An Experimental Investigation into the Effect of Soap on Ignition and Combustion Characteristics of Single Droplets of Glycerol

Abstract

The ignition and combustion characteristics of single droplets of glycerol with soap addition were studied experimentally. Soap was added into a pure glycerol at concentrations of 1 to 5 wt%. A single droplet was suspended on the tip of a silicon carbide fibre and exposed to air at 1023K. The ignition delay time, burnout time and burning rate were determined. A flame emission spectrometer was used to identify the presence of sodium in the flame. Results showed that combustion of the glycerol droplets with soap addition occurred in a two-staged manner: (1) the first stage where glycerol preferentially was evaporated and burned and (2) the second stage where soap was evaporated and burned. The soap addition in the glycerol reduced the ignition delay time, shortened burnout time and improved burning rate of the droplets. Sodium ions detected to present in the flame promoted the combustion rate of the fuel vapour.