苯工质作用下电场对气泡的作用

摘要：为明晰电场对汽─液两相系统的效应，进一步研究 EHD作用下的两相系统中汽泡的行为，揭示 EHD 强化沸腾换热机理，本文对电场作用下汽泡的行为进行了理论研究。从汽泡周围电场分布特性及其受力角度，对不同电场作用下的苯工质的沸腾换热进行理论研究。本课题针对均匀电场下汽泡周围电场分布状况进行研究，选用苯工质、平行平板电极，其中铜板作为零势面，铜网施加 0-16kV 的直流高压电场，加热方式为电加热方式。采用Ansys 计算软件，编程求解出不同电场作用下汽泡周围场强分布特性，对单个汽泡附壁、脱离及多个汽泡生成并部分脱离时电场分布特性进行了数值模拟。结果表明，汽泡周围电场分布不再均匀，其两侧的场强有所增加，靠近汽泡顶部以及底部附近，场强降低,沿球面顶部外法线方向，场强梯度达到最大。随着汽泡数量的增多，电场对汽泡的作用也相应变弱。电场使汽泡周围电场特性发生改变，导致 EHD 强化效果增强。 57146
毕业论文关键词：电水动力学；汽泡；数值模拟；电场特性
The Effect of Electric Field on Bubble under the Action of Benzene Working Medium
Abstract: To clarify the effect of electric field on gas-liquid two-phase system, the EHD effects of bubble behavior, and the mechanism of EHD enhanced heat transfer in the electric field is carried out in this paper. Based on the characteristic of electric field around a bubble and forces on a bubble, the boiling heat transfer enhancement in different electric field using the working fluid benzene were studied theoretically. This research focuses on the numerical simulation of the electric field distribution around the bubble that is under the uniform electric field. The working fluid used in simulation is benzene and the electric field is produced by the parallel plate electrode, in which the copperplate is grounded to the earth, and voltage is performed from 0kV to 16kV. The heating method involved in the research is electric heating. Ansys is used to simulate the electric field distribution of the bubble under different uniform electric field. Also, the simulations is carried out when a bubble attaches, departs or when the formation with partial departure of several bubbles. The results indicate that the electric field distribution around the bubble is no longer uniform, and the electric fields of the two sides are enhanced while near the top and bottom areas the electric fields decrease. Along the outer normal, the gradient of the electric field reaches the maximum. As the numbers of bubbles become more, the effect of electric field on bubbles becomes weaker. So the conclusion is reached that the electric field distribution around the bubbles will be changed by the electric field and thus will enhance the effect of EHD.
Keywords: EHD; bubbles; numerical simulations; electric characteristics

摘要 . i

Abstract i

目录 .. iii

1 绪论 . 1

1.1 课题选择依据及研究意义 1

1.2 EHD强化沸腾换热技术的发展历程 . 2

1.3 EHD强化沸腾换热的研究现状 3

1.3.1 电场特性对 EHD强化沸腾换热的影响 4

1.3.2 工质性质对 EHD强化沸腾换热的影响 4

1.3.3 热流密度对 EHD强化沸腾换热的影响 5

2 EHD 强化换热理论基础 6

2.1 引言 6

2.2 EHD强化传热的机理 . 6

2.3 EHD强化传热的优势 . 8

2.4 电场作用下汽泡行为的变化 .. 9 苯工质作用下电场对气泡的作用:http://www.youerw.com/wuli/lunwen_61733.html