As a widely applied technique in multistage axial compressors,variable stator vanes(VSV)can flexibly rematch the blade rows to fulfil a variety of aerodynamic performance requirements,such as high efficiency and wide ...As a widely applied technique in multistage axial compressors,variable stator vanes(VSV)can flexibly rematch the blade rows to fulfil a variety of aerodynamic performance requirements,such as high efficiency and wide surge margin.The purpose of this paper is to develop an optimization method to quickly determine VSV settings during the preliminary design phase.A mean-line method with a model calibration procedure is adopted to evaluate compressor performance,and the NSGA-II algorithm is employed for automatic optimization.The developed optimization system is then employed to determined re-stagger arrangement in a multistage compressor.A single-speed optimization with performance constraints of specific operating point and a multi-speed optimization with different control laws are conducted.Results are compared with available experimental re-stagger scheme,which verifies the effectiveness of the re-stagger optimization method.Moreover,method is proposed to determine operating parameters of a working point with a user-defined pressure ratio or mass flow rate after variable geometry.展开更多
The re-entrant double-staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent th...The re-entrant double-staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent thermal dissipation properties, as well as easy fabrication. A well-matched waveguide coupler is proposed for the structure. Combining the design of attenuators, a full-scale three-dimensional circuit model for the V-band coupled-cavity traveling- wave tube is constructed. The electromagnetic characteristics and the beam wave interaction of this structure are investigated. The beam current is set to be 100 mA, and the cathode voltage is tuned from 16.8 kV to 15.8 kV. The calculation results show that this tube can produce a saturated average output power over 100 W with an instantaneous bandwidth greater than 1.25 GHz in the frequency ranging from 58 GHz to 62 GHz. The corresponding gain and electronic efficiency can reach over 32 dB and 6.5%, respectively.展开更多
基金The authors would like to thank the National Natural Science Foundation of China(Grant No.51606026)for funding this work.
文摘As a widely applied technique in multistage axial compressors,variable stator vanes(VSV)can flexibly rematch the blade rows to fulfil a variety of aerodynamic performance requirements,such as high efficiency and wide surge margin.The purpose of this paper is to develop an optimization method to quickly determine VSV settings during the preliminary design phase.A mean-line method with a model calibration procedure is adopted to evaluate compressor performance,and the NSGA-II algorithm is employed for automatic optimization.The developed optimization system is then employed to determined re-stagger arrangement in a multistage compressor.A single-speed optimization with performance constraints of specific operating point and a multi-speed optimization with different control laws are conducted.Results are compared with available experimental re-stagger scheme,which verifies the effectiveness of the re-stagger optimization method.Moreover,method is proposed to determine operating parameters of a working point with a user-defined pressure ratio or mass flow rate after variable geometry.
文摘利用CST Microwave Studio计算双排矩形梳状慢波结构的色散并据此确定了0.22THz左右频段（D波段）行波管用慢波结构的尺寸参数.将相速再同步技术应用于基于双排矩形梳状慢波结构的D 波段行波管中,用CSTPIC模拟计算了4例具有不同周期构型的D波段行波管.结果证实：对于无集中衰减器的D波段行波管,在218-232GHz范围内,相速再同步技术使得输出功率从10-13 W 提高到19-28 W,电子效率从1.4%-2.2%提高到2.6%-3.9%;对于具有集中衰减器D波段行波管,在218-232GHz范围内,相速再同步技术使得输出功率从8-16.8 W 提高到32-41 W,电子效率从1.5%-2.8%提高到4.4%-5.7%.此外,无论行波管有无集中衰减器,相速再同步技术都明显改善了行波管的增益平坦度.
基金Project supported by the National Science Fund for Distinguished Young Scholars of China (Grant No. 61125103)the Vacuum Electronics National Lab Foundation, China (Grant No. 9140C050101110C0501)the Fundamental Research Funds for the Central Universities, China (Grant Nos. ZYGX2009Z003 and ZYGX2010J054)
文摘The re-entrant double-staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent thermal dissipation properties, as well as easy fabrication. A well-matched waveguide coupler is proposed for the structure. Combining the design of attenuators, a full-scale three-dimensional circuit model for the V-band coupled-cavity traveling- wave tube is constructed. The electromagnetic characteristics and the beam wave interaction of this structure are investigated. The beam current is set to be 100 mA, and the cathode voltage is tuned from 16.8 kV to 15.8 kV. The calculation results show that this tube can produce a saturated average output power over 100 W with an instantaneous bandwidth greater than 1.25 GHz in the frequency ranging from 58 GHz to 62 GHz. The corresponding gain and electronic efficiency can reach over 32 dB and 6.5%, respectively.
