为探究方腔内相变石蜡的储热性能，基于等效热容法和Boussinesq假设，建立相变石蜡融化储热计算模型，并针对加热方向及约束形式等因素对相变石蜡的储热性能的影响进行研究，并开展相变石蜡融化试验，验证计算模型的正确性。结果表明：相变石蜡融化储热过程是由热传导和自然对流传热综合决定的，其中自然对流传热在相变石蜡融化储热过程中起着极为显著的促进作用；不同加热方向下，相变石蜡表现出截然不同的融化储热效率，其中顶、底、侧边单独加热下的自然对流传热效应依次使储热效率提升了0.01，27.9和13.1倍，即底部热源的储热效率最高；在四面加热下，固相因无约束而下沉至底部，并抑制底部热壁面的自然对流传热效应，此时顶、底、侧热壁面的储热贡献率分别为17.3%，37.3%和22.7%；当固相运动被预埋热电偶等因素限制时，将形成钟型融化前缘，该形态包含了各热壁面单独加热下的融化储热特征，此时顶、底、侧热壁面的储热贡献率分别为19.2%，29.8%和25.5%。

In order to clarify the heat storage performance of phase change paraffin in square cavity, a computational model of phase change paraffin melting and heat storage was established based on the equivalent heat capacity method and Boussinesq hypothesis, and the effects of heating direction and constraint type on the heat storage performance of phase change paraffin were studied. The phase change paraffin melting test was carried out to verify the correctness of the proposed model. The results show that the melting and heat storage process of phase change paraffin is determined by the combination of heat conduction and natural convection heat transfer, and the natural convection heat transfer plays a more significant role in accelerating the heat storage process of phase change paraffin. Moreover, with the different heating directions, the phase change paraffin exhibits distinct melting and heat storage efficiencies. The natural convection heat transfer effects under unilateral heating of upper, bottom, side increase the heat storage efficiencies by 0.01, 27.9 and 13.1 times, respectively. That is to say, the heat storage efficiency of the bottom heat source is the highest. Typically, for the case of heating on the full walls, the unconstrained solid paraffin will sink to contact the bottom wall and as a result, the effect of natural convection heat transfer on the bottom heating wall is greatly suppressed, meanwhile, the heat storage contribution rates of the upper, bottom, side heating walls are 17.3%, 37.3% and 22.7%, respectively. On the other hand, if the motion of solid paraffin is constrained by the embedded thermocouple, a bellshaped melting front will be formed, from which the melting and heat storage characteristics under unilateral heating of each heating wall can be represented. In this case, the heat storage contribution rates of the upper, bottom, side heating walls are 19.2%, 29.8% and 25.5%, respectively.

TK124

国家自然科学基金项目（51908197）；河南省科技攻关项目（202102310262，212102110203）