Experimental study on puffing, auto-ignition and combustion characteristics of an n-pentanol-diesel droplet

Puffing, auto-ignition and combustion characteristics of an n-pentanol-diesel droplet are investigated using the droplet suspension technology under ambient temperatures of 830-930 K and n-pentanol concentrations of 0%-75%. The evolution profile of OH* chemiluminiscence is detected by a monochromator. A spike is observed shortly after the auto-ignition time for all these profiles. After the spike, different n-pentanol concentrations lead to different evolution profiles of OH* intensity. The profile of D75P25 (75% diesel and 25% n-pentanol by mass) witnesses a slight increase and enters a plateau stage. For D25P75, the combustion and extinguishment of n-pentanol vapor lead to the increase and decrease of OH* intensity in a long period, respectively. Furthermore, two auto-ignition delays are obtained by a high-speed camera and a monochromator. The difference between the two auto-ignition delays is nearly irrelevant to n-pentanol concentration at 880 K, while a positive dependence on n-pentanol concentration is shown at 930 K. On the other hand, the higher n-pentanol concentration leads to a longer auto ignition delay at 880 K but a shorter auto-ignition delay at 930 K. Surface and inner puffing modes are observed at 930 K for D25P75 and D75P25, respectively. Many factors lead to different turning phenomena in droplet temperature curves. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study investigated the puffing, auto-ignition, and combustion characteristics of an n-pentanol-diesel droplet using droplet suspension technology. Different n-pentanol concentrations were found to affect the evolution profiles of OH* intensity.