308-螺旋盘管式纳米增强相变蓄热单元蓄热特性研究.pdfVIP

螺旋盘管式纳米增强相变蓄热单元蓄热特 性研究 Experimental and numerical study of the charging process in a nano-enhaned heat storage unit using a helical coil heat exchanger 重庆大学城环学院 杜瑞卿 1 王勇 熊滕 杨勋 摘 要: 以含三氧化二铝纳米颗粒的石蜡为主要材料的相变蓄能单元为研究对象，建立 了内置螺旋形换热器的相变蓄能单元的三维物理和数值模型，并进行了实验验证。实验结果 与数值计算结果吻合较好 （误差均在7.5%以内），验证了数值模型的正确性。基于上述数值 模型，本文分别对两种相变蓄能单元的蓄热特性进行了分析和比较，结果显示：加入纳米颗 粒后，相变材料导热系数明显提高，其总熔化时间缩短近 25%，并且在部分难熔区域 （螺旋 管潜热单元下方边缘区域）相变材料熔化进程明显加快，其熔化时间提前约 2400S，可为提 高蓄热单元性能的技术途径提供参考。 关键词：三氧化二铝 螺旋形换热器 相变蓄能单元 蓄热特性 Abstract: Taking the phase change energy storage unit containing alumina as the main subject, the three-dimensional physical and numerical model of phase change energy storage unit with spiral heat exchanger was built and verified by experiments. The experimental results were in good agreement with the numerical results (the relative errors are within 7.5%), which verified the correctness of the numerical model. Based on the above numerical model, the thermal storage characteristics of the two kinds of PCMs were analyzed and compared respectively. The results showed that the thermal conductivity of PCMs increased obviously with the addition of nano-particles, and the total melting time was shortened by 25%. And in some refractory areas (the battle of the unit), phase change material melting process was significantly accelerated, the melting time advanced about 2400S ，it could provide reference for improving the thermal storage units technical approach.. Keyword: Al O , Spiral heat exchanger, Phase change energy storage unit, Thermal storage 2 3 characteristics 1.引言 在实际工程中常常需要储备多余热能，以备在系统需要时释放。这一过程中能量实现了 时空转换，尤其是太阳能、地热能等可再生能源利用领域，有效存储热能可实现能源的高效 利用。相变潜热蓄热单元作为相变蓄能技术的载体，因其蓄热能力强、可实现模块化设计等 优点而备受关注。然而，常见的相变材料通常导热系数不高，导致其换热效率较低，存在相 1 杜瑞卿.男.1995 年 12 月出生.硕士研究生.400030.重庆大学 B 区2746367548@ 变材料熔化时间较长或相变不充分等问题。 目前在增大相变材料导热系数方面，研究者主要从四个方向展开了研究：多种相变材料 混合、纳米颗粒增强相变材料、金属模板增强相变材料