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In order to optimize the design of fire-fighting equipment, the influence of apertures on the performance of compressed air foam jets was investigated through experiments involving various jet apertures and gas-liquid ratios. The data, including the expansion ratio, liquid drainage time, foam jet range, and width, were collected. It was found that as the jet aperture decreased, the deviation of the actual expansion ratio from the ideal value increases, and the deviation increases as the gas-liquid ratio increases. The minimum jet aperture threshold meeting the stability requirements of the compressed air foam system is determined. The critical gas-liquid ratio for a stable foam jet decreases as the aperture diminishes, and a relationship between the jet aperture and the critical gas-liquid ratio is established. The effect of jet aperture on the diameter of foam D32 and 25% drainage time is not obvious. For gas-liquid ratios below 20, in the same gas-liquid ratio, the jet aperture is inversely proportional to the range and width of the foam. Under the same jet aperture, beyond a certain gas-liquid ratio, the variation in foam range becomes negligible. Additionally, the underlying causes of the observed critical gas-liquid ratio, 25% drainage time, and variations in range and width are analyzed.
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| 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 |
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