고분자와 공기의 다상유동을 고려한 캐비티 내 공기 벤팅의 컴퓨터 모사

우정우; 최성현; 류민영; Jeong Woo Woo; Sung Hyun Choi; Min-Young Lyu

Polymer(Korea), Vol.43, No.6, 816-823, November, 2019

DOI10.7317/pk.2019.43.6.816 Export Citation

고분자와 공기의 다상유동을 고려한 캐비티 내 공기 벤팅의 컴퓨터 모사

Air Venting Simulation for Multiphase Flow of Polymers and Air in the Cavity of a Mold

우정우, 최성현, 류민영 ^{1, †}

한국타이어 중앙연구소
¹서울과학기술대학교 기계시스템디자인공학과

Jeong Woo Woo, Sung Hyun Choi, and Min-Young Lyu^{1, †}

Hankook Tire Technodome, 50, Yuseong-daero 935beon-gil, Yuseong-gu, Daejeon 34111, Korea
¹Department of Machanical System Design Engineering, Seoul National University of Science and Technology, 232 Gongneungro, Nowon-gu, Seoul 01811, Korea

E-mail:

초록

금형의 캐비티를 이용한 고분자 성형공정에서는 캐비티 내 공기의 벤팅이 중요하다. 부적절한 공기의 벤팅은 성형품에 충전부족, 탄화자국 등의 불량을 일으킨다. 따라서 캐비티 내에 재료가 채워질 때 벤트의 위치 및 크기에 따라 공기의 벤팅이 적절한지 예측하고 평가하는 방법이 필요하다. 본 논문에서는 가변 벤팅 홀을 포함하는 캐비티내에서 재료의 유입에 의한 공기의 벤팅 현상을 다상유동을 고려하여 컴퓨터 모사를 시도하였다. 컴퓨터 모사를 통해 시간에 따라 변하는 재료와 공기의 경계면을 예측하였다. 그리고 재료가 캐비티 내에 채워지면서 공기가 재료에 밀려서 벤팅부로 빠져나가는 현상을 분석하였다. 벤팅부에서 공기의 압력과 속도분포를 이용하여 벤팅의 적절함을 평가할 수 있다

Air venting is important in the polymer shaping process, which uses the cavity of a mold. Inadequate air venting invokes a short shot and burn marks in the product. Therefore, it is necessary to evaluate and predict the venting performance according to the vent location and size when the material is introduced into the cavity. In this study, a computer simulation was performed considering the multiphase flow to examine the venting phenomena when the material flows into the cavity, which is equipped with varying venting hole. The computer simulation predicted the interface variation between the material and air as a function of time. The air venting phenomena was analyzed when the occupying material pushed air into the cavity. The suitability of venting can be evaluated using pressure and velocity distribution of air in the venting region.

Keywords:air venting;multiphase flow;variable vent hole;computer simulation;venting velocity

[References]

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Rider WJ, Kothe DB, J. Comput. Phys., 141, 112 (1998)
Tezduyar TE, Compos. Pt. A-Appl. Sci. Manuf., 195, 2983 (2006)
Sussmam M, Smereka P, Osher S, J. Comput. Phys., 114, 146 (1994)
Chang YC, Hou TY, Merriman B, Osher S, J. Comput. Phys., 124, 449 (1996)
Cho MH, Choi HG, Yoo JY, Trans. Korean Soc. Mech. Eng. B, 32, 754 (2008)
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Zhou L, Liu DY, Ou CQ, Eng. Appl. Comput. Fluid Mech., 5, 127 (2011)

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[1] Rosato DV, Rosato DV, Rosato MG, Injection molding handbook, 3rd Ed., Springer Science & Business Media, NewYork, 2012.

[2] Lotti C, Ueki MM, Bretas RES, J. Inject. Mold. Technol., 6, 157 (2002)

[3] Mo JH, Kim HJ, Lyu MY, Elast. Compos., 38, 295 (2003)

[4] Joo ST, Kim YH, Lyu MY, Trans. Mater. Process., 10, 525 (2001)

[5] Lim KH, Korean Chem. Eng. Res., 48(4), 490 (2010)

[6] Song BC, Kim SR, Kang YG, Ham MH, J. Korean Soc. Manuf. Process Eng., 10, 117 (2011)

[7] Woo JW, Yang KM, Lyu MY, Elast. Compos., 51, 263 (2016)

[8] Hirt CW, Nichols BD, J. Comput. Phys., 39, 201 (1981)

[9] Ghosh S, Bull HB, Biochim. Biophys. Acta, 66, 150 (1963)

[10] Broje V, Keller AA, J. Colloid Interface Sci., 305(2), 286 (2007)

[11] Mark JE, Polymer data handbook, Oxford University Press, NewYork, 1999.

[12] Belytschko TB, Kennedy JM, Nucl. Eng. Des., 49, 17 (1978)

[13] Kim SJ, Lim KH, Kim C, Korean-Aust. Rheol. J., 18, 109 (2006)

[14] Myong HK, Trans. Korean Soc. Mech. Eng. B, 33, 443 (2009)

[15] Lee KJ, Yang KS, Kang CW, J. Comput. Fluids Eng., 15, 99 (2010)

[16] Kim JE, Myong HK, J. Computat. Fluids Eng., 11, 14 (2006)

[17] Rider WJ, Kothe DB, J. Comput. Phys., 141, 112 (1998)

[18] Tezduyar TE, Compos. Pt. A-Appl. Sci. Manuf., 195, 2983 (2006)

[19] Sussmam M, Smereka P, Osher S, J. Comput. Phys., 114, 146 (1994)

[20] Chang YC, Hou TY, Merriman B, Osher S, J. Comput. Phys., 124, 449 (1996)

[21] Cho MH, Choi HG, Yoo JY, Trans. Korean Soc. Mech. Eng. B, 32, 754 (2008)

[22] Kim SJ, Hwang WR, J. Comput. Phys., 225, 615 (2007)

[23] Zhou L, Liu DY, Ou CQ, Eng. Appl. Comput. Fluid Mech., 5, 127 (2011)