Full
Outline
A self-oscillating pulsed jet nozzle can convert a continuous jet into a pulsed jet, which effectively enhances rock-breaking efficiency by inflicting periodic "water hammer" damage on the rock. As the core component for regulating jet morphology, the conventional linear structure of the nozzle oscillation cavity suffers from energy dissipation, thereby constraining jet performance. To address this, a study was conducted to investigate the influence of the cavity diameter ratio (the ratio of the oscillation cavity length L to the upper nozzle diameter d1) on the pulsed jet performance within the external field, thereby identifying the optimal range for this ratio. From the perspective of flow field structure, the dynamic relationship between the internal low-velocity zone of the cavity and jet performance was analyzed, and Bezier curves were employed to optimize the wall profile of the oscillation cavity. Rock breaking and punching experiments using the self-oscillating pulsed jet nozzle were performed before and after the shape optimization of the oscillation cavity wall to comparatively verify the optimization effect of the oscillation cavity shape of the nozzle. The results indicate that when the cavity diameter ratio is between 5 and 6, the internal low-velocity zone of the oscillation cavity is minimized, yielding optimal jet performance in the external field. For the optimized nozzle, the average velocity and peak velocity of the external field exhibit increases of 16.99% and 16.74%, respectively. Furthermore, compared with the original nozzle, the diameter, depth, and volume of the punching holes generated by the pulsed jet impact on the rock are enlarged by 25.45%, 24.27%, and 18.32%, respectively. These findings demonstrate that the overall performance of the self-oscillating pulsed jet nozzle is effectively upgraded.
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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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