Patent Application
20090087604
The invention relates generally to an extruded tube for use in a heat exchanger, and more particularly to an extruded tube including a plurality of deformations formed on at least one surface thereof for use in a heat exchanger.
Heat exchangers are used for changing temperature of various working fluids, such as an engine coolant, an engine lubricating oil, an air conditioning refrigerant, and an automatic transmission fluid, for example. The heat exchanger typically includes a plurality of spaced apart fluid conduits or tubes connected between an inlet tank and an outlet tank, and a plurality of heat exchanging fins disposed between adjacent conduits. Air is directed across the fins of the heat exchanger by a cooling fan or a motion of a vehicle, for example. As the air flows across the fins, heat in a fluid flowing through the tubes is conducted through the walls of the tubes, into the fins, and transferred into the air.
One of the primary goals in heat exchanger design is to achieve the highest possible thermal efficiency. Thermal efficiency is measured by dividing the amount of heat that is transferred by the heat exchanger under a given set of conditions (amount of air flow, temperature difference between the air and fluid, and the like) by the theoretical maximum possible heat transfer under those conditions. Thus, an increase in the rate of heat transfer under a given set of conditions results in a higher thermal efficiency.
Typically, to improve thermal efficiency, the air flow must be improved, a pressure drop through the heat exchanger must be reduced, or a surface area of the tubes must be maximized. Prior art attempts to maximize the surface area of the tubes have had a negative affect on pressure drop within the tube, thus decreasing the thermal efficiency of the heat exchanger.
It would be desirable to produce an extruded tube for a heat exchanger, whereby a thermal efficiency of the heat exchanger is maximized, material usage is minimized, and a durability of the tube is maintained.
Consistent and consonant with the present invention, an extruded tube for a heat exchanger, whereby a thermal efficiency of the heat exchanger is maximized, material usage is minimized, and a durability of the tube is maintained, has surprisingly been discovered.
In one embodiment, an extruded tube comprises a top wall, a bottom wall, and a pair of side walls having at least one flow passageway formed therein; at least one web disposed in the flow passageway and extending from at least one of the top wall and the bottom wall; and at least one deformation formed in at least one of the top wall, the bottom wall, and the side walls.
In another embodiment, an extruded tube for a heat exchanger comprises a top wall, a bottom wall, and a pair of side walls having a plurality of flow passageways formed therein; a web disposed in at least one of the flow passageways and extending from at least one of the top wall and the bottom wall; and a plurality of deformations formed on at least one of the top wall, the bottom wall, and the side walls.
In another embodiment, an extruded metal tube for a heat exchanger comprises a top wall, a bottom wall, and a pair of side walls having a plurality of flow passageways formed therein; a web disposed in each of the flow passageways and extending from at least one of the top wall and the bottom wall; and a plurality of deformations formed on the top wall, the bottom wall, and the side walls.
The above, as well as other objects and advantages of the invention, will become readily apparent to those skilled in the art from reading the following detailed description of a preferred embodiment of the invention when considered in the light of the accompanying drawings in which:
The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner.
The first manifold 12 includes an inlet fitting 22, a plurality of tube openings (not shown) formed therein for receiving the first ends 18 of the tubes 16, and an outlet fitting 24. The inlet fitting 22 is adapted to communicate with a source of coolant (not shown). The tube openings provide fluid communication between the first manifold 12 and the tubes 16. The outlet fitting 24 provides an exit for the coolant flowing through the heat exchanger assembly 10 and is typically in communication with the source of coolant or other storage system. A baffle (not shown) is sealingly disposed in the first manifold between the inlet fitting 22 and the outlet fitting 24 to create a substantially fluid tight seal therebetween.
The second manifold 14 includes a plurality of tube openings (not shown) formed therein for receiving the second ends 20 of the tubes 16. The tube openings provide fluid communication between the tubes 16 and the second manifold 14.
