| 1. | The relationship between the air concentration and the scour depth can be expressed as an exponential function . aeration does not affect the shape of scour hole 掺气浓度c _对冲坑深度的影响,可表达为掺气浓度与冲坑无量纲深度的幂函数关系。 |
| 2. | Applying the k - e turbulence model , the distributions of air concentration are predicted for the air - water flow below an aerator . the validity of the numerical solution is demonstrated by the comparison between value measured and calculated 紊流模型计算了强迫掺气设施后的水气两相流,计算结果与实测值的比较表明,所采用的预测方法是行之有效的。 |
| 3. | A kind of measurement was developed to measure the air concentration of water and the result showed the possibility of entrained air existing near the wall of drop shaft . that is to say , the wall of drop shaft may be protected by entrained air from cavitation damage to some extent 本文设计了一种适用于近壁区水流掺气浓度测量的方法,对空腔段水流掺气浓度进行初步测量,发现井壁附近水流存在掺气的可能,这对改善水流空化条件能起到积极作用。 |
| 4. | The ratio of the length to the depth of scour hole decreases with the increasing scour depth , in spite of the reason is the increase of the air concentration , the decrease of the jet velocity or the decrease of the jet thickness . 5 . governing equations of the aerated jet flow are established 掺气对冲坑形态并没有实质性的影响,冲坑的宽深比随冲坑深度的减小而增大,无论造成冲坑深度减小的原因四) 1大学i学博士学位论文是掺气、降低流速还是减小入射水舌厚度,其变化规律都可用相同的直线关系表示。 |
| 5. | The square pattern has been obtained for the first time in dielectric barrier ar / air discharge at atmospheric pressure by using the double water electrodes and its spatio - temporal dynamics is measured by optical method . the phase diagram of pattern types as a function of air concentration and applied voltage by fixing other parameters is given 本论文采用特殊设计的双水电极介质阻挡放电实验装置,首次在氩气与空气的混合气体中获得了大气压常温下的稳定正方网格斑图,并对其进行了时空动力学测量。 |
| 6. | Methods psychological status and neurobehavioral functions of 103 exposed workers and 64 controls were examined with neurobehavioral core test battery recommended by world health organization ( who ) , and meanwhile , air concentrations of aluminum in the workplaces and urine levels of aluminum in the exposed workers were determined 方法采用who推荐的神经行为测试组合,对103名铝作业工人和64名对照工人进行心理状况调查和神经行为功能测试,同时对作业环境空气中铝浓度和作业工人尿铝水平进行测定。 |
| 7. | The fundamental theory and equations for the pressure fluctuation are described and the wall pressure fluctuation is measured . based on the experiment data , the characteristics of pressure fluctuations are analyzed in the three - phase flow of water , air and sand . the effects of air concentration and sediment content on the amplitude and frequency of pressure fluctuations are discussed 建立了多相流压强脉动基本方程,阐述了水流脉动压强基本理论,分析了压强脉动机理;根据试验数据,探讨了水、气、沙三相流体的压强脉动特性,初步得到了高速含沙掺气水流脉动压强的幅值特性与频域特性;提出了脉动压强强度系数、脉动压强极差系数与含沙量、掺气浓度的关系。 |
| 8. | Variations in pressure with and without aeration in cavitation region are measured and the compressible characteristics of pressure waveforms and relation between mach number and compression ratio are analyzed ; the time - averaged pressure profiles of different air concentration in cavitation erosion region are measured , the variations of the pressure with air concentration and effects of back pressure on cavitation erosion are analyzed ; the relations between least air concentration to prevent cavitation erosion and flow velocity are proposed ; the cavitation numbers with and without aeration in cavitation region are compared 实测了空化区掺气前后压力的变化,分析了压力波形的可压缩流特征以及马赫数与压缩比的关系;实测了空蚀区不同掺气浓度的时均压力分布,分析了压力随掺气浓度的变化及背压对空蚀的影响;提出减免空蚀的最低掺气浓度与流速的关系,比较了掺气前后水流的空化数。 |
| 9. | The surface material is liable to erosion wear with high - velocity sediment - laden flow , hi this paper , sand wear mechanisms are discussed and some effects of significant flow factors on material wear are analyzed ; the possibility of preventing erosion wear with aeration is proposed ; based on test data , the formula for calculating the concrete material wall surface wear rate is derived . it is indicated that the wear rate is related to the air concentration , the strength of material , the flow velocity and the sediment content . it is shown that wear rate can be reduced with the help of flow aeration 分析了空蚀与磨蚀的不同物理特征;探讨了沙粒磨蚀机理,提出了影响磨蚀vi河海大学博士学位论文一的因素;研究了掺气抗磨的可能性:建立了混凝土材料壁面磨蚀率的计算公式;说明含沙水流对固壁材料的磨蚀率随掺气浓度、材料强度的增大而减小,随水流流速、含沙量的提高而增大;利用掺气可有效地降低过流表面的泥沙磨蚀率。 |
| 10. | In order to increase the energy dissipation of stepped spillway at iarge unit discharge , the integhty dissipater of aerated splitter pier and steppe characteristics is studied . because of verticaj diffhaion now by aerated splitter and impachng steppe 3 by drop flow , the air concentration and the energy dissipation efficiency are greatly increased ; the potentiality of cavitations is decrease . in special at large unit discharge , this effect is more obvious 掺气分流墩的增加,明显地改善了阶梯面上的压强分布,消除或减小了阶梯凹角内和立面上部的负压;由于掺气分流墩使水流纵向扩散以及挑流落下后在阶梯上的撞击,使水流的掺气浓度和消能率都得到较大的提高,降低了阶梯面空蚀的可能性,特别是在大单宽流量时,这种效果更为明显。 |