The Effects of Salt Water on Bubble Cavitation

Abstract

Experiments were performed to examine differences in bubble cavitation inception, form, and acoustic emission in fresh and salt water. The tests were conducted on an axisymmetric headform known as the ITTC body, and acoustic emission, cavitation bubble size, and cavitation event rates were measured for a variety of cavitation numbers and dissolved air contents at a fixed dynamic head for both fresh and salt water. Differences were detected in the cavitation inception index, cavitation bubble size distribution, and the resulting overall acoustic emission. These differences may be attributed to variations in the freestream nuclei population, and it is hypothesized that the solution of salt reduced the number and size of freestream nuclei. Differences in the overall acoustic emission were attributed to variation in the bubble event rate and average maximum bubble size between the fresh and salt water cavitation.

Fundamentals of Multiphase Flow

“…Whereas fresh water droplets evaporate completely in an atmosphere with less than 100% relative humidity, salt water droplets increase their salinity with evaporation until they reach equilibrium with their surroundings. Parenthetically, it is interesting to note that somewhat similar differences have been observed between cavitation bubbles in salt water and fresh water (Ceccio et al 1997); the bubbles in salt water are smaller and more numerous.…”

Identifying bubble occurrence during pool boiling employing acoustic emission technique

“…Ceccio et al, [34] confirmed there is a significant difference between bubble occurrence in salt water and fresh water. It was noted that the acoustic emission from bubble cavitation in fresh water was lower than that produced by salt water.…”

“…Additionally, they pointed out that small bubbles provided higher frequency acoustic emission compared to large bubbles. Bubbles of similar size created similar acoustic emission regardless whether they were in salt water or fresh water, and the chemical differences did not appear to influence the sound directly [34].…”

Investigation of the influence of flow rate on bubble formation and collapse in ball valves at various opening percentages using an AE technique

“…Ceccio et al [8] established that there are significant differences between bubble cavitation in salt water and fresh water; these were attributed to differences in the bubble event rate and average maximum bubble size between the salt and fresh water. It was noted that the AE from bubble cavitation in fresh water was lower than that for salt water.…”