Hello, and thanks in advance for your responses.

I ran a flow simulation where my boundary conditions did not match my results and am trying to figure out why this is. My model is a 30 leg header with water as the fluid. Each leg tees into a manifold that flows downstream where the flow terminates with a lid. The inlet of the legs are about 50 feet below the outlet. The bc is for a total mass flow rate for all 30 legs to be 24 lb/s and the outlet bc is an enviromental pressure of 50 psia.

My results do not make sense: Only one leg has flow (.67 lb/s), which is equal to the outlet flow, but unequal to my bc of a total of 24 lb/s. All of my other legs have mass flow rates of 0. Also, my pressure drop from inlet to outlet was only about .5 psi. I know it should be significantly more as I have to overcome 50 feet of water head along with major and minor losses through pipe runs and tees.

I think the issue is that I ran the simulation with a mesh setting of 1 and this took 6+ hours. I fear to run the simulation at a mesh setting of 3 or 4 would take exponentially longer.

I will try adding goals to inlet and outlet flow rates, which seems like a redundancy. Any suggestions as to what I did wrong or how to speed up the simulation at higher mesh setting would be much appreciated.

-Chris

The whole thing could be so badly resolved that its not making any sense. If it were me I would make a topologically similar set up and replace the long skinny bits with pieces that are scaled so that the longest stretch is like 5 or 10 diameters in length. Your problem seems more suited to a 1d flow program than a 3D program like FlowSim. You are going to have to make some accommodations for the numerical realities you are facing. Aspect ratio's beyond 10:1 (diameter to length ratio) head into the range of problematic. They can be handled but one should make accommodations to make them practical. Good luck.