| Title |
Analysis of Thermal Recovery Characteristics for SF^6 Gas-Blast Arc within Laval Nozzle |
| Authors |
송기동(Song, Gi-Dong) ; 이병윤(Lee, Byeong-Yun) ; 박경엽(Gyeong-Yeop) ; 박정후(Park, Jeong-Hu) |
| Keywords |
가스차단기 ; 열적회복 ; 전류영점 ; 아크-후 전류 ; 회복전압상승율 gas circuit breakers ; thermal recovery ; current zero ; post-arc current ; ratio of rise of recover voltage |
| Abstract |
In this paper, computer simulations of the physical Phenomena occurring in the arc region before and after current zero were carried out to evaluate the thermal recovery characteristics of a Laval nozzle. A commercial CFD program "PHOENICS" is used for the simulation and the user-coded subroutines to consider the arcing phenomena were added to this program by the authors. The computed results were verified by the comparison with the test results presented by the research group of GE Co.(General Electric Company). In order to investigate the state of the arc region after current zero, the simulation was carried out with three steps. They are steady state arc simulation, transient arc simulation before current zero, and transient hot-gas flow simulation after current zero. The semi-experimental arc radiation model is adapted to consider the radiation energy transport and Prandtl's mixing length model is employed as the turbulence model. The electric field and the magnetic field were calculated with the same grid structure used for the simulation of the flow field. The post-arc current was calculated to evaluate the thermal recovery characteristics after current zero. Compared with the results obtained by GE Co., it has been found that the critical RRRV(ratio of rise of recovery voltage) will be determined previously by this study.his study. |