CFD 模块更新


COMSOL Multiphysics® 6.3 版本为“CFD 模块”的用户引入了雷诺应力湍流模型、分散多相流中的剪切诱导迁移,以及在高马赫数流动接口中包含动能的选项。请阅读以下内容,进一步了解这些更新。

雷诺应力湍流模型

新增的湍流,Wilcox R-ω湍流,SSG–LRR (Speziale–Sarkar–Gatsk/Launder–Reece–Rodi) 接口引入了更高阶的闭合模型,尤其适用于模拟管道中的二次流动、具有明显旋涡或均匀旋转的流动,以及平均流线曲率较大的流动。与涡黏模型 (EVM) 不同,这些接口并不假设雷诺应力与平均应变率一致,因此在复杂流动条件下能够提供更精确的结果。Wilcox R-wSSG–LRR 两种雷诺应力模型的主要区别在于对压力-应变项和远场比耗散率的建模方式。

The COMSOL Multiphysics UI showing the Model Builder with the Turbulent Flow, SSG–LRR node highlighted, the corresponding Settings window, and a semicircular duct in the Graphics window.
利用 SSG–LRR 雷诺应力模型计算半圆形管道中二次流动的流线和相对强度。

分散多相流中的剪切诱导迁移

在高浓度悬浮液中,不可逆的颗粒碰撞会导致颗粒向剪切速率较低的区域迁移,这一现象在颗粒分级和微滤工艺中发挥着重要作用。以中性浮力混合物的压力驱动通道流为例,颗粒通常会在通道中心聚集。现在,混合物模型 多物理场耦合中新增了包含剪切诱导迁移 选项,支持多种物质,并能增强仿真结果的精度。浓悬浮液的两相流建模教学案例现已更新,以便采用这一新特征。

高马赫数流动中的动能和亚音速入口条件

为了提高能量守恒的准确性,高马赫数流动 接口中新增了包含动能 选项,能够更准确地描述黏性功。尽管这种差异通常不大,但在特定情况下,该选项能够显著提升能量守恒效果。此外,针对入口马赫数较低的情况,例如喷射器等内部流动设备,入口 特征中新增了一个亚音速 选项,作为基于特性 选项的低计算需求替代方案。

The COMSOL Multiphysics UI showing the Model Builder with the High Mach Number Flow, k-ε node highlighted, the corresponding Settings window, and a supersonic ejector model in the Graphics window.
喷射器中密度梯度的大小。

New Functionality in the Phase Transport Interfaces

A new Boundary Mass Source boundary condition has been added to the Phase Transport interfaces. This new feature accounts for the consumption or production of different phases due to reactions or other physical processes at boundaries. Boundary conditions will now be easier to set up when, for example, phase transport is coupled to surface reactions. Additionally, to help unify nomenclature across the different physics interfaces, the new Fluid and Porous Medium nodes have replaced the previously available Phase and Transport Properties and Phase and Porous Media Transport Properties nodes in the Phase Transport interfaces.

Power Law Option for Relative Permeabilities

The Porous Medium feature in the Phase Transport in Porous Media interface now includes a new Power law option, making it easier to implement relative permeabilities based on power law expressions. This enhancement simplifies the setup and modeling of permeability behavior in porous media simulations.

The COMSOL Multiphysics UI showing the Model Builder with the Fluid node highlighted, the corresponding Settings window, and a 1D plot in the Graphics window.
Relative permeabilities based on power law expressions being used in the two-phase porous medium flow Buckley–Leverett benchmark model.

Result Templates in the Chemical Species Transport Interfaces

Creating useful and visually appealing plots of reacting systems can be time consuming since there are often many reactants and thus many concentration fields to plot. To save time, there are a number of new Result Templates in the Chemical Species Transport interfaces. Among these, plot array templates are now available that include up to four species concentrations simultaneously in the Graphics window. The Result Templates are available for all Chemical Species Transport interfaces, independent of the add-on product, but are especially useful for the multicomponent transport interfaces included in the modules for chemical engineering as well as in the Porous Media Flow Module, Subsurface Flow Module, and Microfluidics Module.

新的教学案例

COMSOL Multiphysics® 6.3 版本的“CFD 模块”引入了一个新的教学案例。