Acoustic spectra in the region of liquid boiling crisis

An experimental investigation of acoustic characteristics of surface boiling with underheating in a large volume under natural convection conditions is carried out in order to gain knowledge in nature of liquid boiling crisis. The sound recording section of instrumentation enables to register and study both integral characteristics (sound pressure or noise level) and spectral characteristics instantaneous and current acoustic spectra). The frequency range studied was 40Hz-500 KHz. The following critical specific heat flows were obtained during liquid boiling on a heated tungsten wire 70 μm in diameter: 15.8 MW/m2 for water, 20.0 MW/m2 for aqueous solution of n-butanol (2%). The current acoustic spectra reflect all changes in the heat flow. In the boiling crisis region, a steadily increasing number of high frequencies occur in the current spectra, these frequencies subsequently becoming predominant. It was found out that the thermal acoustic turbulence is a necessary boiling characteristic in the critical heat flow range