As mentioned in project JOU2-CT92-0055, the issue of soot emissions is critical and needs basic RTD actions to improve the understanding of its formation and burn-out. This project will investigate the influence of pressure on the formation of soot and pyrolysis compounds. New optical and sampling techniques will be developed for use in hostile highpressure experiments.
The project is composed of three complementary actions:
1. Diagnostics for characterization of pyrolysis products in Diesel spray combustion:
Fluorescence measurements will be performed in high-pressure high-temperature conditions to follow the evolution of heavy molecular weight gaseous products. A multi-image technique that uses only one camera to collect 2 or 4 images of different object fields or the same object field with different wavelength or polarization will be developed. Finally, the characterization of random distributions of intensity level recorded by CCD cameras will be performed to collect statistically significant set of time-resolved images.
2. Chemical sampling of pyrolysis products in a shock tube:
To overcome the sampling issue in shock tube due to short residence times, a modified shock tube where the shocks can be quenched at the properly chosen conditions will be built up. The sampling will be performed when the pressure decay starts. Optical techniques and chemical analysis of the sampled products will be carried out to identify large aromatic structures and their time evolution during the soot inception process.
3. High pressure combustion:
The investigation will consist in burning fuel-rich flames at high pressures and in measuring the maximum concentration of unsaturated hydrocarbons in their reaction zone, as well as the concentration of the hydrocarbons remaining in the burnt gas.
Special attention will be given to the aromatic compounds. At the targeted pressures, classical methods cannot be applied. It will be necessary to compute flame profiles for different conditions and to compare them with experiments.
Funding SchemeCSC - Cost-sharing contracts