Yutao Huo

Dissipative particle dynamics study of nano-encapsulated thermal energy storage phase change material

The nano-encapsulated phase change materials (PCM), which have several good thermophysical properties, were proposed as potential for thermal energy storage. Various PCM have been widely researched on micro and macro perspective by experimental and simulated methods to form a bridge between the microstructure and macroscale properties of the nano-encapsulated PCM. In this study, the dissipative particle dynamics (DPD) simulation method was used to investigate the mesoscopic morphologies and evolution mechanisms of the nano-encapsulated PCM. The coarse-grained and Flory–Huggins-type models were used to obtain the molecular structures and interaction parameters. The results showed that the nano-encapsulated PCM can be fabricated by using n-docosane as a core material and styrene (St), ethyl acrylate (EA) and allyloxy nonyl-phenoxy propanol polyoxyethylene ether ammonium sulfate (DNS-86) as shell materials. The core–shell structures failed to fabricate with excess surfactant and shell materials. The preliminary optimized encapsulation rate of the core material could be useful for the design and experiment of the nano-encapsulated PCM.

Dissipative particle dynamics and experimental study of alkane-based nanoencapsulated phase change material for thermal energy storage

The nanoencapsulated phase change materials (PCM) for thermal energy storage have received much attention recently. In order to understand the morphologies and structure evolution of nanoencapsulated PCM, dissipative particle dynamics (DPD) simulation coupled with an experimental method was performed in this paper. The coarse-grained models of the alkane-based nanoencapsulated PCM system were constructed and the PCM nanocapsules were prepared by using n-octadecane as a core material, and methyl methacrylate (MMA) and methyl acrylate (MA) as shell materials. The results showed that the nanoencapsulated PCM with a shell–core structure were successfully fabricated by DPD simulation. The average diameter of the prepared PCM capsules by using the experimental method is 48.80 nm. The latent heat and melting temperature of the prepared nanoencapsulated PCM is 86.13 kJ·kg−1 and 20.60 °C. The alkane content in the prepared nanoencapsulated PCM is 41.59%. The DPD simulation method was confirmed to benefit the development of nanotechnology in thermal energy storage.

Molecular dynamics simulation of the molar volumes and solubility parameters of straight alkanes

The straight chain n-alkanes used as core materials to fabricate nanoencapsulated and microencapsulated phase change of materials (PCM) have received much attention in recent years. The dissipative particle dynamics (DPD) simulation method has been emerged to investigate the encapsulated PCM from the perspective of mesoscopic. To obtain the Flory–Huggins and repulsion parameters, which is essential for the DPD study, the molar volume and solubility parameter of straight alkanes are investigated by using molecular dynamics (MD) simulation. The results showed that a linear relationship of molar volume (V) with carbon atom number (n) and simulation temperature (T) can be obtained as: V = -31.73 + 0.26T + 14.82n. A nonlinear relationship of solubility parameter (δ) with carbon atom number and simulation temperature can be described as: δ = 18.45-3.66 ×10-2n + 1.07T - 1.20 ×10-5n2 - 9.60 ×10-2T2 - 2.49 ×10-3nT. The equations can be used as a reference for the further DPD simulation in n-alkanes based PCM system.

The Lattice Boltzmann Investigation for the Melting Process of Phase Change Material in an Inclining Cavity

The solid-liquid phase transition process is of significant importance the widely usage of phase change material (PCM), including in thermal energy storage and maintaining working temperature. In this paper, a phase change lattice Boltzmann (LB) model has been established to investigate the effects of inclining angle on the melting process in a cavity filled with PCM, considering three kinds of heat flux distribution: uniform distribution, linear distribution and parabolic symmetry distribution. The simulations results show that for all the heat flux distributions, the slight clockwise rotation of cavity is able to accelerate the melting process. Furthermore, when more heat is transported into the cavity through the middle part (parabolic symmetry distribution) or bottom part (linear distribution), the effects of cavity clockwise rotation on temperature field are more than that of anticlockwise rotation.Copyright