Investigation of acoustic spectral variations in the pool boiling regimes of water on wire heater

This paper presents the experimental investigation of acoustic spectral variations in saturated pool boiling re-gimes of water on a heated wire. In the current study, two different wires of standard wire gauge (SWG) 36 and 42 are considered to investigate the acoustic spectral variations through the pool boiling curve. The amplitude and frequency changes are evaluated for each regime of pool boiling. In a single regime, amplitude rise is observed with respect to the heat flux without any significant change in dominant frequencies. On the other hand, frequency shifts are observed in regime transitions. A change in the diameter of the heater wire has no significant effect on the boiling acoustic spectra. However, the number of high-frequency components increased for the SWG - 42 than the SWG - 36 wire. A frequency peak near 2000 Hz is found to be crucial for boiling regime identification. The sound pressure level (SPL) for SWG - 36 is higher than the SWG - 42, and it is further noted that SPL follows an 'N' shaped pattern for both wires owing to the frequency shifts and variation of mean bubble departure diameter at that heat flux.