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Metal Casting Technologies : June 2007
49 METAL Casting Technologies June 2007 in the Fig. 5, the numerical simulation results and the experimental results are showing a good agreement. Fig. 6 shows the flow patterns in the shot sleeve for the plunger speed of 70cm/sec. As the plunger starts to move, the molten metal in front of the plunger is suppressed high and the top surface of the molten metal touches the upper wall of the shot sleeve. After that, the molten metal pushes the air in front of the melt wave and exhausts the air from the shot sleeve. In the case of fill rate of 30%, it has been reported from several previous studies that the air in the shot sleeve is exhausted desirable by the wave propagation of molten metal in critical plunger speed 65cm/sec. The critical plunger speed is very close from this case plunger speed condition. And so, in this case, the vortex shedding phenomenon from which the molten metal flow is separated from the top wall of the shot sleeve is seen. It is not too serious yet, however, compared with the vortex shedding phenomenon in more higher plunger speed. From the comparison with the two cases, the results from the numerical simulations and experiments are corresponding very well. CONCLUSIONS In this study, numerical simulation system for the flow pattern analysis in the shot sleeve is developed and the accuracy of the numerical simulation is compared with the experimental observations from a water model. In the numerical simulation system, the moving wall is treated as the second fluid in the multi-phase flow calculations. From this study, we have the following conclusions: 1) Air void region in the shot sleeve is appeared when the plunger speed is 30 cm/sec with fill rate of 30%. This plunger speed is less than the critical plunger speed, 65 cm/sec. 2) In the case of plunger speed 70 cm/sec, the vortex shedding phenomenon, which means that the molten metal flow is separated from the top wall of the shot sleeve, is seen. 3) The developed numerical simulation system for the flow pattern analysis in the shot sleeve is very useful to determine the proper condition of the plunger speed in some range of the molten metal fill rate. References 1. K. Fukizawa and H. Shiina, J. Soc. Auto. Eng. Jpn. 46(5), 1992, pp. 66. 2. A. Kaye and A. Street, Die Casting Metallurgy, Butterworths, London, 1982, pp. 231-235. 3. B. D. Nicholas and C. W. Hirts et. al, Tech. Report LA- 8355, Los Alamos Scientific Lab., 1980. 4. R. A. Stoehr and C. Wang, MCWASP, 1991, pp. 725-732. 5. J. H. Kuo, S. M. Pan and W. S. Hwang, MCWASP, San Dego, California, 1998, pp. 149-156. 6. J. R. Brevick, M. Duran and Y. Karni, Transaction of 16th Int. Die Casting Cong. and Expo., 1991, pp. 399-404. The author's of this paper are from the Center for e-Design, KITECH (Korea Institute of Industrial Technology), 994-32, Dongchun-Dong. Yeonsu-Gu, Incheon, 406-800, South Korea. Fill Rate of Shot Sleeve Plunger speed (cm/sec) 1 30% 30 2 30% 50 3 30% 70 Table 1: The setting of the plunger speed for the water model Belec Lab 3000s Spectrometer EXCELLENT PRECISION & ACCURACY! LOW RUNNING COSTS For more details contact: G & C INSTRUMENT SERVICES PTY LTD Phone: (02) 4981 7255 Fax: (02) 49817244 Email: email@example.com www.gcinstrument.com.au