Axial flow heat exchanger devices and methods for heat transfer using axial flow devices
Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.
1. A heat exchanger having a length and a center axis substantially parallel to the length, the heat exchanger comprising:
a heat conducting structure comprising a first cylinder, the first cylinder comprising a first cylindrical surface; and
a heat transfer structure comprising a second cylinder rotatably coupled to the first cylinder to form a gas-filled gap region between the first cylindrical surface of the heat conducting structure and a second cylindrical surface of the heat transfer structure, wherein the second cylinder comprises a first cylindrical wall and a second cylindrical wall parallel to the first cylindrical wall, the first and second cylindrical walls defining a cylindrical region therebetween, and wherein the second cylinder further comprises a plurality of hollow fins disposed inside the second cylinder and configured to rotate about the center axis and to generate flow of a heat transfer medium in a substantially axial direction, the plurality of hollow fins comprising a plurality of respective inner regions, wherein the plurality of hollow fins are attached to the second wall of the second cylinder such that at least one of the inner regions of the fins is fluidly coupled with the cylindrical region of the heat transfer structure.
2. The heat exchanger of claim 1 wherein the heat conducting structure comprises at least one of a metallic material, a heat pipe, or a vapor chamber.
3. The heat exchanger of claim 1 wherein the heat transfer structure is configured to function as a heat pipe.
4. The heat exchanger of claim 1 wherein at least a portion of the heat transfer structure is disposed inside the heat conducting structure.
5. The heat exchanger of claim 1 wherein at least a portion of the heat conducting structure is disposed inside the heat transfer structure.
6. The heat exchanger of claim 1 wherein the gap region comprises a gas maintained at a pressure selected to counteract forces applied to the second surface during rotation of the heat transfer structure.
7. The heat exchanger of claim 1 further comprising a motor coupled to the heat transfer structure and configured to rotate the heat transfer structure relative to the heat conducting structure about a common longitudinal axis of the heat conducting structure and the heat transfer structure.
8. The heat exchanger of claim 1 wherein the first cylindrical wall and the second cylindrical wall are connected by a cap, wherein the cap comprises at least one of a bellows, a flexure, or a corrugated wall.