小管径重力热管流动与传热特征的仿真研究

A Simulation Study of the Characteristics of Flow and Heat Transfer of Gravity Heat Pipe with Small Diameter

运用CFD仿真技术,建立了小管径重力热管(内径为6.8 mm)的流动与传热模型,分析了加热功率和倾角对热管传热性能的影响,并对蒸发段相变行为进行了CFD可视化.研究结果表明:当充液率F_R=50%,加热功率为20～90 W时,增加加热功率会使热管传热热阻先减小后增大.当加热功率为60 W时,随倾角增大,热管的传热热阻先减小后增大,当倾角为75°时,热管的传热性能较好.随热管内相变现象的进行,管内依次出现了泡状流、弹状流等几种经典流型.

The flow and heat transfer model of the small tube diameter gravity heat pipe(the inner diameter is 6.8 mm)was established by using CFD simulation technology,the effect of the heating power and the inclination angle on the heat transfer performance of the heat pipe was analyzed,and the phase change behavior of evaporation section was visualized by CFD.The results show that when the filling ratio is F_R=50%and the heating power is 20~90 W,the heat transfer resistance of the heat pipe decreases first and then increases with the increase of heating power.When the heating power is 60 W,the heat transfer resistance of the heat pipe decreases first and then increases with the increase of the inclination angle of the heat pipe.When the inclination angle is 75 degrees,the heat transfer performance of the heat pipe is good.With the development of phase transition in the heat pipe,such classic flow patterns as bubble flow and slug flow appear in turn in the pipe.