Engine Combustion Network (ECN): Global sensitivity analysis of Spray A for different combustion vessels

Abstract

Global sensitivity analysis was conducted on Spray A of the Engine Combustion Network’s (ECN) experimental conditions across different combustion vessels from different institutions. The main objective was to understand the influence of differences in boundary conditions on specific targets of interest. A list of experimental initial, boundary, and injection conditions with uncertainty ranges were identified for three different ambient conditions for these combustion vessels. Five targets including the liquid length, vapor penetration length, ignition delay, lift-off length, and soot mass in the domain were extracted from hundreds of 3D computational fluid dynamics (CFD) simulations by simultaneously perturbing all the uncertain variables. Each target was analyzed using a global sensitivity analysis (GSA) method and the relative importance of different variables towards specific targets was identified. The uncertainty in the fuel temperature was found to have a profound influence on the liquid length, however, the influence on vapor penetration length, ignition delay, and lift-off length, was rather subtle. Small uncertainties in the initial turbulence level and nozzle diameter was observed to have a significant influence on the vapor penetration. Variables sensitive to ignition delay also showed similar sensitivity to flame lift-off length. The soot mass in the domain was observed to have a closer correlation with the liquid length at least for higher ambient temperature conditions.