Jet engine exhaust augmentation unit

Claim 2

A jet engine exhaust augmentation unit comprising a longitudinally extending augmentation tube having an inlet for receiving the exhaust from a jet engine and an outlet, recycling means for returning a portion of the exhaust from the augmentation tube outlet for reintroduction into the inlet thereof for combination with the jet engine exhaust, and a water injection system for injecting water into the jet engine exhaust for lowering the temperature of the exhaust out of the augmentation tube outlet.

Claim 3

A jet engine exhaust augmentation unit according to claim 1 wherein the recycling means comprises a return shroud having a forward coupling for close coupling a jet engine thereto in alignment with the augmentation tube.

Claim 4

A jet engine exhaust augmentation unit according to claim 2 wherein the forward coupling provides for introducing secondary augmentation air around the jet engine into the inlet of the augmentation tube.

Claim 5

A jet engine exhaust augmentation unit according to claim 1 further comprising secondary air inlet means for introducing secondary air into the inlet of the augmentation tube for combination with the jet engine exhaust.

Claim 6

A jet engine exhaust augmentation unit according to claim 4 wherein the total mass flow rate of the additional fluid introduced into the augmentation tube inlet is no less than the mass flow rate of the jet engine exhaust.

Claim 7

A jet engine exhaust augmentation unit according to claim 1 further comprising a rear discharge conduit having a forward inlet opening in alignment with the augmentation tube for discharging from the augmentation unit the remainder of the exhaust from the augmentation tube outlet.

Claim 8

A jet engine exhaust augmentation unit according to claim 6 wherein the augmentation tube comprises a rear divergent nozzle section with a rear outlet opening in alignment with the discharge conduit inlet opening.

Claim 9

A jet engine exhaust augmentation unit according to claim 7 wherein the rear outlet opening of the divergent nozzle section is larger than and is spaced forwardly of the forward inlet opening of the discharge conduit.

Claim 10

A jet engine exhaust augmentation unit according to claim 8 wherein the recycling means comprises an annular concave deflector for substantially reversing the flow of said returned portion of the exhaust from the augmentation tube outlet.

Claim 11

A jet engine exhaust augmentation unit according to claim 1 wherein the water injection system provides for injecting sufficient water to reduce the temperature of the jet engine exhaust out the augmentation tube outlet to approximately 212* F.

Claim 12

A jet engine exhaust augmentation unit according to claim 1 wherein the water injection system provides for injecting water into the augmentation tube for lowering the temperature of the jet engine exhaust.

Claim 13

A jet engine exhaust augmentation unit according to claim 1 wherein the water injection system provides for injecting water into said returned portion of the exhaust as it is returned for reintroduction to the tube inlet.

Claim 14

A jet engine exhaust augmentation unit according to claim 1 wherein the augmentation tube outlet comprises a plurality of generally radial openings in a rear portion of the augmentation tube.

Claim 15

A turbojet engine exhaust augmentation unit for a turbojet engine test cell comprising a housing with an elongated shroud having a forward opening for receiving a turbojet engine and a rear discharge conduit with a forward inlet opening substantially larger than and in alignment with the rear exhaust opening of the turbojet engine, an elongated augmentation nozzle mounted within the shroud intermediate of and in alignment with the turbojet engine and discharge condUit and having a forward inlet opening for receiving the turbojet engine exhaust and a rear divergent nozzle section with a rear outlet opening in alignment with and forwardly of the discharge conduit inlet opening, the augmentation nozzle forming with the elongated shroud a substantially annular recirculating passage around the nozzle for returning a portion of the exhaust from the rear outlet opening of the nozzle to its forward inlet opening, and water injection means for injecting water into the engine exhaust for lowering the temperature of the exhaust out the rear nozzle outlet opening, the augmentation nozzle being dimensioned so that the engine exhaust flow through the nozzle provides for drawing said returned exhaust portion into the nozzle inlet opening for augmentation of the engine exhaust.

Claim 16

A turbojet engine exhaust augmentation unit for a turbojet engine test cell comprising a housing with an elongated shroud having a forward opening for receiving a turbojet engine and a rear discharge conduit with a forward inlet opening substantially larger than and in alignment with the rear exhaust opening of the turbojet engine, an elongated augmentation nozzle mounted within the shroud intermediate of and in alignment with the turbojet engine and discharge condUit and having a forward inlet opening for receiving the turbojet engine exhaust and a rear divergent nozzle section with a rear outlet opening in alignment with and forwardly of the discharge conduit inlet opening, the augmentation nozzle forming with the elongated shroud a substantially annular recirculating passage around the nozzle for returning a portion of the exhaust from the rear outlet opening of the nozzle to its forward inlet opening, and water injection means for injecting water into the engine exhaust for lowering the temperature of the exhaust out the rear nozzle outlet opening, the augmentation nozzle being dimensioned so that the engine exhaust flow through the nozzle provides for drawing said returned exhaust portion into the nozzle inlet opening for augmentation of the engine exhaust.

Claim 19

A method of augmenting jet engine exhaust in a jet engine test cell according to claim 15 further comprising the step of aspirating secondary air into the jet engine exhaust at a mass flow rate substantially less than the mass flow rate of the exhaust and water mixture aspirated into the jet engine exhaust.