Abstract:

The heat transfer performance of 5 L jacketed polymerizer was studied based on the combination of CFD simulation and heat transfer experiments. The liquid-solid coupled steady-state heat transfer model of the polymerizer was established to obtain the temperature distribution of the metal solid and the fluid in the reactor and the jacket. The CFD simulation results were validated by heat transfer experiments, and the maximum relative error of temperature at each test point was within 1%—5%. The convective heat transfer coefficients of the inner and outer walls of the reactor and the total heat transfer coefficients were obtained by simulation, and the empirical formulas of Nu on the reactor side and the jacket side were correlated. The results show that the variance of the fluid temperature distribution in the reactor is always below 0.002 in the three calculation domains. Among them, the temperature gradients in the solid domain and the heat transfer boundary layer are larger, and the thickness of the boundary layer is about 3.8 mm. In the experiment range, the inlet temperature and reaction exothermic have a significant influence on the reactor temperature, followed by the inlet flow rate, and the stirring speed has the weakest influence. The heat transfer coefficient on the jacket side is much smaller than the heat transfer coefficient on the side of the kettle. Increasing the heat transfer coefficient on the jacket side is the key to improving the heat transfer performance. The heat dissipation on the outer surface of the reactor is proportional to the temperature difference between the inside and outside, and the proportional coefficient is about 3.031 W·K ^-1.

Key words: CFD, stirred vessel, heat transfer, numerical simulation, polymerization, fluid-structure interaction

摘要：

基于CFD模拟与传热实验相结合的方法对5 L夹套聚合釜的传热性能进行研究。建立聚合釜的液固耦合稳态传热模型，获得釜内流体、夹套内流体及金属固体域内温度分布。开展传热实验对模拟结果进行验证，各对比点温度的最大相对误差在1%~5%范围内。通过模拟获得釜内外壁面传热系数及总传热系数，并关联出釜侧及夹套侧 Nu的经验式。结果表明：釜内流体温度分布方差始终在0.002以下，固体域内和传热边界层温度梯度较大，传热边界层厚度约3.8 mm；实验范围内，入口温度和反应放热量对釜内温度的影响显著，入口流速次之，搅拌转速影响最弱；夹套侧传热系数远小于釜侧传热系数，提高夹套侧传热系数是提升传热性能的关键；实验用聚合釜外表面散热量与内外温差呈正比，比例系数约为3.031 W·K ^-1。

关键词: 计算流体力学, 搅拌容器, 传热, 数值模拟, 聚合, 流固耦合