Experimental investigation of the effect of conical type turbulations with different designs placed in the pipe on heat transfer

In this study, the effect of conical type turbulators with 3 different conical angles (30°, 35°, and 40°) on heat transfer inside the pipe was investigated. Heat transfer experiments were carried out with turbulators arranged in 3, 6 and 9 sets. In addition, experiments were carried out with air velocities between 1-10 m/sec with 1 m/sec increments. However, since a centrifugal air compressor with a fixed application power was used for air velocities, the upper limit of the air velocity was determined by the power applied by the compressor. ΔP increased with the increase in the air velocity and the number of turbulator obstacles. At the same time, ΔP decreased as the number of holes on the turbulator increased. The decrease occurred in the friction factor as the Reynolds number increased. The most important effect on the friction factor was primarily the number of obstacles. Then, the second most effective factor was determined as the number of holes on the turbulator. The lowest Nusselt number in parallel and counterflow occurred in the 3-turbulator sets with the least obstacles and the highest number of holes. As the number of turbulator obstacles increased and the number of holes on the turbulator decreased, turbulators produced higher convection and the Nusselt number increased. As the taper angle decreased, the Nusselt number increased in both countercurrent and direct flows.