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전민규,도덕희,Yoshihiro Deguchi 대한기계학회 2019 大韓機械學會論文集B Vol.43 No.11
에너지 자원을 효율적으로 사용하기 위해서는 연소 가스에 대한 정확한 측정이 필요하다. TDLAS 기술로 대상 가스의 온도와 농도를 동시 측정할 수 있다. 현재 가스의 정밀 제어가 필요한 산업공정에 2차원 또는 3차원의 정보를 측정한 실험적 보고는 미비하다. 본 연구에서는 산업공정의 연소를 제어하고 모니터링하고자 CT-TDLAS 시스템을 이용한다. 메탄-공기 예혼합화염의 3차원 온도 분포는 CTTDLAS 시스템에 의해 측정되었으며, 3차원 온도 분포는 2차원 셀의 5개 층으로 측정하였다. 특히 흡수 스펙트럼의 3차원 재구성에 SMART 알고리즘을 적용하였다. 열전대와 CT-TDLAS로 모든 층의 온도를 비교한 결과 온도의 평균 상대오차가 19.7K로 정확하게 측정되었다. In order to use energy resources efficiently, accurate measurement of combustion gases is necessary. Measurement of the temperature and concentration of a target gas is possible with tunable laser absorption spectroscopy (TDLAS) technique. The TDLAS technique can be used to control and monitor combustion in industrial processes. The 3-dimensional temperature distribution of methane-air premixed flame was measured using the constructed computed tomography tunable diode laser absorption spectroscopy (CT-TDLAS) system. The 3-dimensional temperature distributions are measured by five layers of the 2-dimensional cell. The simultaneous multiplicative algebraic reconstruction technique (SMART) algorithm was adopted for reconstructing the absorption coefficients on the meshes. As a result of comparing the temperatures for all the layers using thermocouples and the CT-TDLAS technique, it was possible to accurately measure the average relative error of temperature as 19.7 K.
Optical temperature measurement method of premixed flames using a multi-laser system
전민규,도덕희,Yoshihiro Deguchi 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
The temperature distribution of a methane-air premixed flame was measured by the optical measurement technique. The absorption line was decomposed through 3rd order polynomial analysis, and the simultaneous multiplicative algebraic reconstruction technique (SMART) algorithm was adopted for computed tomography-tunable diode laser absorption spectroscopy (CT-TDLAS) data reconstruction. Methane-air premixed combustion system was used to construct laminar and turbulent flames. A double tube structure was adopted to solve combustion instability factors that occur when turbulent flames are generated. To overcome the high-temperature measurement limitations of a single laser system, two types of distributed feedback (DFB) lasers were mixed and measured. The relative error in temperature was largely confirmed at the central location of the burner. It was about 1.22 % for the laminar flame and 14.47 % for the turbulent flame.
CT-레이저흡수분광법(TDLAS) 성능향상을 위한 레이저 선폭확장 함수 최적 계수 선정에 관한 연구
최두원,조경래,Yoshihiro Deguchi,백태실,도덕희 한국수소및신에너지학회 2016 한국수소 및 신에너지학회논문집 Vol.27 No.6
The performance of the CT-TDLAS (computed tomography-tunable diode laser absorption spectroscopy)is strongly dependent upon the line broadening functions. The line of the laser beam used in the TDLAS is scatteredby the natural broadening, the collisional broadening and the doppler broadening. The influence of the naturalbroadening to the experimental spectra obtained in the TDLAS is negligible. The influences of the collisionalbroadening and the doppler broadening to the experimental spectra are relatively large, in high pressure gas flowsand in high temperature low pressure gas flows, respectively. In this study, optimal coefficients are proposed forthe doppler broadening function by using the experimental data obtained in a flat burner test. The optimalcoefficients were γj=0.16 and n=0.37. Using these coefficients, the temperature and concentration distributions atthe engine exhaust gas pipe have been calculated showing their validities.
컴퓨터토모그래피 레이저흡수분광법(CT-TDLAS) 기반 2차원온도분포 산정 Two-Ratios-of-Three-Peaks (2R3P) 알고리듬 개발
최두원,조경래,심준환,Yoshihiro Deguchi,김동혁,도덕희 한국수소및신에너지학회 2016 한국수소 및 신에너지학회논문집 Vol.27 No.3
In order to improve the performance of temperature field measurements by CT-TDLAS (Computer Tomography Tunable Diode Laser Absorption Spectroscopy), a new reconstruction algorithm, named two-ratiosof- three-peaks method is proposed in this paper. Further, two methods for selecting appropriate initial values of the iterative calculation of CT-TDLAS are proposed. One is MLOS (multiplicative line of sight) method and the other one is ALOS (additive line of sight) method. Two-ratios-of-three-peaks (2R3P) algorithm combined with MART (multiplicative algebraic reconstruction technique) is finally developed for the enhancements of reconstructive calculations. The results have been compared with those obtained by the conventional one-ratio-of-two-peaks (1R2P) algorithm. In order to evaluate the performance of this algorithm, numerical test has been performed using phantom Gaussian temperature distributions with 11×11 square mesh. The performance of the constructed algorithm has been demonstrated by comparing the results obtained in actual burner experiments with those obtained by thermocouples. It has been verified that 2R3P algorithm with MART and MLOS showed best performance than that of 1R2P algorithm.
레이저흡수분광법(TDLAS) 기반 가스온도분포 산정을 위한 상호상관계산 알고리듬 개발
최두원,김광남,조경래,심준환,김동혁,Yoshihiro Deguchi,도덕희 한국수소및신에너지학회 2016 한국수소 및 신에너지학회논문집 Vol.27 No.1
Most of reconstruction algorithms for the calculation of temperature distributions in CT (computed tomography)-TDLAS (tunable diode laser absorption spectroscopy) are based upon two-line thermometry method. This method gives unstable calculation convergence due to signal noise, bias error, and signal mis-matches. In this study, a new reconstruction algorithm based on cross-correlation for temperature calculation is proposed. The patterns of the optical signals at all wave lengths were used to reconstruct the temperature distribution. Numerical test has been made using phantom temperature distributions. Using these phantom temperature data, absorption spectra for all wave lengths were constructed, and these spectra were regarded as the signals that would be obtained in an actual experiments. Using these virtually generated experimental signals, temperature distribution was once again reconstructed, and was compared with those of the original phantom data. Calculation errors obtained by the newly proposed algorithm were slightly large at high temperatures with small errors at low temperature.