基于二维双线性插值的流量计量温度补偿算法研究

Research on Temperature Compensation Algorithm Based on Two-Dimensional Bilinear Interpolation in Flow Measurement

针对超声波式水表为单流速仪表的特点,以及超声波水表采用速度差法测量流量时,计量结果易受温度影响而存在温度适应性较差的问题,提出了一种基于二维双线性插值的温度补偿算法。采用计算流体力学(CFD)数值仿真对管道内流速分布和线速度分布进行分析,先得到了温度对超声波水表计量精度影响的规律,而后通过测量一定数量的超声波水表样本。基于样本的测试数据和数值仿真的结果,建立了温度和流量之间的二维非线性通用温度补偿模型。编写LabVIEW数据处理软件,仿真验证了该二维非线性通用温度补偿模型的补偿效果。最后对多只超声波水表进行实际流量测试。试验结果表明,使用了该温度补偿算法模型后,超声波水表在全流量和全温度下的计量误差可控制在±2%以内,达到了国家2级表的水平,具有较高的商业应用价值。

Ultrasonic water meter is a single flow meter.There are nonlinear errors ultrasonic water meter while utilizing the velocity difference method.A temperature compensation algorithm based on two-dimensional bilinear interpolation is proposed to solve this problem.Through the computational fluid dynamics(CFD)numerical simulation,the velocity and linear velocity distribution in the pipeline are analyzed.The law of the influence of temperature on the measurement accuracy of the ultrasonic water meter is obtained first,then a certain number of ultrasonic water meters are sampled.A two-dimensional nonlinear general temperature compensation model between temperature and flow is established based on the test data of the samples and the results of numerical simulation.The LabVIEW data of processing software is verified the compensation effect of the temperature model.Multiple ultrasonic water meters are used for the actual flow test;the experimental results show that the measurement error of ultrasonic water meter is within±2%after using the temperature compensation algorithm model.It has reached national water meter level 2,which is of high commercial application value.