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An Analysis of the Polymer Melt Flow in Extruder Dies

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๋ฐ˜๋„์ฒด๋””์Šคํ”Œ๋ ˆ์ด๊ธฐ์ˆ ํ•™ํšŒ์ง€ ์ œ12 ๊ถŒ ์ œ2 ํ˜ธ(2013 ๋…„ 6 ์›”) Journal of the Semiconductor & Display Technology, Vol. 12, No. 2. June 2013. 19 ๊ณ ๋ถ„์ž์••์ถœ ๋‹ค์ด์Šค์˜ ์œ ๋™ํ•ด์„ ์ตœ๋งŒ์„ฑ โ€  ยท๊น€๊ด‘์„  โ€  ํ•œ๊ตญ๊ธฐ์ˆ ๊ต์œก๋Œ€ํ•™๊ต ๋ฉ”์นดํŠธ๋กœ๋‹‰์Šค๊ณตํ•™๋ถ€ An Analysis of the Polymer Melt Flow in Extruder Dies Man Sung Choi โ€  and Kwang Sun Kim* โ€  School of Mechatronics Engineering, Korea University of Technology and Education Abstract Extrusion is one of the most important operations in the polymer-processing industry. Balancing the distribution of flow through a die to achieve a uniform velocity distribution is the primary objective and one of the most difficult tasks of extrusion die design. If the manifold in a coat-hanger die is not properly designed, the exit velocity distribution may be not uniform; this can affect the thickness across the width of the die. Yet, no procedure is known to optimize the coat hanger die with respect to an even velocity profile at the exit. While optimizing the exit velocity distribution, the constraint optimization used in this work with allowable pressure drop in the die; according to this constraint we can control the pressure in the die. The computational approach incorporates three-dimensional finite element simulations software STAR- CCM+. These simulations are used with numerical optimization to design polymer coat hanger dies with pressure drop, uniform velocity and temperature variation across the die exit. Key Words : Polymer extrusion, Coat-hanger dies, Flow analysis 1. ์„œ ๋ก  ๊ณ ๋ถ„์ž ์••์ถœํ•„๋ฆ„์˜ ์ œํ’ˆ์„ ์ƒ์‚ฐํ•  ๋•Œ ํ‰ํŒ ๋‹ค์ด ์Šค ๊ฐ€ ์ฃผ๋กœ ์‚ฌ์šฉ๋œ๋‹ค. ๋‹ค์ด์Šค๋Š” ๋‚ด๋ถ€์˜ ์œ ๋กœํ˜•์ƒ์— ๋”ฐ๋ผ T- ๋‹ค์ด์Šค, ํ”ผ์‰ฌ ํ…Œ์ผ(fish tail) ๋‹ค์ด์Šค, ์˜ท๊ฑธ์ด์™€ ๊ฐ™์ด ๊ณก๋ฉด์œผ๋กœ ๋˜์–ด์žˆ๋Š” ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค(coat hanger dies) ๋“ฑ์ด ์žˆ๋‹ค[1]. ๋‹ค์ด์Šค์˜ ์„ค๊ณ„ ์‹œ ์ค‘์š”ํ•œ ์š”์†Œ ์ค‘ ํ•˜๋‚˜๋Š” ์ถœ๊ตฌ์—์„œ ๊ท ์ผํ•œ ํ๋ฆ„์„ ํ™•๋ณดํ•˜๋Š” ๊ฒƒ์ด ๋งค ์šฐ ์ค‘์š”ํ•œ๋ฐ ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค์˜ ๊ฒฝ์šฐ์—๋Š” ๋งค๋‹ˆํด๋“œ ๋ฐ˜๊ฒฝ๊ณผ ๋žœ๋“œ๊ธธ์ด๊ฐ€ ์ฃผ์š”์„ค๊ณ„ ๋ณ€์ˆ˜๋กœ ์ž‘์šฉํ•˜๋ฉฐ, ์ด์™€ ๊ฐ™์€ ๋ณ€์ˆ˜๋“ค์„ ์ตœ์ ํ™” ํ•จ์œผ๋กœ์„œ ๋‹ค์ด์Šค ์ถœ๊ตฌ์—์„œ์˜ ๊ท ์ผํ•œ ํ๋ฆ„์„ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ๋‹ค[2]. ๋”ฐ๋ผ์„œ ์••์ถœ๋‹ค์ด์Šค ๋ฅผ ์„ค๊ณ„ํ•  ๋•Œ๋Š” ๋งŽ์€ ์‹œํ–‰์ฐฉ์˜ค๋ฅผ ๊ฑฐ์ณ์•ผ ํ•˜๊ณ , ์„ค๊ณ„ ๋ณ€์ˆ˜์™€ ๋ณ€์ˆ˜ ๊ฐ„์˜ ์ƒํ˜ธ์ž‘์šฉ์„ ์ดํ•ดํ•ด์•ผ ํ•œ๋‹ค. ๋ณดํ†ต ๋งค์šฐ ํฐ ํญ๊ณผ ๋งค์šฐ ์–‡์€ ๋‘๊ป˜๋ฅผ ๊ฐ€์ง€๋Š” ๊ณ ๋ถ„์ž ์••์ถœ ํ•„๋ฆ„ ๋‹ค์ด์Šค์˜ ์ตœ์ ํ™”๋ฅผ ์œ„ํ•œ ๋ฌธํ—Œ์„ ์‚ดํŽด๋ณด๋ฉด ๋‹ค์ด ์Šค์˜ ํ˜•ํƒœ๊ฐ€ ๋งค์šฐ ๋ณต์žกํ•  ๋•Œ ์œ ๋™์œ ๋กœ๋ฅผ ๋‹จ์ˆœํ™”ํ•œ ์—ฐ ๊ตฌ[3] ๊ฐ€ ์žˆ๊ณ , Smith ๋“ฑ์€ ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค ๋‚ด์˜ ์œ ์ฒด ๋ฅผ ๋‰ดํ†ค์œ ์ฒด, ๋น„๋‰ดํ†ค ์œ ์ฒด๋กœ ๋‚˜๋ˆ„์–ด ๋“ฑ์˜จ ์œ ๋™์„ ๊ฐ€ ์ •ํ•œ ๋‹ค์Œ, ์••๋ ฅ ๊ฐ•ํ•˜๋ฅผ ์ตœ์†Œํ™”ํ•˜์—ฌ ๊ณต์ฐจ๋ฒ”์œ„ ๋‚ด์—์„œ ๋‹ค์ด์Šค ์ถœ๊ตฌ์˜ ์œ ๋™์„ ๊ท ์ผ๋ถ„ํฌ๋กœ ๋งŒ๋“ค์–ด, ๋‹ค์ด์Šค๋ฅผ ์ตœ์ ํ™”ํ•œ ํ•ด์„์ด ์žˆ๋‹ค[4,5]. ๋‹ค์ด์Šค์˜ ์ตœ์ ํ™” ๋ฌธ์ œ๋Š” ๋‹ค์ด์Šค ์ถœ๊ตฌ์˜ ๊ท ์งˆํ•œ ์†๋„๋ฅผ ์–ป๊ธฐ ์œ„ํ•˜์—ฌ ๋‹ค์ด์Šค ๋‚ด ์˜ ์••๋ ฅ์†์‹ค์„ ์ฃผ์–ด์ง„ ๊ณต์ฐจ ๋ฒ”์œ„ ๋‚ด์—์„œ ๊ฐ€๋Šฅํ•œ ํ•œ ์ตœ์†Œํ™”ํ•ด์•ผ ํ•œ๋‹ค. Hurez๋“ฑ์€ ๋„คํŠธ์›Œํฌ ์•Œ๊ณ ๋ฆฌ๋“ฌ (network algorithm) ์œผ๋กœ ๋‹ค์ด์Šค ์„ค๊ณ„๋ฅผ ์ตœ์ ํ™”ํ•œ ์—ฐ ๊ตฌ๊ฐ€ ์žˆ๋Š”๋ฐ ์ด๊ฒƒ์€ ์ž„์˜์˜ ํ˜•์ƒ์— ์ ์šฉํ•˜๊ธฐ์—๋Š” ๋ฌด ๋ฆฌ๊ฐ€ ์žˆ๋‹ค[6]. ๊ณ ๋ถ„์ž ์••์ถœ๊ณต์ •์€ ์žฌ๋ฃŒ์˜ ์œ ๋ณ€ํ•™์ ์ธ ํŠน์„ฑ์œผ๋กœ ์ธํ•˜์—ฌ ๊ท ์ผํ•œ ์œ ๋™ ์ˆ˜์ง€๋ฅผ ๊ณต๊ธ‰ํ•˜๋Š” ๊ฒƒ์€ ๋งค์šฐ ์–ด๋ ต๊ณ , ๋‹ค์ด ์ž…๊ตฌ์˜ ์••๋ ฅ์— ๋”ฐ๋ผ ์ ์„ฑ์ด ๋‹ฌ๋ผ ์ง„๋‹ค[7]. ๋”ฐ๋ผ์„œ ๊ณ ๋ถ„์ž ์••์ถœ๊ณต์ •์—์„œ ์••์ถœ๊ธฐ ๋‹ค์ด์Šค ์„ค๊ณ„๋ฅผ ํ•  ๋•Œ ๊ณ ๋ถ„์ž ์šฉ์œต์ˆ˜์ง€์˜ ์œ ๋™ํ•ด์„์€ ๋งค์šฐ ์ค‘ ์š”ํ•˜๋‹ค[8-10]. ๊ณ ํ’ˆ์งˆ์˜ ์••์ถœ์€ ์••์ถœ๊ธฐ ์ถœ๊ตฌ์—์„œ์˜ ์ฒด ์ ์œ ๋™์„ ์ž˜ ์ œ์–ด ํ•ด์•ผ ํ•˜๋Š”๋ฐ ์ด๊ฒƒ์€ ๋‹ค์ด ๋‚ด์—์„œ์˜ โ€  E-mail : [email protected]
Transcript
Page 1: An Analysis of the Polymer Melt Flow in Extruder Dies

