【摘要】 利用一维焓法建立了第三类边界条件下有限厚度的水存在自然对流时的冻结过程的理论模型 ,并利用类似于反问题的方法 ,结合计算和实验的手段确定了热损系数U值。所建模型和计算结果通过不同的实验条件得到了验证。该模型可用来确定在寒冷气候条件下整体式 (ICS)太阳热水器的冻结厚度与热损系数U值及水层深度的关系。并根据国内一些城市冬季的气象参数 ,给出了典型的计算结果。所得结果可对ICS太阳热水器的设计及对透明盖板材料和选择性涂层的选用提供参考。更多还原

【Abstract】 An one dimensional enthalpy method considering natural convection in the liquid is developed to study the freezing process of water with the third kind boundary condition. The model is verified by indoor experiments and can be of use to determine the relationship between the U value of integrated collector storage (ICS) solar water heaters and the thickness of frozen ice formed in it when exposed to the cold weather conditions for certain period of time. Typical calculation results are presented using diurnal cold winter weather conditions of some cities in China.更多还原