管道复杂流场气固两相流DPM仿真优化

Simulation Optimization of DPM on Gas-Solid Two-Phase Flow in Complex Pipeline Flow Field

针对Fluent中气固两相流离散相模型(DPM)仿真,为提高通用模型对管道节流复杂流场问题仿真时的准确性,在结合气相流场分析与固相颗粒受力分析的基础上,提出DPM优化的4项措施,即从气相速度入口模型、颗粒曳力模型、颗粒壁面碰撞模型、颗粒所受各个力的合理取舍4个方面进行优化.通用模型的优化通过调用Fluent相关宏并编制用户自定义函数(UDF)程序实现.实验已验证优化DPM的准确性明显优于通用DPM,具体体现在:两相流型转换时气相速度区间的模拟,颗粒沉降气相临界速度的模拟方面,这2项指标优化后比优化前分别提高55%和50%;在实验管道局部阻力损失与节流孔板前颗粒速度分布的模拟仿真方面,优化DPM显然具有更准确的优势.通过实流实验与仿真模拟的对比,证明优化是有效的.从研究过程可以得出,模型优化的方法对于其他类似的复杂流场工况具有通用性和工程实用价值.

General discrete phase model（DPM） simulation on gas-solid two-phase flow is now widely employed. In order to improve its accuracy on pipeline throttling with complex flow field, based on analysis combined gas flow field and forces acting on solid phase particles, four optimization measures about the general DPM model are proposed,which include gas inlet velocity model, particle drag model, collision of particles with internal surface of pipeline and reasonable choice of each force on particles. The optimization of general model is achieved by calling Fluent related macro and compiling user defined functions（UDF） program.Experiments verified that the accuracy of the optimized DPM model is significantly superior to the general model,as is shown in the following four aspects： the simulations of the two-phase flow gas velocity conversion interval and the gas critical velocity of particle sedimentation,which increased by 55% and 50% respectively in the optimized model; what is more, the optimized model obviously has more accuracy advantage on local resistance loss in experimental pipe and particle velocity distribution simulation. Through the contrast of experiment and simulation, the optimization is proved to be successful, and it is concluded that the method of optimization is versatile for other pipeline with complex flow field and has practical engineering value.