Fiber optik sıcaklık ölçümü nasıl kullanılır?? What does fiber optic temperature measurement include-INNO

1、 ilkesi fiber optik sıcaklık ölçümü

Fiber optik sıcaklık ölçümü, optik fiberlerin sıcaklığa göre değişen çeşitli optik özelliklerine dayanmaktadır..

Optik genlik değişimi ilkesi: Bileşen tipinde fiber optik sıcaklık sensörleri, optik genliğin sıcaklığa göre değiştiği bir durum vardır. Sıcaklık değiştiğinde, optik fiberin çekirdek çapı ve kırılma indisi değişecektir, fiberde yayılan ışığın düzensiz yollardan dolayı dışarıya doğru dağılmasına neden olur, sonuçta ışığın genliğinde değişikliklere neden olur. Örneğin, bazı yüksek hassasiyetli laboratuvar ölçüm senaryolarında, ışık genliğindeki bu hafif değişiklik özel tespit ekipmanıyla yakalanabilir, böylece sıcaklık değişimi durumunun elde edilmesi.
Polarizasyon düzlemi dönüşü prensibi: Tek modlu bir fiberin polarizasyon düzlemi sıcaklıkla birlikte döner, ve genlik değişimi bir polarizör aracılığıyla elde edilebilir. Sensors based on this principle are of great significance in specific optical research or measurement scenarios sensitive to polarization rotation. Örneğin, when studying the relationship between certain optical materials and temperature, this sensor can be used to accurately obtain the effect of temperature on the rotation of the polarization surface.
Principle of optical phase change: When the length, kırılma indisi, and core diameter of a single-mode fiber change with temperature, the light propagating in the fiber will undergo a phase change. This phase change can be obtained by an interferometer to measure the amplitude change. Örneğin, in a Mach Zehnder interferometer, light from a signal fiber is mixed with a stable reference beam. Due to the influence of temperature on the signal fiber, yayılan optik sinyalin fazı değişir, iki ışık sütunu arasında girişime neden oluyor. Öyleyse, the change in phase can be detected to reflect the temperature change. In some environments that require extremely high temperature measurement accuracy, such as temperature monitoring in some precision instruments in aerospace, this measurement principle based on optical phase change can play an important role.
Based on the principle of spectral variation: the absorption spectrum of some substances changes with temperature, and real-time temperature can be understood by analyzing the spectrum transmitted by optical fibers. This principle is widely used in fiber optic temperature sensors, Örneğin, in fiber optic fluorescence temperature sensors, the emitted fluorescence parameters have a one-to-one correspondence with temperature, ve gerekli sıcaklık, floresans yoğunluğu veya floresans ömrü tespit edilerek elde edilebilir.. Bazı yeni fiber optik sıcaklık sensörleri türleri aynı zamanda optik fiberlerin termal hassasiyetini ve Bragg ızgara etkisini de kullanır. Bragg fiber Bragg ızgarasının yansıyan dalga boyunun sıcaklıkla değişeceği prensibine dayanmaktadır., fiber optik ızgara sıcaklık sensörleri yapılır. Algılama sinyali dalga boyu modülasyonludur, ve ölçüm sinyali ışık kaynağı dalgalanmaları gibi faktörlerden etkilenmez, elyaf bükülme kayıpları, bağlantı kayıpları, ve dedektör yaşlanması.
Radyasyon enerjisinin iletimi prensibine dayanmaktadır: Radyasyon için (kızılötesi) fiber optik sıcaklık sensörleri, ölçülen nesnenin yüzey radyasyon enerjisini iletmek için esas olarak optik fiberlerin birleştirme ve iletim özelliklerini kullanır (ölçülen nesnenin yüzey sıcaklığıyla ilgilidir) to the photodetector and convert it into electrical output. This type of sensor is very practical in some non-contact temperature measurement scenarios, such as measuring the temperature outside a high-temperature furnace, and can obtain surface temperature information without direct contact with high-temperature objects.
Based on the principle of semiconductor absorption characteristics: In a semiconductor absorption type fiber optik sıcaklık sensörü, a cut optical fiber is installed in a thin steel pipe, and a semiconductor temperature sensing thin film (such as GaAs or InP) is sandwiched between the two ends of the fiber. The transmitted light intensity of this semiconductor temperature sensing thin film varies with the measured temperature. When a constant light intensity is input at one end of the optical fiber, the transmission ability of the semiconductor temperature sensing thin film changes with temperature, and the light intensity received by the receiving element at the other end of the optical fiber also changes with the measured temperature. Öyleyse, by measuring the voltage output of the receiving element, the temperature at the sensor position can be remotely measured. In some scenarios where temperature monitoring is required for small devices or specific areas, this sensor can leverage its advantages of being compact and accurate in measurement.

