年間 4 号発行
ISSN 印刷: 1065-3090
ISSN オンライン: 1940-4336
Indexed in
PARTICLE IMAGE VELOCIMETRY AROUND THE VORTEX DIMPLE AT FREE SURFACE
要約
The vortex-induced gas entrainment at free surface should be avoided in the reactor vessel of the liquid metal fast breeder reactor. Since the gas entrainment was induced by the small vortex dimple at free surface, the characteristics of the vortex dimple should be evaluated. In this study, the velocity distributions around the vortex dimple at free surface were measured by a new particle image velocimetry technique. The test section was the vertical cylindrical tank having a free surface. The vortex dimple was formed at the center of the cylindrical tank. The local three-dimensional velocity distributions around the vortex dimple were measured by the velocity vector histogram (WH) method, which was proposed by the authors. In the conventional WH method, a three-dimensional velocity vector histogram was constructed, which needed lots of computer memories. To improve the accuracy and to reduce the memories, a new algorithm were applied to the conventional WH method. In the construction of the histogram, the three-dimensional histogram was divided into three one-dimensional histograms, i.e., the projection histograms. With applying the new algorithm, the more accurate velocity distributions were calculated.