目的:根据飞行员航空生理训练的需要,研制一种分子筛氧浓缩器气源控制装置。方法:该装置由采集系统和控制系统2个部分组成。通过设置相应的传感器实时采集压力、流量和温度,并采用电子式减压器、比例电磁调节阀、加热电炉等作为执行机构...目的:根据飞行员航空生理训练的需要,研制一种分子筛氧浓缩器气源控制装置。方法:该装置由采集系统和控制系统2个部分组成。通过设置相应的传感器实时采集压力、流量和温度,并采用电子式减压器、比例电磁调节阀、加热电炉等作为执行机构,在PID(proportion integral differential)控制器的控制下分别对压力、流量和温度进行调节。结果:性能测试表明,该装置的压力控制最大偏差为1.1%,流量控制最大偏差为2.9%,温度控制最大偏差为1.6%,能够对分子筛气源的压力、流量和温度进行精确控制。结论:该装置具有控制精度高、达到稳定输出时间短、性能稳定等优点,对飞行员航空生理训练具有重要意义。展开更多
This paper introduces a new idea of controlling cavitation around a hydrofoil through a passive cavitation controller called artificial cavitation bubble generator （ACG）. Cyclic processes, namely, growth and implosi...This paper introduces a new idea of controlling cavitation around a hydrofoil through a passive cavitation controller called artificial cavitation bubble generator （ACG）. Cyclic processes, namely, growth and implosion of bubbles around an immersed body, are the main reasons for the destruction and erosion of the said body. This paper aims to create a condition in which the cavitation bubbles reach a steady-state situation and prevent the occurrence of the cyclic processes. For this purpose, the ACG is placed on the surface of an immersed body, in particular, the suction surface of a 2D hydrofoil. A simulation was performed with an implicit finite volume scheme based on a SIMPLE algorithm associated with the multiphase and cavitation model. The modified k-ε RNG turbulence model equipped with a modification of the turbulent viscosity was applied to overcome the turbulence closure problem. Numerical simulation of water flow over the hydrofoil equipped with the ACG shows that a low-pressure recirculation area is produced behind the ACG and artificially generates stationary cavitation bubbles. The location, shape, and size of this ACG are the crucial parameters in creating a proper control. Results show that the cavitation bubble is controlled well with a well-designed ACG.展开更多
A new kind of commercial truck is presented, which has rear air suspension using leaf spring as guiding rod instead of original leaf spring. ADAMS/Car is used as a tool to build the whole truck model. The designed tr...A new kind of commercial truck is presented, which has rear air suspension using leaf spring as guiding rod instead of original leaf spring. ADAMS/Car is used as a tool to build the whole truck model. The designed truck＇s constant-radius cornering analysis and its ride performance simulation analysis under B class random road condition are carried out according to national experimental method standards. Compared the simulation results with the field test results indicate that performance index of the designed air suspension truck＇ s constant-radius cornering and its ride performance meets the design requirements and reaches its prospective target. And resuhs from simulation are similar to those from tests in value and trend, which indicates the virtual prototype is correct. The model can be used further to opti,nize suspension parameters and do some design work on the control system of air suspension.展开更多
Compared with more well-known renewable energy sources, such as wind and solar, the wave energy industry is relatively new. This paper describes the structural design and construction of the oscillating water column ...Compared with more well-known renewable energy sources, such as wind and solar, the wave energy industry is relatively new. This paper describes the structural design and construction of the oscillating water column ＂greenWAVE Energy Converter＂ which was constructed during 2013 and was planned to be deployed in shallow water off the South Australian coast in 2014. Rated initially at 1 MW, the greenWAVE unit will be dedicated to electricity production, although an option is available to produce desalinated seawater. The unit base is constructed from reinforced concrete designed to international maritime codes, and the unit will be founded in approximately 10-15 m of water. The upper portion of the device extends above sea level, housing the airwave turbine and electrical control systems.展开更多
文摘目的:根据飞行员航空生理训练的需要,研制一种分子筛氧浓缩器气源控制装置。方法:该装置由采集系统和控制系统2个部分组成。通过设置相应的传感器实时采集压力、流量和温度,并采用电子式减压器、比例电磁调节阀、加热电炉等作为执行机构,在PID(proportion integral differential)控制器的控制下分别对压力、流量和温度进行调节。结果:性能测试表明,该装置的压力控制最大偏差为1.1%,流量控制最大偏差为2.9%,温度控制最大偏差为1.6%,能够对分子筛气源的压力、流量和温度进行精确控制。结论:该装置具有控制精度高、达到稳定输出时间短、性能稳定等优点,对飞行员航空生理训练具有重要意义。
文摘This paper introduces a new idea of controlling cavitation around a hydrofoil through a passive cavitation controller called artificial cavitation bubble generator （ACG）. Cyclic processes, namely, growth and implosion of bubbles around an immersed body, are the main reasons for the destruction and erosion of the said body. This paper aims to create a condition in which the cavitation bubbles reach a steady-state situation and prevent the occurrence of the cyclic processes. For this purpose, the ACG is placed on the surface of an immersed body, in particular, the suction surface of a 2D hydrofoil. A simulation was performed with an implicit finite volume scheme based on a SIMPLE algorithm associated with the multiphase and cavitation model. The modified k-ε RNG turbulence model equipped with a modification of the turbulent viscosity was applied to overcome the turbulence closure problem. Numerical simulation of water flow over the hydrofoil equipped with the ACG shows that a low-pressure recirculation area is produced behind the ACG and artificially generates stationary cavitation bubbles. The location, shape, and size of this ACG are the crucial parameters in creating a proper control. Results show that the cavitation bubble is controlled well with a well-designed ACG.
基金Sponsored by the National Science Foundation of Shandong Province (Grant No. Y2005F07) and Innovation Foundation of Jilin University(Grant No.2004CX018).
文摘A new kind of commercial truck is presented, which has rear air suspension using leaf spring as guiding rod instead of original leaf spring. ADAMS/Car is used as a tool to build the whole truck model. The designed truck＇s constant-radius cornering analysis and its ride performance simulation analysis under B class random road condition are carried out according to national experimental method standards. Compared the simulation results with the field test results indicate that performance index of the designed air suspension truck＇ s constant-radius cornering and its ride performance meets the design requirements and reaches its prospective target. And resuhs from simulation are similar to those from tests in value and trend, which indicates the virtual prototype is correct. The model can be used further to opti,nize suspension parameters and do some design work on the control system of air suspension.
文摘Compared with more well-known renewable energy sources, such as wind and solar, the wave energy industry is relatively new. This paper describes the structural design and construction of the oscillating water column ＂greenWAVE Energy Converter＂ which was constructed during 2013 and was planned to be deployed in shallow water off the South Australian coast in 2014. Rated initially at 1 MW, the greenWAVE unit will be dedicated to electricity production, although an option is available to produce desalinated seawater. The unit base is constructed from reinforced concrete designed to international maritime codes, and the unit will be founded in approximately 10-15 m of water. The upper portion of the device extends above sea level, housing the airwave turbine and electrical control systems.
