Autoignition of Heavy Fuel Oil Sprays at High Pressures and Temperatures

1990 ◽  
Vol 112 (3) ◽  
pp. 324-330 ◽  
Author(s):  
R. S. G. Baert

This paper reports on an experimental study of the autoignition behavior of several heavy fuel oils in a large constant-volume combustion chamber with single-shot injection. In the experiments the pressure and the temperature of the air in the combustion chamber before fuel injection varied between 30 and 70 bar and between 730 and 920 K. Illumination delay and pressure delay values have been correlated with these pressures and temperatures. It is shown that for all but one of the fuels examined, ignition delay ranking changes little with the choice of ignition delay definition, but more with the pressure and temperature conditions in the combustion chamber. The usefulness of the Calculated Carbon Aromaticity Index is discussed.

Author(s):  
Takaaki Hashimoto ◽  
Senichi Sasaki

The combustion characteristics (ignition delay and combustion period in this paper) of marine heavy fuel oil are affected by many factors such as density, carbon residue, asphaltene, aromaticity and carbon/hydrogen (C/H) ratio. When investigating the causes of operational problems in diesel engines, what properties should we check to find whether the main causes of the problems are related to fuel oil or not? What is the threshold of ignition delay and combustion period of fuel oil? The authors studied these topics using a combustion test apparatus called FIA 100, and arrived at the following conclusions: 1. The aromaticity index (CCAI) and the C/H ratio have good correlation with the combustion characteristics of marine fuel oil. These factors cannot be ignored during troubleshooting. 2. The carbon residue and asphaltene in fuel oil have no correlation with ignition delay, but have some correlation with the combustion period. 3. There is practically no correlation between the average molecular weight of fuel oil, and both ignition delay and combustion period. 4. Tentative threshold values of ignition delay and combustion period can be set for fuel oils of poor quality (flame retardation).


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