内螺纹肋管几何参数对流动与传热的影响

Geometry Effects on Fluid Flow and Heat Transfer in Internal Helical Finned Tubes

以空气（Pr=0．744）为介质，在Re=2000时，对17根内螺纹肋管进行了数值模拟，研究内螺纹肋管的流动与传热特性．在梯形肋几何参数肋高H=0．02-0．06，肋数N=35～50条，螺旋角γ=35°～45°时，分析肋高、肋数、螺旋角的变化对Nu和f的影响，得出Nu和f随N、H增大而增大，随γ增大，Nu和f先增大再减小，Nu在γ=41°达到最大值，f在γ=39°达到最大值．研究表明，最佳肋参数为0．50／40／41．

The characteristics of fluid flow and heat transfer in internal helical finned tubes have been investigated by numerical simulation on seventeen tubes in the Re= 2000, with air as the medium. For a trapezia fin profile, the effects of fin number, fin height and helix angle on the Nu and the f were investigeted in the conditions of fin number N=35°-50°, fin height H=0.02-0.06, helical angle γ=35°-45°. Analysing the impact of fin number, fin height and helical angle on the Nusselt number and the friction factor. It is found that the Nu and the f increase along with the increase of N and H. With the increase of helical angle, Nu and f increase first, then reduce, which are maximum in 41° and 39° respectively,the best rib combination is 0.50/40/ 41.