Flow Separation Analysis of a Turbine Blade NACA 63-415

Abstract

This paper investigate the flow separation behavior of a turbine blade using NACA 63-415 airfoil in three arrangements- without slot, with single slot, with double slot. Computational fluid dynamic simulation are used to study airfoil behavior at 0 to 20 degree angle of attack.to investigate how separation begins and develops. The study targets determination of significant angle of attack at which the flow separation initiates since it influences both the efficiency and performance of the turbine blade. Important aerodynamics factors like pressure distribution, velocity contours and the impact of turbulence are assesses to determine the change in airfoil patterns. Further the research explores whether slot modification at the leading edge are efficient in controlling or postponing flow separation and hence aerodynamic efficiently can be improved. Single and double slot existence is explored to find their effectiveness in enhancing lift to drag ratio, lowering turbulence intensity and ensuring smoother airfoil on the blade surface. This analysis enables design enhancement for achieving more stable and efficient operation of turbines. This study conclusion promote the design of turbine blade with a target to reduce losses in energy and enhance overall efficiency. The work has major repercussions in industries depending on turbine powered applications. This research supports advancing the durability of turbines, stability of running operations as well as their efficiency in using energy.

Introduction

This research investigates how leading-edge slots affect the aerodynamic performance of turbine blade airfoils, specifically targeting the control of flow separation to improve efficiency. The study compares a reference NACA 63-415 airfoil with single and double leading-edge slot configurations, aiming to delay flow separation, increase lift, and reduce drag.

Key Points:

• Flow Separation: Occurs when the boundary layer detaches from the airfoil surface, causing turbulence that increases drag and reduces lift, negatively impacting turbine efficiency and stability.

• Flow Separation Control: Techniques include geometric modifications (leading-edge slots, vortex generators), surface modifications (roughness, shaping), and active flow control methods (suction/blowing, electrohydrodynamic control). Leading-edge slots energize the boundary layer, maintaining airflow attachment longer.

• NACA 63-415 Airfoil: Chosen for its laminar flow optimization, moderate thickness, and high lift-to-drag ratio, making it suitable for turbine blade applications and flow separation studies.

• Slot Design: Single and double slot configurations are modeled and analyzed to assess their effect on flow attachment and aerodynamic performance at various angles of attack. Double slots potentially offer greater control but are less studied.

• Design and Analysis Process: The airfoil coordinates are plotted and modified in AutoCAD to create slots, then imported into ANSYS for mesh generation and CFD simulations. Mesh refinement near the leading edge and separation zones ensures accurate flow behavior capture.

• Computational Setup: The computational domain is defined to simulate realistic flow conditions with boundary placements ensuring accurate inflow and outflow without interference. Mesh parameters are carefully chosen to balance accuracy and computational efficiency.

The study aims to identify which slot configuration better controls flow separation, ultimately enhancing turbine blade performance in industrial applications.

Conclusion

Here, the control of flow separation over a turbine blade with three different leading edge slot configurations- without slot, with single slot, with double slot has been studied by employing the NACA 63-415 airfoil and CFD software Ansys Fluent. The analysis was performed over a variety of angle of attack range from 0 to 20 degree with a particular focus on learning how these slot arrangements will affect flow behaviour, aerodynamic performance and flow separation. The unslotted design exhibited minimal flow separation at lower AoA but experienced marked separation as AoA increased, particularly at higher angles resulting in a substantial loss of aerodynamic efficiency and an increase in drag. The single slot design showed improvements in flow separation control particularly at mid to high AoA as it retarded the start of separation and stabilized the pressure distribution, leading to lower drag and overall improved performance. Still, the double slot concept was the most beneficial having the best overall flow separation control, especially at higher AoA. This arrangement substantially retarded flow separation, providing a smoother and more uniform airflow over the blade surface which led to enhance aerodynamic performance throughout the entire AoA range. For lower AoA all three designs had similar performance, but when the AoA rose above 10 degree, the single and double slot designs were superior to the no slot design, with the double slot arrangement still having the highest aerodynamic efficiency. This design continually improved the lift to drag ratio and had more controlled flow features which are essential in turbine blade applications where stable and efficient performance must be achieved under a range of operation conditions. From the result, the double slot design proved to be the most suitable option for turbine blade applications, especially for situations calling for reliable and consistent performance under higher AoA.

References

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Copyright

Copyright © 2025 Dr. Ajith V S, Anjitha V, Keerthick K, Praveena Prasannan, Sanika Ram E. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.