Abstract: Prior art recuperators or heat exchangers have been restricted in use to only part speed and power application when adapted for use with high pressure gas turbine engine. The present recuperator or heat exchanger has been adapted for use with a high pressure ratio gas turbine engine. The recuperator includes a plurality of air cells being formed by a plurality of primary surface sheets. The primary surface sheets define a first surface and a second surface and has a plurality of corrugations formed therein. Each of the plurality of corrugations has a crest and a root extending from the respective first surface and second surface a preestablished axial distance. The preestablished axial distance from the crest to the first surface being unequal to that of the preestablished axial distance from the root to the second surface.

Abstract: Circular heat exchangers have been used to increase the efficiency of engines by absorbing heat from the exhaust gas and transferring a portion of the exhaust heat to the intake air. The present heat exchanger is built to be more efficient, to better resist the internal forces and pressures and to better withstand the thermal stress from the cyclic operation of the engine. The core has a plurality of heat recipient passages therein which have a uniform cross-sectional area throughout the entire length of the passage. And the core further has a plurality of heat donor passages therein which have a uniform cross-sectional area throughout the entire length of the passage.

Abstract: Circular heat exchangers have been used to increase the efficiency of engines by absorbing heat from the exhaust gases and transferring a portion of the exhaust heat to the intake air. The present heat exchanger is built to better resist the internal forces and pressures and to better withstand the thermal stress from the cyclic operation of the engine. The plurality of evenly spaced individual tension rings are positioned about the outer portion of the core and the plurality of compressive hoops which are positioned at the inner portion of the core resisting the forces which are attempting to separate the passages. The rings and the hoops are in contact with the core and totally in heat transferring relationship with the donor fluid. The rings further expand and contract in response to the temperature changes of the donor fluid and maintain a preestablished force on the core of the heat exchanger.

Abstract: Circular heat exchangers have been used to increase the efficiency of engines by absorbing heat from the exhaust gases and transferring a portion of the exhaust heat to the intake air. The present heat exchanger is built to better seal the cooler recipient fluid from the heated recipient fluid and the donor fluid within the operation of the heat exchanger. The circular heat exchanger is also easily removable from the engine should repair or servicing be required. The manifold is interwoven between the inlet ports and the outlet ports and sealingly separates the cool recipient fluid from the heated recipient fluid. The tongue and groove compensates for the expansion and contraction of the core due to the thermal variations imputed by exhaust from the engine and compensate for such thermal variations.

Abstract: Circular heat exchangers have been used to increase the efficiency of engines by absorbing heat from the exhaust gases and transferring a portion of the exhaust heat to the intake air. The present heat exchanger is built-up from a plurality of preformed involute curved cells stacked in a circular array to provide flow passages and for the donor fluid and the recipient fluid respectively. The stacked cells are welded along a portion of their edges to secure them in the stacked circular array. Each of the cells have a plurality of corners with the core presenting corresponding corners after the cells are welded together. In order to reinforce the core against thermal stresses and forces generated by pressures of the fluids, circumferential welds are provided at each of the corners.

Abstract: The restraint systems presently used with existing heat exchangers or recuperators have a thermal growth rate different than the thermal growth rate of the core of the recuperator. The present thermally balanced restraint system overcomes the problem of a different growth rates by utilizing tie rods which are individually made of a plurality of small diameter rods has a thermal growth rate very near that of the core of the heat exchanger. As the plates of the core thermally expand and contract in response to the heat from the engine exhaust, the plurality of small diameter rods also expand and contract at a rate very near that of the core.