Flow control device for axial flow turbomachines in series

A flow control device for constraining fluid flow between high hub to tip ratio axial flow turbomachines in series comprising:

• a flow constrainer having a first end and a second end, the first end having a diameter substantially equal to a diameter of a drive assembly of a first high hub to tip ratio axial flow turbomachine housed in a first housing, and the second end having a diameter substantially equal to a diameter of a hub of a second high hub to tip ratio axial flow turbomachine housed in a second housing, the flow constrainer being attached only to the first and second housings;
• wherein, when the first and second housings are joined and the flow control device is situated between the first and second high hub to tip ratio axial flow turbomachines, the flow constrainer occupies a volume defined by substantially all the space extending between the drive assembly of the first high hub to tip ratio axial flow turbomachine and the hub of the second high hub to tip ratio axial flow turbomachine, and the flow control device constrains fluid flow downstream of the first high hub to tip ratio axial flow turbomachine to a plurality of blades attached to the hub of the second high hub to tip ratio axial flow turbomachine.