Abstract: A thermal control apparatus including a body defining a centerline axis extended along a height and a circumferential direction extended relative to the centerline axis. The body forms a flow circuit therethrough, an inlet opening, and an outlet opening each in fluid communication with the flow circuit. The flow circuit is extended in parallel flow arrangement along the circumferential direction from the inlet opening to the outlet opening. A cavity is extended at least partially through the body along the centerline axis. A thermal control system includes the thermal control apparatus, a fluid flow device configured to provide a flow of heat transfer fluid to the apparatus through the inlet opening and to receive the flow of heat transfer fluid from the outlet opening of the apparatus, and a flow conduit providing fluid communication of the flow of heat transfer fluid between the fluid flow device and the apparatus.

Abstract: A heat exchanger for an aircraft includes an inlet plenum housing defining an inlet plenum configured to receive a fluid and an outlet plenum housing defining an outlet plenum configured to discharge the fluid. Furthermore, the heat exchanger includes a core configured to heat or cool a first portion of the fluid, with the core defining a plurality of fluid passages extending from the inlet plenum to the outlet plenum. Moreover, the heat exchanger includes a passive bypass defining a passive bypass flow path fluidly coupled to and extending between the inlet plenum and the outlet plenum. As such, the passive bypass flow path is in parallel with at least a portion of the core such that a second portion of the fluid bypasses at least a portion of the core and flows continuously and unobstructed through the passive bypass flow path to the outlet plenum.