| 摘要: |
| 本文建立了以R134a为冷却工质的封闭式喷雾冷却系统，研究了工质过冷度、质量流量和热流密度对喷雾冷却系统换热性能的影响。其中，工质过冷度由喷嘴入口前的过冷段控制，质量流量通过变频齿轮泵调节，热流密度通过改变加热电源电压和电流控制。实验结果表明，在热流密度和质量流量保持不变时，改变过冷度对热源表面温度和换热系数的影响并不明显；在热流密度和过冷度保持不变的条件下，系统存在一个临界质量流量值，在质量流量达到临界值之前，热源表面温度随质量流量的增大而降低，当质量流量高于临界值时，热源表面温度随质量流量的增大而升高；当质量流量和过冷度保持不变时，存在一个热流密度使液滴的蒸发量等于补充量，在此热流密度下热源表面系数能达到最大。 |
| 关键词: 喷雾冷却 传热系数 过冷度 热流密度 质量流量 R134a |
| DOI： |
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| 基金项目:国家自然科学基金（51106170）资助项目。 |
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| Investigation on the Heat Transfer Performance of Spray Cooling System with R134a |
| Qian Chunchao,Xu Hongbo,Shao Shuangquan,Tian Changqing,Zhou Guanghui |
| (Beijing Key Laboratory of Thermal Science and Technology and Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, CAS;School of Energy and Environmental Engineering, Zhongyuan University of Technology) |
| Abstract: |
| In order to investigate the influences of subcooling degree, mass flow rate and heat flux on the performance of the spray cooling system, a closed spray cooling system with R134a was built. The subcooling degree was adjusted by the subcooled section located before the nozzle inlet, the mass flow rate was controlled by the variable gear pump, and the heat flux was dominated by changing the voltage and current of the heating power. The experimental results indicated that, the variation of subcooling degree did not have significantly influence on the heat surface temperature and heat transfer coefficient as the heat flux and the mass flow rate were fixed. When the heat flux and the subcooling degree were constant, there existed a critical value of the mass flow rate, as the mass flow rate was smaller than the critical value the heat surface temperature decreased with the mass flow rate increasing, on the contrary, the heat surface temperature would increase with the mass flow rate increasing when the mass flow rate exceeded the critical value. When the mass flow rate and the subcooled temperature kept constant, there also existed a heat flux value which made the evaporation capacity equal to the supplement of droplets, therefore the heat transfer coefficient could reach the maximum value. |
| Key words: spray cooling heat transfer coefficient subcooling degree heat flux mass flow rate R134a |
