Numerical investigations of laminar flow in coiled pipes

Numerical investigations were done to understand forced laminar fluid flow in rectangular coiled pipes with circular cross-section and characterized by pipe straightness, curvature and torsion. The focus was addressed on exploring the flow pattern and temperature distribution through the pipe. Computer simulations were performed for four rectangular coiled pipes with different angles of the straight tube inclination (9°, 15°, 30° and 45°) at different inlet velocities. The shape of the secondary motions was found to be strongly associated with the axial momentum which depends in turn on the geometric configuration of the pipe. The results show remarkable effects of the straight-tubes inclination on the flow behavior and better heat transfer performance is observed for the coil with smaller angle of straight tube inclination. The results and observations are in a good agreement with the available numerical and experimental works on laminar flow in helical coil pipes.