๋ฐ˜๋„์ฒด๋””์Šคํ”Œ๋ ˆ์ด๊ธฐ์ˆ ํ•™ํšŒ์ง€ ์ œ12๊ถŒ ์ œ2ํ˜ธ(2013๋…„ 6์›”)Journal of the Semiconductor & Display Technology, Vol. 12, No. 2. June 2013.

19

๊ณ ๋ถ„์ž์••์ถœ ๋‹ค์ด์Šค์˜ ์œ ๋™ํ•ด์„

์ตœ๋งŒ์„ฑโ€ ยท๊น€๊ด‘์„ 

โ€ ํ•œ๊ตญ๊ธฐ์ˆ ๊ต์œก๋Œ€ํ•™๊ต ๋ฉ”์นดํŠธ๋กœ๋‹‰์Šค๊ณตํ•™๋ถ€

An Analysis of the Polymer Melt Flow in Extruder Dies

Man Sung Choiโ€  and Kwang Sun Kim*

โ€ School of Mechatronics Engineering, Korea University of Technology and Education

Abstract

Extrusion is one of the most important operations in the polymer-processing industry. Balancing the distribution of flow

through a die to achieve a uniform velocity distribution is the primary objective and one of the most difficult tasks of

extrusion die design. If the manifold in a coat-hanger die is not properly designed, the exit velocity distribution may be

not uniform; this can affect the thickness across the width of the die. Yet, no procedure is known to optimize the coat

hanger die with respect to an even velocity profile at the exit. While optimizing the exit velocity distribution, the constraint

optimization used in this work with allowable pressure drop in the die; according to this constraint we can control the

pressure in the die. The computational approach incorporates three-dimensional finite element simulations software STAR-

CCM+. These simulations are used with numerical optimization to design polymer coat hanger dies with pressure drop,

uniform velocity and temperature variation across the die exit.

Key Words : Polymer extrusion, Coat-hanger dies, Flow analysis

1. ์„œ ๋ก 

๊ณ ๋ถ„์ž ์••์ถœํ•„๋ฆ„์˜ ์ œํ’ˆ์„ ์ƒ์‚ฐํ•  ๋•Œ ํ‰ํŒ ๋‹ค์ด ์Šค

๊ฐ€ ์ฃผ๋กœ ์‚ฌ์šฉ๋œ๋‹ค. ๋‹ค์ด์Šค๋Š” ๋‚ด๋ถ€์˜ ์œ ๋กœํ˜•์ƒ์— ๋”ฐ๋ผ

T-๋‹ค์ด์Šค, ํ”ผ์‰ฌ ํ…Œ์ผ(fish tail)๋‹ค์ด์Šค, ์˜ท๊ฑธ์ด์™€ ๊ฐ™์ด

๊ณก๋ฉด์œผ๋กœ ๋˜์–ด์žˆ๋Š” ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค(coat hanger

dies) ๋“ฑ์ด ์žˆ๋‹ค[1]. ๋‹ค์ด์Šค์˜ ์„ค๊ณ„ ์‹œ ์ค‘์š”ํ•œ ์š”์†Œ

์ค‘ ํ•˜๋‚˜๋Š” ์ถœ๊ตฌ์—์„œ ๊ท ์ผํ•œ ํ๋ฆ„์„ ํ™•๋ณดํ•˜๋Š” ๊ฒƒ์ด ๋งค

์šฐ ์ค‘์š”ํ•œ๋ฐ ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค์˜ ๊ฒฝ์šฐ์—๋Š” ๋งค๋‹ˆํด๋“œ

