Discussion Forum

History: We have a laminar fluid model with 1 inlet and 4 outlets which we are trying optimize flow equality to. Our boundary conditions contain an outlet volumetric flow rate of 100 [cc/min], an inlet pressure of 0 [Pa], and wall boundaries. Solving the model seen in Figure 1 kept resulting in a matrix singularity error. We tried many things to get away from this error. Adding fluid blocks to the outlets seemed to solve the problem and allows the model to run (Figure 2).

A surface integration of the outlet faces adds to 100% of the flow volume set in our boundary conditions (Figure 3). However, surface integration of the surfaces shown in Figure 4 only add up to a fraction of the total flow set in the boundary condition. The interesting thing is that even though the Figure 4 boundaries only add up to a fraction of the total flow rate, the ratio of flow imbalance between channels is equal.

My only explanation is that the surface integration is only taking a portion of the vector componenet of velocity at the Figure 4 boundaries, and therfore, the ratio is right but the total mass flow isn't accounted for. Is that the reason?

Thanks for your time,

Seth