At present, the cross flow fan has a relatively complex internal structure. Although its impeller is symmetrical in the circumferential direction, the airflow activity is asymmetric, and its relative velocity field and absolute velocity field are unstable. The moving medium enters the impeller twice, and the rotor impeller's movement along the circumferential direction continues to change. There is a vortex on the inner side of one side of the impeller circumference that can control all airflow activities, which is called the vortex of cross flow fan. The vortex base is located at a certain point on the inner circumference of the impeller and moves along the circumferential direction depending on the saving situation. It is precisely the presence of this vortex that causes the flow to pass through. Under certain operating conditions, due to the enhanced control force of the vortex at high speeds, the gas inside the cross flow fan cannot be discharged or sucked in normally, resulting in an abnormal situation in the experimental system, known as the surge phenomenon. If the ventilation area is small, the resistance layer resistance is high, and the flow rate inside the pipeline is small, the operational requirements for the cross flow fan are low, and the effect of vortex relief is not significant at low flow rates. But when the speed is high and the ventilation area is large, the control force of the vortex is enhanced, and the gas in the cross flow fan cannot be discharged or sucked in normally, resulting in abnormal conditions in the experimental system.