Hydrodynamic Properties of Annular Cavitator College of Aerospace Sci. & Tech. National University of Defense Technology Changsha, CHINA Presenter: Ming-dong LIN
LOGO NUDT Contents 1. Backgrounds 2. Numerical Method 3. Results & Discussion 4. Conclusion CAV2012, Singapore
LOGO CAV2012, Singapore Backgrounds Fully Wetted Drag ∝ V 3 Propellor Low speed (<70Kn) Navigation styles underwater Supercavitating Drag ∝ V 2 Rocket propulsed Ultrahigh speed (>200Kn) Revolution NUDT
LOGO CAV2012, Singapore Backgrounds Studies of supercavitating flow Logvinovich ( IHM, Ukraine ) proposed the theorem of Independence of Caivity Section Expension, which is testified by many experiments. NUDT
LOGO CAV2012, Singapore 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. NUDT
LOGO CAV2012, Singapore Backgrounds Studies of supercavitating flow Hydrodynamic properties of different cavitators were tested by Kuklinski (NUWC, US). NUDT
LOGO CAV2012, Singapore Backgrounds Critical technologies of long distance supercavitating flight Supercavitating hydrodynamics Water ramjet propulsion system Advanced motion control strategy NUDT
LOGO CAV2012, Singapore Backgrounds Hydrodynamic properties of annular cavitator ? Supercavity water ramjet annular cavitator with water injection of “Shkval-E” NUDT
LOGO Numerical Method CAV2012, Singapore NUDT A. Governing equations The continuity, momentum equations of mixture: The continuity equation of the vapor: The mixture property:
LOGO Numerical Method CAV2012, Singapore NUDT B. Rayleigh-Plesset cavitation model C. Standard turbulence model
LOGO CAV2012, Singapore Numerical Method Vehicle model Computational grids vehicle NUDT 2m 10cm 20cm 500,000 grids
LOGO CAV2012, Singapore Numerical Method Computation setting NUDT CaseP out [MPa]D tube [cm]CaseP out [MPa]D tube [cm] Table 1. Differenct CFD models and boundary conditions
LOGO Results & Discussions Hydrodynamic properties of annular cavitator Cavity size Pressure field Injecting flow CAV2012, Singapore NUDT Drag
LOGO Results & Discussions CAV2012, Singapore NUDT Pressure field Pressure distributions on cavitator surface Stagnation ring moves outward Stagnation ring is stable
LOGO Results & Discussions CAV2012, Singapore NUDT Drag CaseF cav [N]F tube [N]F total [N]Increment[%] Table 2. Forces acted on cavitator region Increase with tube size Increase with outlet pressure
LOGO Results & Discussions CAV2012, Singapore NUDT Injecting flow Mass flow and velocities in different cases
LOGO Results & Discussions CAV2012, Singapore NUDT Cavity size Decrease with tube size Increase with outlet pressure
LOGO Conclusions CAV2012, Singapore NUDT Pressure distribution changes significantly on cavitator surface 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.
College of Aerospace Science and Technology National University of Defense Technology