两相流空隙率测量的ERT技术新算法研究

基于BFGS最优化方法,提出一种新型的ERT图像重建算法:改进的BFGS算法.新算法采取了不精确搜索方向,并用单位矩阵近似代替目标函数的Hessian矩阵,以减小计算量,提高算法的重建速度.将新算法应用于两相流空隙率的测量.数值实验证明,新算法重建图像的质量优于目前常用的灵敏度系数法,空隙率测量的最大绝对误差可小于8%,获取一个空隙率测量值的时间小于0.1s.

Study on the algorithm of ERT for the voidage measurement of two-phase flow

Based on the optimization principle of BFGS algorithm(one kind of the Quasi-Newton methods),a new image reconstruction algorithm of ERT for two-phase flow is proposed.To satisfy the requirement of real-time measurement of two-phase flow,the new algorithm(the modified BFGS algorithm),which results in computation decreasing and image reconstruction speed rising,selects an inexact search direction and the Hessian matrices of the objective function are replaced with identity matrix.Real-time experiments show that the reconstruction speed of the modified BFGS algorithm is superior than that the commonly used sensitivity coefficient algorithm.The maximum error of the voidage measurement is less than 8% and a voidage value is about 0.1 second.The new algorithm is expected to be used in industry for two-phase measurement.