manner at the inner cavity dotting position of the 99 corundum adapter; the glue is ceramic glue; after bonding, it is cured at room temperature for 24 hours, then placed on a heating platform, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

[0016] In the above-mentioned fluid transient temperature sensor based on the FP principle, the 99 corundum adapter is bonded with the corresponding shaft end of the 99 corundum ceramic tube by using ceramic glue; after bonding, the 99 corundum adapter and the 99 corundum ceramic tube are coaxial, and after curing at room temperature for 24 hours, it is placed on a heating platform, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

[0017] In the above-mentioned fluid transient temperature sensor based on the FP principle, the 99 corundum ceramic tube and the 316 stainless steel metal seat are bonded by ring coating through ceramic glue; when bonding, the 99 corundum ceramic tube is perpendicular to the 316 stainless steel metal seat through a tool; it is cured at room temperature for 24 hours, at 70 DEG C for 2 hours, and at 200 DEG C for 4 hours.

[0018] In the above-mentioned fluid transient temperature sensor based on the FP principle, the collimator is adjusted in angle by an external three-dimensional displacement platform, so that the collimator receives reflected light reflected by the transparent reflective sheet; the collimator and the 99 corundum ceramic tube are bonded by AB epoxy glue, and cured at room temperature for 24 hours.

[0019] In the above-mentioned fluid transient temperature sensor based on the FP principle, the optical fiber collimator is connected with the circulator by optical fiber coupler or optical fiber fusion.

[0020] The beneficial effects of the present application compared with the prior art are:

[0021] (1) The present application uses a transparent reflective sheet as a temperature sensing element, which can be made very thin, small in size, fast in heat conduction, and small in heat capacity. In addition, the connection between the transparent reflective sheet and the adapter is in a dot coating manner to reduce the contact area and the heat exchange rate, so that the transient response to temperature change can be realized.

[0022] (2) The present application uses a high-temperature-resistant ceramic tube as a support structure, which can be changed in length to realize accurate measurement of different measurement points.

[0023] (3) The present application uses a collimator as the emitting and receiving end of the optical signal, avoiding the direct entry of optical fiber into the temperature field, thereby improving the overall temperature resistance and the upper limit of temperature measurement.

[0024] (4) The present application uses the FP principle for temperature measurement, has high temperature measurement accuracy, and has the advantages of anti-electromagnetic interference and no attenuation of service life. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The schematic diagram of the fluid transient temperature sensor of the present application is shown in the figure;

[0026] Figure 2 The schematic diagram of the 99 corundum adapter of the present application is shown in the figure;

[0027] Figure 3 The schematic diagram of the interferometric spectrum of the present application is shown in the figure;

[0028] Figure 4 The schematic diagram of the energy spectrum distribution of the interferogram with the EFPI cavity length of the present application is shown in the figure. DETAILED DESCRIPTION

[0029] The present application is further described below in conjunction with examples.

[0030] The present application provides a fluid transient temperature sensor based on the FP principle, which improves the overall structure temperature resistance and temperature measurement upper limit, has long service life, and does not have service life decay problem under the condition of not being damaged by the outside world and keeping the temperature sensing element clean.

[0031] The fluid transient temperature sensor based on the FP principle, as shown in the figure, comprises a transparent reflective sheet 2, a 99 corundum adapter 3, a 99 corundum ceramic tube 4, a 316 stainless steel metal seat 5, a fiber collimator 6, a circulator 7, a wide spectrum light source 8, and a demodulation terminal 9. Figure 1

[0032] The 316 stainless steel metal seat 5 is horizontally placed; the 99 corundum ceramic tube 4 is axially and horizontally placed, and the axially one end of the 99 corundum ceramic tube 4 is overlapped on the 316 stainless steel metal seat 5, and the fiber collimator 6 is coaxially arranged in the inner cavity of the 99 corundum ceramic tube 4 at the end; the 99 corundum adapter 3 is connected with the axially other end of the 99 corundum ceramic tube 4; the transparent reflective sheet 2 is vertically arranged in the inner cavity of the 99 corundum adapter 3, and the transparent reflective sheet 2 is axially perpendicular to the 99 corundum ceramic tube 4; the fluid holes 1 are uniformly arranged on the outer wall of the 99 corundum adapter 3 in the circumferential direction, and the positions of the fluid holes 1 correspond to the positions of the transparent reflective sheet 2; the one end of the fiber collimator 6 extending out of the 99 corundum ceramic tube 4 is connected with the circulator 7 through a cable; the circulator 7 is connected with the wide spectrum light source 8 and the demodulation terminal 9 through optical fibers respectively.

