管道泡状流相分布模式和分布机理研究进展

对管道泡状流的相分布模式和分布机理进行了详细的回顾和介绍。从前人研究的结果发现,相分布与流动条件有关,对于小管径泡状上升流,相分布主要表现为壁面峰值分布、中间峰值分布、中心峰值分布、过渡分布和扁平分布模式;而对于小管径泡状下降流,相分布主要表现为偏离中心峰值分布、钟形分布和中心峰值分布模式。然而对于大管径泡状流,相分布与流向无关,主要表现为壁面峰值分布和中心峰值分布两种模式。除此之外,还存在双峰分布模式和双鞍分布模式。影响相分布的主要因素有气泡尺寸、管道尺寸、气液相速度、气泡的注入位置和注入方法、重力水平,而气泡尺寸为关键因素。调查发现,到目前为止仍未形成一个可以解释所有相分布模式的通用机理。部分物理现象仅通过分析升力、湍流扩散力、壁面斥力以及其他力的平衡给予定性分析。未来应进一步研究相间作用力模型、湍流相干结构对气泡输运机理等问题。

The Role of Phase Errors Distributions in Phased Array Systems Operations

A comprehensive study on the role of the phase errors distribution on the performances of the phased array systems has been led using a complete and behavioral model for radiation-pattern characteristics. The used model has many input parameters and it has a lot of features, such as parameters simulations with results analysis, unconventional two-dimensional color graph representation capability in order to show more clearly the results. The results of the study have been discussed and reported. The main achievement of this work is the demonstration that the RMS phase error is a valuable figure of merit of phased array systems but it is not sufficient to completely describe the behavior of a real system. Indeed, this work has shown how the phase errors distribution actually affects the performances of the phased arrays antennas.