Multiphase Flows

Multiphase Flows Computation

Multiphase flows involving moving interfaces between different fluids/phases are observed in nature as well as in a wide range of engineering applications. With the rapid progress made in computational techniques, a number of practically relevant fluid dynamics problems can now be computed with high accuracy. However, the multiphase flow computation remains as one of the most challenging problems due to their multiple time and length scales such as capillarity, diffusion/conduction, convection, and solid objects. Furthermore, interface topological changes (i.e. merger/breakup) with steep jumps in fluid properties across a phase boundary and mass/heat transfer challenge the computational techniques.

Binary Collision

<binary drop collision>

ADAM3D; adaptive multiphase 3D flow solver

A 3-D adaptive Eulerian-Lagrangian method is developed, utilizing the stationary (Eulerian) frame to resolve the flow field, and the marker-based triangulated moving (Lagrangian) surface meshes to treat the fluid interface. The multiphase fluid boundary is modeled using a continuous interface method, and the solid boundary is treated by a sharp interface method along with the ghost cell method. Details can be found in this link.

The current implementation includes

  • Marker-based interface tracking
  • Fluid/fluid interface: continuous interface method
  • Solid/fluid interface: sharp interface method with ghost cell methodology
  • Contact line treatment
  • Topological changes (merger, breakups)
  • Adaptive grid

Even though the code is able to handle large variety of flow problems ranging from bubble-droplet dynamics to medical science problems such as drug delivery mechanisms, our present effort focuses mainly on space applications.

Applications in space

Micro-gravity condition in space makes the numerical simulation an indispensable choice in studying space life and exploration due to the experimental difficulties on the ground. Especially, understanding the dynamics of the cryogenic propellants in a spacecraft fuel tank is crucial in designing and operating a spacecraft since it determines the amount of fuel delivered to the combustion chamber as well as influences the spacecraft dynamics due to the shift in its center of mass. For example, during spacecraft landing/docking maneuver and/or engine shutdown/restart, the acceleration can decrease or increase suddenly, and consequently, large sloshing motion of cryogenic propellants appears. Followings are some of our research results.

  • binary drop collision
  • Fuel delivery in micro-gravity condition
  • Sloshing liquid motion caused by a sudden reduction of acceleration
  • Dynamics of the liquid-gas interface due to oscillating gravitational acceleration

<sloshing fuel tank flow due to sudden reduction of acceleration>

<Gravity wave with large single jet by low forcing frequency>

<Capillary wave with small multiple jets by high forcing frequency>

References

  1. Sim, J. and Shyy, W., “3-D Adaptive Eulerian-Lagrangian Method for Gravity- and Capillarity-Induced Flows”, AIAA-2009-1150, 47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, Orlando, Florida, Jan. 5-8, 2009.
  2. Uzgoren, E., Sim, J., and Shyy, W., “Marker-based, 3-D Adaptive Cartesian Grid Method for Multiphase Flow around Irregular Geometries”, Communications in Computational Physics, Vol. 5, (2009), pp. 1-41.
  3. Uzgoren, E., Singh, R., Sim, J., and Shyy, W., “Computational modeling for multiphase flows with spacecraft application,” Progress in Aerospace Sciences, Vol. 43(4-6), 2007, pp. 138-192.
  4. Singh, R.K. and Shyy, W., “Three-Dimensional Adaptive Cartesian Grid Method with Conservative Interface Restructuring and Reconstruction”, Journal of Computational Physics, 224 (2007) 150-167
  5. Ye, T., Shyy, W. and Chung, J.C., “A Fixed-Grid, Sharp-Interface Method for Bubble Dynamics and Phase Change”, Journal of Computational Physics, Vol. 174, (2001), pp. 781-815.
  6. Shyy, W., Udaykumar, H.S., Rao, M.M. and Smith, R.W. (authors), “Computational Fluid Dynamics with Moving Boundaries”, Taylor & Francis, Washington, DC, (1996, revised printing 1997, 1998&2001); Dover, New York, 2007.
  7. Shyy, W. (author), “Computational Modeling for Fluid Flow and Interfacial Transport”, Elsevier, Amsterdam, The Netherlands, (1994, revised printing 1997); Dover, New York, 2006.

Researchers