一种测量石蜡相变乳液过冷度的新方法:平衡态比容法  

A new approach to determine the degree of subcooling in phase-change paraffin emulsion: equilibrium volumetry

作　　者：陈琳[1] 武亚飞 车黎明[2] CHEN Lin;WU Yafei;CHE Liming(Department of Wine and Food Engineering,Sichuan Technology and Business College,Chengdu 611830,Sichuan,China;College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,Fujian,China)

机构地区：[1]四川工商职业技术学院酒类与食品工程系,四川成都611830 [2]厦门大学化学化工学院化学工程与生物工程系,福建厦门361005

出　　处：《化工学报》2019年第9期3370-3376,共7页CIESC Journal

基　　金：国家自然科学基金项目(21606185)

摘　　要：石蜡相变乳液是集储热与传热于一体的新型功能流体,具有广阔的应用前景。但石蜡相变乳液在降温时会出现过冷现象,极大降低了其储热与传热的性能。采用差示扫描量热法(DSC)测量石蜡相变乳液的过冷度受到升/降温速率的影响,且升/降温速率越大,测得过冷度越大。提出一种测量石蜡相变乳液过冷度的方法——平衡态比容法。该方法通过测量石蜡相变乳液在不同温度下的比容,以确定乳液中石蜡粒子在升/降温过程中的相变温度,并进一步求解石蜡相变乳液的过冷度。实验结果表明,本研究提出的平衡态比容法能准确测量石蜡相变乳液的过冷度,并从比容变化的角度揭示石蜡相变乳液过冷现象的机理。Paraffin phase change emulsion is a new type of functional fluid that integrates heat storage and heat transfer,and has broad application prospects.However,the application of phase-change paraffin emulsion suffers from subcooling phenomenon,which weakens its ability to store and transfer heat remarkably.The degree of subcooling in phase-change paraffin emulsion is conventionally determined by differential scanning calorimetry(DSC),the result of which is dependent on the heating/cooling rate.As the heating/cooling rate increases,the degree of subcooling is higher.Here an equilibrium volumetric method was presented to determine the degree of subcooling in phase-change paraffin emulsion by measuring its specific volume at different temperatures.The specific volume obtained was plotted against the temperature to identify the phase transition temperature of paraffin during heating/cooling process,then the degree of subcooling was deduced from the phase transition temperatures obtained.The results showed that the degree of subcooling in phase-change paraffin emulsion can be measured accurately using the equilibrium volumetric method presented in this work.The results also revealed the mechanism of subcooling in phase-change paraffin emulsion from the point of view of specific volume change.

关 键 词：比容法 差示扫描量热法 过冷 石蜡 相变 

分 类 号：O648.23[理学—物理化学]