Demonstration of Flow Separation in Pipe Elbow Using ANSYS CFD Flotran for Fluid Mechanics Course

The friction in viscous fluid flows in pipe is normally caused by the interaction between the fluid and the internal wall of the pipe. On the other hand, change in the geometry of the flow path by the introduction of elbow in the piping system also contributes the friction in flow, as a result of flow separation, especially if the bend is sharp. In this paper, a study has been made to simulate the flow separation that occurs in pipe elbow, as part of the teaching attribute in the course of Fluid Mechanics. The study has been conducted by using ANSYS CFD Flotran on the water flows in three types of 2-dimensional elbow models of various bending radii. From the simulation, the occurrences of backward flow, which is inter-related with flow separation, are observed. In addition, the effects of the elbow different bending radius to the flow separation can be shown. Demonstration of the flow simulation helps students in better understanding the flow separation phenomenon that occurs in pipe elbow.