中文摘要：

利用UDF编程定义纳米流体相变源项，对Al2O3-H2O纳米流体在水平管内的沸腾过程进行了数值模拟，分析研究了纳米流体在水平管内沸腾的流型特点，结果表明水平管内沸腾蒸发产生的相变含气率沿着管长方向不断增加，但相同截面位置纳米流体的含气量高于纯水的含气量，有助于强化流体的扰动与混合。对于不同浓度的Al2O3-H2O纳米流体的流型研究表明：颗粒浓度对于纳米流体管内沸腾过程的影响不大。随后将纳米流体与纯水的流型进行比较，结果表明Al2O3-H2O纳米流体使得管内沸腾更剧烈，也更容易沸腾，这将改善水平圆管的流动特性。

英文摘要：

Programming through a UDF definition of nanofluid phase change source term , the Al2 O3 -H2 O nanofluid boiling process is simulated in the horizontal tube ,and the boiling flow pattern characteristics analyzed in the nanofluid horizontal tube .The results show that for boiling in the horizontal pipe , the gas content increases along the length direction , but in the same interface position , the nanofluid of air content is higher than that of pure water of air content ,helpful to enhance the disturbance of the fluid .For different concentrations of Al 2 O3 -H2 O nanofluid flow pattern , particle concentration has little effect on nanofluid tube boiling process .Nanofluid is then compared with pure water flow pattern , the results show that the Al 2 O3 -H2 O nanofluid makes tube boiling more intense and easier .It will improve the flow characteristic of the horizontal circular tube .