`Experiments were performed to study the heat transfer enhancement in a round tube using wire coils as turbulators. The present study investigates the effects of length and segmentation of the wire coil. Experiments were conducted for three different wire coils (1,000, 500, and 300 mm)on the effect of length. The wire coils used to measure the effect of segmentation were three different types, and, total lengths of these wire coils were all the same (500 mm x 1, 100 mm x 5, and 50 mm x 10). The wire coils were made from 1.5 mm diameter copper wire. The test fluid was water. Both heat transfer and friction factor were measured, and are compared with each other. As a result, the heat transfer and the friction factor decrease with increasing clearance. The heat transfer correlations are given as Eq. (7) in the case of the effect of the length, and Eq. (10) in the case of the segmentation.