The Effect of Adding FFST on Secondary Flow Characteristics Near Endwall of Asymmetry Airfoil (Case Study of different camber)

摘要

Energy loss of the flow passed the end wall junctions airfoil caused by the 3D flow separation. One method to reduce this energy loss by adding a Forward Facing Step Turbulent Generator (FFST) was placed on the upstream leading edge. This research aims to study the changes of 3D flow characteristics through end wall junctions of asymmetry airfoil with different camber (British 9C7/22.5C50 and British 9C7/42.5C50) with and without the addition of FFST. This study were conducted experimentally and numerically confirmed by CFD. In experiments to analyze shear stress line obtained through techniques of Oil Flow Visualization at Re_L 1.64 × 10~5. Numerical methods performed are 3-D with viscous model is k-ε Standard, to analyze of the distribution velocity-vector and distribution of isototal pressure loss coefficient at exit. The results showed that the addition of FFST can increase the turbulence intensity in the flow near endwall. So that the flow through the lower side is be able to follow the contour of body airfoil and curling flow in the trailling edge is weaker. In addition, the separation point on the upper side is delayed, so that the wake is narrower and blockage occurs (energy loss) can be reduced. This condition occurs in both weak and strong blade camber. At the British 9C7/22.5C50, the effectiveness of the addition of FFST occurs in angle-of-attack 8°.