๋ฐ˜๊ฒฝ๊ณผ ๋žœ๋“œ๊ธธ์ด๊ฐ€ ์ฃผ์š”์„ค๊ณ„ ๋ณ€์ˆ˜๋กœ ์ž‘์šฉํ•˜๋ฉฐ, ์ด์™€

๊ฐ™์€ ๋ณ€์ˆ˜๋“ค์„ ์ตœ์ ํ™” ํ•จ์œผ๋กœ์„œ ๋‹ค์ด์Šค ์ถœ๊ตฌ์—์„œ์˜

๊ท ์ผํ•œ ํ๋ฆ„์„ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ๋‹ค[2]. ๋”ฐ๋ผ์„œ ์••์ถœ๋‹ค์ด์Šค

๋ฅผ ์„ค๊ณ„ํ•  ๋•Œ๋Š” ๋งŽ์€ ์‹œํ–‰์ฐฉ์˜ค๋ฅผ ๊ฑฐ์ณ์•ผ ํ•˜๊ณ , ์„ค๊ณ„

๋ณ€์ˆ˜์™€ ๋ณ€์ˆ˜ ๊ฐ„์˜ ์ƒํ˜ธ์ž‘์šฉ์„ ์ดํ•ดํ•ด์•ผ ํ•œ๋‹ค. ๋ณดํ†ต

๋งค์šฐ ํฐ ํญ๊ณผ ๋งค์šฐ ์–‡์€ ๋‘๊ป˜๋ฅผ ๊ฐ€์ง€๋Š” ๊ณ ๋ถ„์ž ์••์ถœ

ํ•„๋ฆ„ ๋‹ค์ด์Šค์˜ ์ตœ์ ํ™”๋ฅผ ์œ„ํ•œ ๋ฌธํ—Œ์„ ์‚ดํŽด๋ณด๋ฉด ๋‹ค์ด

์Šค์˜ ํ˜•ํƒœ๊ฐ€ ๋งค์šฐ ๋ณต์žกํ•  ๋•Œ ์œ ๋™์œ ๋กœ๋ฅผ ๋‹จ์ˆœํ™”ํ•œ ์—ฐ

๊ตฌ[3]๊ฐ€ ์žˆ๊ณ , Smith๋“ฑ์€ ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค ๋‚ด์˜ ์œ ์ฒด

๋ฅผ ๋‰ดํ†ค์œ ์ฒด, ๋น„๋‰ดํ†ค ์œ ์ฒด๋กœ ๋‚˜๋ˆ„์–ด ๋“ฑ์˜จ ์œ ๋™์„ ๊ฐ€

์ •ํ•œ ๋‹ค์Œ, ์••๋ ฅ ๊ฐ•ํ•˜๋ฅผ ์ตœ์†Œํ™”ํ•˜์—ฌ ๊ณต์ฐจ๋ฒ”์œ„ ๋‚ด์—์„œ

๋‹ค์ด์Šค ์ถœ๊ตฌ์˜ ์œ ๋™์„ ๊ท ์ผ๋ถ„ํฌ๋กœ ๋งŒ๋“ค์–ด, ๋‹ค์ด์Šค๋ฅผ

์ตœ์ ํ™”ํ•œ ํ•ด์„์ด ์žˆ๋‹ค[4,5]. ๋‹ค์ด์Šค์˜ ์ตœ์ ํ™” ๋ฌธ์ œ๋Š”

๋‹ค์ด์Šค ์ถœ๊ตฌ์˜ ๊ท ์งˆํ•œ ์†๋„๋ฅผ ์–ป๊ธฐ ์œ„ํ•˜์—ฌ ๋‹ค์ด์Šค ๋‚ด

์˜ ์••๋ ฅ์†์‹ค์„ ์ฃผ์–ด์ง„ ๊ณต์ฐจ ๋ฒ”์œ„ ๋‚ด์—์„œ ๊ฐ€๋Šฅํ•œ ํ•œ

์ตœ์†Œํ™”ํ•ด์•ผ ํ•œ๋‹ค. Hurez๋“ฑ์€ ๋„คํŠธ์›Œํฌ ์•Œ๊ณ ๋ฆฌ๋“ฌ

(network algorithm)์œผ๋กœ ๋‹ค์ด์Šค ์„ค๊ณ„๋ฅผ ์ตœ์ ํ™”ํ•œ ์—ฐ

๊ตฌ๊ฐ€ ์žˆ๋Š”๋ฐ ์ด๊ฒƒ์€ ์ž„์˜์˜ ํ˜•์ƒ์— ์ ์šฉํ•˜๊ธฐ์—๋Š” ๋ฌด

๋ฆฌ๊ฐ€ ์žˆ๋‹ค[6]. ๊ณ ๋ถ„์ž ์••์ถœ๊ณต์ •์€ ์žฌ๋ฃŒ์˜ ์œ ๋ณ€ํ•™์ ์ธ

ํŠน์„ฑ์œผ๋กœ ์ธํ•˜์—ฌ ๊ท ์ผํ•œ ์œ ๋™ ์ˆ˜์ง€๋ฅผ ๊ณต๊ธ‰ํ•˜๋Š” ๊ฒƒ์€

๋งค์šฐ ์–ด๋ ต๊ณ , ๋‹ค์ด ์ž…๊ตฌ์˜ ์••๋ ฅ์— ๋”ฐ๋ผ ์ ์„ฑ์ด ๋‹ฌ๋ผ

์ง„๋‹ค[7]. ๋”ฐ๋ผ์„œ ๊ณ ๋ถ„์ž ์••์ถœ๊ณต์ •์—์„œ ์••์ถœ๊ธฐ ๋‹ค์ด์Šค

์„ค๊ณ„๋ฅผ ํ•  ๋•Œ ๊ณ ๋ถ„์ž ์šฉ์œต์ˆ˜์ง€์˜ ์œ ๋™ํ•ด์„์€ ๋งค์šฐ ์ค‘

์š”ํ•˜๋‹ค[8-10]. ๊ณ ํ’ˆ์งˆ์˜ ์••์ถœ์€ ์••์ถœ๊ธฐ ์ถœ๊ตฌ์—์„œ์˜ ์ฒด

์ ์œ ๋™์„ ์ž˜ ์ œ์–ด ํ•ด์•ผ ํ•˜๋Š”๋ฐ ์ด๊ฒƒ์€ ๋‹ค์ด ๋‚ด์—์„œ์˜โ€ E-mail : [email protected]

Page 2: An Analysis of the Polymer Melt Flow in Extruder Dies

20 ์ตœ๋งŒ์„ฑยท๊น€๊ด‘์„ 

๋ฐ˜๋„์ฒด๋””์Šคํ”Œ๋ ˆ์ด๊ธฐ์ˆ ํ•™ํšŒ์ง€ ์ œ12๊ถŒ ์ œ2ํ˜ธ, 2013

์˜จ๋„๋ถ„ํฌ ๋ฐ ์†๋„๋ถ„ํฌ์™€ ๊ด€๊ณ„๋œ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ฝ”