[0033] The working process of the fluid transient temperature sensor is as follows:

[0034] The wide spectrum light source 8 emits a divergent light signal to the circulator 7; the circulator 7 switches the transmission direction of the divergent light signal to be transmitted to the collimator 6; the collimator 6 converts the divergent light signal into a collimated light signal, and sends the collimated light signal to the transparent reflective sheet 2 along the axis of the 99 corundum ceramic tube 4.

[0035] ​The external fluid to be measured enters the inner cavity of the 99 corundum adapter 3 through the fluid hole 1, contacts the transparent reflective sheet 2, and transmits the temperature to the transparent reflective sheet 2; the transparent reflective sheet 2 deforms after being heated; the transparent reflective sheet 2 receives the collimated light signal transmitted from the collimator 6 and reflects it; the collimator 6 receives the reflected light and transmits it to the ring oscillator 7; the ring oscillator 7 switches the transmission direction of the reflected light to the demodulation terminal 9; and the demodulation terminal 9 demodulates the temperature of the external fluid to be measured.

[0036] The transparent reflective sheet 2 is a temperature sensing element; the transparent reflective sheet 2 is made of transparent materials such as quartz, single crystal silicon carbide or single crystal aluminum oxide. The top surface and the bottom surface of the transparent reflective sheet 2 are both provided with FP cavities, that is, both reflect the incoming collimated light signal; after the transparent reflective sheet 2 deforms after being heated, there is a path difference between the reflected light on the top surface and the reflected light on the bottom surface.

[0037] The collimator 6 transmits the reflected light on the top surface and the bottom surface of the transparent reflective sheet 2 to the demodulation terminal 9 through the ring oscillator 7; the demodulation terminal 9 obtains the deformation amount of the transparent reflective sheet 2 according to the path difference of the two reflected lights, and obtains the temperature of the external fluid to be measured according to the known deformation amount-temperature curve of the transparent reflective sheet 2.

[0038] As shown in Figure 2 The transparent reflective sheet 2 is bonded to the inner cavity dispensing position of the 99 corundum adapter 3 in a point coating manner; the glue is ceramic glue; after bonding, it is cured at room temperature for 24 hours, then placed on a heating platform, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

[0039] The end of the 99 corundum adapter 3 without the fluid hole 1 is bonded to the corresponding shaft end of the 99 corundum ceramic tube 4 with ceramic glue; after bonding, the 99 corundum adapter 3 and the 99 corundum ceramic tube 4 remain coaxial, and after curing at room temperature for 24 hours, they are placed on a heating platform, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

[0040] The 99 corundum ceramic tube 4 and the 316 stainless steel metal seat 5 are bonded by ring coating with ceramic glue; when bonding, the 99 corundum ceramic tube 4 is perpendicular to the 316 stainless steel metal seat 5 through a tool; room temperature curing for 24 hours, 70 DEG C curing for 2 hours, 200 DEG C curing for 4 hours.

[0041] The collimator 6 adjusts the angle of the collimator 6 through an external three-dimensional displacement platform, so that the collimator 6 receives the reflected light reflected by the transparent reflective sheet 2; the collimator 6 and the 99 corundum ceramic tube 4 are bonded by AB epoxy glue, and cured at room temperature for 24 hours. The fiber collimator 6 is connected with the ring oscillator 7 by fiber coupler or fiber fusion.

[0042] The working principle of each component of the application is:

[0043] Fluid hole 1: This structure ensures that the fluid to be measured can be in direct contact with the transparent reflector, providing a more rapid and accurate source of temperature values.

[0044] Transparent reflector 2: As a temperature sensing element, its upper and lower surfaces form an FP cavity. The material can be (including but not limited to): quartz, single crystal silicon carbide, single crystal aluminum oxide, etc.

