缩放管管外流动沸腾换热的数值模拟与场协同分析

本文利用FLUENT软件对制冷剂R134a在光管和缩放管水平管外沸腾传热进行了三维数值模拟,得到了其饱和泡状沸腾过程中体积含汽率的分布规律,并比较了它们的换热系数,结果表明:缩放管外侧能够很好地强化沸腾传热.此外,通过改变边界条件分析了质量流量、热流密度的变化对缩放管管外沸腾换热系数的影响.最后应用场协同理论,从局部换热角度分析其强化机理.研究表明:缩放管水平管外沸腾换热得到强化的原因是其凹槽前后的速度场与温度梯度场之间夹角更小,协同程度更好.

Numerical Simulation on the Out- tube Flow Boiling Heat Transfer of the Converging - diverging tube and Field Synergy Analysis

Boiling heat transfer of refrigerant R134a which flowed outside the horizontal light tube and the converging - diverging tube was numerically simulated by FLUENT software in this article. Regularities of the volumetric steam quality distribution during the process of saturation boiling were obtained, their heat transfer coefficients were compared, and results indicate that the outside of the converging - diverging tube can intensify boiling heat transfer. In addition, the impact of different mass flow and heat flux density to the heat transfer coefficient is analyzed by changing its boundary condition. Finally, the strengthening mechanism from the angle of partial heat transfer is analyzed by field synergy principle. Results show that the cause of strengthening heat transfer is the angle between the velocity field and the thermal field, the smaller the angle, the better the synergy degree.