Device and method for active ultrasonic detection of fluid cavitation

Abstract

The invention relates to a device and method for active ultrasonic detection of fluid cavitation. A pair of or multiple pairs of ultrasonic transducers are placed at two sides of a cavitation zone, or one or more receiving and transmitting integrated ultrasonic transducers are placed at the other side of a cavitation zone with a reflecting surface; high-frequency electric signals generated by an ultrasonic signal source drive the ultrasonic transducers through an ultrasonic driver to transmit ultrasonic waves according to the preset frequency; after the ultrasonic waves pass through the cavitation zone, the fluid field information is modulated onto the ultrasonic waves to be received by the ultrasonic transducers; an ultrasonic demodulator demodulates the ultrasonic signals to acquire thedemodulated signals with the fluid field information; a signal conditioning collector performs amplification, anti-aliasing filtering and analog-to-digital conversion on the modulated ultrasonic signals or the demodulated signals; and a signal processor demodulates the modulated ultrasonic signals to acquire the demodulated signals with the fluid field information and perform pattern classification, thereby judging whether the cavitation occurs or not.

Description

technical field [0001] The invention relates to the field of fluid cavitation detection, in particular to an active ultrasonic detection device and method for fluid cavitation. Background technique [0002] Cavitation is a dynamic phenomenon unique to liquids that occurs in liquid regions where the partial pressure is lower than the saturated vapor pressure at that temperature. The operation of equipment such as water turbines, pump blades and ship propellers is plagued by cavitation. Cavitation is one of the main problems affecting the service life and performance of fluid machinery. It will lead to a decrease in mechanical efficiency, increased noise and vibration, and even cause material erosion and structural damage of the blades. [0003] At present, the methods of cavitation detection in engineering applications are mainly based on energy, pressure, vibration and acoustics. Cavitation reduces the efficiency of machinery such as water pumps, turbine hydrofoils, and pr...

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Problems solved by technology

In the actual environment, due to the strong background noise interference during the normal operation of the machine, it is easy to cause misjudgment, especially the identification of the initial stage of cavitation is more difficult

In 1990, Barkhoudarian mentioned the method of active ultrasonic emission in the document "Ultrasonic cavitation detection system" (Source: United States Patent, Patent Number: 5,235,524). The basic principle is to use a large number of cavitation bubbles to block the propagation of ultrasound. The received signal strength judges the cavitation state, but in reality, when a large number of cavitation bubbles are generated, the cavitation of the equipment is already very serious, and it is impossible to diagnose the early cavitation phenomenon

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