1362 Spray Combustion

The effect of fuel properties on the structure of swirling spray flames has been investigated. Droplet size, number density and velocity measurements have been carried out in pressureatomized spray flames using phase/Doppler interferometry. Four fuels with different physical properties were studied, namely n-heptane, methanol, 50/50 methanol/1-dodecanol mixture, and kerosene. The results indicate that droplet mean size and velocity are influenced primarily by the fuel viscosity. No detectable trend could be attributed to changes in surface tension. Fuel volatility seems to have some effect on the spray flame structure, especially in the methanol flame. Flame luminosity is found to increase with increasing C/H ratio and fuel heating value. Droplet size and velocity distributions near the nozzle are found to be quite broad, and include regions of negative velocities. Some evidence has also been found to indicate the occurrence of microexplosions in the methanol/dodecanol mixture flame.