摘要
建立了分形树状通道换热器中层流流动与传热的三维稳态模型,采用流固耦合计算方法对入口水力直径为4mm的矩形截面树状通道内流动换热进行了数值模拟,重点研究了分叉效应对传热的强化机理和换热器受热面的温度分布。研究结果表明:分叉处形成的二次流能有效地强化换热;与传统的蛇形通道相比,分形树状通道换热器具有温度均匀性好、压降小的明显优势。在相同入口雷诺数时,分形树状通道换热器受热面的最大温差远小于蛇形通道换热器,另外,分形树状通道的层流流动压降较之蛇形流道可减小50%以上。同时,加工了分形树状通道换热器及蛇形通道换热器各一套,对数值模拟结果进行了实验验证。实验值与模拟值能较好地吻合,证明了所建流动换热三维数值模型正确可信。
A three-dimensional（3D）steady model for heat transfer and laminar fluid flow in fractal tree-like channel heat sink is developed.The laminar convective heat transfer in the fractal tree-like channel heat sink with an inlet hydraulic diameter of 4 mm for rectangular cross-section is numerically simulated by liquid-solid coupling numerical method.The significant heat transfer enhancement mechanism by the bifurcations and the temperature distribution on heating surface is discussed in detail.The results indicate that the secondary flow motion generated at bifurcations can effectively enhance heat transfer.Fractal tree-like channel heat sink has obvious advantages over the traditional serpentine flow pattern in both heat transfer and pressure drop.Under the same inlet Reynolds number,the maximum temperature difference on the surface of fractal tree-like channel heat sink is far less than that of serpentine flow pattern;the pressure drop of laminar fluid flow in fractal tree-like channel is less than that in serpentine channel by over 50%.In addition,a fractal tree-like channel heat sink and a serpentine channel heat sink are respectively designed and fabricated to conduct the verification experiment for numerical simulation.The temperature distribution and pressure drop measured by experiment are in a good agreement with those obtained by numerical simulation,which verifiesed that the proposed 3D model is reliable.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2010年第3期472-479,共8页
Acta Aeronautica et Astronautica Sinica
基金
航空科学基金(2008ZH69001)
江苏省自然科学基金(BK2008309)
高等学校博士学科点专项科研基金(20070286072)
关键词
分形
换热器
流动
传热
均温性
fractal
heat sink
fluid flow
heat transfer
temperature uniformity
