摘要
蓄热可应对太阳能光热利用中的间歇性问题,可提供平稳的热能输出,提高能源品质。固液相变蓄热因其蓄热密度大、蓄/放热过程温度恒定等优点备受关注。固液相变蓄热过程中存在相变材料熔化与温度不均匀的现象,难熔区域极大地延长了整体相变蓄热时间。本工作提出了一种通过改变蓄热罐形状来改善熔化不均匀现象的设计方法,设计了5种具有不同梯度比的梯形相变蓄热罐;通过数值模拟方法研究了5种梯形蓄热罐的蓄热性能,得出以下结论:增加上部区域相变材料的比例有利于将热量及时传递到固态区域,减小了热量传递的阻力,加快了整体传热速率。增加上部区域相变材料比例(即模型1和模型2)的完全熔化时间较基准模型3的完全熔化时间都有缩短,分别减少了39.06%和29.37%。研究结果为相变蓄热罐结构设计和工程应用提供一定参考。
Thermal storage can solve the intermittent problem of solar energy,which is providing a stable thermal output and improving energy quality.Solid-liquid phase change heat storage has attracted attention due to its advantages of large heat storage density and relatively constant temperature during heat storage/release.However,during solid-liquid phase change heat storage,there is constant inhomogeneity in the melting times and temperatures of the phase change materials(PCMs).The refractory zone greatly prolongs the overall phase change heat storage time.Therefore,this paper proposes improving the unevenness of the melting times by changing the shape of the heat storage tank.Five trapezoidal phase change heat storage tanks with different gradient ratios were designed.The heat storage performance of these tanks were examined using numerical simulations.The results indicated that increasing the proportion of PCMs in the upper region was conducive to the timely transfer of heat to the unmolten PCMs and reduced the resistance of heat transfer,thereby improving the overall heat transfer rate.The complete melting time of Cases 1 and 2 with a larger proportion of PCMs in the upper region was shortened compared to that of Case 3,with reduction ratios of 39.06%and 29.37%,respectively.
作者
张军
赵凤霞
杜昭
阳康
李元基
杨肖虎
ZHANG Jun;ZHAO Fengxia;DU Zhao;YANG Kang;LI Yuanji;YANG Xiaohu(China Northwest Architecture Design and Research Institute Co.,Ltd,Xi’an 710061,Shaanxi,China;School of Human Settlements and Civil Engineering,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2022年第11期3674-3680,共7页
Energy Storage Science and Technology
基金
校企合作重点项目(20210851)。
关键词
潜热蓄热
固液相变
梯形蓄热罐
相界面
传热热阻
latent heat storage
solid-liquid phase transition
trapezoid heat storage tank
phase interface
heat transfer resistance
