Development of Model-based Intelligent Flowmeters

1. 研制了一种基于模型的扫描式LDV传感器智能流量计。它可作为管道中层流和湍流非定常流的标准瞬时流量计。(1)通过增加移频机构，对具有测点随机接入功能的LDV传感部分进行了改进。基于前期科研资助项目60550167的研究成果，构建了一个结构化的智能软件系统。完成了非定常层流的流量计系统。(2)通过改进传感器部分，建立适合基于模型方法的湍流流线模型，成功地将标准智能流量计的应用范围扩展到湍流。首先，利用速度分布的指数定律和混合长度模型，建立了包含时变未知参数的涡流粘度近似表达式。在此基础上，推导了包含参数的流体线模型。将扩展卡尔曼滤波技术应用到模型中，得到一个非线性估计器，用于同时估计未知参数和速度分布。本文还提出了一种管道内非定常流动涡流粘度的估计方法。(3)研制了管内湍流数值模拟装置，并对各种轴对称流型进行了大量实验，验证了标准智能流量计的准确性和可靠性。指出了在实际设置条件下，轴向不对称或偏心流动引起的指示误差的重要性。提出并构造了一种基于工业模型的偏心流型估计和偏心误差自动补偿的智能流量计，该流量计以电磁流量计为传感器部分。未来的研究方向是通过引入多维扫描LDV来完成工业智能流量计。少

1. A model-based intelligent flowmeter with a scanning LDV sensor has been developed. It is to be usable as a standard instantaneous flowmeter for both laminar and turbulent unsteady flows in a pipe.(1) The LDV sensing part with random access function of measuring points was improved by adding a frequency-shifting mechanism. A structured intelligent software system has been constructed based on the results from the previous research of grant-in aid for scientific research 60550167. The flowmeter system is completed for unsteady laminar flows.(2) The application range of the standard intelligent flowmeter has successfully extended to turbulent flows by improving tie sensor part and developing a fluid line models for turbulent flows suitable to model-based method. First, we formulate an approximate expression for eddy viscosity including a time-varying unknown parameter by using the exponential law for velocity profiles and the mixing length model. Then we derive a fluid line model conta … More ining the parameter. The extended Kalman filtering technique is applied to the model to yield a nonlinear estimator for simultaneous estimation of the unknown parameter and velocity profiles. An estimation method of eddy viscosity for unsteady flows in a pipe has also been proposed.(3) A numerical simulator of turbulent flows in a pipe was developed and many experiments for various axially symmetric flow patterns have been done to verify accuracy and reliability of the standard intelligent flowmeter.2. Importance of the indication error due to axially asymmetric or eccentric flows in a pipe under practical setting conditions was pointed out. An industrial model-based intelligent flowmeter which estimates the eccentric flow pattern and compensates the eccentricity error automatically has been proposed and constructed with an electromagnetic flowmeter as the sensor part. Future research will be directed to the completion of the industrial intelligent flowmeter by introducing multidimensional scanning LDV. Less