液氢科氏质量流量计模态分析

Modal analysis of liquid hydrogen Coriolis mass flowmeter

针对液氢科氏质量流量计的开发需求,以双U型科氏质量流量计为分析对象,以液氢为流动工质,在ANSYS Workbench平台上对科氏质量流量计的三种模态(干模态、湿模态和预应力模态)进行仿真计算,探究液氢工质的特殊物性对科氏质量流量计测量管模态的影响。结果显示,液氢温区下测量管的固有频率与常温温区下存在显著差异,这是因为,对于低温工质,温度对材料刚度的影响是显著的。液氢的密度和声速均较低,其在测量管内流动时流体预应力效应和附加质量效应对科氏质量流量计模态的影响均不明显。该项研究结果可为后续液氢科氏质量流量计的振动特性研究和结构优化设计提供依据。

For the development needs of liquid hydrogen Coriolis mass flowmeter, a modal vibration of double U-shaped Coriolis mass flowmeter with liquid hydrogen as the working fluid was simulated by ANSYS Workbench software. The characteristics of different modals(dry modal, wet modal and pre-stressed modal) were analyzed to explore the influence of the special physical properties of liquid hydrogen. The results show that the natural frequency of the Coriolis mass flowmeter measuring tube in the liquid hydrogen temperature region is significantly different from that under normal temperature conditions. This is because, the influence of temperature on the material stiffness is significant especially for the cryogenic working fluid. The density and sound velocity of liquid hydrogen are relatively low, so that the fluid pre-stress and additional mass effect have no obvious influence on the modal of the Coriolis mass flowmeter. The results from this work are important for the vibration characteristics research and optimization design of liquid hydrogen Coriolis mass flowmeter.