Investigation on heat transfer property of aqueous suspension of paraffin microcapsules with different sizes
Aqueous suspension of phase change material(PCM)microcapsules is a new kind of function material that has a bright application prospect in many fields such as the heat dissipation of electronic and electrical e-quipments,and the utilization of new clean energies.It shows an improved heat transfer performance since the PCM microcapsules can absorb lots of latent heat during solid-liquid phase transition in comparison with the base fluid.In this study,a new method of particle size control was introduced for optimizing the overall per-formance of microcapsule suspension in heat transfer and energy consumption.The PCM microcapsules com-posed of octadecane and melamine formaldehyde resin was synthesized by in-situ polymerization,and showed a uniform size distribution.These microcapsules were dispersed in the deionized water by adding a surfactant,and the resultant microcapsule suspension had a good stability.Investigation on the heat transfer of the aqueous sus-pension of PCM microcapsules in a circular tube was conducted,focusing on the effect of microcapsule size.It was found that as the size of microcapsules decreased from 20.0 pm to 2.6 μm,a 20.3％increase in Nussell number of microcapsule suspension and a 33.0％reduction in temperature rise of circular tube could be achieved.This finding confirmed that reducing the size of PCM microcapsules is a feasible and efficient way to improve the comprehensive heat transfer performance of microcapsule suspensions.
paraffin microcapsulemicrocapsule suspensionparticle sizedispersion stabilityconvective heat transfer
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