潜热型功能流体分散稳定性强化及调控机理研究

doi:10.11949/0438-1157.20250453

摘要/Abstract

摘要：

相变微胶囊在液体介质中的分散稳定性是潜热型功能流体服役性能的关键影响因素。通过添加分散剂可强化潜热型功能流体的稳定性，但分散剂本征特性和服役环境等因素对其稳定性的影响规律和调控机理尚不清晰。因此，本文构建了潜热型功能流体的粗粒化分子动力学模型，研究了非离子型、阴离子型和阳离子型分散剂微观结构、组分及温度对潜热型功能流体稳定性的影响规律。结果表明，添加分散剂可改善功能流体中胶囊团聚现象，但分散剂类型和温度对稳定性影响存在显著差异；分散剂对潜热型功能流体分散稳定的促进作用由大到小依次为：非离子型聚乙烯醇（PVA）、阴离子型十二烷基硫酸钠（SDS）、阳离子型十六烷基三甲基溴化铵（CTAB）。

关键词: 相变胶囊, 潜热型功能流体, 分散剂, 粗粒化, 分子动力学模拟

Abstract:

The dispersion stability of phase change microcapsules in liquid media is a key factor affecting the performance of latent heat functional fluids. The stability of latent heat functional fluids can be enhanced by adding dispersants, but the influence mechanisms and regulatory patterns of dispersants' intrinsic properties and service environments on this stability remain unclear. Therefore, this paper constructs a coarse-grained molecular dynamics model of latent heat functional fluids to study the effects of nonionic, anionic, and cationic dispersants' microstructure, composition, and temperature on the stability of latent heat functional fluids. The results show that adding dispersants can improve the aggregation of capsules in functional fluids, but there are significant differences in the stability effects of different types of dispersants and temperatures. The promoting effects of dispersants on the dispersion stability of latent heat functional fluids decrease in the following order: nonionic polyvinyl alcohol (PVA), anionic sodium dodecyl sulfate (SDS), and cationic cetyltrimethylammonium bromide (CTAB).

Key words: phase-change capsules, latent heat functional fluids, dispersants, coarse-graining, molecular dynamics simulation

中图分类号:

任珂, 刘新健, 饶中浩. 潜热型功能流体分散稳定性强化及调控机理研究[J]. 化工学报, DOI: 10.11949/0438-1157.20250453.

Ke REN, Xinjian LIU, Zhonghao RAO. Research on the enhancement and regulation mechanisms of dispersion stability of latent heat functional fluids[J]. CIESC Journal, DOI: 10.11949/0438-1157.20250453.

图/表 15

图1 粗粒化模型及模拟体系初始构型

Fig.1 Coarse-grained model and the initial configuration of the simulation system

表1 潜热型功能流体模型参数

Table 1 Latent heat functional fluid model parameters

体系	尺寸 (nm³)	珠子类型及数量
体系	尺寸 (nm³)	H₂O	C18	MF	SDS	Na⁺	CTAB	Br^-	PVA
M	30×30×60	12000	1200	20000	0	0	0	0
MS1	30×30×60	12000	1200	20000	300	300	0	0
MS2	30×30×60	12000	1200	20000	600	600	0	0
MS3	30×30×60	12000	1200	20000	900	900	0	0
MC1	30×30×60	12000	1200	20000	0	0	300	300
MC2	30×30×60	12000	1200	20000	0	0	600	600
MC3	30×30×60	12000	1200	20000	0	0	900	900
MP1	30×30×60	12000	1200	20000	0	0	0	0	300
MP2	30×30×60	12000	1200	20000	0	0	0	0	600
MP3	30×30×60	12000	1200	20000	0	0	0	0	900

图2 不同分散剂悬浮液体系密度

Fig.2 Density of suspension system with different dispersants

图3 不同温度下不同悬浮液体系构型

Fig.3 Different suspension system configurations at different temperatures

图4 不同温度下悬浮液体系中微胶囊的质心距离随时间的变化

Fig.4 The change of centroid distance of microcapsules with time in suspension system at different temperatures

图5 不同温度下悬浮液体系中微胶囊的质心平均距离

Fig.5 Average centroid distance of microcapsules in suspension system at different temperatures

图6 不同温度下悬浮液体系中微胶囊的均方位移曲线

Fig.6 Mean azimuth shift curve of microcapsules in suspension system at different temperatures

表2 不同悬浮液体系中微胶囊的扩散系数

Table 2 Diffusion coefficients of dispersants and microcapsules in different suspension systems

体系	D_epcm (10^-6cm²/s)
体系	300K	350K
M	0.159	0.367
MS1	0.692	0.949
MS2	0.331	0.828
MS3	0.170	0.605
MC1	0.867	0.929
MC2	0.348	0.740
MC3	0.335	0.569
MP1	0.403	0.457
MP2	0.185	0.450
MP3	0.166	0.403

图7 不同温度下悬浮液体系在不同浓度时的密度分布曲线

Fig.7 The density distribution curve of suspension system at different temperature and different concentration

图8 微胶囊及分散剂分子在X-Z平面上的密度分布

Fig.8 Density distribution of microcapsules and dispersant molecules on the X-Z plane

图9 不同分散剂分子的三维密度等值面

Fig.9 Three-dimensional density contour of dispersant molecule

图10 不同温度下不同悬浮液体系的范德华能

Fig.10 Van der Waals energy of suspension system with different temperatures

图11 不同温度下不同悬浮液体系的静电势能

Fig.11 Electrostatic potential energy of suspension system with different temperatures

图12 不同温度下不同悬浮液体系的平均范德华势能

Fig.12 Average van der Waal energy of suspension system with different temperatures

图13 不同温度下不同悬浮液体系的平均静电势能

Fig.13 Average electrostatic potential energy of suspension system with different temperatures

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