A fuel cell stack that includes cascaded stack stages and tube bundle flow
restrictions for providing a cathode input gas to each stage in the
stack. The stack includes a first flow pipe for providing cathode gas
flow to a first stage of the plurality of stages of the fuel cell stack.
The fuel cell stack also includes a second flow pipe that receives a
cathode exhaust gas flow from the first stage and fresh cathode gas flow,
where the cathode exhaust gas flow and the fresh cathode gas flow are
combined and sent to a second stage of the plurality of stages of the
fuel cell stack. The tube bundle flow restriction is positioned within
the second flow pipe and controls the flow of the cathode gas flow to the
second stage, where the flow restriction provides a laminar flow through
the control valve to the second stage.