Abstract: An arrangement for supplying coolant flow to turbine blades in a gas turbine engine is disclosed which utilizes a preswirl assembly to impart a tangential velocity to the coolant flow substantially greater than the tangential velocity of the rotor at the point at which the air is supplied to the rotor. The overswirled air is injected radially inwardly into an internal passage contained in the rotor, and the coolant flow continues to be an overswirled condition within the internal passageway. The amount of overswirl imparted to the coolant flow is such that the tangential velocity of the coolant flow is greater than the tangential velocity of the blades at the location on the blades the coolant flow is supplied to the blades for blade cooling, thereby resulting in substantially improved efficiency in the cooling system.