To address the issue of abnormal noise at 5 200 Hz occurring in variable refrigerant flow （VRF） indoor units under heating operation，a dedicated test bench for the electronic expansion valve （EEV） was constructed to identify the excitation conditions responsible for this high‑frequency noise.Large eddy simulation （LES），coupled with the Schnerr‑Sauer cavitation model，was employed to compute the temporal evolution of the vapor volume fraction inside the EEV and the corresponding pressure fluctuation spectrum.Additionally，the acoustic finite element method was applied to determine the acoustic cavity modes within the valve chamber.The results indicate that after the refrigerant passes through the throttling region of the EEV，pronounced localized vortices are generated.The pressure at the vortex core drops below the local saturation vapor pressure，triggering localized flash cavitation.The pressure fluctuation frequency induced by cavitation couples with the acoustic cavity mode of the valve chamber at 5 237 Hz，thereby amplifying pressure pulsations near that frequency and radiating audible noise.To mitigate this issue，a chamfered flow‑guiding design on the valve seat and the addition of a buffer chamber were implemented.These modifications effectively suppress cavitation and eliminate the high‑frequency noise during heating operation.