I have modeled a sheet metal intake manifold I intend to make. But I want to do some flow testing in SolidWorks before I make a prototype. But I cannot use FlowXpress if there any openings at all. I have some very minor openings in the assembly due to folds, bends, ect. I want to add welds to close these and be able to use the FlowXpress.

Is this possible? How do I go about doing this?