In order to develop the technique for glass container less melting with acoustic levitation furnace (ALF), sound pressure level (SPL) peaks in ALF were identified and the factor that affected to the SPL distribution were clarified. Sound pressure mode [1,0,13] was adopted as levitation mode, and was observed in the frequency region of 11056-11112Hz at room temperature in the ALF. The SPL peak distribution varied with the kind of gas and the gas temperature. On the other hand, gas flow rate has no effect to the distribution of SPL. Cage, which improves the light absorption efficiency of the sample, has no influence to the SPL distribution in the frequency region from 10 to 20 kHz. The presence of sample, the sample diameter and the sample position in ALF affected to the SPL distribution. The heat convection with turning on the halogen lamps in ALF affected to the SPL distribution. Peak finding ability is good enough to find the nearest SPL peaks within 20 sec. Peak following ability is also good with slowing heat of the sample and cage.

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The aim of this study is to fabricate a compact observing system of two-dimensional Marangoni flow, which is applicable in the falling experiment, and which clarifies the characteristics of the flow, and then to make up an analyzing computer-simulation code of the flow. The equipment is composed of a experimental cell filled by silicone-oil, a lighting laser of the flow, the observing CCD camera and a controller of the system. At a given condition on the earth, the pattern and velocity of the flow are observed by the trace of the aluminium powder which is suspended in the silicone-oil in the experimental cell. The variation of the temperature of the oil with time is also measured by thermocouples. The simulation code has predicted the pattern, the velocity of the flow and developement of the temperature of the oil with time. These predictions are compared with values measured by measurements. The results of the simulation analysis and of the experiments correspond well. The system is expected to be capable of analyzing the characteris­ tics of Marangoni convection even in the falling experiment.

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