First Measurements of the Liquid Phase Temperature in Diesel Sprays

The temperature of the liquid phase in diesel sprays governs droplet vaporization and accordingly the fuel/air mixing processes. The ignition delay and the position of ignition start in diesel sprays are hence functions of the liquid phase temperature.

So far, it has not been possible to directly measure the liquid phase temperature in diesel sprays. It has been numerically calculated using assumptions which are not likely to hold under engine-like conditions.

An optical method based on laser induced fluorescence has been developed allowing the two dimensional measurement of the liquid phase temperature in diesel sprays. The accuracy is estimated to be within ± 10 K.

First results acquired from a bomb are presented in the form of temperature maps showing cyclic deviations of the heating processes.