2、 Technical methods for fiber optic temperature measurement

Point temperature measurement
Principle and operation: Deploy a single temperature probe in certain key areas of the system for measurement. This method is suitable for precise temperature measurement of specific points, elektronik cihazlardaki anahtar çipinin sıcaklığının izlenmesi gibi, veya biyomedikal araştırmalarda hücre kültürü ortamındaki belirli bir noktanın sıcaklık ölçümü. Fiber optik probu hedef konuma yerleştirerek ve fiber optiğin optik özelliklerinden yararlanarak o noktadaki sıcaklık verilerini elde ederek çok doğru yerel sıcaklık bilgisi sağlayabilir..
Uygulama senaryosu özellikleri: Yerel sıcaklık değişikliklerine karşı oldukça hassas olan bazı cihazlarda veya deneysel senaryolarda, nokta sıcaklığı ölçümü önemlidir. Örneğin, ultra hassas optik cihazlarda, Küçük bir bileşendeki sıcaklık değişiklikleri cihazın genel performansı üzerinde önemli bir etkiye sahip olabilir. Nokta sıcaklığı ölçümü bu bileşenin sıcaklığını doğru bir şekilde izleyebilir, providing a guarantee for the stable operation of the instrument. Dahası, this measurement method is relatively simple and cost-effective, making it very practical for situations where only a few specific temperature points need to be monitored.
Quasi distributed measurement
Principle and operation: Connecting single point temperature measurements in series along the direction of fiber propagation can form a quasi distributed measurement that covers multi-point temperature detection. In the production of power systems, it is necessary to measure the temperature gradient field distribution in the airspace, and this technology can be effective. It can achieve temperature measurement at multiple points by connecting multiple measurement points in series on a single optical fiber, utilizing the transmission and temperature sensitivity characteristics of the fiber. Each measurement point can independently reflect temperature changes and transmit this temperature information to monitoring equipment for centralized processing through optical fibers.
Uygulama senaryosu özellikleri: In large power facilities such as substations, high-voltage transmission lines, vesaire., temperature monitoring of multiple key parts is required. Quasi distributed measurement can achieve temperature monitoring of multiple points on a single optical fiber, reducing the complexity and cost of wiring. Aynı zamanda, in some large industrial equipment or building structures, such as large boilers, köprüler, vesaire., quasi distributed measurement technology can also be used to monitor the temperature at different locations, in order to timely detect potential temperature anomalies and prevent accidents.
Fully distributed measurement
Principle and operation: Fiber optics can serve as both a channel for optical signal transmission and a temperature sensitive material for conducting temperature changes. The dağıtılmış fiber optik temperature measurement system can be achieved by deploying a monitoring device and a sensing fiber. The monitoring cost per unit fiber length decreases with the increase of sensing distance, which is currently a highly promising engineering temperature measurement solution. It is based on the principle of optical time domain reflectometry (OTDR) of optical fibers and the Raman scattering effect of optical fibers. By analyzing the backward Raman scattering light in the optical fiber, it obtains temperature distribution information along the fiber. Laser pulses interact with fiber molecules, Rayleigh saçılması gibi çeşitli saçılma olaylarına neden olur, Brillouin saçılması, ve Raman saçılması. Raman saçılım ışığının yoğunluğu sıcaklığa bağlıdır, ve fiber boyunca sıcaklık dağılımı, Raman saçılım ışığının yoğunluk değişiklikleri ölçülerek elde edilebilir..
Uygulama senaryosu özellikleri: Geniş bir alanın sıcaklığının izlenmesini gerektiren bazı senaryolarda, uzun mesafeli petrol boru hatları gibi, büyük depolama tesisleri, vesaire., tamamen dağıtılmış ölçüm, tüm alanın sıcaklık izlemesini sağlamak için bir optik fiber kullanabilir. Gerçek zamanlı olarak doğru ve sürekli sıcaklık verileri sağlayabilir, küçük sıcaklık değişikliklerini tespit edin, ve geniş bir aralık ve uzun mesafe boyunca mekansal sıcaklık dağılımının gerçek zamanlı ve hızlı, çok noktalı ölçümünü elde edin. Boru hatlarının güvenli bir şekilde işletilmesi açısından bu büyük önem taşımaktadır., yangınları önlemek, ve izleme maliyetlerini ve karmaşıklığını büyük ölçüde azaltır.
Fiber optic temperature sensing technology based on fluorescent radiation
Principle and Operation: The working mechanism of fluorescence temperature measurement is based on the fundamental physical phenomenon of photoluminescence. Fotolüminesans olarak adlandırılan olay, ışık emisyonu olgusudur, which refers to the emission of light when a material is excited by ultraviolet, görünür, or infrared light. In fiber optic temperature sensors, the fluorescence characteristics of certain substances are utilized, and the intensity or lifetime of fluorescence changes when the temperature changes. Measure temperature by detecting changes in these fluorescence parameters. Örneğin, Mississippi State University in the United States uses a commercial epoxy adhesive as a temperature indicator (PAHs). PAHs emit fluorescence when excited by ultraviolet light, and the intensity of fluorescence decreases as the temperature around the epoxy adhesive increases. By detecting changes in fluorescence intensity, temperatures within the range of 20 °C'ye 100 ℃ can be measured.
Uygulama senaryosu özellikleri: This technology is more suitable in some scenarios where high temperature measurement accuracy is required and the environment is relatively stable. Örneğin, temperature monitoring in cell culture environments in the biomedical field, or temperature measurement in the study of heat dissipation performance of some small electronic devices. Due to the sensitivity of fluorescence characteristics to temperature changes and the ability to adapt to different temperature measurement ranges by selecting appropriate fluorescent materials, accurate temperature measurement results can be provided in these scenarios. Bu sırada, compared to other technologies, fluorescence radiation fiber optic temperature sensing technology may have a smaller device size, making it easier to use in environments with limited space.

