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H ydrodynamic Properties of Annular Cavitator

H ydrodynamic Properties of Annular Cavitator. Presenter: Ming-dong LIN. College of Aerospace Sci. & Tech. N ational U niversity of D efense T echnology Changsha, CHINA. 1. Backgrounds. 2. Numerical Method. 3. Results & Discussion. 4. Conclusion. Contents. CAV2012, Singapore.

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H ydrodynamic Properties of Annular Cavitator

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  1. Hydrodynamic Properties of Annular Cavitator Presenter: Ming-dong LIN College of Aerospace Sci. & Tech. National University of Defense Technology Changsha, CHINA

  2. 1. Backgrounds 2. Numerical Method 3. Results & Discussion 4. Conclusion Contents NUDT CAV2012, Singapore

  3. Navigation styles underwater • Supercavitating • Drag∝ V2 • Rocket propulsed • Ultrahigh speed • (>200Kn) • Fully Wetted • Drag∝ V3 • Propellor • Low speed • (<70Kn) Backgrounds Revolution CAV2012, Singapore NUDT

  4. Backgrounds • Studies of supercavitating flow • Logvinovich (IHM, Ukraine) proposed the theorem of Independence of Caivity Section Expension, which is testified by many experiments. CAV2012, Singapore NUDT

  5. Backgrounds • Studies of supercavitating flow • Kunz, Lindau, et.al (APL, The Pennsylvania State University, US) improved numerical method for both partial and fully developed supercavities, and coupled the flow simulation with the vehicle trajectory. CAV2012, Singapore NUDT

  6. Backgrounds • Studies of supercavitating flow • Hydrodynamic properties of different cavitators were tested by Kuklinski(NUWC, US). CAV2012, Singapore NUDT

  7. Backgrounds • Critical technologies of long distance supercavitating flight • Supercavitating hydrodynamics • Water ramjet propulsion system • Advanced motion control strategy CAV2012, Singapore NUDT

  8. Backgrounds • Hydrodynamic properties of annular cavitator Supercavity annular cavitator with water injection of “Shkval-E” water ramjet ? CAV2012, Singapore NUDT

  9. Numerical Method A. Governing equations The continuity, momentum equations of mixture: The continuity equation of the vapor: The mixture property: CAV2012, Singapore NUDT

  10. Numerical Method • B. Rayleigh-Plessetcavitation model • C. Standard turbulence model CAV2012, Singapore NUDT

  11. Numerical Method • Vehicle model • Computational grids 10cm 20cm 2m vehicle • 500,000 grids CAV2012, Singapore NUDT

  12. Numerical Method • Computation setting Table 1. Differenct CFD models and boundary conditions CAV2012, Singapore NUDT

  13. Drag Hydrodynamic properties of annular cavitator Pressure field Cavity size Injecting flow Results & Discussions CAV2012, Singapore NUDT

  14. Results & Discussions • Pressure field Stagnation ring moves outward Stagnation ring is stable Pressure distributions on cavitator surface CAV2012, Singapore NUDT

  15. Results & Discussions • Drag Table 2. Forces acted on cavitator region Increase with tube size Increase with outlet pressure CAV2012, Singapore NUDT

  16. Results & Discussions • Injecting flow Mass flow and velocities in different cases CAV2012, Singapore NUDT

  17. Results & Discussions • Cavity size Decrease with tube size Increase with outlet pressure CAV2012, Singapore NUDT

  18. Conclusions • Pressure distribution changes significantly on cavitatorsurface which results in the increase of the drag. • The injecting flow is proportional to the tube size, and decreases with the outlet pressure. • Compare with disk, the annular cavitator generates smaller cavity. The cavity size decreases with the tube size and increases with the outlet pressure. CAV2012, Singapore NUDT

  19. Thank You ! College of Aerospace Science and Technology National University of Defense Technology

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