通过数值模拟的方法，根据分形原理设计了三套管式相变蓄热器的肋片并分析其蓄、放热特性，运用(火积)耗散原理对其蓄、放热过程进行分析。结果表明：相比其他结构的相变蓄热器，安装分形肋片的相变蓄热器可使蓄、放热时间缩短，效率提高；模型2（T形分形模型）和模型3（Y形分形模型）比模型1（直肋模型）的蓄热时间分别缩短了35.64%和33%，放热时间分别缩短了47.65%和43.4%；模型2和模型3相比模型5（2倍填充直肋模型）所需蓄、放热时间基本接近，说明分形设计只需较低的金属填充量便可达到很好的蓄、放热效果；安装分形肋片的相变蓄热器在蓄、放热过程中(火积)耗散率（或其绝对值）下降更快，可逆性更好，换热效率更高。

With numerical simulation method,the fins of the threetube type phase change thermal accumulator were designed by fractal principle,and the thermal storage and release characteristics of accumulator were analyzed.At the same time,the entransy dissipation theory was used to analyze the process of thermal storage and release.Results show that compared with other types of accumulator,phase change thermal accumulators with fractal fins reduce the thermal storage and release time and increase efficiency.Thermal storage time of model 2 (Tshaped fractal model) and model 3 (Yshaped fractal model) were reduced by 35.64% and 33%,respectively,compared with model 1,while the thermal release time was reduced by 47.65% and 43.4%,respectively.Model 2 and model 3 are relatively close to the storage and release time of model 5 (2 times filling straightfin model),indicating that the fractal design requires a lower metal filling amount to achieve a good thermal storage and release effect.The phase change thermal accumulator with fractal fins has a faster drop of entransy dissipation rate (or absolute value),better reversibility and higher heat exchange efficiency during the process of thermal storage and release.

TK124

国家自然科学基金（51306120）