3、 Application scenarios of fiber optic temperature measurement

Sanayi sektörü
Güç sistemi: In power stations, fiber optic temperature sensors can be used to monitor the temperature of power generation equipment such as generators, transformatörler, vesaire. Örneğin, in transformers, fiber optic temperature sensors can monitor the oil temperature inside the transformer and the temperature of key components in real time, which helps to detect potential overheating problems in a timely manner and prevent serious accidents such as equipment damage or even fires caused by overheating. Dahası, fiber optic sensors have the characteristic of resisting electromagnetic interference and can work stably in strong electromagnetic environments such as power systems. In high-voltage transmission lines, fiber optic temperature sensors can monitor the temperature of the line in real time. When the line experiences abnormal temperature rise due to overload or other reasons, they can provide timely warnings to ensure the safe operation of the transmission line.
Petrokimya endüstrisi: Fiber optic temperature sensors play an important role in the extraction, toplu taşıma, and storage of petroleum. In oil wells, it can be used to monitor downhole temperature, understand the distribution of reservoir temperature, and provide data support for oil extraction. In terms of oil pipelines, fiber optic temperature sensors can be installed along the pipeline to monitor the temperature in real time. Once abnormal temperature is detected due to leaks or external environmental factors (such as the impact of permafrost melting on the pipeline), measures can be taken in a timely manner to prevent accidents such as oil spills. Monitoring the oil temperature inside the oil tank during storage helps ensure the quality and safe storage of the oil.
Manufacturing industry: In the manufacturing process of large machinery, such as automobile engines, aviation engines, vesaire., fiber optic temperature sensors can be used to monitor the temperature during the production process. Örneğin, monitoring the mold temperature during the engine casting process can optimize the casting process and improve product quality. Monitoring tool temperature during mechanical processing can adjust cutting parameters in a timely manner and extend tool life. Ek olarak, temperature monitoring of key components can help ensure assembly accuracy in some high-precision mechanical assembly processes.
Tıp alanı
Internal temperature monitoring of the human body: Fiber optic temperature sensors can be made into tiny probes for measuring the internal temperature of the human body. Örneğin, in some minimally invasive surgeries, fiber optic temperature sensors can be inserted into the human body through a catheter to monitor the temperature around the surgical site in real time, avoiding tissue damage caused by thermal damage during the surgery. During the process of tumor hyperthermia, fiber optic temperature sensors can accurately measure the temperature inside the tumor tissue, ensuring that the temperature of the hyperthermia is within the effective treatment range while avoiding overheating damage to surrounding normal tissues.
Medical equipment temperature monitoring: In some medical devices, such as magnetic resonance imaging (MR) teçhizat, X-ray machines, vesaire., fiber optic temperature sensors can be used to monitor the temperature of key components inside the equipment. Due to the large amount of heat generated by these devices during operation, if the temperature of the components is too high, it may affect the performance of the equipment or even cause equipment failure. Through real-time monitoring by fiber optic temperature sensors, timely heat dissipation measures can be taken to ensure the normal operation of the equipment.
Environmental protection field
Atmospheric temperature monitoring: In meteorological research, fiber optic temperature sensors can be used for measuring atmospheric temperature. Compared with traditional meteorological temperature measurement equipment, fiber optic temperature sensors have the characteristics of anti electromagnetic interference and high accuracy. Fiber optic sensors can be installed on meteorological towers or balloons to measure atmospheric temperature at different heights, providing more accurate data for meteorological research, weather forecasting, ve diğer uygulamalar.
Su sıcaklığı izleme: In water environment monitoring, fiber optic temperature sensors can be used to measure the temperature of water bodies such as rivers, göller, ve okyanuslar. Su sıcaklığının uzun süreli izlenmesi sayesinde, su kütlelerinin termal ortamındaki değişiklikler anlaşılabilir, su ekosistemlerinin ve iklim değişikliğinin su kütleleri üzerindeki etkisini incelemek için büyük önem taşıyan. Örneğin, bazı büyük göllerde, fiber optik sıcaklık sensörlerinin farklı derinlik ve konumlara yerleştirilmesiyle, Su sıcaklığı katmanlaşmasının göl ekosistemi üzerindeki etkisini analiz etmek için gölün tamamının su sıcaklığı dağılım haritası çizilebilir..
Toprak sıcaklığı izleme: Tarımsal ve ekolojik araştırmalarda, Fiber optik sıcaklık sensörleri toprak sıcaklığını izlemek için kullanılabilir. Toprak sıcaklığının bitkilerin büyümesi ve gelişmesi üzerinde önemli bir etkisi vardır.. Toprak sıcaklığını izleyerek, Tarımsal üretime yönelik rehberlik sağlanabilir, optimal ekim zamanının belirlenmesi gibi, sulama zamanı, vesaire. Ekolojik araştırmalarda, changes in soil temperature can also affect the activity of soil microorganisms and the conversion of nutrients in the soil. Fiber optic temperature sensors can provide accurate temperature data for these studies.
Other special fields
In the aerospace field, fiber optic temperature sensors can be used to monitor the temperature of high-temperature components inside aircraft engines during testing and operation, ensuring the safe operation of the engine under extreme conditions such as high temperature and high pressure. In spacecraft, fiber optic temperature sensors can be used to monitor temperature changes outside the spacecraft, which is crucial for protecting internal equipment and instruments from extreme temperature fluctuations. Bu sırada, in the development process of aerospace materials, fiber optic temperature sensors can also be used to test the performance of materials under different temperature conditions.
Military field: In military equipment such as tanks, missiles, vesaire., fiber optic temperature sensors can be used to monitor the temperature of key components inside the equipment. During the launch process of missiles, fiber optic temperature sensors can monitor the temperature of missile engines and other components in real time, ensuring the normal launch and flight of missiles. In the construction and maintenance of military facilities, fiber optic temperature sensors can be used to monitor environmental temperature, ensuring the safety and stability of military facilities.

