CIESC Journal ›› 2019, Vol. 70 ›› Issue (9): 3370-3376.DOI: 10.11949/0438-1157.20190293

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

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

Lin CHEN1(),Yafei WU2,Liming CHE2()   

  1. 1. Department of Wine and Food Engineering, Sichuan Technology and Business College, Chengdu 611830, Sichuan, China
    2. College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
  • Received:2019-03-27 Revised:2019-06-20 Online:2019-09-05 Published:2019-09-05
  • Contact: Liming CHE

一种测量石蜡相变乳液过冷度的新方法:平衡态比容法

陈琳1(),武亚飞2,车黎明2()   

  1. 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
  • 通讯作者: 车黎明
  • 作者简介:陈琳(1985—),男,硕士,讲师,zerochenlin@126.com
  • 基金资助:
    国家自然科学基金项目(21606185)

Abstract:

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.

Key words: volumetric method, DSC, subcooling, paraffin, phase transition

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。

关键词: 比容法, 差示扫描量热法, 过冷, 石蜡, 相变

CLC Number: