流体声速高精度相位法测量研究

利用流体中的声速进行溶液浓度的测量是无损检测的一种重要方法,但是声速很小的变化范围限制了浓度的精确测量.介绍了一种流体声速高精确相位测量新技术,从被测流体的声速范围出发选择合适的测量距离,使设定的最高声速和最低声速传播的相位差为2π,分析测量距离和声速比以及测量频率的关系,通过AD转换测量电压并计算出声速.此方法被应用到牛奶浓度的声速测量中,实验结果证明本方法进行流体声速测量快速精确,在酸碱以及其他溶液浓度的检测中具有广阔的应用前景.

Investigation on Acoustic Velocity Precise Measurement for Liquid Using Phase Detection Technique

The solution concentration measurement with the acoustic velocity in liquid is an important technique in Nondestructive Examination （NDE）. The precise measurement of acoustic velocity for liquid using phase detection technique is proposed in the paper. Based on the velocity range, the sound propagation distance is confirmed to make the phase difference from 0 to 2π between the set values of the maximum and minimum velocities. The relations among the distance, the velocity ratio and the sound frequency are analyzed and the velocity can be calculated with AD detection. The technique was applied in milk concentration measurement, the favorable results proved that the proposed technique provides the accurate and rapid measurement of acoustic velocity and suggests the prosperous future in the concentration measurement for the acid and alkali or the other solutions.