Multiparameter Measurement in Ethylene Diffusion Flame Based on Time-Division Multiplexed Tunable Diode Laser Absorption Spectroscopy

Abstract

An optical method for measuring soot volume fraction, flame temperature, and concentration of combustion products in a diffusion flame based on time-division multiplexed tunable diode laser absorption spectroscopy technique is presented in this article. By moving the slot burner with an electric platform, two-dimensional profile of soot volume fraction, flame temperature, and gas concentrations along the flame sheet with 1-mm spatial resolution were obtained simultaneously. The flame temperature and soot volume fraction were simultaneously on-line monitored using one distributed feedback diode laser with a center wavelength at 1397.83 nm. Tunable diode laser absorption spectroscopy based temperature measurements in the flame were carried out by two-line thermometry of H 2 O and compared with the thermocouple technique. The attenuation of tunable diode laser intensity caused by soot extinction and gas absorption after transmitting through the diffusion flame was detected. And the soot volume fraction was determined quantitatively with laser extinction based on Rayleigh limit assumption. Two tunable distributed feedback diode lasers with center wavelength at 2001.6 and 2302 nm were used to determine the CO 2 concentration and CO concentration, respectively. The experimental results of soot volume fraction, flame temperature, and the mole fraction of combustion products by varying concentrations of CO 2 added in the diffusion flame were analyzed.

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].…”

Ultra-Low Sampled and High Precision TDLAS Thermometry Via Artificial Neural Network

“…6, could be distinguished. The concentration of water vapor in the Heating equipment could be extracted by the DAS method [26]. The mole fraction was approximately 0.01.…”

Simultaneous Detection of Multiple Atmospheric Components Using an NIR and MIR Laser Hybrid Gas Sensing System

“…Traditionally, multilasers used in a multi-gas detection system will induce an optical interference effect, when a single photodetector was used without time-division multiplexing. , Thus, an interference test is necessary to verify the proposed MIR and NIR coupled gas sensor system. For this issue, an intermittent blocking experiment was performed.…”

“…Due to the molecular properties of the analytes of interest, their strong absorption lines suitable for high-sensitivity detection are clearly separated; therefore, it is almost impossible to achieve simultaneous measurement of CO, N 2 O, and CH 4 with a single laser in current TDLAS. Thus, multilaser-based gas sensor systems were usually employed to achieve detection of multi-gas species. − For example, Santoni et al presented an evaluation of aircraft observations of CO 2 , CH 4 , N 2 O, and CO by combining a direct absorption pulsed quantum cascade laser spectrometer (QCLS) with three pulsed quantum cascade lasers. Kostinek et al reported simultaneous airborne in situ observations of CH 4 , C 2 H 6 , CO 2 , CO, and N 2 O using a quantum and interband cascade laser spectrometer.…”