竖直管道内湍流混合对流换热研究

STUDIES OF TURBULENT MIXED CONVECTION HEAT TRANSFER IN A VERTICAL TUBE

本文对空气在竖直圆管中的湍流混合对流换热进行了实验研究和数值模拟,并对异种气体(氦气)对混合对流换热的影响进行了初步的实验研究。研究发现,空气在竖直圆管中向上流动时,随着热流密度的不断增大,出现换热恶化现象。如果浮升力足够大,则换热效果在降到最低点后又好转。在实验过程中,由于实验条件所限没有发现异种气体对混合对流换热有显著的影响。

Turbulent mixed convection heat transfer of air in a vertical tube was investigated through experiments and numerical simulation. Preliminary experimental study was also carried out on the influence of other gas (Helium) on convection heat transfer. The results indicate that for upward flow in a vertical tube, with the increasing of heat flux, heat transfer is reduced by the influence of buoyancy and impairment of heat transfer occurs. If the buoyancy is big enough, heat transfer is impaired to the lowest point and then is recovered. In the experiments with input of other gas (Helium), significant influence was not found due to the limitation of experiment facility.