4、 Factors affecting the accuracy of fiber optic temperature measurement

Factors related to the inherent characteristics of optical fibers
Fiber optic materials: Different fiber optic materials have different coefficients of thermal expansion and optical properties, which can affect the accuracy of temperature measurement. Örneğin, certain special fiber optic materials may experience significant refractive index changes when subjected to temperature fluctuations, while others remain relatively stable. If inappropriate fiber optic materials are selected in high-precision temperature measurement scenarios, it may lead to significant deviations in measurement results.
Fiber length: Temperature changes can cause changes in fiber length. According to the principle of thermal expansion and contraction, when the temperature changes by 1 °C, the change in length of single-mode fiber per kilometer may not differ significantly. Fakat, in long-distance fiber temperature measurement, the accumulation of these small length changes may affect measurement accuracy. Örneğin, in long-distance distributed fiber optic temperature measurement systems, if the changes in fiber length due to temperature variations cannot be accurately compensated for, it may lead to misjudgment of temperature.
The refractive index variation of optical fibers: The refractive index of optical fibers varies with temperature, which affects the propagation characteristics of light in optical fibers, such as the phase and propagation speed of light. When the refractive index of optical fibers changes due to temperature fluctuations, fiber optic sensors that measure temperature based on phase changes or light propagation time will be affected, dolayısıyla ölçüm doğruluğunu azaltır.
External environmental factors
The complexity of environmental temperature changes: The environmental temperature itself may be uneven, with temperature gradients or rapid temperature fluctuations. In such a complex temperature environment, fiber optic sensors may not accurately reflect the true temperature situation. Örneğin, in outdoor environments, there is a large temperature difference between day and night, and direct sunlight during the day may cause the local temperature of the fiber optic cable to rise, while at night it will rapidly decrease. This frequent temperature change will pose a challenge to measurement. Dahası, the environmental temperature may also be affected by factors such as airflow and humidity, further increasing the complexity of temperature measurement.
External interference sources: In some special application scenarios, harici parazit kaynaklarının varlığı fiber optik sıcaklık ölçümünün doğruluğunu etkileyebilir. Örneğin, endüstriyel ortamlarda, güçlü elektromanyetik alanlar gibi faktörler var, titreşim, ve kimyasal korozyon. Güçlü elektromanyetik alanlar, fiber optik sensörlerdeki optik sinyallerin iletimini engelleyebilir, ölçüm hatalarına yol açan; Titreşim, optik fiberlerin hafif bükülmesine veya yer değiştirmesine neden olabilir, Işığın yayılma yolunu etkileyen ve dolayısıyla ölçüm doğruluğunu etkileyen; Kimyasal korozyon optik fiberlerin yüzeyine zarar verebilir veya optik özelliklerini değiştirebilir, sensörlerin performansının azaltılması.
Sensör cihazlarıyla ilgili faktörler
Işık kaynağı kararlılığı: Fiber optik sıcaklık sensörleri için, ışık kaynağının stabilitesi çok önemlidir. If the intensity or wavelength of the light source fluctuates, it will affect the accuracy of sensors that measure temperature based on changes in light intensity or wavelength. Örneğin, in fiber Bragg grating temperature sensors, the fluctuation of the light source may lead to inaccurate measurement signals because the sensing signal is wavelength modulated, and the instability of the light source can cause wavelength measurement deviations.
