摘要:EHD强化传热是电流体动力学的一个重要研究方向,它可以应用到低温制冷,热力发电等多个领域。本文介绍了国内外学者进行的实验研究,以及EHD强化传热的机理,并设计了电场强化平板换热实验装置。实验装置主要包含沸腾室,冷凝室,制冷系统,电源系统,数据控制系统五个部分。采用R11制冷剂作为实验工质,在外加均匀高压直流电场下,在加热面中上的工质发生沸腾。
电极由网状高电位电极和块状低电位电极板组成:电极网由绝缘边框与支柱支撑,水平布置在低电位电极正上方;低电位电极上表面即为换热面,除此表面外均被绝热绝缘材料密封。实验工质在电场作用下以一定功率下加热,在换热面产生气泡,气泡聚集进入沸腾室上部的冷凝室冷却。冷却水由外部制冷装置提供,采用水泵强制其对流循环。49402
整个装置与测量元件、控制元件、计算机连接,实现自动测量与控制,实验数据也可自动采集。全文完成了对电场强化平板换热装置结构原理、设计尺寸、组件和材料的全面介绍。
毕业论文关键词:水电动力学;强化换热;均匀电场;R11;池沸腾
A Study And Design on Electric Field-enhanced Plate Heat Transfer Device
Abstract EHD enhancement of heat transfer, which can be used in cryogenic refrigeration, power generation, etc., is an important research field of electrodynamics. This study reviewed experimental investigations and the mechanism of EHD enhancement of heat transfer, as well as introduced my design of an experiment device for researching EHD-enhanced heat transfer between mesh and plate electrodes. This device consists of boiling chamber, cooling chamber, refrigeration system, power supply system and control system. This investigation uses R-11 refrigerant as heat transfer medium under uniform electric field.
Electrode system consists of high voltage copper mesh electrode and grounding copper block electrodes. Copper mesh has an epoxy frame and was supported by epoxy columns, while copper block electrode was covered by epoxy to insulate heat and electricity except its top surface, which acted as the heat transfer surface. The experiment medium was heated under electric field with certain power rate, then medium near the heat transfer surface began to boiling and generating bubbles. These bubbles gathered and entered the cooling chamber, where the R-11 gas was cooled and condensed and then flowed back to boiling chamber. Water, as cooling medium, was provided by the refrigeration system. And a pump was used to ensure the forced circulation of water.
To automatically monitor and control the experiment, measuring equipment, controlling equipment and a computer was connected with this device. The data from the experiment can also be recorded by computer.
In all, this study presents a general introduction of the EHD-enhanced plate heat transfer device with its structure, mechanism, geometry size, components and materials.
Keywords: Electrohydrodynamics; heat transfer enhancement; uniform electric field; R-11; pool boiling
目 录
1 绪论 1
1.1 课题研究的目的和意义 1
1.2 国内外研究现状与水平 2
1.3 电场强化平板换热装置设计的主要内容 3
2 EHD强化换热机理概述 4
2.1 单相气体工质中EHD强化换热机理分析 4
2.2 单相液体工质中EHD强化换热机理分析 5
2.3 EHD强化沸腾换热机理分析 6
2.3.1 电场中汽泡所受的力