| 摘要: |
| 实验研究了填充泡沫金属的圆管内制冷剂与润滑油混合物流动沸腾换热特性。实验对象为两根分别填充5PPI、90%孔隙率与10PPI、90%孔隙率泡沫铜的圆管，以及相同管径的光管。实验工况为蒸发压力995kPa，质流密度为10~30 kg/(m2.s)，热流密度为3.1~9.3kW/m2，入口干度0.175~0.775，油浓度为0~5%。实验结果表明：纯制冷剂工况下，泡沫金属的存在强化流动沸腾换热，换热系数最多提高185%；含油工况下，泡沫金属强化换热的效果弱化；相同工况下，更小的孔径可以提高流动沸腾换热系数，相比5PPI泡沫金属的实验数据，10PPI的泡沫金属可以使换热系数最多提高0.6倍。基于流型建立了填充泡沫金属的圆管内制冷剂与润滑油流动沸腾换热系数的预测模型，预测模型与98%的实验数据误差在±30%以内。 |
| 关键词: 流动沸腾 换热特性 泡沫金属 制冷剂 润滑油 |
| DOI： |
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| 基金项目:国家自然科学基金（50906048）资助项目。 |
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| Heat Transfer Characteristics of Refrigerant-oil Mixture Flow Boiling inside Circular Tubes Filled with Metal Foam |
| Hu Haitao,Zhu Yu,Ding Guoliang,Sun Shuo |
| (Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University) |
| Abstract: |
| The heat transfer characteristics of refrigerant-oil mixture flow boiling inside circular tubes filled with metal foam were experimentally investigated. The metal foams are 5 ppi / 95% porosity and 10 ppi / 95% porosity copper foams. The experimental conditions include saturation pressure of 995 kPa, mass flux from 10 to 30 kg/(m2.s), heat flux from 3.1 to 9.3 kW/m2, inlet vapor quality from 0.175 to 0.775, and oil concentration from 0% to 5%. The experimental results show that: metal foam enhances the flow boiling heat transfer coefficient of refrigerant by a maximum of 185% at oil free conditions, while the enhancement effect of metal foam is weaken at oil presence conditions; the flow boiling heat transfer coefficient for the circular tube filled with high ppi metal foam is higher than that for the tube filled with low ppi ones. A new correlation of heat transfer coefficient for refrigerant-oil mixture flow boiling inside circular tubes filled with metal foam is developed based on the flow pattern, and it can agree with 98% of the experimental data within a deviation of ±30%. |
| Key words: flow boiling heat transfer characteristics metal foam refrigerant oil |
