Numerical Prediction of Two-Phase MHD Power Generation System Using Cavitating Flow of Electrically Conducting Magnetic Fluid

摘要

A new concept of a two-phase MHD power generation system using a cavitating flow of an Electrically Conducting Magnetic Fluid (ECMF) is proposed, and the driving and power generation performance of the system is numerically predicted. A typical computational model for cavitating flow of a mercury-based magnetic fluid is proposed and several flow characteristics, taking into account the strong nonuniform magnetic field, are numerically investigated to realize the further development and high performance of the proposed new type of two-phase fluid driving system using magnetic fluids. Based on numerical results, the two-dimensional structure of the cavitating flows as well as the cloud cavity formation of the ECMF through a vertical converging-diverging channel are shown in detail. The numerical results demonstrate that an effective two-phase electromagnetic driving force and fluid acceleration, and high power density can be obtained by the practical use of magnetization of the working fluid of ECMF. Also clarified is the cavitation number of ECMF in the case of a strong magnetic field with a larger value than that in the case of a nonmagnetic fluid. Further clarified is the precise control of the cavitating flow in ECMF that is possible by effective use of the magnetic body force that acts on cavitation bubbles.