冷藏运输用Al_2O_3-H_2O纳米流体蓄冷相变时间分析

利用恒温浴槽分别对质量分数为5%,Al2O3粒径分别为10,20,50,100,500 nm和粒径为10 nm,质量分数分别为5%,10%,12%,15%,20%的两组Al2O3-H2O纳米流体进行冻结,分析了纳米流体和去离子水在冻结过程中的温度变化,讨论了Al2O3粒径和浓度对冻结过程的影响。结果表明,在去离子水基液中加入Al2O3纳米颗粒,减少了凝固相变时间,且当质量分数为5%时,相变时间随粒径增大而增加,粒径为10 nm时,相变时间最短;当粒径为10 nm,质量分数小于10%或大于12%时,相变时间均随质量分数的增大而增加,但质量分数为12%时,相变时间最短。相对于冰作为蓄冷材料,纳米蓄冷材料可节省蓄冷时间,有效提高能源利用效率。

research on time of phase chanGe of Al2 O3-H2 O nanofluid in refriGerated transport

A constant temperature bath was used to cool Al2 O3-H2 O nanofluids with different particle sizes of 10 ,20 ,50 ,100 and 500 nm（ mass fractions of 5%）and different mass fractions of 5%,10%,12%, 15% and 20%（ particle size of 10 nm）. By analyzing the change of temperature in the freezing process, the effects of particle sizes and concentration of Al2 O3 on the freezing time were studied. The results show that the Al2 O3 nanoparticles added to aqueous solution of deionized water reduce the time of phase change,the time increases with the diameters of Al2 O3 nanoparticles increasing when the mass fraction is 5%,and it is shortest when the diameter of Al2 O3 nanoparticles is 10 nm;When the diameter of Al2 O3 nanoparticles is 10 nm,the time spent in this process increases with the mass fraction of nanoparticles in-creasing when the mass fraction is less than 10% or greater than 12%,but it is shortest when the mass fraction is 12%. Compared with ice as the storage material,nanofluids save the cool storage time and im-prove the energy efficiency.