ํŠธํ–‰์–ด ๋‹ค์ด์Šค ์ž…๊ตฌ์—์„œ์˜ ์••๋ ฅ๋ณ€ํ™”๊ฐ€ ๋‹ค์ด์Šค ๋‚ด๋ถ€์™€

์ถœ๊ตฌ์—์„œ์˜ ์šฉ์œต์ˆ˜์ง€์˜ ์†๋„๋ถ„ํฌ, ์˜จ๋„๋ถ„ํฌ ๋ฐ ๊ท ์ผ

์œ ๋™์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ์ˆ˜์น˜ํ•ด์„์„ ํ†ตํ•˜์—ฌ ์•Œ์•„๋ณด๊ณ ,

๊ณ ๋ถ„์ž ์••์ถœ๊ธฐ ๋‹ค์ด์Šค ์„ค๊ณ„์˜ ๊ธฐ์ดˆ์ž๋ฃŒ๋กœ ํ™œ์šฉํ•˜๊ณ ์ž

ํ•˜์˜€๋‹ค.

2. ๊ณ ๋ถ„์ž์••์ถœ๊ธฐ ๋‹ค์ด์Šค์˜ ์œ ๋™ํ•ด์„

์ข‹์€ ๋‹ค์ด์Šค ์„ค๊ณ„๋Š” ๋‹ค์ด์Šค ์ „๋ฐ˜์— ๊ฑธ์ณ ๊ท ์ผํ•œ ์••

๋ ฅ๊ฐ•ํ•˜๋ฅผ ์–ป๋Š” ๊ฒƒ์ด๋‹ค. ์ด๋ฅผ ์œ„ํ•ด ์ ์ ˆํ•œ ๊ณ ๋ถ„์ž์ˆ˜์ง€

์˜ ๋ฌผ์„ฑ์ž๋ฃŒ์™€ ๊ณต์ •์กฐ๊ฑด์„ ์„ ์ •ํ•˜์—ฌ ์œ ๋™ํ•ด์„์„ ํ•ด์•ผ

ํ•œ๋‹ค. ์••๋ ฅ๊ฐ•ํ•˜์— ๊ด€๊ณ„๋˜๋Š” ๋ณ€์ˆ˜๋Š” ์šฉ์œต์ˆ˜์ง€์˜ ์œ ๋Ÿ‰,

์œ ๋™์ €ํ•ญ, ๊ณ ๋ถ„์ž์ ์„ฑ ๋“ฑ์ด ์žˆ๋‹ค. ์œ ๋™ํ•ด์„์„ ์œ„ํ•œ ๊ฐ€

์ •์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค. ์œ ๋™์€ ์ธต๋ฅ˜์ด๊ณ , ์ ๋„๋Š” ์˜จ๋„์™€ ๋ณ€

ํ˜• ์†๋„์˜ ํ•จ์ˆ˜๋กœ์„œ ์ ์„ฑ ์†Œ์‚ฐ์— ์˜ํ•œ ์—ด ๋ฐœ์ƒ์ด ๊ณ ๋ ค

๋˜์—ˆ๋‹ค. ๊ทธ๋ฆฌ๊ณ  ๋‹ค์ด์Šค์™€ ๊ณ ๋ถ„์ž ์šฉ์œต์ฒด ์‚ฌ์ด๋Š” ๋‹จ์—ด

๊ฒฝ๊ณ„์กฐ๊ฑด์ด ์ ์šฉ๋˜์—ˆ์œผ๋ฉฐ, ํ•ด์„์€ ๊ณ ๋ถ„์ž์••์ถœ๊ธฐ ์‹œ์Šค

ํ…œ ์ค‘ ๋‹ค์ด์Šค์— ๊ตญํ•œํ•˜์˜€๋‹ค. ๋˜ํ•œ ๋‹ค์ด์Šค ๋‚ด์˜ ์œ ์ฒด๋Š”

์ •์ƒ์ƒํƒœ,๋น„์••์ถ•์„ฑ, ๋น„๋‰ดํ„ด์œ ์ฒด๋กœ ๊ฐ€์ •ํ•˜์˜€๋‹ค.

2.1. ์งˆ๋Ÿ‰ํ‰ํ˜•๋ฐฉ์ •์‹(mass balance equation)

์งˆ๋Ÿ‰ํ‰ํ˜•๋ฐฉ์ •์‹์€ ์—ฐ์†๋ฐฉ์ •์‹์ด๋ผ๊ณ ๋„ ํ•˜๋ฉฐ, ์งˆ ๋Ÿ‰

๋ณด์กด๋ฒ•์น™์— ๋”ฐ๋ฅธ ๊ณต์‹์ด๋‹ค. ๊ฒ€์‚ฌ์ฒด์  ๋‚ด์˜ ์งˆ๋Ÿ‰ ๋ˆ„์ ์†

๋„๋Š” ๊ฒ€์‚ฌ์ฒด์ ์— ๋“ค์–ด๊ฐ€๋Š” ์งˆ๋Ÿ‰์˜ ์œ ๋Ÿ‰์—์„œ ๊ฒ€์‚ฌ์ฒด์ 

์„ ๋น ์ ธ๋‚˜๊ฐ€๋Š” ๊ฐ’์„ ๋บ€ ๊ฒƒ์ด๋‹ค. ์ง๊ต์ขŒํ‘œ ๊ณ„์—์„œ ์ˆœ์ˆ˜

์œ ์ฒด์— ๋Œ€ํ•œ ์งˆ๋Ÿ‰ํ‰ํ˜•๋ฐฉ์ •์‹์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค.

(1)

์—ฌ๊ธฐ์„œ xi๋Š” Cartesian ์ขŒํ‘œ(i = 1,2,3)์ด๊ณ , vi๋Š” xi๋ฐฉ

ํ–ฅ์œผ๋กœ์˜ ์†๋„์„ฑ๋ถ„ ฯ๋Š” ์œ ์ฒด์˜ ๋ฐ€๋„์ด๋‹ค,

2.2. ์šด๋™๋Ÿ‰ํ‰ํ˜•๋ฐฉ์ •์‹

์ฒด์ ์˜ ์šด๋™๋Ÿ‰์€ ์งˆ๋Ÿ‰x์†๋„์ด๋‹ค. ์šด๋™๋Ÿ‰ํ‰ํ˜•๋ฐฉ์ •์‹

(momentum balance equation)์€ ์šด๋™๋Ÿ‰๋ณด์กด๋ฒ•์น™์— ๋”ฐ

๋ฅธ ์‹์ด๊ณ , ์šด๋™๋ฐฉ์ •์‹์ด๋ผ๊ณ ๋„ ํ•œ๋‹ค. ๊ณ ๋ถ„์ž ์œ ๋™์‹œ์Šค

ํ…œ์—์„œ ๊ด€์„ฑ๋ ฅ๊ณผ ์ฒด์ ๋ ฅ์€ ์ผ๋ฐ˜์ ์œผ๋กœ ๋ฌด์‹œ๋˜๋Š”๋ฐ, ์ง

๊ต์ขŒํ‘œ๊ณ„์—์„œ ์šด๋™๋Ÿ‰ํ‰ํ˜•๋ฐฉ์ •์‹์€ ๋‹ค์Œ๊ณผ ๊ฐ™์ด ์ฃผ์–ด

์ง„๋‹ค.

