Abstract :In most of the investigations on energy loss and friction factor of internal flow, circular tube is applied due to their wide availability and practicality. However, in some advanced engineering applications such as miniaturization of electrical devices, microscale heat pipes and medical tubes, the polygonal cross-sectional tube is often deployed. To investigate the flow energy requirement and flow characteristics of polygonal pipe,
numerical simulation assisted by CFD commercial software ANSYS Fluent has been conducted. Stress-Strain Transport k-? model has been applied to resolve the sensitivity of non-slip wall. In our simulation, we have considered water flow across the pentagon, hexagon and heptagon at turbulent region of Re from 5×105 to 5×106. Our simulation found that power lost will increase with respect to smaller number of polygonal edges. At low Reynolds number, the power loss will be generally higher too.