[0045] Adapter 3: As a protective and supporting structure for the transparent reflector, it can provide protection for the transparent reflector from damage caused by collisions with foreign objects in the fluid, while connecting the transparent reflector to the ceramic tube. The typical structure is shown in Figure 2 .

[0046] Ceramic tube 4: As the overall supporting structure of the temperature sensing part, the length of the ceramic tube can be determined according to the different temperature measurement positions, so that the temperature sensing part is directly at the temperature measurement point, achieving more accurate temperature measurement.

[0047] Metal seat 5: As the overall supporting and fixing structure of the sensor, the metal material can achieve better heat dissipation function after the ceramic tube is heated.

[0048] Collimator 6: This sensor is an active temperature measuring device, which can convert the divergent light transmitted in the optical fiber into a collimated light beam, emitting and receiving light signals.

[0049] Circulator 7: Controls the transmission direction of the light signal in the optical fiber.

[0050] Light source module 8: Emits light signals.

[0051] Demodulation module 9: Processes signals according to the return light signals.

[0052] Adapter structure 3 schematic diagram as Figure 2 , the dispensing position in the figure is a step structure, the transparent reflector is placed after dispensing, the adapter structure can protect the transparent reflector from damage caused by collisions with foreign objects in the fluid, and at the same time, the position of the transparent reflector can change with the change of the supporting rod, so that temperature measurement at any point in the flow field can be achieved; The size of the fluid hole can be changed according to the size of the foreign matter that may exist in the flow field, so as to protect the transparent reflector. The design of this fluid hole makes the fluid directly contact the transparent reflector, making the temperature measurement more accurate and rapid, thereby improving the response speed.

[0053] Use transparent reflector 2 as temperature sensing element, in order to achieve the purpose of transient temperature measurement, the thickness of this piece should be as low as possible to reduce the heat capacity, so as to improve the response speed.

[0054] The collimator 6 is used as the transmitting and receiving device of the optical signal. The collimator can output collimated light and receive the reflected signal from the upper and lower surfaces of the transparent reflector 2. Since the light is collimated, the length change of the ceramic tube 4 does not affect the signal measurement, so that the length change can be generated to realize the temperature measurement at any point in the full flow field range.

[0055] The selection of the light source should consider the light transmission band of the collimator 6 and the identification band of the demodulation module 9. The demodulation module 9 obtains the interference spectrum period information by Fourier transform of the reflected light signal spectrum, and then obtains the EFPI cavity length, and cooperates with the known calibration curve to obtain the measured temperature value.

[0056] Selection and connection of transparent reflector and adapter: The material selection of the two should be considered in terms of adaptability to the measured temperature range and compatibility with the fluid. The connection method usually adopts the adhesive method. In order to reduce the contact area between the transparent reflector and the adapter, and thus reduce the heat exchange speed between the two, improve the response speed of the sensor, the adhesive method adopts the point coating method for bonding. The selection of glue can be based on the material of the transparent reflector and the temperature range of the temperature measurement.

[0057] Connection of adapter and ceramic tube: usually adopts the adhesive method. Since the materials are both ceramic, ceramic glue can be usually selected for bonding.

[0058] Connection of ceramic tube and metal seat: usually adopts the adhesive method. The selection of glue can be based on the temperature range of the temperature measurement. Typical ones are ceramic glue or epoxy glue.

[0059] Connection of fiber collimator and metal seat: usually adopts the adhesive method. The typical glue used can be epoxy glue.

[0060] Embodiment

[0061] Fluid transient temperature sensor installation process is:

[0062] Step one: the transparent reflector 2 selects a quartz sheet with a thickness of 50 um and a diameter of 5 mm as a temperature sensing element, and uses a ceramic glue with high viscosity to bond it at the glue point of the adapter by point coating. When bonding, the transparent reflector 2 and the fluid hole 1 are kept at a vertical angle by a tool. After curing at room temperature for 24 hours, it is placed on a heating platform and cured at 70℃ for 2 hours and at 200℃ for 4 hours.

[0063] Step two: the adapter without fluid hole is coated with ceramic glue at one end of the 99 corundum ceramic tube 4. When bonding, the 99 corundum adapter 3 and the 99 corundum ceramic tube 4 are kept parallel by a tool. After curing at room temperature for 24 hours, it is placed on a heating platform and cured at 70℃ for 2 hours and at 200℃ for 4 hours.

