AN INVESTIGATION INTO ACOUSTICS AND VIBRATION OF CPAP DEVICES: NUMERICAL PREDICTION OF CENTRIFUGAL FAN ACOUSTICS AND VIBRATION

摘要

Continuous Positive Air Pressure (CPAP) devices are used to generate pressurized airflow to relieve upper airways and allow Obstructive Sleep Apnea (OSA) patients to breathe comfortably and easily. The airflow path in these devices consists of several components including but is not limited to inlet and outlet ducts, a centrifugal fan, a humidifier and a human interface. These components contribute significantly to the noise generated by the airflow. This research paper present a numerical study of a centrifugal fan performed with commercial ANSYS software package to predict the sound and vibration produced by the centrifugal fan. The methodologies are following: first, the unsteady flow field is computed using the CFD model to obtain aerodynamic quantities and sound sources. Then, the finite element method (FEM) is used to predict the flow-induced vibration using the predicted aerodynamic quantities. Finally, the Ffowcs-William and Hawkings's (FW-H) acoustic analogy is used to predict the acoustic pressure at the far-field using the sound sources from the unsteady simulation.