基于最小二乘曲面拟合的流量计量温度补偿算法

针对时差法超声波式热量表流量计量结果受流体温度影响而存在的非线性误差问题，提出了基于最小二乘曲面拟合的温度补偿算法，通过建立温度和流量之间的非线性映射模型实现温度补偿。在实现温度补偿后，针对超声波式热量表自身计量特性的差异，进一步提出多温度点误差二次修正算法，根据相邻温度点的流量计量误差和可变权值计算当前的流量计量误差，对误差进行二次修正，实现流量计量的全局优化。实验表明，流量计量误差在±2.0%以内，具有较高的工程应用价值。

Temperature Compensation Algorithm Based on Least Squares Curve Fitting in Flow Measurement

There are serious non-linear errors in flow measurement of ultrasonic heat meter utilizing time difference method.This paper gives detailed calculation and analysis to explain that the errors are caused by the changes of flu?id temperature. To solve this problem,a temperature compensation algorithm based on least squares curve fitting is proposed. Temperature compensation is realized through establishing a non-linear mapping model between flow rate and fluid temperature. However,each meter has different metrological properties. So this paper puts forward an er?ror second-order correction algorithm further. The error of flow rate at current temperature is calculated according to the errors at two adjacent temperature spots and variable weight. The flow measurement global optimization is real?ized by second-order correction. Experimental verification showed that flow measurement error was between ± 2.0%. So this algorithm has definite value to engineering application.