[0064] Step three: 99 corundum ceramic tube 4 and 316 stainless steel metal seat 5 are adopted ring coating mode, and ceramic glue is used for bonding, and when bonding, 99 corundum ceramic tube 4 is perpendicular to 316 stainless steel metal seat 5 through a tool, and the bonding is cured at room temperature for 24 hours, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

[0065] Step four: the angle of the collimator 6 is adjusted through an external three-dimensional displacement platform to make the collimator 6 receive reflected light reflected by the transparent reflecting sheet 2; and the collimator 6 is bonded with the 99 corundum ceramic tube 4 through AB epoxy glue, and cured at room temperature for 24 hours.

[0066] Step five: the optical fiber collimator 6 is connected with the MOI through an optical fiber connector.

[0067] Step six: the sensor is connected with a fixed position through the 316 stainless steel metal seat, and the temperature sensing depth reaches the measured point, and the measurement can be started.

[0068] The demodulation mode adopted in the demodulation device is double-beam interference demodulation, and the typical reflection spectrum of the EFPI sensor obtained by the demodulation terminal is as shown in the schematic view Figure 3 .

[0069] I (v) = A + Bcos (4p dv) (1

[0070] Wherein:

[0071] v = 1 / lambda (2

[0072] A, B are constant terms, lambda is wavelength, and d is the cavity length of the FP cavity. After filtering the direct current, (1 formula can be written as:

[0073] I (v) = integral P (f) exp (i2p f v) df (3

[0074] P is the frequency spectrum distribution corresponding to the interference spectrum, f is the frequency, and the Fourier transform is carried out, that is, the distribution of spectral energy with the EFPI cavity length can be obtained, and the schematic view is as shown in the schematic view Figure 4 , the abscissa of the peak value is read, and the cavity length value can be obtained, and the temperature value of the measured fluid can be obtained by combining the known calibration curve.

[0075] The transparent reflecting sheet is used as the temperature sensing element, the material and thickness of the reflecting sheet are variable, different materials can be suitable for different temperature measurement requirements, and thinner thickness corresponds to smaller heat capacity, and in addition, the special dispensing mode reduces the heat exchange rate, and faster response speed is realized.

[0076] The application has novel structure, uses ceramic tube with high temperature resistance as support structure, length can be changed, realizes accurate measurement for different measuring points; uses collimator as light signal sending and receiving end, on one hand, can avoid optical fiber directly entering temperature field to be directly affected, thereby improving overall temperature resistance and temperature measurement upper limit, on the hand, through using collimator, makes divergent light become collimated light, provides possibility for length change of ceramic tube; adopts tubular structure, diameter can be controlled below 6mm, can cause as small as possible damage to to-be-measured flow field; optical principle measurement, can be used in strong electromagnetic interference environment; long service life, theoretically, under the condition that the temperature sensing element is not damaged and kept clean, there is no service life attenuation problem.

[0077] Although the application has been disclosed with the above preferred embodiments, it is not intended to limit the application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the application by using the disclosed methods and technical contents without departing from the spirit and scope of the application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the application, which does not deviate from the technical solutions of the application, belongs to the protection scope of the technical solutions of the application.

