摘要为了研究喷雾冷却的换热特性，搭建了以 R134a 为冷却工质的闭式循环喷雾实验台， 并基于该实验台开展了相变冷却实验，实验分别在不同工质流量、热流密度和过热度下 进行，通过实验数据分析了喷雾冷却系统的换热性能。结果表明，控制工质进口温度和 热流密度保持不变，当流量较小时，换热机理以蒸发沸腾相变为主，热源表面温度高； 而随着流量的增大，换热机理由蒸发相变逐渐向单相对流换热过渡，热源表面温度降低 且分布趋于均匀。而控制较高工质流量和工质进口温度保持不变，热流密度较小时，热 源表面的温度较低，换热机制以单相对流为主，换热系数较低；随着热流密度的增大， 热源表面温度升高，换热机制由单相强迫对流向蒸发沸腾过渡，换热系数增大。80460

毕业论文关键词 喷雾冷却 热流密度 蒸发沸腾 单相对流 换热系数

毕 业 设 计 说 明 书 外 文 摘 要

Title The research of multi-nozzle spray cooling technology

Abstract In order to study heat transfer characteristics of spray cooling, building a cooling closed cycle spray bench, R134a as working fluid。 It’s based on the experiment station to carry out a phase change cooling experiment in a different working fluid flow, heat flux and superheat, respectively carried out by analyzing the experimental data of heat transfer performance of spray cooling system。 The results showed that the working fluid inlet temperature control and heat flux remains unchanged, when the flow is small, the boiling heat transfer mechanism to evaporate phase becomes the primary heat source surface temperature is high; and as the flow increases, heat transfer machine reason evaporation phase change gradually transition to the single-phase flow heat exchange, the heat source to reduce the surface temperature and the distribution tends to be uniform。 The higher mass flow rate and control of the working fluid inlet temperature remains constant heat flux is small, the surface temperature of the heat source is low, single-phase flow heat transfer mechanisms mainly lower heat transfer coefficient; With the increase of heat flux, the temperature of heat surface is higher , heat transfer mechanism by a single phase forced to transition to the evaporator boiling heat transfer coefficient increases。

Keywords  Spray cooling  Heat flux  Evaporation boiling   Single-phase flow Heat transfer coefficient

目 录

1 引言 1

1。1 课题研究背景 1

1。2 喷雾冷却的国内外研究现状 2

1。2。1 喷雾相变冷却传热机理研究 3

1。2。2 喷雾冷却传热特性影响因素 3

1。3 主要研究内容 4

2 喷雾相变冷却实验 5

2。1 喷雾实验系统 5

2。2 实验内容及过程 8

2。3 喷雾冷却换热性能参数 9