Abstract: The flow and heat transfer mechanism in the shell side of corrugated double-pipe heat exchanger are studied numerically based on the k-ε model. The independent analysis of first layer thickness and main flow region grid are carried out using hexahedral mesh in the whole region combined with dense mesh in the corrugation region. Compared the data from empirical formula with computational results, the accuracy of numerical methods is verified. The strengthening heat transfer mechanism is revealed by analyzing the difference of the flow and heat transfer parameters distribution (speed, temperature and turbulent kinetic energy and turbulence dissipation rate) between corrugated tube and smooth tube. Meanwhile, the local Nusselt numbers and pressure drop distributed law along the corrugation wall is also analyzed. The results indicate that the detached vortex formed at the downstream side of corrugation which resulting in an obvious effect of heat transfer augmentation destroys the velocity and temperature boundary layer meanwhile increase the frictional resistance and thermal diffusivity.

Key words: outward convex corrugated double-pipe heat exchangers, k-ε model, Nusselt number, pressure drop, heat transfer enhancement

摘要： 针对波节套管换热器壳程中的流动和传热机理进行了k-ε的数值模拟研究。采用六面体网格结合波节区域加密的特殊划分方法，进行了首层网格间距和主流区网格间距的无关性分析。数值模拟结果与经验公式进行对比，验证了数值模拟方法的准确性。对比分析了波节管和光管中流动和传热参数（速度、温度、湍动能和湍流耗散率）的性能差异，揭示了波节管的强化换热机理。同时，分析了波节管的局部Nusselt数和阻力降沿壁面的变化规律。结果表明流体在波节的去流侧形成了一个脱体旋涡，破坏了流体的速度边界层和温度边界层，同时使得其内部的摩擦阻力和热扩散能力明显提高，起到了明显的强化换热效应。

关键词: 波节套管换热器, k-ε模型, Nusselt数, 阻力降, 强化换热