Numerical study on the duty cycle of a pulsed jet in the combustion flow field

Abstract The study of steady fuel injection schemes is becoming more and more mature and has been widely used in the combustion chamber, while the time effect of fuel injection is also worth studying. This paper discusses the effect of pulse jets with different duty cycles on the combustion efficiency of hydrogen gas using the same jet parameters. The combustion flow fields are calculated with Reynold-averaged multi-component N-S equations, based on the finite volume method. The result shows that when the duty cycle is increased, the hydrogen mass flow rate increases, the impulse interference is enhanced, the amount of hydrogen combusted increases, and the total pressure recovery coefficient decreases, which is still larger than the steady jet. At the duty cycle of 0.75, the amount of hydrogen combusted increases by about 14% compared to the steady jet. When the duty cycle is 0.25, the total pressure recovery coefficient of the exit section of the combustion chamber increases by about 9.2% compared with the steady jet.