According to the configuration design requirements of the air film damper in the aero engines

the mechanics model of the air film damper was built based on the extrusion gap flow theory and energy equation. Therefore

the equivalent stiffness coefficient and the equivalent damper coefficient were obtained. The amplification factor's expression was also obtained through derivation from the vibration equations. Research results revealed that

the air cavity thickness

the initial cavity pressure

the modal frequency and the location of the absorbing vibration plate were the key parameters which determined effect of vibration reduction. The optimization air cavity thickness was determined by the boundary layer thickness and vibration frequency

thus the best value could be acquired according to the particular case in order to depress the vibration response to the maximum extent. The damper coefficient increased with the increase of the initial cavity pressure. The nature frequency of the additional plate was recommended to be close to that of blade

and the absorbing vibration plate was suggested to be installed on the location with the maximum vibration response

in order to obtain the best effect of vibration reduction.