An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly. The engine assembly may include a first monolithic body segment and a plurality of second monolithic body segments directly coupled or directly couplable to the first monolithic body segment. The first monolithic body segment may define a combustion chamber and a recirculation pathway in fluid communication with the combustion chamber. The recirculation pathway may be configured to recirculate combustion gas through the combustion chamber. The plurality of second monolithic body segments may respectively define at least a portion of a piston chamber and a plurality of working-fluid pathways fluidly communicating with the piston chamber.

A heat exchanger for a gas turbine engine includes a heat exchanger body having a first surface and a second surface oriented at least partially at an oblique angle relative to the first surface. The heat exchanger body defines a plenum extending between the first and second surfaces. Furthermore, the heat exchanger body defines a fluid passage extending through the second surface such that the fluid passage is in fluid communication with the plenum. The fluid passage, in turn, includes first and second portions. The first portion intersects the plenum at an intersection and defines a line of projection extending normal to the second surface. The second portion defines a line of projection extending normal to the first surface. The fluid passage further includes a curved portion extending from the first portion to the second portion.

A multilayered material system includes at least one of a liner sheet and a cellular core, and a multilayered composite joined to the at least one of a liner sheet and a cellular core. The multilayered composite includes hollow microspheres dispersed within a metallic matrix material.

A heat exchanger includes a core. The core includes a first layer and a second layer. The first layer includes a first plurality of fluid inlets. The second layer includes a second plurality of fluid inlets. The heat exchanger also includes a fluid header attached to the core adjacent the first plurality of fluid inlets and the second plurality of fluid inlets. The fluid header includes an inlet, an outlet, a plenum between the inlet and the outlet, and a flow control mechanism within the plenum. The flow control mechanism selectively directs fluid through the first plurality of fluid inlets, through the second plurality of fluid inlets, or through both the first plurality of fluid inlets and the second plurality of fluid inlets.

A heat exchanger assembly includes a first member defining fluid passages therein for a first heat exchanger fluid. A second member defines fluid passages therein for a second heat exchanger fluid. The second member is engaged to the second member with an interference fit. A method of assembling a heat exchanger includes thermally resizing at least one of a first heat exchanger member and a second heat exchanger member and assembling the second heat exchanger member to the first heat exchanger member. The method includes thermally equalizing the first and second heat exchanger members to engage the second heat exchanger member to the first heat exchanger member with an interference fit.

A heat exchanger assembly includes a first member defining fluid passages therein for a first heat exchanger fluid. A second member defines fluid passages therein for a second heat exchanger fluid. The second member is engaged to the second member with an interference fit. A method of assembling a heat exchanger includes thermally resizing at least one of a first heat exchanger member and a second heat exchanger member and assembling the second heat exchanger member to the first heat exchanger member. The method includes thermally equalizing the first and second heat exchanger members to engage the second heat exchanger member to the first heat exchanger member with an interference fit.

An apparatus and method of forming a heat exchanger includes forming a monolithic core body having a first set of flow passages and a core coefficient of thermal expansion, and additively manufacturing onto the monolithic core a first manifold defining a first fluid inlet for the first set of flow passages.

An apparatus and method of forming a heat exchanger includes forming a monolithic core body having a first set of flow passages and a core coefficient of thermal expansion, and additively manufacturing onto the monolithic core a first manifold defining a first fluid inlet for the first set of flow passages.

A core body includes a structure having a plurality of connected unit cells. At least one unit cell has one or more sidewalls that are curved and define a portion of an inner passageway within and through the unit cell. The one or more sidewalls define multiple orifices and include a cone disposed between at least some of the orifices. A dimple is defined along an outer surface of the unit cell at the cone. The outer surface at least partially defines an outer passageway that is sealed from the inner passageway by the one or more sidewalls. The one or more sidewalls are configured to transport one or more of thermal energy from a first fluid or a component of the first fluid flowing in the inner passageway to a second fluid flowing in the outer passageway without the first fluid mixing with the second fluid.

A method of manufacturing a heat exchanger. The method includes additively manufacturing a first body with a first plurality of passages extending through the first body. Additively manufacturing a second body with a second plurality of passages extending through the second body. The method also includes, interlocking the first body with the second body such that the first plurality of passages is aligned with the second plurality of passages and fluidically connected with the second plurality of passages.