扭曲椭圆管在MVR系统降膜蒸发器上的应用研究

Practical research on twisted elliptical tube in the falling film evaporator of MVR system

传统降膜蒸发器的体积和质量过大,耗材多,实际应用效果差。文中通过理论计算与CFD数值模拟方法对比分析了扭曲椭圆管与直圆管在降膜式蒸发器中的差别,使得这2种办法相互验证了结论的可靠性。文中主要分析采用扭曲椭圆管降膜蒸发器的管侧与壳侧的传热膜系数在不同关键参数影响下优于直圆管的现象,并且剖析关键参数与传热膜系数之间的内在关系,总结了扭曲椭圆管的应用规律。结果显示扭曲椭圆管的管侧传热膜系数与壳侧传热膜系数和整体压降均优于直圆管,具有重要的工程应用价值。

The traditional falling film evaporators had excessive volume and mass, which consumed expensive materials and performed badly in practical application. By the method of theoretical calculation and CFD numerical stimulation, the coefficients of tube-side and shell-side heat transfer between the twisted elliptical tube and plain tube in the falling film evaporator were compared and analyzed. The reliability of the conclusion was verified by the above methods. The phenomenon that falling film evaporator with twisted elliptical tubes was better than the one with plain tube in terms of the heat transfer coefficients of shell-side and tube-side under various critical parameters was analyzed. Additionally, the internal relationship between critical parameters and heat transfer coefficients was also considered. Finally, the application rules of twisted elliptical tubes were summarized. The results show that the twisted elliptical tube are better than the circle tube on the heat transfer coefficient as well as the overall pressure drop of tube-side and shell-side heat transfer. In all, this kind of structure is valuable in the industrial application.