Smoothed Particle Hydrodynamics - Application
Filling a rectangular mould
High pressure die casting (HPDC) is used extensively to fabricate
complex-shaped objects using light metals. Liquid metal is injected at
high speeds under very high pressure. The resulting flow is extremely
complicated, with substantial droplet and fragment formation. HPDC
dynamics are not well understood; poor filling may cause defects that can
lead to high rejection rates.
Such complex free-surface phenomena can be examined numerically using
smoothed particle hydrodynamics (SPH). For the simulations considered
here, emphasis was placed on the physical complexity of the flow, rather
than the geometrical complexity of the mould.
The filling of a 10x50 mm rectangular mould has been computed using
two-dimensional SPH simulations. As shown in the figures below, liquid
metal is forced through the shot sleeve into the gate before jetting into
the mould. The gate constriction increases the pressure and acceleration
of the metal from the piston speed of 3 m/s up to around 50 m/s as it
enters the 1 mm gate. For this example, the liquid is assumed to be
isothermal, and the air initially in the mould is neglected.
Velocity contours of the liquid metal in the shot
sleeve at different times
Despite the simple shape of the mould geometry, the animation below
shows the highly complex nature of the resulting flow. The plots are
coloured according to local velocity magnitude. More details concerning
this application can be found in [1].
Animation of the filling of the
rectangular mould
Reference
[1] P.W. Cleary and J. Ha, SPH modelling of isothermal
high pressure die casting, Proceedings of the 13th Australasian Fluid
Mechanics Conference (Melbourne, 1998), pp. 663-666.
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