電磁場加熱による過渡沸騰現象のメカニズム解明

Mechanism of transient boiling phenomena generated by microwave heating

鈴木 翔太*; 金子 暁子*; 阿部 豊*; 鈴木 政浩 ; 瀬川 智臣 ; 藤井 寛一

Suzuki, Shota*; Kaneko, Akiko*; Abe, Yutaka*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi

核燃料サイクルの脱硝転換工程で行われる電磁波(マイクロ波)加熱時の沸騰挙動を解明するために、容器,溶液,加熱の特性が沸騰挙動に及ぼす影響を評価した。溶液の沸騰や流動挙動を高速度カメラにより撮影し、液面を放射温度計、容器表面の温度をサーモグラフィによりそれぞれ計測した。液面の温度は103.2Cを示しており、液体は過熱状態となっていた。また、突沸発生付近の時点での容器表面のサーモグラフィの温度補正値は105.8Cを示した。容器表面よりも溶液内部の温度は高いことが予想され、溶液の中心付近にマイクロ波加熱のエネルギーが集中し、過熱状態となった結果、単一気泡が発生し、突沸に至ったと考えられる。

The influences of vessel, solution and heating properties for boiling behavior were evaluated to clear them in the electro-magnetic wave (microwave) heating of the de-nitrate conversion process of nuclear fuel cycle. Boiling and fluid behavior of solution were observed by the high speed video camera, the temperature of solution level were measured by radiation thermography, and the temperature of the vessel surface was measured by thermography. The temperature of solution level was 103.2 degree, which showed that the solution was overheated. The corrected temperature on the vessel surface measured by thermography was 105.8 degree. It is expected that the inner temperature of solution is higher than that of vessel surface. It is considered that the energy of microwave concentrates at the core of solution, and flushing is leaded by generating the uniform nucleation according to overheating.