多孔壁面管强化大容积沸腾换热特性研究

Enhancement of Pool Boiling Heat Transfer on Porous Surface Tube

针对非能动余热换热器大容积沸腾换热工况,采用高温饱和蒸汽作为加热热源,对机械加工多孔壁面管和光管的大容积沸腾换热特性进行实验研究。结果表明,多孔壁面管对大容积沸腾换热具有很好的强化能力,多孔壁面管可使沸腾换热系数较光管提高68%~75%,壁面过热度降低约1.5℃;受管外沸腾和管内凝结之间传热耦合的影响,换热管轴向壁面温度表现出特定的分布特征。在实验研究的基础上,对多孔壁面管强化沸腾换热的机理进行了分析。

In this paper,the pool boiling heat transfer characteristics of a machined porous surface tube are investigated experimentally,considering the boiling operating condition of passive residual heat removal exchanger.The experiments have been carried out with high-pressure saturated steam condensation in tube as heating source and the results show that the porous surface tube has a considerable boiling heat transfer enhancing ability： the porous surface tube can increase the boiling heat transfer coefficient about 68%~75% and the wall superheat decreases about 1.5℃;With the combined effect of condensation inside tube and boiling outside tube,the axial wall temperatures of heat transfer tube are neither uniform nor linear distribution,but represent some particular distribution characteristics.On the base of the experimental investigation,the enhanced mechanism of porous surface tube is also analyzed.