To research the mitigation performance of rocket ignition overpressure by water mist layer

the theory of plane wave propagation in different medium was applied to expore the mechanism for ignition overpressure mitigation by water mist layer. And

main influential factors of ignition overpressure mitigation performance were obtained from theory analysis. Furthermore

the influence rules of the factors on the mitigation performance were studied by numerical computation and the proper value ranges of influential factor under the conditions of rocket safety launching were given. At last

the parameter levels of influential factors for numerical computation cases were arranged by the uniform design. Meanwhile

the parametric model of the influential factors to the mitigation performance was built by regression

and the mitigation efficiency was optimized. The numerical results show that the main influential factors include water droplets diameter

water mist volume fraction and water mist layer thickness. And

there are two different mitigation mechanisms between water droplet and ignition pressure pulse which are closely related to droplet diameter. In addition

there is a parametric model of the influential factors to the mitigation performance when the influential factors falls within some value ranges

and fiducially probability of the model is not less than 95%.