论文部分内容阅读
通过质量分数为5%～20%的潜热型功能热流体在扁管内的对流换热特性实验,研究了相变材料微胶囊质量分数、质量流量等因素对流体换热性能的影响。实验发现,流量较小的情况下,功能流体传热性能优于水且随着质量分数的升高而增强,而当流量较大的情况下,接近入口处的功能流体的传热性能则弱于水。以改进的Nusselt数评价,入口段内,质量分数为10%和20%的潜热型功能热流体的平均换热能力比水分别提高了6.7%和16.2%。实验质量分数范围内的潜热型功能热流体均表现出牛顿流体的特性,且其黏度较符合Vand关系式。
The convective heat transfer characteristics of latent heat functional fluid with mass fraction of 5% ~ 20% were studied in a flat tube. The effects of phase change material microcapsule mass fraction and mass flow rate on heat transfer performance were studied. The experimental results show that the heat transfer performance of the functional fluid is better than that of the water and is enhanced with the increase of the mass fraction when the flow rate is small. However, when the flow rate is large, the heat transfer performance of the functional fluid near the inlet is weak In the water. According to the improved Nusselt number, the average heat transfer capacity of latent heat functional fluid with mass fraction of 10% and 20% in the inlet section is 6.7% and 16.2% higher than that of water respectively. The latent heat function hydrothermal fluids within the experimental mass fraction all show Newtonian fluid properties, and their viscosities are in accordance with the Vand formula.