United States of America As Represented by the Secretary of the Air Force

John E Leland

Rengasamy Ponnappan

Lanchao Lin

Richard Harris

Jerry E Beam

Elliot B Kennel

Mark S Perry

A passive thermal spreader and method of fabrication are disclosed. The passive thermal spreader includes a heat transfer plate formed from laminated plates including an internal sealed thermosyphon defined within the interface of the plates. The preferred embodiment of the passive thermal spreader selected to illustrate the invention includes a pair of distinct thermosyphons defined within the interface of three laminated, stacked plates. Each thermosyphon includes a plurality of channels arranged boustrophedonically. Each of the channels includes an elongate straight portion and an end turn portion for connection to the adjacent channel elongate straight portion. Each elongate straight portion includes a channel divider. The channel divider directly contributes to the high performance of the thermal spreader of the present invention by assisting the transport of the working fluid.

Passive thermal spreader and method

A finned heat exchanger is disclosed. The heat exchanger includes a unitary fin array with a multiplicity of fin banks. Each of the fin banks include a plurality of raised, folded fins for heat transfer. The fin banks extend in a transverse direction and are spaced apart in a longitudinal direction. The fin banks are retained within the fin array by looped expansion turns. The fin array is mounted on a dielectric substrate base. A closed flow channel for directing a flow of coolant is created by adding a cap to the substrate base.

Finned heat exchanger

A passively cooled electromechanical actuator is disclosed. The passively cooled electromechanical actuator includes a rotor having an output shaft rotatably received within a stator. A pair of inner supports connect the stator to a pair of mounting platforms. The mounting platforms are attached to the inner surfaces of an aircraft wing and are in thermal communication therewith. A pair of closed, capillary tube thermosyphons containing a working fluid are in thermal communication with the stator, the inner supports and the mounting platforms. During operation, the thermosyphons receive heat from the stator and transport it to the mounting platforms whereupon it is convected or radiated to the atmosphere from the aircraft wings. The inner supports have a phase change material received within for providing temporary thermal energy storage during transient conditions.

Cooling of electromechanical actuator with phase change material and thermosyphons containing working fluid

A micro channel heat pipe and method of fabrication are disclosed. The micro channel heat pipe includes a wire cloth wick having micro capillary channels formed by a corrugation extrusion process. The wick is inserted into the heat pipe housing in a shrink fit, enhancing heat transfer. The porous nature of the wire cloth wick permits free passage of the working fluid within both the closed and open micro capillary channels, doubling the number of micro capillary channels available for heat transference.

Micro channel heat pipe having wire cloth wick and method of fabrication

A corrugated fin heat pipe and method of fabrication. The micro channel heat pipe includes a tubular housing split longitudinally into two halves. A pair of corrugated fin elements defining a plurality of adjacent closed and open micro capillary channels are attached to the inner surface of the housing halves. Material is removed from the closed micro capillary channels along a portion of the longitudinal axis to create regions consisting entirely of open micro capillary channels, maximizing heat flux in those regions. The housing halves are reattached and the heat pipe housing is enclosed by a pair of end caps.

Method of making micro channel heat pipe having corrugated fin elements

A new system for removing heat energy from the rotor of a rotating electrical machine is disclosed. Rotating electrical machines include electric motors, electric generators and the like. The cooling system includes the prior art components of an integral heat pipe rotor shaft, that is, a hollow rotor shaft in which an inner cavity is filled with a suitable working fluid to make an integral heat pipe for removing heat from the rotor. The heat pipe includes an evaporator section inside the rotor and a condenser section extending outside the rotor and the electrical machine housing. The present invention adds a spray chamber surrounding the condenser section. The spray chamber is integrated with the electrical machine housing. Liquid coolant enters the spray chamber and is sprayed through nozzles onto the condenser section to remove the heat transferred from the rotor. The liquid coolant may be routed through a preheater before entering the spray chamber.

Spray cooled condenser for an integral heat pipe shaft in high power

A micro consideration of the phase change or boiling cooling of an electronic part is disclosed including focus on a heat exchanging problem that is encountered in the use of this phase change cooling in the presence of realistic flow rates and energy dissipations. The combination of coolant flow and projection of the cooled part into the coolant stream flow is shown to result in difficulties that make such cooling less desirable for electronic and other purposes without use of improvement such as, is achieved in the present invention. Preclusion of these difficulties (involving coolant vapor) by the addition of a small geometric shape or other vapor-considered alterations of the cooled part environment are also disclosed. Results of the achieved improved cooling are shown in graphic relationships. The disclosed invention is couched in terms of electronic part cooling but is applicable to a variety of other heat exchange situations.

Enhanced nucleate boiling heat transfer for electronic cooling and

A pressure vessel for nuclear energy powered thermionic fuel elements is disclosed. An inner cylindrical nuclear fuel heat source is surrounded by cylindrical layers of, in outward order, an emitter, a gap, a collector, an insulator and a cladding layer. A hexagonal pressure vessel surrounds the other parts of the thermionic fuel element and forms liquid metal coolant passages between the inside corners of the hexagon and the cladding. Longitudinally, each thermionic fuel element comprises a middle active zone between two 20% enriched uranium zones to reduce the critical mass of the system for safety. Beryllium zone endcaps act as neutron reflectors and further reduce the critical mass. A plurality of thermionic fuel elements is arrayed into a reactor core with brazed together pressure vessel hexagon sides. In the event of a leak, or other coolant flow failure, the pressure vessel sides act as thermal conduction fins and transfer waste heat to adjacent pressure vessels where coolant flow has not failed.

Thermionic fuel element pressure vessel

A long life, very low friction pump for use in a heat pipe pump or the like is disclosed. A first pump uses magnetically confined ferrofluid rings as both sealer and lubricant for a sliding pump piston in a two sided piston pump that minimizes the seal pressures on both sides of the ferrofluid seals. A second pump uses a magnetically confined ferrofluid slug as a self-sealing and self-repairing pump piston.

Ferrofluid piston pump for use with heat pipes or the like

A long life, very low friction pump for use in a heat pipe pump or the like s disclosed. A first pump uses magnetically confined ferrofluid rings are both sealer and lubricant for a sliding pump piston in a two sided piston pump that minimizes the seal pressures on both sides of the ferrofluid seals. A second pump uses a magnetically confined ferrofluid slug as a self-sealing and self-repairing pump piston.

Growing community of inventors

Kettering, OH, United States of America

John E Leland