水平管道气泡发展规律

The velocity influence of bubble development in the horizontal pipeline

为了获得水平管道内的气泡变化规律,在欧拉模型的基础上加载PBM模型(颗粒群平衡模型),考虑实际情况下气泡的聚并以及破碎等动力学行为,耦合Realizable k-epsilon湍流模型,计算得出水平管道中不同颗粒粒径的气泡数密度变化规律以及气泡的分布规律,分析气泡粒径分布在水平管道中达到稳态所用的时间.计算结果表明:不是所有粒径的气泡都存在于水平管道中,气泡数量分布存在差异,气泡粒径分布会随时间变化而达到稳态,结合克拉贝龙方程计算分析出气泡分布是动态平衡的,不同粒径气泡数量变化都是随时间单调变化的.此研究可以为空调系统启停阶段蒸发器和冷凝器中空气与制冷剂产生热交换过程中气泡破灭提供理论基础.

In order to get the air bubble development rule in the horizontal pipeline,this paper uses the PBM（ populations balance model） model based on Euler model, taking the consideration of the bubble coalescence and breakage dynamics behavior in actual. It couples with Realizable k-epsilon turbulence model,and computates the different particle size air bubbles distribution and number density change rule in the horizontal pipeline. It analyzes how long the bubble size distribution reaches the steady state. Results show that not all the size of bubbles exist in horizontal pipeline,the bubble distribution has some differences,and the bubble size distribution changes with the time and reaches the steady state. It uses the carat pi-nong equation to work out the bubble distribution which is the dynamic equilibrium, and different size of bubble number monotonously changes with the time. This research can apply the theory basis to the bubble breakage during the heat transforming process happened between air and refrigerant on the evaporator and condenser on the air-conditioning start-stop stage.