中文摘要：

文中数值模拟了套管的导热系数、纵向长度和肋数对纵向导热的影响,随着纵向长度的增大,纵向导热的影响急剧减小。导热系数和肋数的增加都会使纵向导热的影响增加。对纵向长度小于100 mm短管来说,纵向导热越大热短路造成的损失越大,使整个换热芯传热效率相应幅度地降低;对管长大于100 mm,材料导热系数小于46 W/（m·K）的回热器及换热介质为气体的来说,可以忽略纵向导热的影响。

英文摘要：

In this paper, a conjugated heat transfer problem of conduction and convection in concentric tubes with longitudinal fins is studied by means of numerical simulation. 3D temperature and fluid flow fields are simulated for three-split concentric tube recuperator with longitudinal fins for gas fluid flow. The numerical simulation results show that the ratio of longitudinal heat conduction amount with the total heat transfer amount decreases quickly as longitudinal length increasing. If the conduit is long enough about 100 mm, and with solid thermal conductivity about 46 W/（m·K） , and the heat transfer media of gas, the longitudinal heat conduction could be neglected.