Abstract
A method for measuring the aerodynamic excitation force of the rotating fan has been developed. In this study, the aerodynamic excitation force of the rotating fan was measured using test system with a four-bladed fan, an induction motor, pressure gauges, and a high-stiffness wall. The aerodynamic pressure of the rotating fan makes several peak frequency components that are Nz-frequency excitation force. "Nz" is [Rotational speed of motor "N"×Number of fans "z" (Hz)]. We used the static pressure previously measured to analyze the vibration response of a thin plate structure. The thin plate structure was a 900×740×3.5mm aluminum plate lies at a distance of 10mm to 7mm against the fan. To calculate the vibration response of a thin plate excited by the aerodynamic force of rotating fan, the measured pressure was transformed into the excitation force and phase angle. Acceleration response of the thin plate excited by the rotating fan was determined by using the transformed force and the F-E model. Only the basic frequency of blade-passing component, at which the largest pressure occurs, was used in this calculation. Using the transformed force and phase of rotating fan, the vibration response of a thin plate structure was accurately calculated.
