Question

The flow rate of liquid metal into the downsprue of a mold = 1 liter/sec. the cross-sectional area at the top of the sprue = 800 mm-square and its length = 275 mm. what area should be used at the base of the sprue to avoid aspiration of the molten metal

Answer 1

Flow rate of liquid metal into the downsprue is 1 Litre/sec
e.g., Rate of flow of liquid metal { R } = 10⁶ mm³/ sec [ actually, 1Litre = 1000 cm³ , so, 1Litre = 1000 × 1000 mm³ ]
Velocity of metal liquid { V } = $\bold{\sqrt{2gh}}$
Here , g = 9800 mm/sec² [ because g = 9.8 m/s² ]
h = 275 mm
so, velocity of flow of Metal liquid { V } = $\bold{\sqrt{2\times9800\times275}}$
V = 2321.6 mm/sec

Now, for avoid aspiration of molten metal , area should be used at the base = rate of flow of liquid metal /velocity of flow of liquid metal
= 10⁶/2321.6 mm²
= 430.73 mm²

Hence, area should be at the base to avoid aspiration of molten metal is 430.73 mm²