Experimental study of thermodynamic effects of cavitation on pressure fluctuation and radiated noise in high-temperature and high-pressure water

Similar to other thermosensitive fluids, high-temperature and high-pressure water is influenced by thermodynamic effects during cavitation. This paper presents an experimental study on the cavitation of high-temperature and high-pressure water flowing through an orifice plate. The experiments were conducted with a maximum fluid pressure of 8 MPa and a maximum temperature of 553 K. At a working fluid temperature of 529 K and a cavitation number of 1.33, the maximum temperature difference observed in the cavitation region was 17.38 K, leading to a significant drop in local liquid's saturation vapor pressure by 1.13 MPa. The study involves timefrequency analysis of the pressure fluctuations within the pipe and the radiated noise outside the pipe, using a novel combination of Variational Mode Decomposition (VMD) and Fast Hilbert Transform (FHT). The results indicate that the thermodynamic effects are closely related not only to the cavitation intensity but also to the physical properties of the working fluid. Enhanced thermodynamic effects suppress cavitation intensity, thereby reducing the amplitude of pressure fluctuations and radiated noise. Changes in the patterns of pressure fluctuations and sound pressure fluctuations reflect variations in cavitation intensity. However, under the same working conditions, the dominant frequencies of pressure fluctuations and sound pressure fluctuations are not entirely consistent. This study provides valuable insights into understanding the thermodynamic effects of cavitation in high-temperature and high-pressure water, which is crucial for applications in nuclear power plants and steam boilers.