Calculations and Test Measurements of In-Cylinder Combustion Velocity of Hydrogen-Air Mixtures Considering the Effect of Flame Instability

The combustion characteristics of hydrogen-air mixtures have significance significant impact on the performance and control of hydrogen-fueled internal combustion engines and the combustion velocity is an important parameter in characterizing the combustion characteristics of the mixture. A four-cylinder hydrogen internal combustion engine was used to study hydrogen combustion; the combustion characteristics of a hydrogen mixture were experimentally studied in a constant-volume incendiary bomb, and the turbulent premixed combustion characteristics of hydrogen were calculated and analyzed. Turbulent hydrogen combustion comes under the folded laminar flame model. The turbulent combustion velocity in lean hydrogen combustion is related not only to the turbulent velocity and the laminar burning velocity, but also to the additional turbulence term caused by the instability of the flame. The formula to calculate turbulent combustion velocity considering instability is proposed and verified by experiments. This formula can be used to calculate the combustion velocity under the boundary conditions of the hydrogen internal combustion engine, which is instrumental for hydrogen internal combustion engine design and optimization.