As more clearly shown in
The tubes 16 include a plurality of deformations 38 formed therein. In the embodiment shown, the deformations 38 are formed on the top wall 28 and the bottom wall 30 of the tubes 16. However, it is understood that the deformations 38 can be formed on only one of the top wall 28 and the bottom wall 30, and may also be formed on the side walls 32, 34 of the tubes 16. As shown, the deformations 38 are formed as indentations or recesses in exterior surfaces of the top wall 28 and the bottom wall 30 which form corresponding protuberances or ridges on interior surfaces of the top wall 28 and the bottom wall 30. The deformations 38 are formed on the top wall 28 and the bottom wall 30 in a generally repeating pattern in the embodiment shown, wherein the deformations 38 are formed in alternating flow passageways 26 and are substantially evenly spaced along the length and width W of the tubes 16. It is understood that other patterns can be formed on the tubes 16 as desired. The deformations 38 cause the webs 36 to protrude toward and abut or nearly abut one another.
As shown in
In use, a first fluid (not shown) is caused to flow through the inlet fitting 22 into a first section of the first manifold 12 on a first side of the baffle. The first fluid can be any conventional fluid such as automatic transmission fluid, power steering fluid, or engine oil, for example. The first fluid then flows into the flow passageways 26 of a first set of the tubes 16 through the corresponding tube openings formed in the first section of the first manifold 12. The first fluid contains thermal energy which is transferred to the interior surfaces of the tubes 16 as the first fluid flows through the flow passageways 26. A second fluid (not shown) is caused to flow through the spaces 40 between adjacent tubes 16, and contacts the exterior surfaces of the tubes 16. The second fluid can be any conventional fluid such as air, for example. The thermal energy transferred to the tubes 16 by the first fluid is transferred to the second fluid as the second fluid contacts the exterior surfaces of the tubes 16.
The first fluid then flows into and out of the second manifold 14 in a U-shaped pattern as is known in the art. Upon exiting the second manifold 14, the first fluid flows through a second set of the tubes 16 corresponding to a second section of the first manifold 12 on a second side of the baffle. The first fluid then enters the second section of the first manifold 12 through the corresponding tube openings formed therein, and out of the first manifold 12 through the outlet fitting 24. When flowing through the tubes 16 corresponding to the second section of the first manifold 12, additional heat is transferred from the first fluid to the second fluid as previously described herein.
The deformations 38 formed in the tubes 16 provide additional surface area for the first fluid to contact within the flow passageways 26 of the tubes 16. Further, within each of the flow passageways 26, a fluid boundary layer is caused to detach from the interior surface of the tube 16 at the deformations 38 as the first fluid changes direction. The fluid boundary layer then reestablishes itself and continues to grow downstream of the deformation 38. The fluid boundary layer is caused to detach repeatedly in a periodic pattern. The periodic detachment of the fluid boundary layer and change in fluid direction maximizes the transfer of thermal energy from the first fluid to the interior surface of the tubes 16 by disrupting a laminar flow pattern of the first fluid. Accordingly, a thermal efficiency of the heat exchanger assembly 10 is maximized.
The tube 116 includes a plurality of deformations 138 formed therein. In the embodiment shown, the deformations 138 are formed on the top wall 128 and the bottom wall 130 of the tube 116. However, it is understood that the deformations 138 can be formed on only one of the top wall 128 and the bottom wall 130, and may also be formed on the side walls 132, 134 of the tubes 16 as desired. The deformations 138 are formed as indentations or recesses in exterior surfaces of the top wall 128 and the bottom wall 130, and corresponding protuberances on interior surfaces of the top wall 128 and the bottom wall 130. The deformations 138 are formed on the top wall 128 and the bottom wall 130 in generally repeating patterns in the embodiment shown, wherein the deformations 138 are formed in adjacent flow passageways 126 and are substantially evenly spaced apart along the length and width W2 of the tube 116. It is understood that other patterns of deformations 138 can be formed on the tube 116 as desired, such as a random pattern, for example. The deformations 138 cause the webs 136 to protrude toward and abut or nearly abut one another.
