External Grids with Negative Flow

[rohrerph]

Hi everyone,

I have created a gas network that connects to two external grids. When I run the network simulation, everything functions correctly, with both external grids supplying mass flow into my network. However, I've encountered an issue when I scale down the load of the sinks or switch off some sinks. The total required mass flow decreases, resulting in one external grid supplying gas into the system (positive flow) while the other external grid experiences a negative flow, indicating that gas is exiting the system. This effectively means the network is transporting gas through the system without consuming it and then releasing it back out, which is not the desired behavior.

Both external grids have their pressures set equally. Has anyone experienced a similar issue or knows how to resolve it so that gas can only enter the network through the external grids and cannot flow back out?

Thanks for your help!