The thermal stability characteristics of four kerosine-type fuels are examined using a heated-tube apparatus that allows independent control of fuel pressure, fuel temperature, tube-wall temperature, and fuel flow rate. It is a closed loop system, and fuel flows through the heated tube for periods ranging from 6 to 22 h. The deposition rates of carbon on the tube walls are measured by weighing the tube before and after each test. The results obtained show that tube-wall and fuel temperatures both have a marked influence on deposition rates, the impact of fuel temperature being stronger than that of wall temperature. It is also found that deposition rates increase continuously with increases in tube-wall temperature. This finding contradicts the results of previous studies, which had led to the conclusion that deposition rates increase with increase in wall temperature up to a certain value, beyond which any further increase in wall temperature causes the deposition rate to decline.

No abstract

The thermal stability characteristics of four kerosine-type fuels are examined using a heated-tube apparatus which allows independent control of fuel pressure, fuel temperature, tube-wall temperature, and fuel flow rate. It is a closed loop system, and fuet flows through the heated tube for periods ranging from 6 to 22 hrs. The deposition rates of carbon on the tube walls are measured by weighing the tube before and after each test. The results obtained show that tube-wall and fuel temperatures both have a marked influence on deposition rates, the impact of fuel temperature being stronger than that of wall temperature. It is also found that deposition rates increase continuously with increases in tube-wall temperature. This finding contradicts the results of previous studies which had led to the conclusion that deposition rates increase with increase in wall temperature up to a certain value beyond which any further increase in wall temperature causes the deposition rate to decline.

marked influence on deposition rates, the impact of fuel temperature being stronger than that of wall temperature. They also show that deposition rates increase continuously with increase in wall temperature and do not decline at wall temperatures above around 650 K as the results of previous studies would appear to suggest. Comparisons of the results obtained with light-distillate fuels of different aromatics content indicates that deposition rates are enhanced by an increase in aromatic content, the effect becoming less pronounced for fuels of higher aromatic content.