抄録
The distribution of sounding pressure level (SPL) in an acoustic levitation furnace (ALF) was measured under low gravity as a function of sounding frequency at different gravity levels ranging from 0 to 2.5 G. The gravity level were produced in an aircraft while traversing special parabolic trajectories. The SPL spectrum exhibited characteristic peaks and the intensity (height) and distribution of which as a function of sound frequency are of primary importance for levitating a material, while SPL peaks height and distribution were found to be independent on gravity at room temperature. They were found to vary with gas temperature at 1 G. The gravity level and the heating condition of ALF affected SPL distribution and peak height. The SPL peak searching ability was investigated during the flight in heating and cooling cycle. The SPL fell down sometimes and failed to serach the paek. THe SPL peak frequency varied with the gas temperature. The SPL was found to vary with the level of gravity, that is, it decreased at entry in theparabolic flight and increased at recovery.
