抄録
A liquid mercury target for high-power pulsed spallation neutron sources is installed in the Materials and Life science experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC). The pressure waves are generated by the rapid thermal expansion of mercury due to the high-intense pulsed-proton beam bombardment. The pressure waves induce cavitation, and the cavitation causes severe erosion damage on the mercury enclosure vessel made of stainless steels. Therefore, the cavitation is a major issue to realize a high-power stable operation. Gas microbubbles injection into mercury is one of the effective techniques to suppress the pressure. A swirl-flow bubble-generator has been developed and installed in the mercury target at J-PARC. In this study, dependencies of the vane angle and reduction rate of the Venturi were parametrically investigated through the water experiment in order to optimize the swirl-flow bubble-generator for decreasing the aspiration pressure without increasing pressure drop at the bubble-generator. The result showed that the swirl-flow bubble-generator was aspirated more air gas volume as increased in the Venturi reduction.
