Soot oxidation in gas turbines using heavy fuels. 2

Most of the work carried out, so far, in the study of soot oxidation has used laboratory flames and shock tubes in connection with graphite to avoid the difficulty in determining the history of soot particles in complex practical flames such as those of the gas turbine. Therefore, a soot oxidation model is developed to calculate the soot burning rate in the secondary zone of a gas turbine combustor operating with heavy fuels including blends of gas oil and residual fuel oil. The combustor pressure is raised to 1.0 MPa, inlet air temperature to 460 K, primary air/fuel mass ratio to 25 and total air/fuel mass ratio to 120. The capability of the model is found to be favourable when evaluated at the exhaust plane. Furthermore, it is noted that, at full power, the soot level in the primary zone can decrease ≈ 1000 times in its travel through the secondary zone before emerging as smoke. A disparity in the peak soot burning rate is noted between fuels at the idle condition. At full power this disparity disappears.