面向两种特殊情况的科氏质量流量计驱动方法和系统

发布时间：2019-04-03 08:36

【摘要】：科氏质量流量计用于流体质量流量的直接测量,测量准确度高,重复性好,而且还能同时实现流体的体积流量、密度、温度等多参数和不同流体状况下的测量,具有广阔的应用前景。本文针对科氏质量流量计在科研实验和实际工业应用中面临的两种特殊情况,即特殊流量管型和特殊测量介质两种情况,研制相应的驱动系统和研究相应的驱动方法,有效地解决了所面临的技术难题。针对微弯或直管式科氏质量流量传感器,输出信号频率高,相位差小的特点,且现有变送器系统无法保证已有算法实时性处理的问题,研制基于TMS320C6726型DSP为核心的高频科氏质量流量计数字驱动系统硬件平台。根据系统功能的需要合理分配资源,利用总线结构克服DSP资源不足；扩展常用电路和外设接口,实现仪表功能；采用数字合成的方式合成驱动信号,保证流量计在批料流／两相流下仍能正常工作。针对带有噪声的1001 Hz的信号测量,所研制的数字驱动系统硬件平台具有0.1级的测试精度。水流量标定实验结果表明,匹配艾默生DN25口径的Q型传感器,在11：1的量程比内,测量精度优于0.08%,重复性达到0.03%。针对科氏质量流量计应用于工业测量两相流的过程中,所面临的传感器信号波动范围大,流量管无法维持两相流下最佳幅值振动的问题,研究变传感器信号设定值的驱动控制方法。分析影响流量管振动幅值大小和稳定性的因素；提出跟踪传感器信号幅值、变传感器信号设定值的控制方法；进行两种设定值方法的对比实验,并对两相流信号的波动特性进行标准差评估和PDF分析。对比实验表明,在不同含气量和控制及时性的情况下,变传感器设定值的控制方法均具有良好的信号跟踪和幅值控制的性能,流量管振动较平稳,传感器信号幅值波动范围小,极大地减小了两相流测量过程中的波动性。
[Abstract]:Coriolis mass Flowmeter is used for direct measurement of fluid mass flow. It has high accuracy and good repeatability. It can also realize the measurement of fluid volume flow, density, temperature and other multi-parameters and different fluid conditions at the same time. It has a wide application prospect. Aiming at the two special situations faced by Coriolis mass Flowmeter in scientific research experiment and practical industrial application, that is, special flow tube type and special measuring medium, the corresponding driving system and driving method are developed in this paper. The technical problems are solved effectively. Aiming at the characteristics of micro-bend or straight-tube Coriolis mass flow sensor, the output signal frequency is high and the phase difference is small, and the existing transmitter system can not guarantee the real-time processing of the existing algorithms. A hardware platform for digital driving system of high frequency Coriolis mass Flowmeter based on TMS320C6726 DSP is developed. According to the need of system function, resource allocation is reasonable, using bus structure to overcome the shortage of DSP resource, expanding common circuit and peripheral interface to realize instrument function. The driving signal is synthesized by digital synthesis to ensure that the Flowmeter can still work properly under batch / two-phase flow. For the signal measurement of 1001 Hz with noise, the hardware platform of the developed digital drive system has a test precision of 0.1 level. The experimental results of water flow calibration show that the accuracy of the Q sensor matching Emerson DN25 caliber is less than 0.08% and the repeatability is 0.03% within the range ratio of 11:1. In view of the problem that Coriolis mass Flowmeter is used in industrial measurement of two-phase flow, the range of sensor signal fluctuation is large, and the flow tube can not maintain the optimal amplitude vibration of two-phase flow. The driving control method of variable sensor signal setting value is studied. The factors affecting the vibration amplitude and stability of flow tube are analyzed, and the control method of tracking sensor signal amplitude and variable sensor signal setting value is put forward. Two methods of setting values are compared, and the wave characteristics of two-phase flow signals are evaluated by standard deviation and PDF analysis. The comparison experiment shows that the control method of variable sensor set value has good performance of signal tracking and amplitude control under different gas content and timely control, the vibration of flow tube is stable, and the range of amplitude fluctuation of sensor signal is small, and the control method of variable sensor set value has good performance of signal tracking and amplitude control under the condition of different gas content and timely control. The fluctuation in the measurement process of two-phase flow is greatly reduced.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH814.6

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