Unsteady cavitation characteristics of liquid hydrogen in perforated plate flowmeters

With the growing development and application of hydrogen energy across various fields, liquid hydrogen is regarded as one of the most promising methods for hydrogen storage and transportation. Accurate flow measurement during transportation is crucial. However, cavitation tends to occur when liquid hydrogen flows through throttling flowmeters, potentially compromising the safety and stability of the system. Therefore, controlling cavitation and improving measurement accuracy are pressing technical challenges. This study focuses on the recently developed perforated plates, combining the Large Eddy Simulation model and the Schnerr-Sauer cavitation model to numerically analyze the unsteady cavitation characteristics of liquid hydrogen. Specifically, it investigates the effects of different inlet velocities and perforated plate configurations on the cavitation number, bubble shedding frequency, pressure fluctuations, and entropy production. By analyzing the evolution of the cavitation process, its periodic behavior, and energy loss, this study explores the regulatory role of perforated plate structures in cavitation intensity and flow field stability, with comparisons made against single-hole plates. The results indicate that at higher cavitation intensity, the aggregation effect enhances the prominence of low-frequency periodic behaviors in the bubble shedding process. Entropy production analysis reveals that the total entropy production is primarily driven by velocity gradients. Regarding perforated plate structures, the 7-hole plate, which exhibits the lowest cavitation intensity, shows a 140 % increase in cavitation number and a 16.7 % reduction in total entropy production compared to the single-hole plate. Furthermore, as the number of perforations increases, turbulence-induced resistance and channel-induced resistance exhibit opposite trends, with cavitation intensity closely linked to their combined effect. These findings not only provide a theoretical basis for the design and optimization of perforated plates in liquid hydrogen transport systems but also offer new insights and strategies for cavitation control and prevention.