Synergistic effect of swirl flow and prechamber jet on the combustion of a natural gas-diesel dual-fuel marine engine

•Mixture formation and combustion of a dual-fuel marine engine were numerically studied.•The scavenging swirl governs in-cylinder natural gas stratification prior to ignition.•The prechamber layout determines jet flame propagation and wall heat loss.•The fuel consumption was optimized by synergistically coordinating the scavenging swirl and the prechamber jet.