【摘要】 为分析采集凝固热热泵系统凝固换热器的特性,需要掌握地表水紊流工况的相变换热规律.基于准稳态近似方法与假想等壁温模型,分析凝固换热器中紊流水的管内冻结特性,并采用定义的当量平均表面换热系数比Kh和潜热显热比KSL讨论紊流水冻结换热特性.结果表明:紊流时,管半径和沿水流流动方向距离对冻结特性的影响不明显,雷诺数、管壁温和进口水温影响较为明显;随着无量纲凝固时间增长,换热性能急剧下降,入口水温与管壁温度越低、管径越小、管长越大、雷诺数越小,换热特性越好.所得结果将为凝固换热器优化设计及热泵系统性能改善提供重要参考.更多还原

【Abstract】 In order to analyze the characteristics of the freezing latent heat exchanger in heat pump system with freezing latent heat collection,the freezing and heat transfer of surface water need to be mastered under turbulent condition. Based on the imaginary wall temperature model and the quasi-steady approximate method,this paper analyzes the freezing characteristics of turbulent surface water in the tube of freezing latent heat exchanger with parameters,such as Kh and KSL. The results indicate that the radius and the distance along the flow direction have no obvious influence on the freezing characteristics,but the Reynolds number,the pipe wall temperate and supply water temperature affect the solidification characteristics obviously. With the increase of dimensionless freezing time,the heat transfer performance drops quickly,and freezing heat transfer characteristics are better with the lower entrance water temperature,the lower pipe wall temperature,the smaller radius,the longer tube length,and the smaller Reynolds number. The study provides an important reference to the optimization design of the device and the performance improvement of the heat pump system.更多还原