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采用Fluen软件对纳米颗粒强化相变蓄冷特性进行了数值模拟,重点分析纳米粒子添加量和Gr数对蓄冷性能的影响,并解释其换热机理。研究结果表明:纳米颗粒的体积分数是影响纳米颗粒强化相变材料结冰时间的一个主要因素,但Gr数对其结冰时间影响不大。对于一给定的Gr数,随着纳米粒子体积分数的增加,结冰时间减少,纳米粒子体积分数为1.0%时,纳米颗粒强化相变材料的结冰时间降低了16.3%。这是由于纳米颗粒强化相变材料具有较高的导热系数。另一方面,由于纳米颗粒强化相变材料融解潜热降低,则纳米颗粒强化相变材料结冰时,每单位质量的纳米颗粒强化相变材料需要的能量较少,所以纳米颗粒强化相变材料具有较高的热释放率,在相变储能应用中具有巨大优势。
Fluen software was used to simulate the phase-change thermal storage characteristics of nano-particles. The effects of nano-particle addition and Gr number on the storage performance were analyzed emphatically. The heat transfer mechanism was explained. The results show that the volume fraction of nanoparticles is one of the main factors that affect the icing time of nanoparticle-reinforced PCMs, but the Gr number has little effect on the icing time. For a given Gr number, the icing time decreases with the increase of the volume fraction of nano-particles. When the volume fraction of nano-particles is 1.0%, the icing time of the nano-particles is reduced by 16.3%. This is due to the higher thermal conductivity of nanoparticle-reinforced phase change materials. On the other hand, since the melting latent heat of the nanoparticle-reinforced phase-change material is reduced, the amount of energy per unit mass of the nanoparticle-reinforced phase change material is less required when the nanoparticle-reinforced phase change material is frozen, and thus the nanoparticle-reinforced phase change material has The higher heat release rate offers great advantages in phase-change energy storage applications.