Heat Exchanger Assembly

Abstract

A heat exchanger assembly including first and second manifolds for transferring heat between a coolant and a flow of air. Tubes extend between the manifolds for conveying the coolant therebetween. Air fins are disposed between adjacent tubes, and each air fin has a cross-section presenting a legs extending between the adjacent tubes at equal and opposing angles to one another and bases interconnecting alternate ends of the adjacent legs to present a serpentine pattern. Each base extends through an arc between the ends of the adjacent legs and defines a lead-in radius interconnecting each base with one of the legs and an exit radius interconnecting each base with the end of the adjacent leg. The equal and opposing angles are in the range of 1 to 4 degrees. The lead-in and exit radii are in the range of 0.05 to 0.15 mm. The middle radius is in the range of 0.5 to 1.5 mm.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]A heat exchanger assembly for transferring heat between a coolant and a flow of air, and specifically to an improved air fin design.[0003]2. Description of the Prior Art[0004]Japanese Patent Application No. 10365226, issued to Hiroshi et al., shows a heat exchanger assembly for transferring heat between a coolant and a flow of air. The '388 application includes a first manifold and a second manifold, and a plurality of tubes extending in spaced and parallel relationship with one another between the first and second manifolds for conveying the coolant between the first and second manifolds. Adjacent tubes are spaced from one another by a fin space, and a plurality of air fins are disposed in the fin spaces. Each of the air fins has a cross-section presenting a plurality of legs and a plurality of bases interconnecting alternate ends of adjacent legs and engaging the adjacent tubes to present a serpentine pattern. Each of...

AI Technical Summary

Benefits of technology

[0007]The legs of the air fins are angled to maintain the structural integrity of the heat exchanger, i.e. to prevent the legs from collapsing during the manufacturing or use of the heat exchanger. However, the maximum angle is set at 4 degrees to maximize the length of the louvers on the legs of the air fin, and thereby avoid a pressure drop penalty, which results from having shorter louvers. Such a pressure drop negatively impacts the performance of the heat exchanger. Additionally, the angled legs improve the ability of the heat exchanger to shed water.

[0008]The lead-in and exit radii are minimized in order to maximize the length of the louvers, and thereby limit the pressure drop penalty explained above. However, the lead-in and exit radii must be large enough to allow the forming tool to release from the air fin at production speeds.

[0009]Finally, during the brazing process of joining the manifolds, tubes, and air fins together, because the areas of contact between the air fins and the flat sides of the tubes is not flat, but instead has a middle radius, capillary action by the brazing material occurs during the brazing process. In other words, a portion of the liquefied brazing material is pulled along the middle radius of the air fin. Upon cooling, the brazing material solidifies to form a strong fillet bonding the tubes to the air fins. This fillet is not only structurally strong, but it is also thermally conductive, thereby improving heat conduction from the coolant in the tubes to the air fins.

Problems solved by technology

Such a pressure drop negatively impacts the performance of the heat exchanger.

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