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针对不同结垢厚度的圆管进行数值模拟,分析在层流和紊流两种流动状态下,污垢对速度场和温度场以及它们之间的协同程度—协同角及协同数的影响。数值模拟结果表明,对于层流和紊流,其平均场协同数均随着污垢厚度的增加而增加,随着雷诺数的增加而减小;平均场协同角则相反;紊流时场协同数大于层流时的场协同数,协同角小于层流时的协同角;紊流时局部场协同数沿轴向呈现逐渐减小,在入口段时场协同数减小的速率最快,进入充分发展段后比较平缓。局部协同角沿轴向在入口段显著增加,在0.04 m处流体开始进入紊流充分发展段,局部协同角逐渐趋于一定值。层流时局部协同数和局部协同角在进入充分发展段后均达到恒定值。
The effects of fouling on the velocity field and the temperature field and the degree of synergism between them - synergistic angle and synergistic number were analyzed in the two flow regimes of laminar flow and turbulent flow. The results of numerical simulation show that the average synergy number of laminar flow and turbulent flow increases with the increase of fouling thickness and decreases with the increase of Reynolds number. The synergistic angle of mean field is opposite. The synergy angle is smaller than that of laminar flow when laminar flow is more than that of laminar flow. Synergy number of local field in turbulent flow decreases gradually along the axial direction, and the synergy decreases rapidly at the entrance, After the development of relatively flat section. The local synergistic angle increases significantly along the axial direction at the inlet section. At 0.04 m, the fluid begins to enter the full turbulence stage and the local synergy angle gradually approaches a certain value. The local synergistic numbers and local synergistic angles in laminar flow reach a constant value after entering the full development stage.