Study on combustion behavior of sodium droplet. Combustion experiment of suspended sodium droplet. JFY2000-2001 joint research report

Experimental studies have been performed since JFY1997 for the combustion of suspended sodium droplet in order to understand the detailed phenomenology of its ignition and burning behavior. The author has accumulated to date the high-speed camera picture data of change in a droplet surface and its neighboring gas phase of spontaneous ignition of suspended sodium droplet is air flow, after establishing fundamental experimental techniques to observe the process. In the study from JFY 2000 to 2001, a system was developed which enable to measure the temperature of sodium droplet and of flame zone. The study includes the improvement of droplet generation system so as a prevent the oxidation of suspended droplet generation system so as to prevent the oxidation of suspended droplet. The temperature measurement system consists of silica-coated fine R-type thermocouple of 20 μm in diam. adopted to ensure excellent responsibility, and its driving apparatus. The driving system is composed of pulse motor, its controller and delay circuit, and its performance was confirmed by several tests. It was shown from the preliminary tests that the basic technique was established for detailed temperature measurement around the time of droplet ignition, though several problems should be investigated furthermore such as electrical noise removal in temperature measurement and effect of thermocouple coating. (author)