Helical coils are used for heating or cooling in process tanks. When a fluid flows through a curved tube, centrifugal force acting upon the various elements of fluid moving with different velocities causes secondary circulation. Secondary flow results in higher heat transfer characteristics. Further, secondary flow stabilizes the laminar flow leading to a higher critical Reynolds number for transition from laminar to turbulent flow.
To determine the friction factor for a fluid flowing through the coil.
To compare Pressure drop in helical coil with that in a straight pipe of same length, inside diameter and surface roughness.