To analyze the noise characteristics of restriction orifice in aircraft air conditioning duct system and carry out the noise reduction optimization design of restriction orifice plate

the computational fluid dynamics method is used to calculate the steady flow field of a straight duct with the restrictor orifice at first and explore the flow state of the airflow through the orifice. Then

according to the large eddy simulation method and the Ffowcs Williams and Hawkings(FW-H) equation

the transient flow field and acoustic calculation of the duct are carried out

and the flow-induced noise characteristics of restriction orifice at the aircraft cockpit monitoring point are analyzed. Finally

the effects of restriction orifices with different aperture on the cockpit monitoring points are compared and studied

and a better low-noise structure design form of the orifice plate is proposed. The research results show that increasing the flow aperture can improve the noise reduction effect

but the pressure drop performance is reduced

and the noise reduction of the restriction orifice needs to be considered comprehensively with its pressure drop performance.