Pressure loss analysis in 90 degree pipe elbows

In this study, it is aimed to investigate three-dimensional turbulent flows numerically in sharp pipe elbows and rounded pipe elbows with circular cross-sections. The main objective is to see the main differences between the sharp pipe elbow and rounded pipe elbow models and to present results that can be used as a reference for further studies. Another objective of this study is to identify the model that minimizes the pressure loss. The elbow with a circular cross-section has a radius of 0.15 m and 0.125 m, whereas the inlet and outlet lengths of both elbows are 2 m, respectively. The radius of curvature is between 0.125 m and 0.75 m, respectively. The RNG (renormalization group) k-epsilon model was applied as a turbulence model. The reason for using this model is explained in detail. Elbow losses were also investigated along with the effect of the flow velocity and bending radius on these losses. Furthermore, the pressure contours, turbulence contours, velocity contours, velocity streamline and velocity vectors obtained from the numerical results were compared with each other by considering the pipe diameter, bending diameter ratio and flow velocity. In addition, head loss, inlet pressures, pressures along the pipe due to the elbows of all cases were tabulated and graphed. According to the results, significant amounts of losses were prevented through the utilization of the bending radius on the elbows and losses decreased until bending diameter ratio was 5; however, no further decrease was observed after that.