| Summary: | 碩士 === 國立成功大學 === 材料科學(工程)學系 === 85 === The fluid flow、heat transfer and gas entrapment
phenomena during the die casting process have great
effects on the qualities of die castings. In this
study, efforts have been made to develop a three dimensional
mathematical model to simulate the die casting process,
including the flow pattern of molten metal in the shot
sleeve and during mold filling, heat transfer during mold
filling and the related defect prediction. The system is aimed
to help die casting engineers to determine optimal
plunger speed in the die casting operation and optimal
gating/running system as well as overflow/venting system in the
die casting die. In the first part of this study
an integrated fluid flow and heat transfer analysis
system was developed and an actual gear pump die casting was
tested to illustrate how the filling proceed、velocity
and temperature distribution during filling and when
and where the gas entrapment would occur during the low
speed die casting process. The simulated results were also
verified by water model experiments. In
the second part of this study a three dimensional analysis
system with variable space regular mesh was developed
to numerically simulate the flow pattern of molten
metal in the shot sleeve in a cold chamber die casting machine.
The results of the simulations were compared to the water model
experiments and data published by the North American
Die Casting Association to assure the accuracy of the
program. With the aid of the system, it is possible to
determine the optimal plunger speed in the die casting
operation.
|
|---|