(2)

์—ฌ๊ธฐ์„œ, ฯ„ij๋Š” ์‘๋ ฅ ํ…์„œ(stress tensor)์ด๋‹ค.

2.3. ์—๋„ˆ์ง€ํ‰ํ˜•๋ฐฉ์ •์‹

์—๋„ˆ์ง€ํ‰ํ˜•๋ฐฉ์ •์‹(energy balance equation)์€ ๊ฒ€์‚ฌ

์ฒด์  ๋‚ด์—์„œ ํŠน์ •ํ•œ ์—ด์  ๋‚ด๋ถ€์—๋„ˆ์ง€์˜ ์ฆ๊ฐ€๋ฅ ์ด ์—๋„ˆ

์ง€์œจ๊ณผ ์—ด์ „๋„ ๋ฐ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์œจ์„ ํ•ฉํ•œ ๊ฒƒ๊ณผ ๊ฐ™๋‹ค๋Š”

๊ฒƒ์ด๋‹ค. ์—๋„ˆ์ง€ ๋ณด์กด๋ฒ•์น™์€ ์—ด์—ญํ•™ ์ œ1๋ฒ•์น™์— ๋”ฐ๋ฅธ ๊ฒƒ

์ด๋‹ค. ๋งŒ์•ฝ ๋ฐ€๋„๊ฐ€ ์ผ์ •ํ•˜๋‹ค๊ณ  ํ•˜๋ฉด ์—๋„ˆ์ง€๋ฐฉ์ •์‹์€ ๋‹ค

์Œ๊ณผ ๊ฐ™๋‹ค.

(3)

์—ฌ๊ธฐ์„œ h๋Š” ์—”ํƒˆํ”ผ์ด๊ณ , q j๋Š” xi๋ฐฉํ–ฅ์œผ๋กœ์˜ ์—๋„ˆ์ง€

ํ™•์‚ฐ์„ ๋‚˜ํƒ€๋‚ด๋ฉฐ, ๋‹ค์Œ๊ณผ ๊ฐ™์ด ํ‘œํ˜„๋œ๋‹ค.

(4)

์—๋„ˆ์ง€๋ฐฉ์ •์‹์€ ๋น„ ๋“ฑ์˜จ๊ณผ์ •(non-isothermal process)

์„ ํ•ด์„ํ•˜๋Š”๋ฐ ์ด์šฉ๋œ๋‹ค. ๊ณ ๋ถ„์ž์••์ถœ์— ์žˆ์–ด์„œ ์žฌ๋ฃŒ๋Š”

์••์ถœ๊ธฐ๋ฅผ ํ†ต๊ณผํ•˜๋ฉด์„œ ํฐ ์˜จ๋„๋ณ€ํ™”๋ฅผ ์•ผ๊ธฐํ•˜๋ฏ€๋กœ, ์—๋„ˆ

์ง€๋ฐฉ์ •์‹์€ ์••์ถœ๊ณต์ •์˜ ํ•ด์„์— ๋งŽ์ด ์‚ฌ์šฉ๋œ๋‹ค.

2.4. ๋‹ค์ด์Šค ๋ชจ๋ธ๋ง(modeling of dies)

ํ•ด์„์— ์‚ฌ์šฉ๋œ ๋‹ค์ด์Šค๋Š” ์ฝ”ํŠธํ–‰์–ด ๋‹ค์ด์Šค์ด๋‹ค. ์ด๊ฒƒ

์€ ๋‹ค์ด์Šค๊ฐ€ ์ ์ ˆํ•˜๊ฒŒ ์„ค๊ณ„๋˜๋ฉด ๊ณ ์˜จ์—์„œ๋„ ๊ฐ€๋™์กฐ๊ฑด

์— ๋ฌด๊ด€ํ•˜๊ฒŒ ์–‘ํ˜ธํ•œ ์šฉ์œต๋ถ„ํฌ๋ฅผ ์œ ์ง€ํ•˜๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค. ์ด

์‹œ์Šคํ…œ์˜ ๋‹จ์ ์€ ์œ ๋™์ฑ„๋„์˜ ํ˜•์ƒ์ด ๋ณต์žกํ•˜์—ฌ ์ œ์ž‘๋น„

์šฉ์ด ๊ณ ๊ฐ€์ธ ์ ์ด๋‹ค. ๋‹ค์ด์Šค์˜ ๋ชจ๋ธ๋ง์€ Solidworks

2010๊ณผ STAR- CCM+์„ ์‚ฌ์šฉ ํ•˜์˜€๊ณ [11], ๊ณ ๋ถ„์ž์••์ถœ

๊ธฐ์˜ ๋‹ค์ด์Šค๋ฅผ ๋ชจ๋ธ๋งํ•˜์—ฌ ํ•ด์„์„ ์ง„ํ–‰ํ•˜์˜€๋‹ค. STAR-

CCM+๋Š” ํ•˜๋‚˜์˜ ํ†ตํ•ฉ๋œ ํŒจํ‚ค์ง€ ๋‚ด์—์„œ, ์„ธ๊ณ„์—์„œ ๊ฐ€์žฅ

ํฌ๊ด„์ ์ธ ๊ณตํ•™์ , ๋ฌผ๋ฆฌ์  ์‹œ๋ฎฌ๋ ˆ์ด์…˜์ด ๊ฐ€๋Šฅํ•˜๊ณ  ์—ด์œ 

๋™, ์—ด์ „๋‹ฌ ๋ฐ ์‘๋ ฅ์„ ํฌํ•จํ•˜๋Š” ๋ฌธ์ œ๋ฅผ ํ’€๊ธฐ ์œ„ํ•œ ๊ณตํ•™

์ ์ธ ํ”„๋กœ์„ธ์Šค๋ฅผ ์ œ๊ณตํ•œ๋‹ค. ๋‹ค์ด์Šค ํ‹ˆ์ƒˆ์˜ ๊ฐ„๊ทน์€ ๋งค์šฐ

์ž‘์€๋ฐ, ์ด๋Ÿฐ ๋ฏธ์†Œ ๊ฐ„๊ทน์—์„œ์˜ ์œ ๋™์„ ํ•ด์„ํ•˜๊ธฐ ์œ„ํ•ด์„œ

๋Š” ์บ์‹œ์˜ ํฌ๊ธฐ๊ฐ€ ์•„์ฃผ ์ž‘์•„์•ผ ๋œ๋‹ค. ์ด๊ฒƒ์€ ์ „์ฒด ๊ทธ๋ฆฟ

๋“œ(grid)์˜ ์ˆ˜๊ฐ€ ๋Š˜์–ด๋‚˜๊ฒŒ ๋˜์–ด ํ•ด์„์‹œ๊ฐ„์ด ์ฆ๊ฐ€๋˜๋Š”

