【摘要】 针对科氏力流量计(CMF)在液氢等低温流体应用时因大温差、两相流等导致测量精度下降的技术难点,详细报道了中国在测量管理论优化、大温差和两相流影响机理等方面的研究进展。现有研究通过基于欧拉梁理论的测量管解析模型提出了一个可用于测量管结构优化的无量纲频率比f_r,同时指出低温测量时大温差将导致测量管材料的弹性模量和剪切模量等物性非线性改变,引入热应力及热应变等不利影响,导致流量计零点漂移并降低测量精度。研究分析了两相流对科氏力流量计的影响机制,揭示其由于解耦效应和有限声速效应造成测量管振动失稳。最后研究给出研制的科氏流量计的水和液氮实验测试结果,同时介绍了液氢流量计标定装置的研制情况,指出了低温CMF未来发展方向。更多还原

【Abstract】 To address the technical challenges in the measurement accuracy of Coriolis mass flowmeters( CMF) when applied to cryogenic fluids such as liquid hydrogen, which arise from large temperature differences and two-phase flow conditions a detailed review of domestic research progress is presented, covering areas such as measurement tube theory optimization and the mechanisms underlying the effects of large temperature differences and two-phase flow. A dimensionless frequency ratiof_rapplicable to measurement tube optimization has been proposed in existing research using an analytical tube model based on Euler-Bernoulli beam theory. Meanwhile, the study indicates that in cryogenic measurements, large temperature differences induce nonlinear changes in the physical properties for material properties of the flowmeter measurement tube, such as elastic modulus and shear modulus, and introduce adverse effects such as thermal stress and thermal strain. Consequently, zero drift is induced and the measurement accuracy of CMF is reduced. Research analyzes the influence mechanisms of two-phase flow on CMF and reveals that it causes vibration instability in the measurement tube due to the decoupling effect and the finitesound-speed effect. Finally, the research concludes by presenting the water and liquid nitrogen test results of the developed CMF, along with the development status of a liquid hydrogen flowmeter calibration setup, and outlines the future development directions for cryogenic CMF.更多还原