Loading...

Numerical Investigation of Cavity Control with Utilization of Artificial Cavity Generator

Peyvastenejad, Amin | 2018

2760 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51490 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Javadi, Khodayar
  7. Abstract:
  8. Cavitation is a phenomenon that liquid turns into vapor in constant temperature. Cavitation has been assorted into variant models that cloud cavitation is one of them. Cloud cavitation has an unsteady regime which shed cavity into its surrounding that contribute to oscillations, shocks and efficiency reduction of hydrodynamic machines. Triping of boundary layer for enhancing turbulent intensity is a method for preventing cloud cavitation. In this thesis firstly we have simulated boundary layer on 2D NACA0015 hydrofoil with 8 degree attack angle and no cav( ) condition. According to laminar separation location, we have placed some artificial cavity generator(ACG) with size of boundary layer order on hydrofoil surface, investigateing cavtation behavior on hydrofoil with and without ACG on cloud cavitation condition( ). For cavitaion numerical simulation we have used PISO algorithm with RANS turbulence model (k-ω SST) using open source solver openFoam 3.x. scince RANS models solely are not capable of capturing cloud cavitation, corrections has been implemented according to Rebuid et al. in this thesis four ACG with 0.12,0.15,0.3,0.3 millimetre size placed respectively on 0.088C, 0.115C, 0.257C, 0.275C where C is chord length. Locations on 0.088C and 0.275C with their respective size did not much impacted oscillations jumps on lift versus time diagram, albeit declined FFT (fast fourier transform) amplitude of lift versus time diagram with respect to no ACG FFT amplitude of lift versus time. Regarding to 0.257C with 0.3 mm size, it had comparatively good effect in declining sudden oscillation jumps in lift versus time diagram and FFT amplitude of lift versus time with respect to no ACG FFT amplitude of lift versus time. But the location at 0.115C with 0.15mm size, had great impact on damping lift versus time sudden jumping oscillation and had approximately 90% reduction on FFT aplitude of lift versus time diagram with respect to no ACG FFT ampllitude of lift versus time
  9. Keywords:
  10. Artificial Cavitation Generator ; Rebound Effect ; OpenFOAM Software ; NACA 0015 Ainfoil ; Cloud Cavitation ; Cavitation Control

 Digital Object List

 Bookmark

...see more