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

Jerry E Beam

John F Leonard

Rengasamy Ponnappan

John E Leland

Elliot B Kennel

Edward T Mahefkey

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 rotor structure for an electrical generator, motor or the like is described which comprises a rotatable generally cylindrically shaped heat pipe defining an internal vapor chamber having an evaporator end and a condenser end, a plurality of radial fins regularly spaced on the periphery of the heat pipe, each fin defining an internal chamber communicating with and extending radially from the vapor chamber, a vaporizable liquid disposed within said heat pipe, and a heat exchanger in thermal contact with the condenser end of the heat pipe.

Rotor cooling structure

A new method for making a heat pipe wick and arteries includes drilling. Radial holes around the circumference of the heat pipe container at its ends and stringing monofilament polymer lines inside the container between corresponding holes. The container is rotated at a slow rate while a slurry of nickel powder mixed into a viscous binder of water, Polyox and Methocel is injected inside the container to cover the inside surface of the container and the lines. The rotational rate of the container is then increased to force the slurry to level out to an uniform depth set by the thickness of sleeves attached at each end of the container. Forced air is blown through the inside of the rotating pipe to dry the slurry and form a green wick. After stopping rotation of the pipe, it is then heated inside a sintering oven in a reducing atmosphere to disintegrate the binder and polymer lines and to leave a sintered metal wick having hollow longitudinal arteries.

Method of manufacturing heat pipe wicks and arteries

A new method for making a sintered metal heat pipe wick is practiced by mixing nickel powder into a slurry with a viscous binder comprising water. Polyox and Methocel. The mixture is then injected inside a rotating stainless steel cylindrical heat pipe container, or pipe, to completely coat the inside surface of the pipe. The rotational rate of the pipe is then increased to force the slurry to level out to a uniform depth set by the thickness of sleeves attached at each end of the pipe. Forced air is then blown through the inside of the rotating pipe to dry the slurry and form a green wick. After stopping rotation of the pipe, it is then heated inside a sintering oven in a reducing atmosphere to disintegrate the binder and leave a sintered metal final composition of the wick. Thus produced wicks prevent 'hot spots' because they have a more uniform thickness and are attached more evenly and securely than prior art heat pipe wicks to the inside walls of the heat pipe container.

Method of manufacturing heat pipe wicks

A thermal storage apparatus for use with space-based burst power supplies. Lithium hydride is encapsulated within spherical hollow capsules. Each capsule is made of a three layer hollow shell. The inner layer of each shell is molybdemum, the middle layer silicon carbide, and the outer layer molybedum. The lithium hydride occupies only about sixty percent of the interior volume of each capsule at ambient temperatures to allow for thermal expansion. The outer diameter of each capsule is 3 cm. The thickness of the layers is 0.1 mm for the inner and outer layer, and 0.3-0.5 mm for the middle layer. The capsules are arranged in a packed array for use in heat storage. A heat transfer working fluid, such as lithium, sodium or potassium, transfers heat to and from the packed array.

Lih thermal storage capsule/heat exchanger

A heat pipe with an improved wick design has an unheated section of greater wick wall thickness next to the evaporator section of the heat pipe and on the opposite side of the evaporator section from the condenser section. The greater wick wall thickness acts as a reservoir of liquid heat pipe working fluid to prevent dry out of the wick during pulsed high thermal energy transfer conditions and to eliminate the need to enforce quasisteady state heat input requirements during start-up operation.

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Beavercreek, OH, United States of America

Jerry E Beam