Yinjie Zhuo, Chengxu Tu, Xiang Li, Haohao Xu, Jiaxiang Wang, Weijie Chen, Qingsong Shi, Yexin Lu, Di Xiao, Fubing Bao
Research on standard device of liquid hydrogen flow driven by air pressure
As an important link in the industry chain of hydrogen energy, liquid hydrogen has great potential in civil aviation, shipping, and urban public transportation, and is a also key component in the future large-scaleindustrialization of hydrogen energy. The accuracy of liquid hydrogen flow measurement is crucial in its preparation, storage, transportation, application, and trade settlement during the whole industry chain running. The liquid hydrogen flow standard device is the core equipment to check and calibrate the liquid hydrogen flowmeter, which is the key link to ensure the reliable flow measurement of liquid hydrogen. As a low-temperature fluid with ultra-low viscosity and low density, the non-negligible error would be introduced when the flowmeter is calibrated using other fluids instead such as water, especially in the tiny flow range. Therefore,it is necessary to develop a flow standard device for actual-flow calibration of the liquid hydrogen flowmeters.In this paper, based on the existing research of cryogenic fluid standard devices at home and abroad, a liquid hydrogen flow standard device based on the bi-directional dynamic mass method is designed, using helium to drive the liquid hydrogen in the tank, which can provide the standard flow rate in the small flow range for the calibration and verification of the flowmeter under test. The system is designed to take into account the cryogenic temperature, low viscosity, high flammability and explosivity of the liquid hydrogen, as well as the measurement accuracy. Compared with the cryogenic pump, the high-pressure helium source can provide a more stable and smaller flow rate to achieve the higher accuracy and robustness of the calibration and verification of the flowmeters under the small flow rate of the device. The bi-directional dynamic mass method with reverse drive can avoid the influence of additional pipe capacity on the actual error generated during measurement, effectively reduce the measurement uncertainty of the device and improve the measurement system of the liquid hydrogen flow.