Toroidal coolant-collection manifold

A system for cooling a combustion chamber (32) of an engine, such as a rocket engine, is provided. The system (32) has a plurality of coolant tubes or passages (34) surrounding the combustion chamber (32), a torroidal coolant-collection manifold (36) for receiving coolant from the coolant tubes or passages (34) and for discharging the coolant through a discharge port (40), and a plurality of turning vanes (44) within the torroidal manifold (36) for reducing pressure loss and improving pressure uniformity associated with the torroidal coolant-collection manifold (36).