scholarly journals Measurement Enhancement on Two-Dimensional Temperature Distribution of Methane-Air Premixed Flame Using SMART Algorithm in CT-TDLAS

2019 ◽  
Vol 9 (22) ◽  
pp. 4955
Author(s):  
Min-Gyu Jeon ◽  
Deog-Hee Doh ◽  
Yoshihiro Deguchi
Keyword(s):  
Temperature Distribution ◽  
Measurement Accuracy ◽  
Premixed Flame ◽  
Tunable Diode Laser ◽  
Line Of Sight ◽  
Reconstruction Technique ◽  
Algebraic Reconstruction Technique ◽  
Multiplicative Algebraic Reconstruction Technique ◽  
Laser Absorption ◽  
Diode Laser Absorption

In this study, the temperature distribution of the Methane-Air premixed flame was measured. In order to enhance the measurement accuracy of the CT-TDLAS (Computed tomography-tunable diode laser absorption spectroscopy), the SMART (simultaneous multiplicative algebraic reconstruction technique) algorithm has been adopted. Further, the SLOS (summation of line of sight) and the CSLOS (corrective summation of line of sight) methods have been adopted to increase measurement accuracies. It has been verified that the relative error for the temperatures measured by the thermocouples and calculated by the CT-TDLAS was about 10%.

Limited View Tomography of Combustion Zones Using Tunable Diode Laser Absorption Spectroscopy: Simulation of an Algebraic Reconstruction Technique

2012 ◽  
Author(s):  
Avishek Guha ◽  
Ingmar Schoegl
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Second Harmonic ◽  
Tunable Diode Laser ◽  
Reconstruction Technique ◽  
Algebraic Reconstruction Technique ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Diode Laser Absorption ◽  
Algebraic Reconstruction

Temperature and concentration distributions of a simulated flame were reconstructed with the help of computer tomography and tunable diode laser absorption spectroscopy (TDLAS). Reconstructions were based on the simulated numerical values of temperature and concentration of a stationary flame. Integrated absorption measurements along the line-of-sight (LOS) across the flames due to absorption by water vapor (H2O) in the near infra-red (NIR) region, specifically the 6930–6940 cm−1 range, were simulated to obtain the projection values for tomography. Spectroscopic parameters for the absorptions transitions, such as line-strengths, transition wavenumbers, collisional broadening coefficients and coefficients for their temperature dependency were selected from the HITRAN 2004 database. Simulated LOS data are inverted using a multiplicative algebraic reconstruction technique (MART), which are known to outperform traditional filtered back projection methods for cases with limited numbers of views. Based on spatially resolved reconstructions of spectroscopic data, temperature and concentration distributions are calculated using the wavelength modulation spectroscopy with second harmonic detection (WMS-2f) technique. A parametric study based on the number of views, orientation of views and number of rays per view required by the ART is performed in order to assess requirements for an acceptable reconstruction.

A study on two-dimensional temperature and concentration distribution of Propane-Air premixed flame using CT-TDLAS

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040020 ◽  
Author(s):  
Min-Gyu Jeon ◽  
Jeong-Woong Hong ◽  
Deog-Hee Doh ◽  
Yoshihiro Deguchi
Keyword(s):  
Absorption Spectroscopy ◽  
Polynomial Regression ◽  
Concentration Field ◽  
Tunable Laser ◽  
Premixed Flame ◽  
Tunable Diode Laser ◽  
Reconstruction Technique ◽  
Laser Absorption Spectroscopy ◽  
Multiplicative Algebraic Reconstruction Technique ◽  
Laser Absorption

To use supplying gases and energy resources efficiently, accurate measurement of irregular gas is necessary. The TDLAS (Tunable laser absorption spectroscopy) technique can be used to control and monitor the supplying gas conditions and combustion of industrial processes. Recently, CT-TDLAS (Computed tomography-tunable diode laser absorption spectroscopy) has been developed to measure the temperature and concentration field of gases. In this study, the 2-dimensional temperature distribution of the Propane-Air premixed flame in several mixing conditions of fuel has been measured by the constructed CT-TDLAS system. 2-Dimensional temperature distributions are measured by 16 path cells. Further, the third-order polynomial regression analysis was applied to resolve the absorption spectra from the incident and transmitted light for a particular gas. The SMART (simultaneous multiplicative algebraic reconstruction technique) algorithm has been adopted for reconstructing the absorption coefficients on the detecting area. As a result of comparing the temperature for the 2-dimensional detecting area using the thermocouple and CT-TDLAS technique, it has been verified that the relative error for the temperatures measured by the thermocouples and calculated by the CT-TDLAS was up to 8%.