๊ฒฐ๊ณผ๋ฅผ ์ดˆ๋ž˜ ํ•˜๊ฒŒ ๋œ๋‹ค. ๋ณธ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ์—์„œ๋Š” ๋ณต์žกํ•œ

ํ˜•์ƒ์— ์ ํ•ฉํ•œ ๋ฉ”์‹œ(mesh)์ธ ๋‹ค๋ฉด์ฒด ๋ฉ”์‹œ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ

ํ•ด์„์„ ์ง„ํ–‰ํ•˜์˜€๋‹ค.

Fig. 1์€ ์‹คํ—˜์— ์‚ฌ์šฉ๋œ ๊ณ ๋ถ„์ž ์••์ถœ๊ธฐ์˜ ๋‹ค์ด์Šค๋ฅผ

Solidworks๋กœ ๋ชจ๋ธ๋งํ•œ ๊ฒƒ์ด๋‹ค.

Fig. 2๋Š” STAR-CCM+์œผ๋กœ ์ธก๋ฉด๋ถ€์˜ ๋ฉ”์‹œ๋ฅผ ์ƒ์„ฑ

ํ•˜์˜€๋‹ค.

Fig. 3์€ ์œ ๋™ ํ•ด์„์„ ์œ„ํ•ด ๋‹ค์ด์Šค์˜ ๋ฉ”์‹œ๋ฅผ ์ƒ์„ฑํ•œ

๊ทธ๋ฆผ์ด๋‹ค.

ฯโˆ‚vjโˆ‚xj------- 0=

โˆ‚p

โˆ‚xi-------

โˆ‚ฯ„ij

โˆ‚xj-------=

โˆ‚

โˆ‚xi------- ฯvjh qj+( ) ฯ„ij

โˆ‚vi

โˆ‚xj-------=

qj โˆ’kAโˆ‚T

โˆ‚xj-------=

Page 3: An Analysis of the Polymer Melt Flow in Extruder Dies

๊ณ ๋ถ„์ž์••์ถœ ๋‹ค์ด์Šค์˜ ์œ ๋™ํ•ด์„ 21

Journal of KSDT Vol. 12, No. 2, 2013

2.5. ํ•ด์„์กฐ๊ฑด

Table 1 ์€ ๋‹ค์ด์Šค ์ž…๊ตฌ์••๋ ฅ, ๊ณ ๋ถ„์ž ์˜จ๋„ ๋ฐ ๋‹ค์ด

์Šค ์˜จ๋„๋ฅผ ์ž…๋ ฅ์กฐ๊ฑด์œผ๋กœ ํ•œ ๊ฒƒ์œผ๋กœ, ๋‹ค์ด์Šค์˜ ์ž…๊ตฌ

์••๋ ฅ์„ ๋ณ€ํ™”์‹œ์ผœ ์œ ๋™ํ•ด์„์„ ํ•˜์˜€๋‹ค.

Table 2๋Š” ํ•ด์„์— ์‚ฌ์šฉ๋œ ๊ณ ๋ถ„์ž์ˆ˜์ง€์ธLDPE์˜ ๋ฌผ์„ฑ

๊ฐ’์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค.

Fig. 4๋Š” ๋‹ค์ด์Šค ๋‚ด์˜ ์œ ๋™์„ ํ•ด์„ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋‹ค์ด

์Šค๋ฅผ ๋ชจ๋ธ๋ง ํ•œ ๊ฒƒ์ด๊ณ , ๋‹ค์ด์Šค์˜ ์ถœ๊ตฌ๋ถ€๋ถ„์— 20๊ฐœ์˜

ํ‘œ์ ์„ ํ‘œ์‹œํ•˜์—ฌ, ๊ฐ๊ฐ์˜ ์†๋„์˜ ํฌ๊ธฐ๋ฅผ ํ•ด์„ํ•˜์˜€๋‹ค.

3. ํ•ด์„๊ฒฐ๊ณผ

3.1. ๋‹ค์ด์Šค๋‚ด์˜ ์šฉ์œต์ˆ˜์ง€์˜ ์†๋„๋ถ„ํฌ ํ•ด์„

๊ณ ๋ถ„์ž ์••์ถœ๊ธฐ์˜ ๋‹ค์ด์Šค ์„ค๊ณ„๋ฅผ ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์šฉ์œต

์ˆ˜์ง€์˜ ์†๋„๋ถ„ํฌ๋ฅผ ์•Œ ํ•„์š”๊ฐ€ ์žˆ๋‹ค.

Fig. 5(a)์—์„œ ์•Œ ์ˆ˜ ์žˆ๋“ฏ์ด ๋‹ค์ด์Šค ์ž…๊ตฌ ์••๋ ฅ์ด

10 kgf/cm2์ผ ๋•Œ ๋งค๋‹ˆํด๋“œ์—์„œ ์•ฝ 0.7 m/min ์ •๋„์ด

๊ณ , ๋‹ค์ด์Šค์˜ ๋ ๋‹จ์—์„œ 2 m/min. ์†๋„๋Š” ๊ฑฐ์˜ ๊ท ์ผ

ํ•œ ๋ถ„ํฌ๋กœ ์œ ๋™์„ ํ•˜์˜€๋‹ค.

Fig. 5(b)์—์„œ๋Š” Fig. 5(a)์™€ ๊ฐ™์€ ์กฐ๊ฑด์—์„œ ์†๋„์žฅ์„

์œ ๋™ ๋ฒกํ„ฐ(vector)๋กœ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ, ๋‹ค์ด์Šค ์ถœ๊ตฌ์—์„œ

์†๋„์˜ ๋ถ„ํฌ๊ฐ€ ๋งค์šฐ ๊ท ์ผํ•˜๋‹ค.

