A Numerical Investigation of Unsteady Bubbly Cavitating Nozzle Flows
نویسندگان
چکیده
The effects of unsteady bubble dynamics on cavitating flow through a converging-diverging nozzle are investigated numerically. A continuum model that couples the Rayleigh–Plesset equation with the continuity and momentum equations is used to formulate unsteady, quasi-one-dimensional partial differential equations. Flow regimes studied include those where steady-state solutions exist, and those where steady-state solutions diverge at the so-called flashing instability. These latter flows consist of unsteady bubbly shock waves traveling downstream in the diverging section of the nozzle. An approximate analytical expression is developed to predict the critical backpressure for choked flow. The results agree with previous barotropic models for those flows where bubble dynamics are not important, but show that in many instances the neglect of bubble dynamics cannot be justified. Finally the computations show reasonable agreement with an experiment that measures the spatial variation of pressure, velocity and void fraction for steady shockfree flows, and good agreement with an experiment that measures the throat pressure and shock position for flows with bubbly shocks. In the model, damping of the bubble radial motion is restricted to a simple ‘‘effective’’ viscosity, but many features of the flow are shown to be independent of the specific damping mechanism. © 2002 American Institute of Physics. @DOI: 10.1063/1.1416497#
منابع مشابه
One-dimensional Bubbly Cavitating Flows through a Converging-diverging Nozzle
A non-barotropic continuum bubbly mixture model is used to study the one-dimensional cavitating ow through a converging-diverging nozzle. The nonlinear dynamics of the cavitation bubbles are modeled by the Rayleigh-Plesset equation. Analytical results show that the bubble/bubble interaction through the hydrodynamics of the surrounding liquid has important e ects on this con ned ow eld. One clea...
متن کاملIntroduction One - Dimensional Bubbly Cavitating Flows Through a Converging - Diverging Nozzle
A nonbarotropic continuum bubbly mixture model is used to study the one-dimensional cavitatingjow through a converging-diverging nozzle. The nonlinear dynamics of the cavitation bubbles are modeled by the Rayleigh-Plesset equation. Analytical results show that the bubble/bubble interaction through the hydrodynamics of the surrounding liquid has important effects on this conjined JEow jield. One...
متن کاملAcoustic saturation in bubbly cavitating flow adjacent to an oscillating wall
Bubbly cavitating flow generated by the normal oscillation of a wall bounding a semi-infinite domain of fluid is computed using a continuum two-phase flow model. Bubble dynamics are computed, on the microscale, using the Rayleigh–Plesset equation. A Lagrangian finite volume scheme and implicit adaptive time marching are employed to accurately resolve bubbly shock waves and other steep gradients...
متن کاملNumerical investigation of upward air-water annular, slug and bubbly flow regimes
In this paper, numerical investigation of upward two phase flow of air-water has been studied. Different conditions of flow regimes including annular, wispy annular, slug, churn and bubbly are simulated based on Hewitt and Roberts map, and a good agreement between the experimental data of the map and the numerical simulation has been observed. Accordingly, a proper CFD model in CFD software of ...
متن کامل