Isothermal Two-Fluid Based CFD of Solid-Liquid Slush Flows for Propulsion Systems

Slushes are two-phase solid-liquid single-species cryogenic fluids that exhibit an increased density and a greater heat capacity with respect to normal boiling point fluids. This promising features are of large interest for applications that exploit the slush as a thermal fluid, like super magnets refrigeration or air conditioning, and for aerospace systems that use slush fluids as fuel or oxidizer. Several programs in the frame of the research on Slush Hydrogen (SLH2) as a new-generation fuel for aerospace propulsion system have been started in the past and still continue to be performed at the present. In this work we present a numerical simulation based on a finite-volumes discretization using the software library OpenFOAM and a two-fluid model carried on solid-liquid multiphase flows (slurry) and slush flows inside a typical pipe geometry, very common in propulsion pipelines. A benchmark with previous experiments and simulations is also performed to assess the degree of accuracy of the code in predicting pressure drops and solid phase fraction dispersion. The effects of particle size, inlet velocity and concentration is also investigated.