Performance of photodetector: The sensitivity, wavelength resolution, and other performance indicators of the photodetector will affect the measurement accuracy. If the sensitivity of the photodetector is insufficient, it may not be able to accurately detect weak changes in the light signal, thereby affecting temperature measurement. Örneğin, floresans radyasyonuna dayalı fiber optik sıcaklık sensörlerinde, floresans yoğunluğundaki veya ömründeki küçük değişiklikleri tespit etmek gereklidir. Fotodetektörün hassasiyeti yeterli değilse, bu değişiklikler doğru bir şekilde elde edilemez, Sıcaklık ölçüm hatalarına yol açan. Bu sırada, fotodedektörün dalga boyu çözünürlüğü yüksek değil, bu aynı zamanda dalga boyu değişikliklerine bağlı olarak fiber optik sıcaklık sensörlerini ölçerken ölçüm doğruluğunu da azaltabilir.
Sensörlerin paketlenmesi ve kurulumu: Sensörlerin ambalaj malzemesi ve yapısı, ısının iletimini ve sensörlerin sıcaklığa tepki verme hızını etkileyebilir.. Ambalaj malzemesinin ısıl iletkenliği zayıfsa, sensörün sıcaklık değişikliklerine tepki olarak gecikmesine neden olur, dolayısıyla ölçüm doğruluğunu etkiler. Kurulum işlemi sırasında, if there is poor contact between the sensor and the object being measured, or if the installation position is not reasonable, the measurement results may not accurately reflect the true temperature of the object being measured. Örneğin, when measuring the temperature of small electronic device chips, if the fiber optic temperature sensor is not installed in close contact with the chip, it may measure the temperature of the surrounding environment instead of the actual temperature of the chip.

5、 Equipment types for fiber optic temperature measurement

Bileşen tipi fiber optik sıcaklık sensörü
Working principle and characteristics: Component based fiber optic temperature sensors use the characteristics of the fiber itself to sense temperature changes and measure them. Örneğin, using a sensor that changes the amplitude of light with temperature, the core diameter and refractive index of the optical fiber change with temperature, causing the light propagating in the fiber to scatter outward due to uneven paths, resulting in changes in light amplitude; Using a sensor that rotates the polarization surface of a single-mode fiber, the polarization surface of the fiber rotates with temperature, ve genlik değişimi bir polarizör aracılığıyla elde edilir; By using a sensor that detects changes in optical phase, the length, kırılma indisi, and core diameter of a single-mode fiber vary with temperature, causing a phase change in the light propagating in the fiber. This phase change is then measured by an interferometer to obtain amplitude changes. The advantage of component type fiber optic temperature sensors is that they directly utilize the characteristics of the fiber itself and have high sensitivity. Fakat, its disadvantage is that it requires high quality and performance of the optical fiber, and requires more precise instruments and technology to ensure measurement accuracy during manufacturing and use.
Uygulama senaryosu: It is more suitable for temperature monitoring scenarios in laboratory research or high-end precision instrument equipment that require extremely high temperature measurement accuracy and relatively stable measurement environments. Örneğin, temperature monitoring inside high-precision optical instruments, or precise measurement of small temperature changes in physical and chemical experiments.