基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件...基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500k V、电流6.2k A、引导磁场强度0.46T时,得到频率为9.40GHz、功率为900MW、脉宽为32ns的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。展开更多
Direct numerical simulation (DNS) of incompressible magnetohydrodynamic (MHD) turbulent channel flow has been performed under the low magnetic Reynolds number assumption.The velocity-electric field and electric-electr...Direct numerical simulation (DNS) of incompressible magnetohydrodynamic (MHD) turbulent channel flow has been performed under the low magnetic Reynolds number assumption.The velocity-electric field and electric-electric field correlations were studied in the present work for different magnetic field orientations.The Kenjeres-Hanjalic (K-H) model was validated with the DNS data in a term by term manner.The numerical results showed that the K-H model makes good predictions for most components of the velocity-electric field correlations.The mechanisms of turbulence suppression were also analyzed for different magnetic field orientations utilizing the DNS data and the K-H model.The results revealed that the dissipative MHD source term is responsible for the turbulence suppression for the case of streamwise and spanwise magnetic orientation,while the Lorentz force which speeds up the near-wall fluid and decreases the production term is responsible for the turbulence suppression for the case of the wall normal magnetic orientation.展开更多
文摘基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500k V、电流6.2k A、引导磁场强度0.46T时,得到频率为9.40GHz、功率为900MW、脉宽为32ns的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。
基金supported by the National Natural Science Foundation of China (Grant Nos. 10272105 and 10602006)
文摘Direct numerical simulation (DNS) of incompressible magnetohydrodynamic (MHD) turbulent channel flow has been performed under the low magnetic Reynolds number assumption.The velocity-electric field and electric-electric field correlations were studied in the present work for different magnetic field orientations.The Kenjeres-Hanjalic (K-H) model was validated with the DNS data in a term by term manner.The numerical results showed that the K-H model makes good predictions for most components of the velocity-electric field correlations.The mechanisms of turbulence suppression were also analyzed for different magnetic field orientations utilizing the DNS data and the K-H model.The results revealed that the dissipative MHD source term is responsible for the turbulence suppression for the case of streamwise and spanwise magnetic orientation,while the Lorentz force which speeds up the near-wall fluid and decreases the production term is responsible for the turbulence suppression for the case of the wall normal magnetic orientation.
