# US 10,309,733 B2 · Apparatus and method for increasing boiling heat transfer therein > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,733 B2 - Document ID: US10309733B2 - Status: Granted - Kind: B2 - Application number: 14/383,346 - Filed: 2013-05-24 - Published: 2015-03-12 - Granted: 2019-06-04 - Earliest claimed: 2012-05-24 - Assignees: Purdue Research Foundation - Applicants: Purdue Research Foundation - Inventors: Tae Young Kim; Suresh V. Garimella - Web page: https://patentgrep.com/patent/US10309733B2 ## CPC - F28F 13/187: {especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites} - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) ## Abstract An apparatus and a method of enhancing boiling heat transfer therein capable of increasing both the critical heat flux and nucleate boiling heat transfer of a working fluid. The method includes placing free particles on a surface so as to define narrow corner gaps and cavities at interfaces between the particles and the surface and heating the surface while the surface is contacted by the working fluid to bring the working fluid to a boil, with the result that bubble nucleation is facilitated and nucleate boiling heat transfer from the surface is increased. ## Claims ### Claim 1 A method of increasing boiling heat transfer from a surface, the method comprising: placing free particles on a surface so that the free particles are not affixed to the surface and are free to move on and relative to the surface, the free particles defining narrow corner gaps and cavities at interfaces between the free particles and the surface; and heating the surface while the surface is contacted by a working fluid to bring the working fluid to a boil and cause the free particles to continuously move on and relative to the surface, at least some of the free particles remaining in contact with the surface and the narrow corner gaps and cavities thereof facilitating bubble nucleation and increasing nucleate boiling heat transfer from the surface; wherein the free particles comprise at least a first group of the free particles having first diameters and at least a second group of the free particles having second diameters that are different from the first diameters, wherein the first diameters are sized to increase the critical heat flux of the working fluid and the second diameters are sized to decrease the temperature necessary to facilitate bubble nucleation in the working fluid. ### Claim 2 (depends on 1) The method of claim 1, wherein heating the surface causes translational or rolling motions of the free particles. ### Claim 3 (depends on 1) The method of claim 1, the method further comprising using the working fluid in a phase-change process to cool an apparatus. ### Claim 4 (depends on 3) The method of claim 3, wherein the apparatus is chosen from the group consisting of industrial engines, industrial reactors, industrial plants, electronics, and electromechanical systems. ### Claim 5 (depends on 1) The method of claim 1, wherein the free particles are spherical. ### Claim 6 (depends on 1) The method of claim 1, wherein the free particles are non-spherical. ### Claim 7 (depends on 1) The method of claim 1, wherein the working fluid is water. ### Claim 8 (depends on 7) The method of claim 7, wherein the free particles have average diameters that are millimeter-sized. ### Claim 9 (depends on 7) The method of claim 7, wherein the average diameters are between about three and about six millimeters. ### Claim 10 (depends on 1) The method of claim 1, wherein the working fluid is a fluorocarbon. ### Claim 11 (depends on 10) The method of claim 10, wherein the working fluid is perfluorohexane. ### Claim 12 (depends on 10) The method of claim 10, wherein the free particles have average diameters that are micrometer-sized. ### Claim 13 (depends on 10) The method of claim 10, wherein the average diameters are about ten micrometers. ### Claim 14 (depends on 1) The method of claim 1, wherein the free particles placed on the surface are in a quantity to promote boiling over the entirety of the surface during boiling. ### Claim 15 (depends on 1) The method of claim 1, wherein the free particles form a layer on the surface having a thickness approximately equal to a diameter of one of the free particles. ### Claim 16 (depends on 1) The method of claim 1, wherein the free particles placed on the surface are in a quantity adapted to substantially cover the entirety of the surface during boiling. ### Claim 17 (depends on 1) The method of claim 1, wherein the free particles are formed of a material that is more conducting than the working fluid. ### Claim 18 (depends on 1) The method of claim 1, wherein the free particles have a weight sufficient for the free particles to remain on or near the surface during boiling. ### Claim 19 (depends on 1) The method of claim 1, wherein the surface is a portion of an apparatus chosen from the group consisting of industrial engines, industrial reactors, industrial plants, electronics, and electromechanical systems. ### Claim 20 A method of increasing boiling heat transfer from a surface, the method comprising: placing free particles on a surface so that the free particles are not affixed to the surface and are free to move on and relative to the surface, the free particles defining narrow corner gaps and cavities at interfaces between the free particles and the surface; and heating the surface while the surface is contacted by a working fluid to bring the working fluid to a boil and cause the free particles to continuously move on and relative to the surface, the narrow corner gaps and cavities facilitating bubble nucleation and increasing nucleate boiling heat transfer from the surface; wherein the free particles comprise at least a first group of the free particles having first diameters and at least a second group of the free particles having second diameters that are different from the first diameters, wherein the first diameters are sized to increase the critical heat flux of the working fluid and the second diameters are sized to decrease the temperature necessary to facilitate bubble nucleation in the working fluid. ### Claim 21 (depends on 20) The method of claim 20, the method further comprising using the working fluid in a phase-change process to cool an apparatus chosen from the group consisting of industrial engines, industrial reactors, industrial plants, electronics, and electromechanical systems. ### Claim 22 (depends on 20) The method of claim 20, wherein the first group is placed on the surface in a different quantity than the second group. ### Claim 23 An apparatus comprising: a heated surface; a working liquid in contact with the surface; and free particles submerged in the working fluid and located on the surface but not affixed to the surface so that the free particles are free to move on and relative to the surface, the free particles defining narrow corner gaps and cavities at interfaces between the free particles and the surface, wherein the working fluid is boiling as a result of heat transfer from the surface to the working fluid and causes the free particles to continuously move on and relative to the surface, and wherein bubble nucleation and an increase in nucleate boiling heat transfer from the surface are facilitated by the narrow corner gaps and cavities of at least some of the free particles that remain in contact with the surface; wherein the free particles comprise at least a first group of the free particles having first diameters and at least a second group of the free particles having second diameters that are different from the first diameters, wherein the first diameters are sized to increase the critical heat flux of the working fluid and the second diameters are sized to decrease the temperature necessary to facilitate bubble nucleation in the working fluid. ### Claim 24 (depends on 23) The apparatus of claim 23, wherein the apparatus is chosen from the group consisting of industrial engines, industrial reactors, industrial plants, electronics, and electromechanical systems.