旋流片支撑缩放管管束传热与流动的数值模拟

通过数值模拟,以水为工质,研究了湍流时旋流片支撑缩放管管束管间的传热综合性能,并与无支撑光滑管管束、无支撑缩放管管束及旋流片支撑光滑管管束的传热性能进行了对比,分析了不同结构参数对其传热综合性能的影响;揭示了旋流片支撑缩放管管间流体速度场与温度场之间的协同性。结果表明:旋流片支撑急扩慢缩型缩放管管束相对急缩慢扩型具有更好的传热综合性能,且都比旋流片支撑光滑管管束的传热综合性能好,但二者都没有对应的无支撑缩放管管束综合性能好;具有小角度跟大扭率结构的旋流片更有利于旋流片支撑管束传热综合性能的提高;相对旋流片支撑光滑管管束与无支撑缩放管管束,旋流片支撑缩放管管束强化传热的原因在于传热场协同的增强作用更为明显。考虑管间支撑物支撑管束与抗振的必要性,旋流片支撑缩放管管束是一种高效的壳程强化传热措施,文中条件下通过优化,最大传热综合性能能达到1.057。

Numerical simulation on heat transfer and flow characteristics of converging-diverging tube bundles supported with regularly spaced twisted tapes

The periodic heat transfer and flow characteristics of water in converging-diverging tube(CD) bundles supported with regularly spaced twisted tapes(RSTT) were studied and compared with the thermal performances of plain tube bundles,bare CD bundles and plain tube bundles supported with RSTT by numerical simulation.In addition,the effect of different geometric parameters of RSTT and field synergy between velocity and heat flow field were also discussed.The results indicate that the CD bundles with longer converging pitch have a better overall thermal performance than the ones with longer diverging pitch,and the overall thermal performances of CD bundles supported with RSTT are higher than that of plain tube bundles supported with RSTT but lower than that of bare CD bundles.It shows that RSTT with bigger twist ratio and smaller rotation angle is in favor of improving the overall thermal performance.The results obtained also show that the CD bundles supported with RSTT have a better field synergy than the bare CD bundles and plain tube bundles supported with RSTT,resulting in having a better heat transfer enhancement compared with the bare CD bundles and plain tube bundles supported with RSTT.Considering the stable and ant-vibration necessity between tube bundles,the insertion of RSTT into CD bundles is a kind of high efficient heat transfer enhancement method.Under the optimum conditions,the max heat transfer overall performance can reach 1.057.