流体粘弹性对喷墨印刷液滴参数影响

目的研究粘弹性非牛顿流体中聚合物参数对喷墨液滴形成过程中各项数据的关系,通过所得数据进行数值处理,构成关于聚合物参数变量的液滴类型空间。方法模拟实验中采用FENE-CR流体模型,将FENE-CR流体模型中的本构方程与纳维斯托克斯方程和连续介质力学相结合,推导出流体聚合物参数与流体粘弹性的关系。建立液滴喷射模型,采用Flow 3D数值模拟方法模拟聚合物参数变化对喷墨液滴形成过程的影响。结果得到了聚合物参数(聚合物延展性L、聚合浓度C和聚合物De值)对喷墨印刷中墨滴断裂过程的各项主要数据:主液滴最终速度vf、液滴尺寸V、墨尾最大长度Z,墨尾一次断裂时间tb的具体关系曲线。结论对于非牛顿粘弹性流体,虽然高分子聚合物在整个流体中所占比例很小,但是它的存在对流体粘弹性变化影响显著,聚合物种类和浓度的不同会最终导致液滴形成过程中各项数值发生巨大的变化。

Effect of Fluid Viscoelasticity on the Droplet Parameters of Inkjet Printing

Objective To study the relationship between the viscoelastic polymer parameters of non-newtonian fluid and the data obtained during the process of inkjet droplet formation. And to composite the droplet type spaces with the variable parameters through numerical processing. Methods In the simulation experiment, the FENE-CR fluid model was adopted, and the constitutive equation of the FENE - CR fluid model was combined with Navier-Stokes equation and continuum mechanics to deduce the relationship between the fluid viscoelasticity and the polymer fluid parameters. The droplet spray model was established, and the 3D numerical simulation method was used to simulate the impact of polymer parameter changes on the inkjet droplet formation process. Results Through the numerical simulation method we got the relationship between the polymer parameters (polymer ductility L, polymer concentration C and polymer De value) and the main data such as the main droplet final velocity vf, droplet size V, the tail maximum length Z and the tail first breakage time tb in the process of the inkjet printing drops formation. Conclusion For non-Newtonian viscoelastic fluids, although the proportion of polymer in the fluid was very low, its impact on the changes of fluid viscoelasticity was significant. The different type and concentration of polymer led to dramatic changes in the values of the final droplets formation process.