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Numerical Simulation of Cavitating Flows with Thermodynamic Effects

Farajollahi, Amir Hamzeh | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43235 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Hejranfar, Kazem
  7. Abstract:
  8. In this study, the numerical simulation of cavitating flows for cryogens fluids is performed. The algorithm employs the homogenous, multiphase Euler/Navier-Stokes equations with the interface capturing method. The thermodynamic and thermal effects substantially impact the cavitation dynamics of cryogenic fluids and therefore these effects should be considered by solving the energy equation in conjunction with the mass and momentum conservation, and updating the fluid physical properties. Here, two cavitation modeling strategies, namely, the barotropic cavitation model and the transport equation-based model are used. Both laminar and turbulent cavitating flows are studied in this work. For turbulence flow computations, the algebraic two-layer Baldwin-Lomax (BL) turbulence model is used. The system of governing equations for both the cavitation modeling strategies is discretized using a central difference finite volume scheme. To account for density jumps across the cavity interface, the numerical dissipation terms with suitable density and pressure sensors are employed. A preconditioning technique is implemented to reduce the stiffness of the system of equations and to improve the performance of the solution algorithm in modeling cavitating flows. Numerical simulations of cavitating flows by employing real fluid properties of liquid nitrogen, liquid hydrogen and liquid oxygen over 2D and axisymmetric geometries for different conditions are carried out and the results obtained are compared with the available numerical and experimental results. Results reveal that the thermal effects are demonstrated under consistent conditions by the reduction in cavity length and the increase in effective cavitation number. The study shows that the solution algorithm presented is accurate and robust for predicting cavitating flows of cryogenic fluids
  9. Keywords:
  10. Mass Transfer ; Cavitation ; Precondition Algorithm ; Cryogenic Fluids ; Modified Barotropic Model

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