多通道超声波气体流量计的数学模型

在超声波气体流量计的实际测量中,多种不同因素引起流量测量的误差,其中流场分布是引起误差一个很重要的原因。采用多通道流量计可以较好地克服这一影响。但由于流体具有粘滞性,管道截面上不同半径处的流体速度各不相同,所以声通道测量的流体平均流速与实际管道中流体的面平均流速仍存在差异。对多通道超声波气体流量计的数学模型进行了研究,通过理论计算多通道超声流量计各通道的动力校正因子及权系数,由测得的若干超声传播路径上的线平均流速计算得到面平均流速,从而提高流量的测量精度。并将此应用于研制的四通道流量计中,进行了实验验证。

Mathematic model of multi-path ultrasonic gas flowmeter

There are many factors to cause the measurement error in the practical application of ultrasonic flowmeter,and the flow velocity profile is a very important factor.Using the multi-path ultrasonic flowmeter is an effective method to decrease the measurement error.However,the flow velocity is not the same at different point（along the radius direc-tion） in the pipe cross-section because of fluid viscosity.So the average flow velocity measured by the multi-path flow-meter is still different from the actual average flow velocity.The mathematic model of multi-path ultrasonic gas flow-meter is studied in this paper.The average linear flow velocity could be converted into the average cross-sectional flow velocity via the dynamic calibration factor and weight coefficient,which are calculated by the mathematic model.So the measurement accuracy could be improved.The software of the mathematic model is applied in the four-path ultra-sonic flowmeter for comparison experiment.