中文摘要：

在线超声磨粒检测结果与超声换能器声场特性密切相关,在线油液超声磨粒传感器也是基于换能器声场特性设计的,运用数值模拟方法可以有效地分析超声波声场的特性。首先从理论方面分析了在线超声磨粒检测方法;然后利用时域有限差分法求解KZK方程对超声换能器声场进行仿真;最后搭建润滑油超声波声场分布测量实验系统实际测量超声波声场特性。仿真与实验结果表明：利用时域有限差分法求解KZK方程能够很好的模拟聚焦超声换能器在润滑油中的声场分布情况,聚焦超声换能器的焦斑区域呈椭圆形,长轴约为4 mm,短轴约为0.4 mm,仿真结果与实验结果具有较好的一致性。研究结果为下一步的超声磨粒传感器设计奠定了基础。

英文摘要：

The result of online ultrasonic detection of wear debris has close relations with acoustic field features of ultrasonic transducer. Online sensor of wear debris in oil is designed by acoustic field features of ultrasonic transducer. Numerical simulation method can effectively analyze the characteristics of ultrasonic sound field. First,online ultrasonic detection method of wear debris is theoretically reviewed. Then,the finite-difference time-domain method（ FDTD） is utilized to solve KZK equation for simulating sound field of ultrasonic transducer. Finally,an experimental system is set up for distribution measurement of ultrasonic sound field in lubrication,and ultrasonic acoustic field feature is measured. The results of simulation and experiment show that FDTD＇ s utilization to solve KZK equation can effectively imitate acoustic field distribution of focused ultrasound transducer in oil. Focal spot of focused ultrasound transducer has an oval shape,and major axis is 4mm and minor axis is 0.4mm. Simulation and experiment show the good consistency. The research builds the foundation for next ultrasonic sensor design of wear debris.