Claims

1. A fluid transient temperature sensor based on the FP principle, characterized in that: It comprises a transparent reflector (2), a 99 corundum adapter (3), a 99 corundum ceramic tube (4), a 316 stainless steel metal seat (5), a fiber collimator (6), a circulator (7), a wide spectrum light source (8), and a demodulation terminal (9). The 316 stainless steel metal seat (5) is horizontally placed; the 99 corundum ceramic tube (4) is axially and horizontally placed, and the axial one end of the 99 corundum ceramic tube (4) is overlapped on the 316 stainless steel metal seat (5), and the fiber collimator (6) is coaxially arranged in the inner cavity of the one end of the 99 corundum ceramic tube (4); the 99 corundum adapter (3) is connected with the axial other end of the 99 corundum ceramic tube (4); the transparent reflector (2) is vertically arranged in the inner cavity of the 99 corundum adapter (3), and the transparent reflector (2) is axially perpendicular to the 99 corundum ceramic tube (4); the fluid holes (1) are uniformly arranged on the outer wall of the 99 corundum adapter (3) in the circumferential direction, and the positions of the fluid holes (1) correspond to the positions of the transparent reflector (2); the one end of the fiber collimator (6) extending out of the 99 corundum ceramic tube (4) is connected with the circulator (7) through a cable; the circulator (7) is connected with the wide spectrum light source (8) and the demodulation terminal (9) through optical fibers respectively. The working process of the fluid transient temperature sensor is as follows: The wide spectrum light source (8) emits a divergent light signal to the circulator (7); the circulator (7) switches the transmission direction of the divergent light signal to be transmitted to the fiber collimator (6); the fiber collimator (6) converts the divergent light signal into a collimated light signal, and sends the collimated light signal to the transparent reflector (2) along the axial direction of the 99 corundum ceramic tube (4); The external fluid to be measured enters the inner cavity of the 99 corundum adapter (3) through the fluid holes (1), and contacts the transparent reflector (2) to transmit the temperature to the transparent reflector (2); the transparent reflector (2) is deformed after being heated; the transparent reflector (2) receives the collimated light signal transmitted by the fiber collimator (6) and reflects it; the fiber collimator (6) receives the reflected light and transmits it to the circulator (7); the circulator (7) switches the transmission direction of the reflected light to be transmitted to the demodulation terminal (9); the demodulation terminal (9) demodulates the temperature of the external fluid to be measured; The top surface and the bottom surface of the transparent reflector (2) are both provided with FP cavities, i.e., both of them reflect the incoming collimated light signal; after the transparent reflector (2) is deformed after being heated, there is an optical path difference between the reflected light of the top surface and the reflected light of the bottom surface; The fiber collimator (6) transmits the reflected light of the top surface and the bottom surface of the transparent reflector (2) to the demodulation terminal (9) through the circulator (7); the demodulation terminal (9) obtains the deformation amount of the transparent reflector (2) according to the optical path difference of the two reflected lights, and obtains the temperature of the external fluid to be measured according to the known deformation amount-temperature curve of the transparent reflector (2).

2. A fluid transient temperature sensor based on FP principle according to claim 1, characterized in that: The transparent reflector (2) is a temperature sensing element; the transparent reflector (2) is made of transparent materials such as quartz, single crystal silicon carbide or single crystal aluminum oxide.

3. A fluid transient temperature sensor based on FP principle as claimed in claim 1, wherein: The transparent reflective sheet (2) is bonded by spot coating on the inner cavity spot gluing position of the 99 corundum adapter (3); the glue is ceramic glue; after bonding, it is cured at room temperature for 24 hours, then placed on a heating platform, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

4. A fluid transient temperature sensor based on FP principle according to claim 1, characterized in that: The 99 corundum adapter (3) is bonded with the corresponding shaft end of the 99 corundum ceramic tube (4) by ceramic glue at the end without fluid hole (1) in the axial direction; after bonding, the 99 corundum adapter (3) and the 99 corundum ceramic tube (4) are coaxial, and after curing at room temperature for 24 hours, they are placed on a heating platform, cured at 70 DEG C for 2 hours, and cured at 200 DEG C for 4 hours.

5. A fluid transient temperature sensor based on FP principle as claimed in claim 1, wherein: The 99 corundum ceramic tube (4) and the 316 stainless steel metal seat (5) are bonded by ring coating through ceramic glue; when bonding, the 99 corundum ceramic tube (4) is perpendicular to the 316 stainless steel metal seat (5) through a tool; it is cured at room temperature for 24 hours, at 70 DEG C for 2 hours, and at 200 DEG C for 4 hours.

6. A fluid transient temperature sensor based on FP principle as claimed in claim 1, wherein: The optical fiber collimator (6) is adjusted in angle by an external three-dimensional displacement platform to make the optical fiber collimator (6) receive reflected light reflected by the transparent reflective sheet (2); the optical fiber collimator (6) is bonded with the 99 corundum ceramic tube (4) by AB epoxy glue, and cured at room temperature for 24 hours.

7. A fluid transient temperature sensor based on FP principle according to claim 6, characterized in that: The optical fiber collimator (6) is connected with the circulator (7) by fiber coupling or fiber fusion.

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