To investigate electrostatic accumulation induced by cryogenic liquid hydrogen (LH2) flow in pipelines, a test system was constructed with LH2 as the primary working medium. Using vacuum insulation, insulated connections, electrostatic shielding, and other measures, as well as the application of the leakage charge method, safe and accurate measurement of extremely low-level charge quantities generated by LH2 flow under cryogenic conditions was achieved. The charge accumulation characteristics under multiple flow conditions with Reynolds numbers (Re) below 2×105 were analyzed. The experimental results indicated that notable flow charging phenomena occurred during LH2 flow with extremely low electrical conductivity in pipelines. Furthermore, charge accumulation demonstrated a linear growth during the test period. Within the range of pipe lengths and Reynolds numbers covered by the experiment, the average charge density decreased with an increase in the flow velocity; however, the rate of decrease gradually diminished. The average charge density of flow decreased with increasing pipe diameter. The developed electrostatic accumulation test system for low-temperature LH2 pipe flow provided an important platform support for conducting LH2 electrostatic tests. This study validated the feasibility of the electrostatic measurement method for LH2, providing design guidance for exploring the electrostatic laws of LH2 and the boundary of safe flow velocity.
| 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 |