Loading...

The Investigation of Vortex Generators Effects on the Efficiency of Axial Flow Fans

Shekaridahaj, Morteza | 2022

267 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55073 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Farhanieh, Bijan
  7. Abstract:
  8. The ever-increasing need for energy compels researchers to investigate different manners of energy saving. Aَs we know well, one of the effective ways to save energy is to improve the energy consumption of turbomachinery devices such as axial flow fans. Fans are the most applicable of turbomachinery which supply needed airflow, which can be used in ventilation systems, Cooling systems for cars and machines, smoke extraction, and supply required air for firing. Therefore, improving their efficiency can play a significant role in reducing energy consumption and enhancing energy storage. One of the most critical factors in reducing the efficiency of the fans is the stall phenomenon, which can also lay the groundwork for posing some problems like increasing noises, making fatigue in fan impellers, and increasing the system vibration. The stalling of the axial flow fans is capable of being compared with the situation of the airplane wings during the separation of the boundary layer passing from them. In this situation, with the increasing angle of the attack, the lifting force will first increase; however, it will abruptly decrease when the angle of the attack increases over the critical value because of the separation of the boundary layer flow passing from the wings. By enlisting the helping hand of VGs, we are able to control the boundary layer flow to increase the lifting force of the airplane wing or the fan blade and decrease the drag force exerted on them. In this way, we can improve the aerodynamic efficiency of the fans and, as a result, reduce energy consumption. In this research, we Investigated two industrial reversible axial flow fans consisting of elliptic blade profiles, which are provided by 8 and 12 blades, respectively. By utilizing the CFD approach and using CFX code as a commercial one, VGs were simulated in two varied configurations due to their chordwise location on the blade. The results indicated that implementing VGs can pave the way for delaying the stall angle. As a result, in the best case for eight blade-fan, enlisting the helping hand of the VGs was able to increase the maximum lift coefficient by about 9.87 percent and decrease the maximum drag coefficient by approximately 43.67 percent
  9. Keywords:
  10. Turbomachines ; Boundary Layer Flow ; Stalling ; Vortex Generators ; Boundary Control ; Axial Fan ; Boundary Layer Separation

 Digital Object List

 Bookmark

No TOC