Two-Dimensional Temperature Measurement in a High-Temperature and High-Pressure Combustor Using Computed Tomography Tunable Diode Laser Absorption Spectroscopy (CT-TDLAS) with a Wide-Scanning Laser at 1335–1375 nm

Abstract

Tunable diode laser absorption spectroscopy (TDLAS) technology is a developing method for temperature and species concentration measurements with the features of non-contact, high precision, high sensitivity, etc. The difficulty of two-dimensional (2D) temperature measurement in actual combustors has not yet been solved because of pressure broadening of absorption spectra, optical accessibility, etc. In this study, the combination of computed tomography (CT) and TDLAS with a wide scanning laser at 1335–1375 nm has been applied to a combustor for 2D temperature measurement in high temperature of 300–2000 K and high pressure of 0.1–2.5 MPa condition. An external cavity type laser diode with wide wavelength range scanning at 1335–1375 nm was used to evaluate the broadened H2O absorption spectra due to the high-temperature and high-pressure effect. The spectroscopic database in high temperature of 300–2000 K and high pressure of 0.1–5.0 MPa condition has been revised to improve the accuracy for temperature quantitative analysis. CT reconstruction accuracy was also evaluated in different cases, which presented the consistent temperature distribution between CT reconstruction and assumed distributions. The spatial and temporal distributions of temperature in the high-temperature and high-pressure combustor were measured successfully by CT-TDLAS using the revised spectroscopic database.

Simultaneous Determination of Non-Uniform Soot Temperature and Volume Fraction from Flame Images

“…Since equation (10) comprises the integral of wavelength 𝜆, it cannot be simply solved. Therefor this paper develops equation (11) about temperature 𝑇 and uses the Newton iteration method to solve the temperature distribution:…”

“…The non-contact measurement will not interfere with the measured flame flow field, which has certain advantages in flame temperature measurement. The laser spectroscopy is one of the non-contact temperature measurement methods, including laser interference holography [6][7][8], tunable semiconductor laser absorption spectroscopy (TDLAS) technology [9][10][11][12] and scattering (LRS) technology [13][14][15][16]. In recent years, the measurement of the temperature fields of the flame section has been performed by combining the TDLAS and CT technologies [11,17,18].…”

“…The laser spectroscopy is one of the non-contact temperature measurement methods, including laser interference holography [6][7][8], tunable semiconductor laser absorption spectroscopy (TDLAS) technology [9][10][11][12] and scattering (LRS) technology [13][14][15][16]. In recent years, the measurement of the temperature fields of the flame section has been performed by combining the TDLAS and CT technologies [11,17,18]. The laser spectral temperature measurement technology has the advantages of high measurement accuracy and large measurement range.…”

Carbon Dioxide Concentration Estimation in Nonuniform Temperature Fields Based on Single-Pass Tunable Diode Laser Absorption Spectroscopy

“…There have been studies to reconstruct the temperature and concentration fields of flue gases such as tomographic reconstruction methods and simultaneous measurements of many different laser paths. 19,21 However, such full-field reconstruction methods not only require complete optical access to the target field but also require as many emitting and receiving optics as the laser paths, making it difficult to implement as a real-time concentration monitoring technique. On the other hand, although the line shape of absorption features changes with variations in temperature and concentration, these changes are relatively small.…”

Relative Entropy Regularized TDLAS Tomography for Robust Temperature Imaging

“…Since the first experimental demonstration of high-speed chemical species tomography [1], interest in Tunable Diode Laser Absorption Spectroscopy (TDLAS) tomography has grown rapidly, with a focus on non-invasive imaging of critical combustion parameters, e.g. temperature [2][3][4][5], gas concentration [3][4][5][6][7], pressure [8,9] and velocity [10], in reactive flows. High-fidelity temperature imaging is of critical interest, as the temperature distribution directly relates to heat transfer and reveals combustion efficiency and temperature-dependent creation of pollutants, such as NOx and CO.…”