Use of the tube 116 is substantially the same as previously described herein for the tube 16. Similarly, the deformations 138 formed on the tubes 116 provide for additional surface area for thermal energy transferred from the first fluid to the tubes 116. Accordingly, a thermal efficiency of the heat exchanger assembly 10 is maximized.
The tube 216 includes a plurality of deformations 238 formed therein. In the embodiment shown, the deformations 238 are formed on the top wall 228, the bottom wall 230, and the arcuate upper and lower portions 233, 235 of the side walls 232, 234 of the tube 216. The deformations 238 are formed as indentations or recesses in exterior surfaces of the top wall 228, the bottom wall 230, and the arcuate upper and lower portions 233, 235 and corresponding protuberances on interior surfaces of the top wall 228, the bottom wall 230, and the arcuate shaped upper and lower portions 233, 235. The deformations 238 are formed on the top wall 228, the bottom wall 230, and the arcuate shaped upper and lower portions 233, 235 of the side walls 232, 234 in generally repeating patterns in the embodiment shown, wherein the deformations 238 are formed in adjacent flow passageways 226 and on the arcuate shaped upper and lower portions 233, 235 of the side walls 232, 234, and are substantially evenly spaced apart along the length and width W3 of the tube 216. It is understood that other patterns of deformations 238 can be formed on the tube 216 as desired, such as a random pattern, for example. The deformations 238 cause the webs 236 to protrude toward and abut or nearly abut the interior surface of the tube 216.
Use of the tube 216 is substantially the same as previously described herein for the tube 16. Similarly, the deformations 238 formed on the tubes 216 provide for additional surface area for thermal energy transferred from the first fluid to the tubes 216. Accordingly, a thermal efficiency of the heat exchanger assembly 10 is maximized.
The tube 316 includes a plurality of deformations 338 formed thereon. In the embodiment shown, the deformations 338 are formed on the top wall 328 of the tube 316. However, it is understood that the deformations 338 can be formed on the bottom wall 330 and the side walls 332, 334 of the tube 316 as desired. The deformations 338 are formed as indentations or recesses in an exterior surface of the top wall 328 and corresponding protuberances on an interior surface of the top wall 328. The deformations 338 are formed on the top wall 328 in a generally repeating pattern in the embodiment shown, wherein the deformations 338 are formed in alternating flow passageways 326, and are substantially evenly spaced apart along the length and width W4 of the tube 316. It is understood that other patterns of deformations 338 can be formed on the tube 316 as desired, such as a random pattern, for example. The deformations 338 cause the webs 336 to protrude toward and abut or nearly abut one another.
Use of the tube 316 is substantially the same as previously described herein for the tube 16. Similarly, the deformations 338 formed on the tubes 316 provide for additional surface area for thermal energy transferred from the first fluid to the tubes 316. Accordingly, a thermal efficiency of the heat exchanger assembly 10 is maximized.
The tube 416 includes a plurality of deformations 438 formed therein. In the embodiment shown, the deformations 438 are formed in the top wall 428 of the tube 416. However, it is understood that the deformations 438 can be formed in the bottom wall 430 and the side walls 332, 334 as desired. The deformations 438 are formed as indentations or recesses in an exterior surface of the top wall 428 and corresponding protuberances on an interior surface of the top wall 428. The deformations 438 are formed in the top wall 428 in a generally repeating pattern in the embodiment shown, wherein the deformations 438 are formed in the flow passageway 426 and are substantially evenly spaced along the length and width W5 of the tube 416. It is understood that other patterns of deformations 438 can be formed in the tube 416 as desired such as a random pattern, for example. The deformations 438 cause the webs 436 to protrude toward and abut or nearly abut the interior surface of the tube 416.
Used of the tube 416 is substantially the same as previously described herein for the tube 16. Similarly, the deformations 438 formed on the tubes 416 provide for additional surface area for thermal energy transferred from the first fluid to the tubes 416. Accordingly, a thermal efficiency of the heat exchanger assembly 10 is maximized.
From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.
