高聚物稀溶液射流的湍流模型及其数值结果

Turbulence Model of Water Jet with Polymer Additives and its Numerical Results

本文根据理论分析和某些实验结果,提出了适用于高聚物稀溶液湍流射流的K-ε模型,并用差分方法进行了数值计算。结果表明:与清水射流相比,在相同的初始状态下,高聚物添加剂能改变湍动能及其耗散率的分布特性,使雷诺应力减小,离散减弱,中心线速度增加,密集性提高。这些结果与实验数据和理论分析相吻合。

A modified K-ε turbulence model of the plane water-jet with polymer additives is developed. By using finite difference method, the model equations are solved numerically. The calculated results show that, by dissolving very small amount of polymer additives ia water, it can inerease the centerline velocities, reduce the spreading rate, enhance coherence, smooth the surface of jet, and then markedly improve the jet quality, as compared with pure water-jet under identical conditions.The effects of polymer on the turbulence are mainly to suppress small-scale eddy motion, change the properties of distribution of turbulent kinetic energy and its dissipation rate, and decrease Reynolds stress. At last, according to the viscoelasticity of polymer, the machanism of improving the jet quality with polymer additives is discussed.