Correlation between ignition delay time and cetane number of fuel using a shock tube.

Claudio Marcio Santana¹; Jose Eduardo Barros¹

¹ UFMG

doi:10.20906/CPS/CON-2016-0126

Resumo

The objective of this study is to correlate the ignition delay times of S25 Diesel fuel ethanol with 5% additive enhancer cetane number, B100 Biodiesel and Diesel reference, measured in a shock tube with cetane numbers of the respective fuels. The shock tube is a metal tube that the gas at low pressure and high pressure are separated by a diaphragm. When the diaphragm (make of material cupper and aluminum) breaks on predetermined conditions (high pressure in this case) produces shock waves that move from the high pressure chamber (known the compression chamber or Driver section) for low pressure chamber (known the expansion chamber or Driven section). The tests were performed under the following initial conditions of the driver section: 30 bar of pressure breakup diaphragm and temperature of 100 °C. For determining and recording the ignition delay time it was used pressure sensors with high acquisition rate (differential sensors) and detect sensor flame. With information from pressure sensors and sensor flame the delay time was determined. Were obtained in testing the speed of propagation of shock waves incident and reflected. It is measured ignition delay times of ethanol additive, Diesel S25, Diesel reference and biodiesel B100. The results was compared with the ignition delay times measured for other authors. It was concluded that the delay time of ethanol with 5% additive was at least twice that of the delay time Diesel S25. The delay time of biodiesel B100 was approximately four times greater than the time delay Diesel S25. The delay time of the Diesel reference was smaller than the S25.

Palavras-chave: combustion; Igniton delay time; shock tube