【作者】 高正平；

【导师】 罗惕乾；

【作者基本信息】 江苏大学 ， 流体力学， 2006， 硕士

【摘要】 基于碰撞理论和电凝并理论,荷电颗粒的输运流场直接影响了凝并流场。本文进行凝并的前期研究工作,利用试验方法研究荷电气固两相流动管内输运的流场特性,探讨细微颗粒的荷电机理和有效充电方法,使用先进流场测量技术PIV研究外加电场对颗粒流场的作用。主要研究内容如下:1.分析荷电颗粒的受力,并比较主要作用力的数量级关系,从而简化了受力,且建立荷电颗粒运动微分方程。采用雷诺输运定理、平均原理以及高斯定理建立荷电气固两相流动体平均守恒方程组。2.自行设计网状接触感应电极充电装置,颗粒以接触、感应方式荷电,试验所得:充电电压低于-10kV,颗粒的荷质比随充电电压的降低而增加,在-60kV时基本达到饱和荷电量,且荷质比与充电电压成非线性关系。3.设计荷电气固两相流动试验系统,测量了荷电颗粒在输运段运动的重要参数——颗粒沉积量。试验表明随着充电电压的降低,颗粒的沉积量减小,并在靠近电极区域颗粒的沉降逐渐均匀。对比非荷电颗粒,荷电颗粒的受力中增加了电场力、颗粒间诱导电场力以及由电场脉动引起的流场脉动对颗粒的作用力,随着充电电压的降低,这几个力在输运过程中逐渐起主要作用。4.本文首次采用PIV技术对荷电气固管内流动流场进行研究,获得不同充电工况下流动瞬态流场信息,并就流场特性随电压的改变进行分析,结果表明:随着充电电压的减小,荷电气固输运流场中速度、涡量的分布值随电压的降低而增加,湍动能的分布呈现单峰特性,在-50kV时达到最大值。更多还原

【Abstract】 Based on collision theory and the theory of charged coagulation, the convey flow flied of charged particle determine the coagulation flow field. this thesis research the flow characteristic of convey process of charged gas-solid two phase flow in the pipeline by experiment, including probe into charge mechanism and availibity electrification technique, then use advanced flow field measure technique-PIV system to research the additional electric field effect on particle flow field, the content are as follows:1. The mostly force on a charged particle under a quantitatively unit is analyzed ,and eventually predigest the force and established a movement differential equation of charged particle. Based on Reynolds transport equation, the continuity, momentum and energy equation of charged gas-solid two phase flow are established, volume average conservation equation of this flow is established.2. Designed a new contacting and inductive web charged electrode, particle obtained charge by means of touching and inductiving. The experimentation concluded that if charged voltage is under -10kV, the lower charged voltage is , the larger charge to mass ratio is, and the ratio actived a saturation at -60kV charged voltage ,and the relation of charge to mass with charged voltage is non-linear.3. Contrived a charged gas-solid two phase flow tentative system ,which measured a importance parameter-particle aggradation quantity in the convey pipeline. In course of experiment, it is found that as the charged voltage decreasing, the less aggradation quantity is obtained, and gradually the aggradation is uniform near the electrode. Compared with non-charged particle, an electric field force、electric field force interparticles and a force because of impulsive motion of flow exert on charged particle.4. The thesis firstly researched the flow field of charged gas-solid two phase flow in the convey pipeline by using PIV system. At last, some information of instantaneous flow field under diversified charged voltage is obtained, and analysis about the flow variety as the voltage increasing. The conclusion indicated that the velocity, vorticity of charged gas-solid flow fluctuate with increasing voltage, and turbulent kinetic energy reaches the most value at -50kV.更多还原