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Under single-nozzle operating conditions, the radial force of the runner for large-scale impulse turbine abnormally increases, severely affecting shafting stability. This study establishes a dynamics model of the bearing-rotor system incorporating the runner, main shaft, and bearing supports. The critical speed and vibration mode characteristics of the shafting system were calculated by using COMSOL Multiphysics software. And then the transient response characteristics under different radial hydraulic thrust forces were analyzed. The results indicate that the first-order critical speed of the unit shafting is 534.49 r/min, meeting the design specification requirements. The radial hydraulic thrust under single-nozzle operation can be considered as a constant radial force. The centroids of shaft orbits in all guide bearings exhibit displacement under radial hydraulic thrust, with the maximum offset observed in the turbine guide bearing. Analysis reveals that during single-nozzle operation, the resultant radial force on the water guide bearing concentrates on the one side, fluctuating within approximately ±1.5° relative to the jet direction. This research can provide reference for structural optimization and operational control of impulse turbine units under special operating conditions.
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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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