Patent Application
20120227949
The present invention relates to heat exchangers, and more particularly to a heat exchange structure configured to operate in an air stream.
Heat exchangers are devices used transfer heat from one medium to another. For example, in a heat exchanger, air may flow over a coil carrying hot engine coolant, and heat from the coil may be released into the air. Common applications for heat exchangers include air conditioning, refrigeration, space heating, power plants, chemical plants, sewage treatment, and car radiators.
Heat exchangers come in many forms, and can have different structures depending on the heat load to be transferred and the environment in which the heat exchanger is used. Efficient heat exchangers are able to transfer large amounts of heat from one medium to another. Typical heat exchange structures have surfaces such as walls separating heat transfer fluids from one another.
The flow paths of the heat transfer fluids can be arranged in various ways. Some heat exchangers have channels that carry the heat transfer fluids in two different directions that are substantially perpendicular to one another. For example, as shown in
The coolant flow portions 16 have closed surfaces 17 that are broadside to the air stream 14, so that the coolant fluid 18 can flow through the coolant flow portions 16 in a direction perpendicular to the flow of the air stream 14. In typical heat exchangers, the closed surfaces 17 are blunt, flat-faced surfaces. As a result, when the air stream 14 enters the air flow portions 12, the air experiences a pressure drop due to flow separation occurring at the blunt closed surfaces 17 of the coolant flow portions 16. Therefore, typical heat exchangers may be inefficient for operation in an air stream, because the pressure of the air entering the heat exchanger may be reduced.
Accordingly, there is a need for a heat exchange structure that can transition air through a heat exchanger with less pressure drop.
The present invention relates to heat exchangers, and more particularly to a heat exchange structure configured to operate in an air stream. The efficiency of a heat exchanger can be improved by decreasing the resistance to fluid flow through the heat exchanger. In one embodiment, a heat exchange structure includes coolant flow portions having a substantially closed surface directed into an air stream, and air flow portions having air passages directed into the air stream. The substantially closed surfaces of the coolant flow portions have aerodynamic shapes at their leading edges. The aerodynamic shapes of the closed surfaces facilitate the flow of air through the air flow portions and decrease the pressure drop of the air flowing through the heat exchanger.
In one embodiment, a heat exchange structure configured to operate in an air stream includes coolant flow portions, each of the coolant flow portions having at least one substantially closed surface directed into the air stream; and air flow portions disposed between adjacent coolant flow portions for receiving air from the air stream, the air flow portions having air passages directed into the air stream; the substantially closed surface of the coolant flow portions having an aerodynamic shape.
The substantially closed surface may be at a leading edge of the coolant flow portions directed into the air stream. The substantially closed surface may have a shape that is convex into the air stream. Each coolant flow portion may have a trailing edge at an end of the coolant flow portion opposite the leading edge. The trailing edge may have a shape that is tapered rearwardly away from the leading edge.
The heat exchange structure may be configured in a free air stream, in an air duct, or in an air plenum.
In another embodiment, a method of manufacturing a heat exchange structure configured to operate in an air stream includes providing coolant flow portions, each of the coolant flow portions having at least one substantially closed surface; arranging the coolant flow portions such that the substantially closed surface is directed into the air stream; providing air flow portions between adjacent coolant flow portions, the air flow portions having air passages for receiving air from the air stream; arranging the air flow portions such that the air passages are directed into the air stream; and configuring the substantially closed surface of the coolant flow portions to have an aerodynamic shape.
The step of configuring the substantially closed surface of the coolant flow portions to have an aerodynamic shape may further include designing the aerodynamic shape to be convex into the air stream. The method of manufacturing the heat exchange structure may further include designing each of the coolant flow portions to have a trailing edge at an end opposite the substantially closed surface, wherein the trailing edge has a shape that is tapered rearwardly away from the substantially closed surface.
The present invention relates to heat exchangers, and more particularly to a heat exchange structure configured to operate in an air stream. The efficiency of a heat exchanger can be improved by decreasing the resistance to fluid flow through the heat exchanger. In one embodiment, a heat exchange structure includes coolant flow portions having a substantially closed surface directed into an air stream, and air flow portions having air passages directed into the air stream. The substantially closed surfaces of the coolant flow portions have aerodynamic shapes at their leading edges. The aerodynamic shapes of the closed surfaces facilitate the flow of air through the air flow portions and decrease the pressure drop of the air flowing through the heat exchanger.
As shown in
In other words, in
The additional shapes 23 and 25 also increase the available surface area for heat transfer along the leading and trailing edges of the coolant flow portions 26. As a result, the coolant flow portions 26 in
Each of the coolant flow portions 46 has a rounded shape 43 at a leading edge followed by a sharp, tapered shape 45 at a trailing edge. The rounded shape 43 at the leading edge of each coolant flow portion 46 is convex into the air stream 44. As such, flow separation in the air stream 44 can be reduced, because the air clings to the aerodynamic surfaces of the rounded shapes 43, rather than separating. In addition, the tapered shape 45 at the trailing edge of each coolant flow portion 46 draws the air flowing into the air passage past the surface of the coolant flow portion 46, toward the exit of the air passage. Accordingly, the aerodynamic shapes 43 and 45 of the coolant flow portions 46 may facilitate the transition of air through the heat exchange structure. While in
A heat exchange structure according to embodiments of the present invention may be used in various types of heat exchangers, such as heat exchangers configured to operate in a duct or a plenum. In addition, a heat exchange structure according to embodiments of the present invention may be used in a heat exchange apparatus configured to operate in a free air stream, as described in U.S. Patent Application No. ______, filed concurrently with this application, which is incorporated herein by reference.
According to another embodiment of the present invention, a method of manufacturing a heat exchange structure configured to operate in an air stream includes providing coolant flow portions, each of the coolant flow portions having at least one substantially closed surface, arranging the coolant flow portions such that the substantially closed surface is directed into the air stream, providing air flow portions between adjacent coolant flow portions, the air flow portions having air passages for receiving air from the air stream, arranging the air flow portions such that the air passages are directed into the air stream, and configuring the substantially closed surface of the coolant flow portions to have an aerodynamic shape.
In one embodiment, the step of configuring the substantially closed surface of the coolant flow portions to have an aerodynamic shape further includes designing the aerodynamic shape to be convex into the air stream. The method may further include the step of designing each of the coolant flow portions to have a trailing edge at an end opposite the substantially closed surface, wherein the trailing edge has a shape that is tapered rearwardly away from the substantially closed surface.
As this invention has been described herein by way of exemplary embodiments, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that the invention described herein may be embodied other than as specifically described herein. For example, the leading and trailing edges of the coolant flow portions may have any aerodynamic shape, and are not limited to tapered, rounded, and elliptical shapes. Further, it is to be understood that the steps of the methods described herein are not necessarily in any particular order.
