Centrifugal casting is a process of producing castings by causing molten metal to solidify in rotating moulds.  The quality of the final centrifugal casting is mainly depending upon the flow pattern of the molten metal and flow pattern interm depends upon the rotational speed of the casting.

When the molten metal is poured onto the surface of a rotating centrifugal casting mold   all of it is not picked up immediately. The friction between the molten metal and the mold leads to rotational velocity which is imparted to the liquid. During this the rate of cooling of the hot metal is rapid due to the turbulent flow where fluid and the mould rotate at different speeds. After the inner surface of the mold is covered fully by a thin layer of melt, the rest of it experiences a drag. With the optimum spinning speed, all the metal is picked up and held firmly in the mold wall forming a uniform thickness liquid cylinder that finally solidifies. But solidification rate is slower compared to earlier because of negligible relative velocity between the liquid and the cylinder.  Hence at speeds below the critical speed, liquid fails to form a uniform cylinder leading to imperfect casting. Excessive speed of rotation also produces a poor casting because of hot tear.

Since relative velocity between the rotating mould and the fluid is an important parameter which affects the cooling rate of molten metal in centrifugal casting it is very much required to focus on to cooling rate of the molten metal at different mold speeds. But the Centrifugal casting process is a rapid process with mould & melt being opaque it is not possible to visualize the flow patterns. And also during solidification the density of the liquid metal is continuously increases. But from brief survey of the literature, it is surprising to note that many investigations have been directed at the solution of a particular case and no attempts have been made for generalization. Hence it is necessary to make preliminary examinations of the nature of the flow of fluids in a partially filled rotating cylinder at various speeds to study the various fluid patterns and also the rate of cooling at different rotational speeds. And further the simulation of the process has to be carried out.
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