Evaluation of 3D measurement using CT-TDLAS

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940018 ◽  
Author(s):  
Min-Gyu Jeon ◽  
Deog-Hee Doh ◽  
Yoshihiro Deguchi ◽  
Takahiro Kamimoto ◽  
Minchao Cui
Keyword(s):  
Absorption Spectroscopy ◽  
Manufacturing Process ◽  
Numerical Test ◽  
Maximum Error ◽  
Tunable Diode Laser ◽  
Reconstruction Technique ◽  
Laser Absorption Spectroscopy ◽  
Multiplicative Algebraic Reconstruction Technique ◽  
Distribution Method ◽  
Laser Absorption

In order to satisfy the requirements of high quality and optimal material manufacturing process, it is important to control the environment of the manufacturing process. Depending on these processes, it is possible to improve the quality of the product by adjusting various gases. With the advent of the tunable laser absorption spectroscopy (TDLAS) technique, the temperature and concentration of the gases can be measured simultaneously. Among them, computed tomography-tunable diode laser absorption spectroscopy (CT-TDLAS) is the most important technique for measuring the distributions of temperature and concentration across the two-dimensional planes. This study suggests a three-dimensional measurement to consider the irregular flow of supplying gases. The simultaneous multiplicative algebraic reconstruction technique (SMART) algorithm was used among the CT algorithms. Phantom datasets have been generated by using Gaussian distribution method. It can show expected temperature and concentration distributions. The (HITRAN) database in which the thermo-dynamical properties and the light spectra of H2O are listed were used for the numerical test. The relative average temperature error ratio in the results obtained by the SMART algorithm was about 3.2% for temperature. The maximum error was 86.8 K.

Modeling and Simulation of Mass Flow Measurement Process by TDLAS

2013 ◽  
Vol 631-632 ◽  
pp. 1032-1036
Author(s):  
Xin Zhou ◽  
Guang Yu Wang ◽  
Dong Sheng Qu
Keyword(s):  
Modeling And Simulation ◽  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Mass Flow ◽  
Flow Measurement ◽  
Measurement Accuracy ◽  
Calculated Data ◽  
Tunable Diode Laser ◽  
Laser Absorption ◽  
Diode Laser Absorption

Based on the mass flow measurement by tunable diode laser absorption spectroscopy (TDLAS), the process of air flow measurement was modeled and simulated. Using the Gridgen software, we drew the model inlet grid. And we used fluid calculation program to calculate gas condition in the inlet model. Under the set conditions, we got the mass flow of the model. Compared the mass flow which is measured by the TDLAS technology with the calculated data, we can obtain the measurement accuracy of TDLAS.

Thermal Boundary Layer Effects on Line-of-Sight Tunable Diode Laser Absorption Spectroscopy (TDLAS) Gas Concentration Measurements

2018 ◽  
Vol 72 (6) ◽  
pp. 853-862 ◽  
Author(s):  
Zhechao Qu ◽  
Olav Werhahn ◽  
Volker Ebert
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Thermal Boundary Layer ◽  
Temperature Gradients ◽  
Tunable Diode Laser ◽  
Line Of Sight ◽  
Gas Concentration ◽  
Laser Absorption ◽  
Diode Laser Absorption ◽  
Thermal Boundary Layers

The effects of thermal boundary layers on tunable diode laser absorption spectroscopy (TDLAS) measurement results must be quantified when using the line-of-sight (LOS) TDLAS under conditions with spatial temperature gradient. In this paper, a new methodology based on spectral simulation is presented quantifying the LOS TDLAS measurement deviation under conditions with thermal boundary layers. The effects of different temperature gradients and thermal boundary layer thickness on spectral collisional widths and gas concentration measurements are quantified. A CO2 TDLAS spectrometer, which has two gas cells to generate the spatial temperature gradients, was employed to validate the simulation results. The measured deviations and LOS averaged collisional widths are in very good agreement with the simulated results for conditions with different temperature gradients. We demonstrate quantification of thermal boundary layers’ thickness with proposed method by exploitation of the LOS averaged the collisional width of the path-integrated spectrum.

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