The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of th...The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of the tip-jet rotor composite power system, studying the effects of intake mode, inner cavity structure, propellant components, and injection amount on the characteristics of the composite power system. The results show that when a single high-temperature exhaust gas enters, the gas generator outlet fluid is uneven and asymmetric;when two-way high-temperature exhaust gas enters, the outlet temperature of the gas generator with a tilted inlet is more uniform than that with a vertical inlet;adding an inner cavity improves the temperature and velocity distribution of the gas generator's internal flow field;increasing the energy of the propellant is beneficial for improving the available moment.展开更多
A novel air-powered twin-rotor piston engine(ATPE) utilizing a differential velocity driving mechanism to achieve a high output torque was proposed.The ATPE had eight separated rotary cylinders which can dynamically e...A novel air-powered twin-rotor piston engine(ATPE) utilizing a differential velocity driving mechanism to achieve a high output torque was proposed.The ATPE had eight separated rotary cylinders which can dynamically enlarge the engine displacement as a result of the special driving mechanism,which was named dynamic volume expansion.The mathematical model of ATPE comprising a dynamic model and a thermodynamic model was established under the assumption of no mechanical friction.The model was numerically simulated in Matlab.The results show that shortage of low output torque confusing traditional air-powered engines can be overcome.The average output torque sharply increases to 100 N·m,which is about three times that of traditional air-powered engines with equal cylinder displacement under the pressure of 0.6 MPa at 480 r/min.ATPE can be used to drive vehicles directly without transmission box,therefore the energy transfer efficiency of ATPE can be increased.Furthermore,benefitting from the novel gas distribution system,the engine shows an ability in self-adjusting under different loads.The arrangements of air ports automatically adjust the open interval of air ports according to the load,which may simplify the speed control system.展开更多
This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(...This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(ASEAN)Power Grid.This study focuses on modeling and evaluating the dynamic performance of the interconnected system,considering the high penetration of renewable sources.Power flow,small signal stability,and transient stability analyses were conducted to assess the ability of the proposed linked power system models to withstand small and large disturbances,utilizing the Power Systems Analysis Toolbox(PSAT)software in MATLAB.All components used in the model are documented in the PSAT library.Currently,there is a lack of publicly available studies regarding the implementation of this specific system.Additionally,the study investigates the behavior of a system with a high penetration of renewable energy sources.Based on the findings,this study concludes that a system is generally stable when interconnection is realized,given its appropriate location and dynamic component parameters.Furthermore,the critical eigenvalues of the system also exhibited improvement as the renewable energy sources were augmented.展开更多
含高比例新能源交直流混联电网的稳定特性已发生深刻变化,功角稳定依然是威胁系统安全运行的关键问题,相关研究对标准算例的真实性、合理性及代表性提出更高的要求。该文根据实际电网拓扑和数据,构建适用于功角稳定特性研究的功角稳定...含高比例新能源交直流混联电网的稳定特性已发生深刻变化,功角稳定依然是威胁系统安全运行的关键问题,相关研究对标准算例的真实性、合理性及代表性提出更高的要求。该文根据实际电网拓扑和数据,构建适用于功角稳定特性研究的功角稳定机电暂态仿真算例(Chinese society for electricalengineering-rotoranglestability,CSEE-RAS),该系统以500kV为主网架,包含2个区域、1个交流通道、1个直流通道。提供2种运行方式,分别对应动态、暂态功角稳定场景,上述场景新能源出力占比均在50%以上。考虑新能源出力占比、机组接入位置和控制策略等因素,量化不同因素对稳定水平的影响。敏感性分析结果表明,该算例较为全面地反映了机电暂态尺度下的不同功角稳定特性,且具有灵活的拓展能力,可为功角稳定分析与控制的相关研究提供基础平台,有助于不同结论的横向比较和研究人员科研效率的提升。展开更多
文摘The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of the tip-jet rotor composite power system, studying the effects of intake mode, inner cavity structure, propellant components, and injection amount on the characteristics of the composite power system. The results show that when a single high-temperature exhaust gas enters, the gas generator outlet fluid is uneven and asymmetric;when two-way high-temperature exhaust gas enters, the outlet temperature of the gas generator with a tilted inlet is more uniform than that with a vertical inlet;adding an inner cavity improves the temperature and velocity distribution of the gas generator's internal flow field;increasing the energy of the propellant is beneficial for improving the available moment.
基金Projects(51105365,51475464)supported by the National Natural Science Foundation of China
文摘A novel air-powered twin-rotor piston engine(ATPE) utilizing a differential velocity driving mechanism to achieve a high output torque was proposed.The ATPE had eight separated rotary cylinders which can dynamically enlarge the engine displacement as a result of the special driving mechanism,which was named dynamic volume expansion.The mathematical model of ATPE comprising a dynamic model and a thermodynamic model was established under the assumption of no mechanical friction.The model was numerically simulated in Matlab.The results show that shortage of low output torque confusing traditional air-powered engines can be overcome.The average output torque sharply increases to 100 N·m,which is about three times that of traditional air-powered engines with equal cylinder displacement under the pressure of 0.6 MPa at 480 r/min.ATPE can be used to drive vehicles directly without transmission box,therefore the energy transfer efficiency of ATPE can be increased.Furthermore,benefitting from the novel gas distribution system,the engine shows an ability in self-adjusting under different loads.The arrangements of air ports automatically adjust the open interval of air ports according to the load,which may simplify the speed control system.
文摘This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(ASEAN)Power Grid.This study focuses on modeling and evaluating the dynamic performance of the interconnected system,considering the high penetration of renewable sources.Power flow,small signal stability,and transient stability analyses were conducted to assess the ability of the proposed linked power system models to withstand small and large disturbances,utilizing the Power Systems Analysis Toolbox(PSAT)software in MATLAB.All components used in the model are documented in the PSAT library.Currently,there is a lack of publicly available studies regarding the implementation of this specific system.Additionally,the study investigates the behavior of a system with a high penetration of renewable energy sources.Based on the findings,this study concludes that a system is generally stable when interconnection is realized,given its appropriate location and dynamic component parameters.Furthermore,the critical eigenvalues of the system also exhibited improvement as the renewable energy sources were augmented.
文摘含高比例新能源交直流混联电网的稳定特性已发生深刻变化,功角稳定依然是威胁系统安全运行的关键问题,相关研究对标准算例的真实性、合理性及代表性提出更高的要求。该文根据实际电网拓扑和数据,构建适用于功角稳定特性研究的功角稳定机电暂态仿真算例(Chinese society for electricalengineering-rotoranglestability,CSEE-RAS),该系统以500kV为主网架,包含2个区域、1个交流通道、1个直流通道。提供2种运行方式,分别对应动态、暂态功角稳定场景,上述场景新能源出力占比均在50%以上。考虑新能源出力占比、机组接入位置和控制策略等因素,量化不同因素对稳定水平的影响。敏感性分析结果表明,该算例较为全面地反映了机电暂态尺度下的不同功角稳定特性,且具有灵活的拓展能力,可为功角稳定分析与控制的相关研究提供基础平台,有助于不同结论的横向比较和研究人员科研效率的提升。
