分支结构血管中血液的对流换热分析

用有限元方法数值模拟了血管分支结构内血液流动的三维速度场和温度场,得到了分支血管壁面3个典型径向角度的局部努塞尔数和血管截面平均努塞尔数沿管长的变化曲线.结果表明:分支血管入口处的速度场和温度场分布与单管的分布明显不同;不同径向角度的局部努塞尔数相差很大;分支血管入口处截面平均努塞尔数大于单个直管内截面平均努塞尔数,且出现一个极大值Numax.计算了不同分支角度和分支半径比时的截面平均努塞尔数,结果表明:分支角度和半径比对Numax的大小和位置有一定影响;半径比越小,分支血管内截面平均努塞尔数趋于稳定值的速度越快.

The convective heat transfer in furcated blood vessels

A finite element model was developed to simulate the 3-D velocity and temperature distributions in a vessel system including a bifurcated blood vessel and two branches.The effect of the angel between vessels and bifurcation ratio were taken into account,and the local Nusselt number at three typical radial angels and the mean Nusselt number on a section in the branching vessel were obtained.Results show that: the flow and temperature fields were highly unlike the distributions of a single vessel;the local Nusselt number were different at different radial angels;in the entrance region of the branching vessel the mean Nusselt number on a section was larger than that in a single vessel,and there was a maximum of mean Nusselt number whose value and location varied as the different furcating angel or bifurcation ratio;the mean Nusselt number decays rapidly at a small bifurcation ratio.