-There are the grooves inside tubes. It increases the heat transfer surface area and effects the flow field near a wall. In this case it enhances the heat transfer. -The heat transfer coefficient increases about one time -The pressure drop in a internally finned tube is only 20% higher than that of a plain. -It draws heat of water outside tube and reduces the temperature of water when refrigerant is boiling in tube. Chiller with the internally finned tubes can be used in condition. -In general the internally finned tube is manufactured into straight, given length and hardness according to a design.
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