Numerical and experimental investigation of the thermal performance characteristics of different types of turbulators placed in the pipe

In this study, numerical and experimental investigation of the effects of different types of turbulent generating elements placed in the pipe on heat transfer and pressure drop was investigated by the method called the passive heat transfer enhancement technique. In line with this goal, a three-stage analysis was carried out, the first two being numerical and the third experimental. In the first stage, equilateral triangular cross-section helical wires of different steps are placed in the pipe, and in this examination, pitch ratios (p/D = 1, 2, and 3), section lengths (a = 5 and 6 mm), and distances of helical wires between the pipe wall. (s=1, 2 mm) as a basis, helical wires in equilateral triangular cross-sections were examined as single, double, and triple by a numerical method, inspired by DNA geometry, and the results obtained for single helical wire were confirmed by experimental results in the literature. In order to determine how advantageous the improvement in heat transfer is, the performance evaluation criterion (PEC) value was calculated and the highest PEC was obtained as 1.98 at a low Reynolds number and s=1 mm, a=6 mm, p/D=1. In the second examination, it was determined that the constant pitch ratio of square helical wires (p/D =1), three different wall-wire distances (s=1, 2, and 3 mm), and different edge lengths (a=3, 4, and 5 mm). The effect on heat transfer improvement was investigated by a numerical method. In the CFD program, triangular helical wires and square helical wires were both analyzed using the periodic method and k- turbulence modeling. The highest PEC of 1.36 was obtained when Re=5500, a=5 mm, and s = 1 mm. In the third study, the effect of curved fin-type turbulators on heat transfer improvement was experimentally investigated. In this context, 12 different modified turbulators were produced. The parameters that distinguish the turbulators from each other are blade angle (15°, 30°), blade direction (positioned parallel to or opposite the flow), and positioning of the blades in one open and one closed manner. It was observed that it was higher than It has been observed that the performance of turbulators placed with the blade opening facing the flow is higher than the performance of turbulators placed opposite the flow. The highest PEC = 1.79 obtained in the experimental analysis was obtained for the lowest Reynolds number, 16213. In addition, thanks to the control circuit added to the experimental setup, the results were determined more accurately and safely.