针对如何在网格环境中提高整个网格平台的性能和效率问题,提出了逼近理想解的排序法,即TOPSIS(technique for order preference by similarity to ideal solution)多指标综合评价模型,对网格节点的网络性能进行评价,将评价结果用于网格...针对如何在网格环境中提高整个网格平台的性能和效率问题,提出了逼近理想解的排序法,即TOPSIS(technique for order preference by similarity to ideal solution)多指标综合评价模型,对网格节点的网络性能进行评价,将评价结果用于网格资源分配决策,得到了最短任务完成时间的资源分配方案。用网格模拟器GridSim搭建了包括路由器的网格环境,测试及与随机算法对比结果表明了TOPSIS多指标网格资源分配决策算法的可用性和高效性。展开更多
The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner struct...The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner structures due to its moving parts. In order to study the rotating flow near the injector tip, which was observed from the cold flow experiment using water and air, a numerical simulation was adopted and a verification of the numerical model was later conducted. For the verification process, three types of experimental data including velocity distributions of gas flows, spray angles and liquid distribution were all compared using simulated results. The numerical simulation was performed using a commercial simulation program with the Eulerian multiphase model and axisymmetric two dimensional grids. The maximum and minimum velocities of gas were within the acceptable range of agreement, however, the spray angles experienced up to 25% error when the momentum ratios were increased. The spray density distributions were quantitatively measured and had good agreement. As a result of this study, it was concluded that the simulation method was properly constructed to study specific flow characteristics of the pintle injector despite having the limitations of two dimensional and coarse grids.展开更多
文摘针对如何在网格环境中提高整个网格平台的性能和效率问题,提出了逼近理想解的排序法,即TOPSIS(technique for order preference by similarity to ideal solution)多指标综合评价模型,对网格节点的网络性能进行评价,将评价结果用于网格资源分配决策,得到了最短任务完成时间的资源分配方案。用网格模拟器GridSim搭建了包括路由器的网格环境,测试及与随机算法对比结果表明了TOPSIS多指标网格资源分配决策算法的可用性和高效性。
基金supported by Advanced Research Center Program(NRF-2013R1A5A1073861)through the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)contracted through Advanced Space Propulsion Research Center at Seoul National University
文摘The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner structures due to its moving parts. In order to study the rotating flow near the injector tip, which was observed from the cold flow experiment using water and air, a numerical simulation was adopted and a verification of the numerical model was later conducted. For the verification process, three types of experimental data including velocity distributions of gas flows, spray angles and liquid distribution were all compared using simulated results. The numerical simulation was performed using a commercial simulation program with the Eulerian multiphase model and axisymmetric two dimensional grids. The maximum and minimum velocities of gas were within the acceptable range of agreement, however, the spray angles experienced up to 25% error when the momentum ratios were increased. The spray density distributions were quantitatively measured and had good agreement. As a result of this study, it was concluded that the simulation method was properly constructed to study specific flow characteristics of the pintle injector despite having the limitations of two dimensional and coarse grids.
