Measurement of Temperature Distribution Based on Optical Fiber-Sensing Technology and Tunable Diode Laser Absorption Spectroscopy

Abstract

Temperature is an important physical quantity in most industrial processes. Distributed temperature sensor (DTS), fiber Bragg grating (FBG), and tunable diode laser absorption spectroscopy (TDLAS) are three primary techniques for temperature measurement using fiber optic sensing and spectrum technology. The DTS system can monitor space temperature field along the fiber in real time. In addition, it also can locate a fire source using two sections of optical fibers which are placed orthogonally to each other. The FBG temperature sensor is used to measure the point temperature. The temperature sensitivity of the bare FBG is 10.68 pm/ C and the linearity is 0.99954 in the range of 30-100 C. Based on tunable diode laser absorption spectroscopy (TDLAS), two-dimensional (2D) distribution reconstructions of gas temperature are realized using an algebraic reconstruction technique (ART). The results are in agreement with the simulation results, and the time resolution is less than 1 s.

Fabrication and characterization of up-converting β-NaYF4:Er3+,Yb3+@NaYF4 core–shell nanoparticles for temperature sensing applications

“…The HR-TEM image in Fig. 2b presents a representative nanoparticle with size of 36 nm and lattice distance of 0.3 nm corresponding to d-spacing for the (110) lattice plane of hexagonal β phase of NaYF 4 structures, suggesting that the [110] is the preferred growth direction of the NaYF 4 :Er 3+ ,Yb 3+ CNP. The clear difference between core and shell part of the nanoparticle observed in TEM images may results from the difference in the porosity of the particular parts of the nanocrystal.…”

“…6f) 15 . Additionally, the electrons from the 4 S 3/2 level of Er 3+ ions can be nonradiatively relaxed to the 4 Figure 6. The UC emission spectra (a), CIE1931 chromaticity diagram (b), and integrated intensities (c) of blue ( 2 H 11/2 , 4 S 3/2 → 4 I 15/2 ) and red ( 4 F 9/2 → 4 I 15/2 ) emission bands of core β-NaYF 4 :2%Er 3+ ,19%Yb 3+ nanoparticles upon 976 nm laser diode excitation in range of 0.73 to 9.95 W/cm 2 .…”

“…Temperature is an important physical parameter which governs many fields of science, such as medicine, biology, microelectronics, physics, and chemistry 1. Therefore, many methods of temperature measurements, both contact and non-contact, have been developed based on the mechanical, electrical or optical characteristics [2][3][4] . However, to determine the temperature of small, moving or inaccessible objects, the non-contact luminescent thermometry which exploits thermal changes of spectral or temporal properties of the phosphor attached to the object is a preferred technique 4,5 . One of the most extensively investigated group of lanthanide-based luminescent thermometers are those which for temperature sensing, take advantage of thermally coupled energy levels, like in the case of Er 3+ , Tm 3+ , Ho 3+ , Pr 3+ or Eu 3+6-10 .…”

Temperature Distribution Comparison in Smooth and Stepped Functions

“…where 𝐴(𝑡) = − [1 + 6𝜋𝑡 + 18(𝜋𝑡) 2 + 36(𝜋𝑡) 3 + 54(𝜋𝑡) 4 The above series solution can be implemented in a multistage manner to get a piecewise continuous solution with high accuracy.…”

“…Examples of the applications are in processes of fluid filtration in reservoirs [1] and also, temperature distribution can partly cause thermal stress effects in the study of interference fit processes and thermal creeping [2]. Furthermore, temperature distribution knowledge is important in industrial processes, and this led to the innovation of temperature sensors like Distributed Temperature Sensor (DTS), Fiber Bragg Grating (FBG), and Tunable Diode Laser Absorption Spectroscopy (TDLAS) which are mostly applied in many fields including petrochemical, to make sure that the progress of production and safety of personnel is smooth [3]. Application of temperature distribution is also experienced in floor cooling systems by radiation [4], where a good understanding of floor structure temperature distribution facilitates the attainment of floor comfort and prevents possible condensation when the cooling occurs during summer.…”