| 摘要 |
A heat-dissipating fan has a housing and an impeller. The housing has a receiving space and one or more guide rings. The receiving space forms an airflow inlet and an airflow outlet. The guide ring is mounted near the airflow outlet and has one or two guide surfaces formed thereon and facing the airflow inlet. The impeller is mounted rotatably in the receiving space and has a hub and multiple blades. Airflow channels formed between adjacent blades each have a cross-section narrowed from a top end of the guide ring to the airflow outlet. Each blade has a receiving notch formed in a bottom edge thereof, corresponding to a cross-section of the guide ring and defines a gap between the blade and the guide ring. Airflow is speeded up in the airflow channels based on Venturi effect, such that a heat-dissipating efficiency of the fan is improved.
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