旋转状态下蛇形通道内流动与换热的机理研究

 在已有的实验研究结果的基础上,应用较好符合实验结果的数值模拟程序及划分网格方法,分别数值计算了旋转所产生的几个因素对流动与换热的影响机理。结果表明:由于在垂直于旋转半径截面上哥氏力分布的不均匀,产生了流体流型的两个变化,即主流的偏移和二次流动旋涡的出现。离心浮升力对通道内流动与换热的影响不大。旋转速度变化时,在旋转变化的起始时刻系统的角速度力对通道内流体的流动影响比较明显。各种力的作用综合效果不是简单线形迭加的,而是交替起主导作用,决定流体流动结构、影响换热结果。

Study on Mechanism of Turbulent Flow and Heat Transfer in Rotating Passages

A two-equation turbulence model with additional term for Coriolis and buoyancy is used to study the mechanism of various force action and interaction effect in rotating serpentine passages. The simulation results in rotating serpentine passages are almost consistent with the experimental data. Then, numerical tests are carried out for cases with only Coroilis force, buoyancy force caused by Coroilis force, buoyancy force caused by Centrifugal force, Coroilis force and it’s buoyancy force, and all forces caused by rotation respectively. The results indicates that the buoyancy, the angular acceleration forces and the cross-stream secondary flow caused by unbalance distribution of the Corilis affect the convective heat transfer. Coroilis force plays an important role in flow and heat transfer in rotational passage. Coroilis force increases pressure loss in the passage with ribs while centrifugal buoyancy force decreases pressure loss.