Fig. 6์—์„œ๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ ์••๋ ฅ์ด 20 kgf/cm2์ผ ๋•Œ์˜

์†๋„๋ถ„ํฌ์ด๋‹ค. ๋งค๋‹ˆํด๋„์˜ ์†๋„๋Š” Fig. 5(a)์˜ ์†๋„๋ถ„

ํฌ์™€ ์œ ์‚ฌํ•˜๋‚˜, ํ”„๋ฆฌ๋žœ๋“œ(pre-land)์˜ ๋ ๋‹จ์—์„œ์˜ ์†

๋„๊ฐ€ ์กฐ๊ธˆ ๋นจ๋ผ์ง€๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ์ด๊ฒƒ์€ ์••๋ ฅ์ด

์ฆ๊ฐ€ํ•  ๋•Œ ์šฉ์œต์ˆ˜์ง€์˜ ์ ์„ฑํšจ๊ณผ๊ฐ€ ์ด ๋ถ€๋ถ„์—์„œ ์•ฝํ™”๋˜

๋Š” ํ˜„์ƒ์œผ๋กœ ์—ฌ๊ฒจ์ง„๋‹ค.

Fig. 7์—์„œ๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ ์••๋ ฅ์ด 30 kgf/cm2 ์ผ ๋•Œ์˜

์†๋„๋ถ„ํฌ์ด๋‹ค. ๋งค๋‹ˆํด๋“œ์™€ ํ”„๋ฆฌ๋žœ๋“œ ๋ถ€๋ถ„์˜ ์œ ๋™์†๋„

๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ ์••๋ ฅ์ด ์ฆ๊ฐ€ํ•ด๋„ ๊ทธ ๋ณ€ํ™”๊ฐ€ ๊ฑฐ์˜ ์—†์Œ

์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ์—ฌ๊ธฐ์„œ ๋‹ค์ด๋žœ๋“œ(die lan)์˜ ์ค‘์•™๋ถ€์—์„œ

์œ ๋™์†๋„๋Š” ์ƒ๋Œ€์ ์œผ๋กœ ์ž‘๋‹ค. ์ด๊ฒƒ์€ ์ค‘์•™๋ถ€์—์„œ์˜ ํ”„

๋ฆฌ๋žœ๋“œ์˜ ํญ์ด ์ƒ๋Œ€์ ์œผ๋กœ ํฐ ๊ฒƒ์— ๊ธฐ์ธํ•œ ๊ฒƒ์œผ๋กœ ์—ฌ

๊ฒจ์ง„๋‹ค.

Fig. 8์—์„œ๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ ์••๋ ฅ์ด 40 kgf/cm2 ์ผ

๋•Œ์˜ ์†๋„๋ถ„ํฌ์ด๋‹ค. Fig. 8์—์„œ๋„ ์•ž์˜ ํ•ด์„ ๊ฒฐ๊ณผ์™€ ๊ทธ

Fig. 1. Modeling of extruder dies.

Fig. 2. Grid system of front view for dies.

Fig. 3. Typical mesh used in the calculations.

Table 1. Simulation condition for analysis.

Simulation

No.

Inlet Pressure

[kgf/cm2]

Mass Temp.

[oK]

Dies Temp.

[oK]

S1 10

493 497S2 20

S3 30

S4 40

Table 2. Physical properties of LDPE.

Thermal conductivity ฮบ [W/moCโˆ’1] 0.3-0.335

Density ฯ [kg/m3] 910-928

Specific heat C [J/kg.K] 1800-3400

Viscosity ฮท [Pa-s] 91

Fig. 4. A numerical simulation model.

Page 4: An Analysis of the Polymer Melt Flow in Extruder Dies

22 ์ตœ๋งŒ์„ฑยท๊น€๊ด‘์„ 

๋ฐ˜๋„์ฒด๋””์Šคํ”Œ๋ ˆ์ด๊ธฐ์ˆ ํ•™ํšŒ์ง€ ์ œ12๊ถŒ ์ œ2ํ˜ธ, 2013

๊ฒฝํ–ฅ์ด ๋งค์šฐ ์œ ์‚ฌํ•˜๋‹ค. Fig. 5 ~Fig. 8์˜ ํ•ด์„ ๊ฒฐ๊ณผ๋ฅผ

์‚ดํŽด๋ณด๋ฉด ๋‹ค์ด์Šค์ž…๊ตฌ์˜ ์••๋ ฅ์ด 10 kgf/cm2์”ฉ ์ฆ๊ฐ€ํ•จ์—

๋”ฐ๋ผ ์šฉ์œต์ˆ˜์ง€์˜ ์†๋„ํฌ๊ธฐ๊ฐ€ ์•ฝ 2.4 m/min.์ฆ๊ฐ€ํ•˜๋Š”

๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๊ณ , ๋‹ค์ด์Šค์˜ ์ž…๊ตฌ ์••๋ ฅ์ด ๋‹ค์ด์Šค ์ถœ๊ตฌ

์†๋„์— ์˜ํ–ฅ์„ ๋ฏธ์นœ๋‹ค๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค.

Fig. 9๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ์—์„œ์˜ ์••๋ ฅ๊ณผ ๋‹ค์ด์Šค ์ถœ๊ตฌ์—์„œ

์˜ ์œ ๋™์†๋„์˜ ๊ด€๊ณ„๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ ๋งค์šฐ ์„ ํ˜•์ ์ธ

๊ด€๊ณ„๋ฅผ ๊ฐ€์ง€๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ์ด์— ๋Œ€ํ•œ ํšŒ๊ท€์‹์œผ๋กœ

ํ‘œํ˜„ํ•˜๋ฉด ์‹(5)์™€ ๊ฐ™๊ณ , ๋‘ ๋ณ€์ˆ˜์™€์˜ ์ˆ˜์ •์ƒ๊ด€๊ณ„์ˆ˜ R2

์€ 99%์ด๋‹ค.

(5)Pdo 0.14Vav=

Fig. 5. (a) Velocity distribution in dies (S1), (b) Velocity

distribution in dies (S1).

Fig. 6. Velocity distribution in dies (S2).

Fig. 7. Velocity distribution in dies (S3).

Fig. 8. Velocity distribution in dies (S4).

Fig. 9. Pressure at dies inlet vs. average velocity at dies

outlet.

Page 5: An Analysis of the Polymer Melt Flow in Extruder Dies

๊ณ ๋ถ„์ž์••์ถœ ๋‹ค์ด์Šค์˜ ์œ ๋™ํ•ด์„ 23

Journal of KSDT Vol. 12, No. 2, 2013

์—ฌ๊ธฐ์„œ Pdo๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ์—์„œ์˜ ์••๋ ฅ์ด๊ณ , Vav์€ ๋‹ค

์ด์Šค ์ถœ๊ตฌ์—์„œ ํ‰๊ท  ์œ ๋™์†๋„์ด๋‹ค.

