大曲率结构化表面湍流流场特性对比研究

湍流模型选择对于小尺寸大曲率圆管内软性磨粒流湍流流场模拟计算具有重要影响.针对此问题,提出使用标准k-ε模型与考虑两相磨粒流平均流动中的旋转及旋流流动情况的重整化群(RNG)k-ε模型进行仿真对比研究的方法.基于颗粒动力学理论的欧拉模型,对软性磨粒流的控制方程进行求解.通过使用两种湍流模型,对小尺寸大曲率圆管内湍流流动进行仿真计算,得到了两湍流模型下软性磨粒流流场的速度、压力、湍动能等数值模拟结果.仿真结果对比分析表明:标准k-ε模型模拟得到的速度值与实验值存在一定误差,而RNG k-ε模型仿真的速度值误差相对较小;标准k-ε模型对湍动能的估值计算比RNG k-ε湍流模型高,难以计算有滞止点的流动过程;RNG k-ε湍流模型能更有效地模拟有大曲率带分离的湍流流动,从而证明该模型更适合小尺寸大曲率圆管内软性磨粒流湍流流动的研究.

Comparative Study on Turbulent Flow Field Characteristics of Large Curvature Structural Surface

urbulence model selection is pivotal in simulation calculation for turbulence field of soft abrasive flow in circular tube with small size and large curvature.Aiming at this problem,a method was proposed regarding comparative study between standard k-ε model and Renormalization Group(RNG)k-ε model considering rotation and swirl in the mean flow of two-phase abrasive flow.Based on Euler model combining with particle dynamics theory,the governing equations for soft abrasive flow were solved.Soft abrasive turbulent flow in circular tube with small size and large curvature was simulated by using the two turbulence models,and then numerical simulation results including soft abrasive flow velocity,pressure and turbulent kinetic energy etc were obtained.Comparative analysis of simulation results demonstrate that some error exist in published experimental data and simulative velocity obtained through standard k-ε model,while velocity error from RNG k-ε model is relatively smaller than that of the previous model.Estimation of turbulent kinetic energy simulated by standard k-ε model is higher than by RNG k-ε model,which results in the difficulty to calculate flow process with stagnation point.Therefore the RNG k-ε model is more effective to simulate the turbulent flow of large curvature with separation.All above conclusions indicate that RNG k-ε model is more appropriate to study the turbulence of soft abrasive flow in circular tube with small size and large curvature.