Static and transient cavitation threshold measurements for mercury with dissolved air and helium

Cavitation onset in mercury is an important aspect affecting operation and safety of accelerator-driven neutron source facilities employing mercury-filled targets. Cavitation in such systems can occur in the bulk and at liquid-structure interfaces under a range of (oscillating pressure) frequencies. Two different apparatus types were designed and utilized for obtaining practically relevant cavitation threshold data. Transient and static cavitation thresholds of mercury as a function of the cover gas (helium or air), fluid temperature and pressure are reported. Both static and transient cavitation onset pressure thresholds were found to increase linearly with cover gas pressure. Additionally, the cavitation threshold as a function of dissolved gases were also measured and found to vary significantly between air and helium. Over the examined range, the effect of fluid temperature was found to be small and within experimental error