Abstract: For studying the principle, property and law of air disturbulance noise produced by rubbing and breaking machine, the three dimensional inner flow fields were simulated with Fluent software. The simulated results could directly show its properties and state of the flow fields. Comparing numerical simulation curves with experiment data, the maximum relative error was less than 8%. The distributions of pressure and velocity of flow fields were obtained from the simulated results under the condition of rotating rate at 2 800 r/min. By analyzing the simulated results of flow field, both rotation noise and eddy current noise were produced when the low-speed airflow from inlet was affected by high-speed rotating rotor. In addition, a reversed flow was formed in the outlet, which could cause a block and produce noise.