Fig. 1. Laminar pool flame setup

Fig. 2. Average fuel consumption rate tested under pool flame condition

Fig. 3. Optical path design of 2D laser-induced incandescence

Fig. 4. Relationship between normalized LII signal intensity and laser energy density

Fig. 5. Relationship between extinction coefficient and transmission/incident intensity ratio

Fig. 6. Main reactions in transesterification process^[12]

Fig. 7. Preparation process of biodiesel from waste cooking oil—pretreatment and transesterification processes

Fig. 8. Actual flame images (left) and corresponding soot volume fraction (SVF) distribution images (right). 2D SVF of flame is derived from HAB of 0-32 mm. Flame appearance and soot volume fraction distribution of different blend fraction of palm biodiesel at (a) 20%, (b) 40%, (c) 60%, (d) 80%, and (e) 100% with diesel, and neat biodiesel from (f) conventional diesel, (g) waste cooking oil, (h) rice bran, (i) duck, and (j) goose

Fig. 9. Relationship between soot volume fraction peak value and biodiesel blending fraction

Fig. 10. Relationship between total soot volume and biodiesel blending fraction

Fig. 11. Relationship between predicted diffusion flame temperature and biodiesel blending volume fraction

Fig. 12. Relationship between visible flame height and calculated flame temperature

Fig. 13. Predicted visible flame height based on Roper's model as a function of calculated flame temperature

Fig. 14. SEM images of soot particles and mean particle diameter distributions.(a)-(c), (g)-(i) SEM images of soot particles; (d)-(f), (j)-(l) mean particle diameter distributions. D0, P, D, G, W, and R represent diesel, palm, duck, goose, waste cooking oil, and rice bran biodiesels, respectively. Best lognormal fitting of particle diameter distribution is shown as a curve