Cavitation phenomena is one of the principal factors which compromise the life-span and performance of the fluid machinery. A novel method named active ultrasonic detection was proposed, which emitted a high frequency carrier wave to the area round cavitation district with transmission method. The fluid motion would exert an influence on the high frequency carrier wave, which induced that the fluid field information was modulated on the ultrasonic carrier wave, so the fluid field information could be gained through the demodulation of the ultrasonic carrier signal. Based on the experimental dataset from shaft flow pump in different flow rates,combining high speed photography verifying method, a pattern classifier based on support vector machine was set up to achive the active ultrasonic detection of the pump cavitation. This method can detect the new born cavitation accurately, and supply the relevant alarm, to avoid the further development of cavitation.%空化是影响液流机械使用寿命与性能的主要因素之一.提出一种主动超声探测方法,该方法通过透射方式对空化区域或其附近发射高频超声波,流体的运动会对其中传播的超声波产生影响,流体运动信息调制到超声载波上,通过对已调超声信号的解调,得到流场相关信息.以不同状态下的轴流泵空化流场实验数据为依据,结合高速摄像验证手段,建立基于支持向量机的SVM模式识别分类,实现对螺旋桨空化的主动超声监测.该方法可以较精确地探测到空化初生阶段,及时提供早期的空化状态报警,避免空化进一步发展.
展开▼
