流型频繁切换下科氏质量流量计驱动特性研究

在科氏质量流量计测量过程中,流量管振动幅值的控制很重要。当单相流与气液两相流频繁切换的情况发生时,使用当前的控制方法流量管会出现振动幅值大幅衰减和超调的问题。为此,设计了一套实验方案,进行实验,分析了出现该问题的原因。针对该问题,提出变驱动周期的方法和变积分限幅值的方法,在所研制的数字式科氏质量流量变送器上实时实现,并进行实验验证。实验结果表明,变驱动周期的方法有效地降低了单相流切换到气液两相流时流量管振动幅值衰减的程度,变积分限幅值的方法很好地解决了气液两相流切换到单相流时流量管振动幅值大幅超调的问题。

Study on drive characteristics of Coriolis mass flowmeter under flow pattern switching frequently

The control of vibration amplitude of flow tube is very essential for Coriolis mass flowmeter (CMF) in the application of measurement.When the single-phase flow and gas-liquid two-phase flow switch to each other frequently,the current control method would lead to a large attenuation and overshoot of vibration amplitude.Therefore,the experimental scheme is designed and conducted.The reason of the problem is analyzed,and then the variable drive cycle method and the variable integral-limiting-value method are proposed.Two methods are realized in real time on the developed digital mass flow transmitter and verified experimentally.The experimental results show that the variable drive cycle method reduces the attenuation degree of the vibration amplitude effectively when the single-phase flow switch to the gas-liquid two-phase flow,and the variable integral-limiting-value method solves the significant overshoot of the vibration amplitude well when the gas-liquid two-phase flow switch to the single-phase flow.