抄録
Cavitation-induced vibration and erosion of pipes is a potentially damaging factor in piping systems. To prevent it, a detection method for cavitation phenomena should be developed. In power plants, especially, it is desirable to detect them from outside pipes during operation. Detection of cavitation phenomena was experimentally investigated in this paper using accelerometers mounted on the outer surface of a pipe upstream and downstream from an orifice. The following results were obtained. (1) With the progression of cavitation, output voltage of the accelerometer varied, and the amplitude and number of the pulse-shaped signals increased. However, it would likely be difficult to distinguish them from noises in an operating plant. (2) It was difficult to recognize the characteristic frequency of cavitation, because the power spectrum density was broad up to the accelerometer limit of 45 kHz. (3) The flow directional distribution of RMS (root mean square) values of accelerometer output voltage varied greatly with the progression of cavitation. Therefore, from comparison of RMS values obtained upstream and downstream from the orifice it seems possible to detect cavitation phenomena in the piping systems of operating plants.
