基于UDF二次开发黏弹性流体数值研究

Numerical Research on Secondary Development of Viscoelastic Fluid Based on UDF

针对目前工业上对黏弹性流体数值模拟计算存在计算复杂、收敛状况较差等缺点,课题组基于商业软件FLUENT中二次开发模块UDF,提出了一种基于FLUENT软件核心求解器数值计算黏弹性流体流场的程序编制方法。该编程思路及方法具有普适性,可被推广至具有不同本构关系的黏弹性流体的数值计算。课题组通过多个实例验证了该编程方法的可行性及所编制程序的可靠性,同时提出了"定常问题的非定常化计算"的数值计算方法以提高黏弹性流场数值计算的稳定性与收敛性。结果表明:使用此种方法不仅具有计算方便、可靠等优点,且可以实现不同种类黏弹性流体模型的数值模拟研究。选用合适的时间步长、定常问题非定常算法可以有效加快收敛速度,增强收敛的稳定性。

In view of the shortcomings of current industrial numerical simulation calculations for viscoelastic fluids such as complex calculations and poor convergence, a programming method for numerical calculation of viscoelastic fluids based on the FLUENT software core solver was proposed on the basis of the secondary development module UDF in the commercial software FLUENT. The proposed programming idea and methods were universal and can be extended to the numerical calculation of viscoelastic fluids with different constitutive relations. The feasibility of the programming method and the reliability of the program through multiple examples were verified, and a numerical calculation method of "unsteady iteration of steady problems" was proposed to improve the stability and convergence of the numerical calculation of the viscoelastic flow field. The results show that this method not only has the advantages of convenient and reliable calculation, but also can realize the numerical simulation research of different types of viscoelastic fluid models. The selection of appropriate time step and the unsteady iteration for steady problems can effectively accelerate the convergence speed and enhance the stability of convergence.