Quantitative measurements of soot particles in a laminar diffusion flame using a LII/LIS technique

Abstract

Methods to investigate soot formation are studied experimentally with a co-flow burner. In this study, the soot volume fraction, soot particle diameter and number density in a laminar diffusion flame are measured using LII/LIS (laser-induced incandescence/laser-induced scattering) techniques. For the purpose of quantification, validation tests needed to be conducted before the LII/LIS techniques were applied to measure soot formation, and the development of algorithm was also required to analyse the raw data. In the present study, extinction and scattering tests with a co-flow burner were performed to acquire calibration data. From these results, we decided the optimal laser beam intensity and obtained the LII signal from the diffusion flame. In addition, the algorithm for the LII/LIS simultaneous measurement was developed and applied to this algorithm to measure the soot volume fraction in the diffusion flame.

Investigation of optical properties of aging soot

“…Line-of-sight-attenuation (LOSA) is a well-established soot diagnostic valuable for soot volume fraction, f v , mapping [33,36,69,70]. In LOSA measurements, the optical transmissivity of an aerosol containing medium is measured along a linear path through the medium.…”

“…Despite these recommendations, many contemporary inflame studies of soot use visible wavelengths for soot detection and the optical properties of mature, post-flame soot in the measurement evaluation (e.g., [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]). The same is true of commonly used commercial soot detection systems [2].…”

Experimental determination of distributions of soot particle diameter and number density by emission and scattering techniques

“…Available measurement techniques of particle size include the optical [1][2][3][4][5][6][7][8][9][10] and the non-optical measurement techniques. [5,[11][12][13][14] Due to the non-intrusion characteristic, real-time capability, and convenience of simultaneous multidimension measurement, optical methods have been used by numerous researchers for the measurement of particle parameters.…”

Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions

“…The magnitude of the signal can be correlated with the volume fraction 55 of particles in the detection region. This technique has been used extensively for qualitative [3-56 6] and even quantitative measurements [7][8][9]. However, quantitative measurements require a 57 firm understanding of the factors that influence the LII signal, which are detailed in [10].…”