Aiming at the issue that the conventional volute profile fails to completely enclose the impeller, the imPact of the profile's incompleteness on the fan's performance is explored, and a novel profile design approach is proposed. This method commences from the tongue and designs the Archimedes spiral around the impeller for an entire cycle to guarantee the uniformity and full development of the airflow within the volute. Through CFD simulation, the influence of the variation of the envelope angle on the flow field, efficiency, and noise characteristics of the fan is determined. The results indicate that when the envelope angle is gradually increased to the shape line encomPassing the impeller, the efficiency of the centrifugal fan is significantly enhanced and the operational noise is reduced. Under the design condition, the total pressure efficiency is elevated by 7.67% and the noise is decreased by 3.89 dB. A new line design method with complete impeller envelopment can notably improve the fan's performance and holds significant guiding value for the fan design.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |