导热增强型定形相变材料的制备及导热机理研究
发布时间：2018-11-09 17:39
【摘要】：相变材料的相变潜热蓄热或蓄冷,具有蓄能密度大、温度变化小的特点,在太阳能利用、工业余热、建筑节能和废热回收等领域有着广泛的应用。作为固--液相变材料,石蜡具有化学稳定性好、相变潜热大、来源广泛、无过冷和相分离现象、价格低廉等优点,在相变材料方面得到广阔应用。但其需封装、热导率小的缺点,制约了其在储热领域中的应用。本文以石蜡为相变材料,高密度聚乙烯(HDPE)为支撑材料,采用熔融共混法制备石蜡/HDPE定形相变材料(Phase change m a t e r i a l,P C M),对其微观形貌、渗漏率及热性能等进行测试表征。并探究添加剂及制备工艺对石蜡/HDPE定形PCM渗漏率的影响。研究结果表明,石蜡和HDPE相容性良好。石蜡/HDPE定形PCM相变焓与石蜡含量有关。当在石蜡/HDPE定形PCM中添加质量分数为0.1%的过氧化二异丙苯(D C P)和0.1%的抗氧剂1 0 1 0,在1 5 0℃下熔融共混时,可以获得低渗漏率定形相变材料。以石蜡为相变材料,HDPE为支撑材料,膨胀石墨(EG)为导热填料,采用熔融共混法制备石蜡/HDPE/EG导热定形PCM,对其微观形貌、热导率、渗漏率及热性能等进行测试表征,并探究石蜡/H D P E/E G导热定形P C M热导率的影响因素。研究结果表明,石蜡、H D P E和E G三者之间相容性良好。添加E G后,定形P C M渗漏率有所提高,但随EG含量的增加而降低,EG质量分数为15%时,渗漏率低于0.6%。热导率随EG含量的增加而增加,EG质量分数为15%时,热导率为1.265 W/(m·K),提高率达144%。导热定形PCM的相变焓随EG含量的增加变化不大。采用二甲苯溶解法探究H D P E及E G对石蜡的包覆作用及E G的分布情况,提出石蜡/HDPE/EG导热定形PCM的导热机理。研究结果表明,HDPE形成的空间网状结构以及EG的多孔结构均对石蜡起到良好的包覆作用。HDPE的空间网状结构对EG也起到包覆作用。蠕虫状EG吸附大量石蜡,分布于HDPE形成的空间网状结构中。石蜡/HDPE定形PCM中加入EG后,导热载体由声子变为自由电子,大大提高了传热速率。
[Abstract]:Phase change latent heat storage or cold storage of phase change materials has been widely used in the fields of solar energy utilization industrial waste heat building energy saving and waste heat recovery because of its high energy storage density and small temperature change. As a solid-liquid phase change material, paraffin has many advantages, such as good chemical stability, large latent heat of phase transition, wide source, no undercooling and phase separation, low price and so on, so it has been widely used in phase change materials. However, its application in the field of heat storage is restricted by its disadvantages of packaging and low thermal conductivity. In this paper, paraffin wax as phase change material, high density polyethylene (HDPE) as supporting material, paraffin wax / HDPE fixed phase change material (Phase change m a t e r i a ln P C M), were prepared by melt blending method. The leakage rate and thermal property were measured and characterized. The effects of additives and preparation process on the leakage rate of paraffin / HDPE PCM were investigated. The results show that the compatibility of paraffin and HDPE is good. The enthalpy of phase transition of paraffin / HDPE PCM is related to the content of paraffin. When 0.1% diisopropyl peroxide (D C P) and 0.1% antioxidant (1010%) were added into paraffin / HDPE PCM, the low leakage setting phase change material could be obtained by melt blending at 150 鈩，
本文编号：2321108
[Abstract]:Phase change latent heat storage or cold storage of phase change materials has been widely used in the fields of solar energy utilization industrial waste heat building energy saving and waste heat recovery because of its high energy storage density and small temperature change. As a solid-liquid phase change material, paraffin has many advantages, such as good chemical stability, large latent heat of phase transition, wide source, no undercooling and phase separation, low price and so on, so it has been widely used in phase change materials. However, its application in the field of heat storage is restricted by its disadvantages of packaging and low thermal conductivity. In this paper, paraffin wax as phase change material, high density polyethylene (HDPE) as supporting material, paraffin wax / HDPE fixed phase change material (Phase change m a t e r i a ln P C M), were prepared by melt blending method. The leakage rate and thermal property were measured and characterized. The effects of additives and preparation process on the leakage rate of paraffin / HDPE PCM were investigated. The results show that the compatibility of paraffin and HDPE is good. The enthalpy of phase transition of paraffin / HDPE PCM is related to the content of paraffin. When 0.1% diisopropyl peroxide (D C P) and 0.1% antioxidant (1010%) were added into paraffin / HDPE PCM, the low leakage setting phase change material could be obtained by melt blending at 150 鈩，
本文编号：2321108
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