水中火花放電による圧力波の発生とその伝ぱ (新編集方針に基づく論文)

抄録

Experimental basic research is performed for the indentification of cavitation bubbles or other bodies in liquid flow through ducts, valves, or impellers by using a pressure wave as a detector. In rectangular closed tanks of 200×337×250mm (made of acrylic resin) and 300×450×400mm (made of brass) filled with water, a pulse-shaped pressure wave is generated by an instantaneous small spark discharge. The pressure fluctuation due to the pressure wave is measured at a point on the wall by a high-frequency pressure transducer, and the data are recorded by A/D converter. The measured wave fluctuations differ from one another, depending on wall condition and the existence of and size of bodies in water. When we use acrylic resin and brass as wall material, both the phase and amplitude of the reflecting wave are changed due to the wall condition. When stainless steel spheres with diameters of 50.8, 30.2, and 19.1mm are set within the tank, the pressure wave passes through the sphere and diffracts around it. By interpreting the precisely measured output pressure wave signals, we can identify bodies of simple shape.