Abstract: This paper presented numerical simulation of Fe2O3-water and Al2O3-water nanofluids flow in a constant density of heat flow rate inner grooved copper tube by computational fluid dynamics，and analysis effect of particle concentrations on convective heat transfer coefficient in different Reynolds numbers，various radial and axial locations of tubes. The comparison between the simulated and experimental results showed that the simulation agreed well with the eperimental results. Simulation demonstrated that when Re number was in the range of 1000 to 2000，the heat transfer effects of Fe2O3-water nanofluids were better than that of an equal mass fraction of Al2O3-water nanofluids on the inner grooved copper radial and axial direction. When the mass fraction of Al2O3-water nanofluid was 0.4%，convective heat transfer coefficient increased to 38.8% on the axial direction. The mass fraction of Fe2O3-water nanofluids increased by 0.3%，convective heat transfer coefficient increased up to 26.5%. Re number had stronger influence on convective heat transfer coefficient (up to 78%). The best mass percentage for the convective heat transfer of Fe2O3-water and Al2O3-water nanofluids was around 4%.

Key words: nanofluid, numerical simulation, heat transfer, convective heat transfer characteristics

摘要： 利用计算流体力动力学方法对恒定热流密度内螺纹铜管中的Fe2O3-水和Al2O3-水纳米流体的换热特性进行数值模拟，分析了纳米流体的质量分数、Re数和管道的不同水平位置对对流换热系数的影响，并将模拟结果与实验结果进行了对比，得到的模拟结果与实验结果趋于一致。模拟结果表明：在Re数为1000～2000的范围内，内螺纹铜管的径向与轴向方向上，Fe2O3-水纳米流体的传热效果好于同等质量分数的Al2O3-水纳米流体，轴向方向上，当Al2O3-水纳米流体的质量分数为0.4%时，对流换热系数最大提高38.8%。Fe2O3-水纳米流体的质量分数提高0.3%时，对流换热系数最大提高26.5%，而Re数变化对对流换热系数的影响要更强一些，最大提高78%。Fe2O3-水和Al2O3-水纳米流体的对流换热系数增长趋势的最佳质量分数在4%左右。

关键词: 纳米流体, 数值模拟, 传热, 对流换热系数