混凝土内部T型弯管流动换热数值模拟

Numerical simulation of flow heat transfer on T-junction embedded in concrete

采用有限元方法计算了三通弯管的流场分布和换热效率。获得了T型弯管横截面的平均速度和Nu换热系数沿管程的分布曲线。数值结果表明,弯曲位置附近流场分布复杂,弯曲位置后水流量得到二次分配;分支管壁出现分离区和回流区,横截面出现二次流。Nu数在主管和分支管沿管长方向均出现衰减,且分支管衰减比率大于横向管。在数值分析混凝土结构温度场中,应注意弯管节点附近施加不同的换热系数。

A finite element method was developed to simulate the flow field distribution and the heat transfer efficiency of T-junction in concrete.The mean water velocity and Nusselt numbers on each section were obtained in this manuscript.Numerical results show that the flow field distribution was very complex and a new flow velocity was distributed in the junction position.A separation zone and recirculation zone appeared in the vicinity of bifurcation pipe wall,and a secondary flow appeared in the cross section.Nusselt number decreased gradually along the pipeline of the main pipe and the branch pipe,and the heat loss ratio in branch pipe is greater than main pipe.It suggested that the Nusselt heat transfer coefficient should be piecewise loaded the boundary conditions,when employ a numerical simulation method to analyze the concrete temperature field.