CATEGORIES FOR ARTICLE LINKS BELOW

Radiator Fins

Increasing the radiator fin count, or number of fins per inch, provides more surface area for the transfer of heat to the cooling air. However, increasing the fin count increases the restriction of the radiator to cooling airflow. Lower cooling airflows result in lower heat transfer. In every installation there is an optimum combination of fin performance and core restriction that will produce maximum heat transfer. Increasing the core restriction from this optimum point by increasing fin count will reduce the heat transfer performance of the radiator. On the other hand, if the original radiator has a very low fin count, increasing will improve heat transfer. In general, for high performance applications, fin counts from 12 fins per inch to 16 fins per inch are optimum. Increasing the fin count above 16 fins per inch will almost always result in reduced heat transfer performance. Since, as we have seen, in a given installation under “steady-state” conditions the radiator must transfer the given heat load no matter what, the reduced heat transfer performance resulting from an excessively restrictive high fin count must be compensated for by increased coolant temperature, possibly to the point of overheating.

Radiators may be made with plate fins. In this case, the tubes are inserted through stacks of relatively flat fins that have tube holes in them. The tube holes in the fins have collars on them which help to provide the solder or braze bond between the fins and tubes. These collars tend to limit the fin spacing to a maximum of about 13 fins per inch.

Radiators may also be made with serpentine fins. In this case, rows of tube are stacked with layers of corrugated fins. The fins become bonded to the tubes where the tips of the fin convolutions touch the tubes during solder baking or brazing. Soldered plate fin radiators are usually structurally stronger that soldered serpentine radiators and are more expensive to manufacture. Brazed serpentine radiators are usually stronger structurally that nay soldered radiator.

Radiator fins, whether plated or serpentine types, may be louvered or non-louvered. Louvered fins turbulate the air passing through the radiator to increase the “scrubbing action” of the cooling air, providing greatly improved heat transfer with some increase in air restriction. Louvered fins also tend to become clogged with dust and debris more readily than non-louvered fins, but for high performance applications are the only way to go. Non-louvered fins are typically used on farm and construction equipment, operating in dirty environments. Non-louvered fins may be made with patterns of dimples, waves, or bumps in order to provide turbulation without clogging.

Core Depth and Number of Rows of Tubes

-IMPROVEMENT RULE- #4 Increasing the fin count may help, but it may hurt. Increasing the count above 16 fins per inch will almost always hurt.

-IMPROVEMENT RULE- #5 A plate fin radiator and a serpentine fin radiator of the same fin count, tube size, tube rows, face area, core depth, etc., will have the same heat transfer performance. However, serpentine fin radiators can be made with higher fin counts, sometimes resulting in improved performance.

-IMPROVEMENT RULE-#6 Louvered fins provide greatly improved heat transfer with some increase in cooling air restriction. Changing from a non-louvered radiator to a louvered radiator core almost always improves heat transfer performance.

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