Fig. 10์€ Fig. 4์—์„œ ๋ชจ๋ธ๋งํ•œ 20๊ฐœ์˜ ์ ์—์„œ ์œ ๋™

์†๋„๊ฐ’์„ ๊ทธ๋ž˜ํ”„๋กœ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. ๋‹ค์ด์Šค ์ž…๊ตฌ ์••๋ ฅ์ด

10 kgf/cm2, 20 kgf/cm2์—์„œ๋Š” ์†๋„ ๊ฐ’์ด ๊ฑฐ์˜ ๊ท ์ผํ•˜๊ฒŒ

๋‚˜ํƒ€๋‚จ์„ ๋ณผ ์ˆ˜ ์žˆ์ง€๋งŒ, 30 kgf/cm2๊ณผ 40 kgf/cm2 ๊ฒฝ์šฐ

์ถœ๊ตฌ์˜ ์†๋„๊ฐ€ ๋” ๋นจ๋ผ์ง€๋ฉด์„œ ๊ฐ ์ ๋งˆ๋‹ค ํฐ ๋ณ€๋™์ด ๋ฐœ

์ƒํ•˜๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ์ถœ๊ตฌ์—์„œ์˜ ๊ท ์ผํ•˜์ง€ ์•Š์€ ์†

๋„๊ฐ€ ๊ฒฐ๊ตญ ์ œํ’ˆ์˜ ํ’ˆ์งˆ์— ํฐ ์˜ํ–ฅ์„ ๋ฏธ์น˜๋ฏ€๋กœ, ์œ ๋™์†

๋„์˜ ๋ณ€๋™์„ ์ค„์ด๋ฉด์„œ ์ƒ์‚ฐ๋Ÿ‰์„ ๊ทน๋Œ€ํ™” ํ•  ์ˆ˜ ์žˆ๋Š” ์ตœ

์ ์˜ ๋‹ค์ด์Šค ์ž…๊ตฌ์••๋ ฅ ์„ ์ •์ด ํ•„์š”ํ•˜๋‹ค.

3.2. ๋‹ค์ด์Šค๋‚ด์˜ ์šฉ์œต์ˆ˜์ง€์˜ ์˜จ๋„๋ถ„ํฌ ํ•ด์„

๊ณ ๋ถ„์ž ์••์ถœ๊ธฐ์˜ ๋‹ค์ด์Šค ์„ค๊ณ„๋ฅผ ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์šฉ์œต

์ˆ˜์ง€์˜ ์†๋„๋ถ„ํฌ ์ด์™ธ์— ์˜จ๋„๋ถ„ํฌ๋ฅผ ์•Œ ํ•„์š”๊ฐ€ ์žˆ๋‹ค.

๋‹ค์ด์Šค์˜ ๋งค๋‹ˆํด๋“œ๋Š” ์Šฌ๋ฆฟ์˜ ํญ๋งŒํผ ์šฉ์œตํ๋ฆ„์„ ๊ท ์ผ

ํ•˜๊ฒŒ ๋ถ„ํฌ๋˜๋„๋ก ํ•ด์•ผ ํ•˜๊ณ , ์šฉ์œต์ฒด๊ฐ€ ์ผ์ •ํ•œ ๋ณ€ํ˜•, ์˜จ

๋„, ์ฒด๋ฅ˜์‹œ๊ฐ„์˜ ์ด๋ ฅ)์„ ๊ฐ–๋„๋ก ํ•ด์•ผ ํ•œ๋‹ค. ๋˜ํ•œ ๋‹ค์–‘

ํ•œ ์ž‘๋™์กฐ๊ฑด ๋ฐ ์žฌ๋ฃŒ์— ๋Œ€์‘ํ•ด์•ผ ํ•œ๋‹ค. ๋งค๋‹ˆํด๋“œ๊ฐ€ ์žˆ

๋Š” ๊ด‘ํญ์˜ ์Šฌ๋ฆฟ ๋‹ค์ด์Šค๋ฅผ ํ•ด์„์ ์œผ๋กœ ์„ค๊ณ„ํ•  ๋•Œ๋Š” ์›

ํ•˜๋Š” ์œ ๋™๋ถ„ํฌ๋ฅผ ๊ฐ€์ •ํ•  ์ˆ˜ ์žˆ๋‹ค๋Š” ๊ฒƒ๊ณผ ์ฒด์ ์œ ๋™๊ณผ

๊ธฐํ•™ํ•™์ ์ธ ํ˜•์ƒ์— ๋”ฐ๋ฅธ ์••๋ ฅ์†์‹ค์„ ๊ณ ๋ คํ•  ์ˆ˜ ์žˆ๋Š”

์ด์ ์ด ์žˆ๋‹ค. ๋งŒ์•ฝ์— ์šฉ์œต์ฒด์˜ ํ‰๊ท ์œ ๋Ÿ‰์ด ๊ด‘ํญ ๋‹ค์ด์˜

์ถœ๊ตฌ๋‹จ๋ฉด์ ์œผ๋กœ ๋น ์ ธ๋‚˜๊ฐ€๋Š” ์œ ๋Ÿ‰๊ณผ ๊ฐ™๋‹ค๋ฉด ๋‹ค์ด์Šค๋ฅผ

ํ†ต๊ณผํ•˜๋Š” ๋ชจ๋“  ์œ ์„  ๊ฒฝ๋กœ์˜ ์œ ๋™์ €ํ•ญ์€ ๋ฐ˜๋“œ์‹œ ๊ฐ™๊ฒŒ

๋œ๋‹ค.

Fig. 11์—์„œ๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ์˜ ์••๋ ฅ์ด 10 kgf/cm2 ์ผ

๋•Œ์˜ ๊ฒฝ์šฐ ๋‹ค์ด์Šค์˜ ์˜จ๋„๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. ๋งค๋‹ˆํด

๋“œ์˜ ์˜จ๋„๋Š” 493oK ์ •๋„๋กœ ๋ถ„ํฌ๋˜์–ด ์žˆ๊ณ , ํ”„๋ฆฌ๋žœ๋“œ์—

์„œ ๋‹ค์ด๋žœ๋“œ ๊นŒ์ง€๋Š” 496oK ์ •๋„๋กœ ์•ฝ 3oK ์ •๋„ ์ƒ์Šนํ•˜

์˜€๋‹ค. ๊ทธ๋ฆฌ๊ณ  ๋‹ค์ด์Šค ์ถœ๊ตฌ์—์„œ์˜ ์˜จ๋„๋ถ„ํฌ ๋Š” 497oK์˜

๊ท ์ผ ๋ถ„ํฌ๋กœ ์ด๋ฃจ์–ด์ ธ ์žˆ๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋‹ค์ด์Šค

์ž…๊ตฌ์™€ ์ถœ๊ตฌ์˜ ์˜จ๋„ ์ฐจ์ด๋Š” 4oK๋กœ ์ ๋‹ค.

Fig. 12์—์„œ๋Š” ๋‹ค์ด์Šค ์ž…๊ตฌ์˜ ์••๋ ฅ์ด 20 kgf/cm2 ์ผ

๋•Œ ์˜ ๊ฒฝ์šฐ ๋‹ค์ด์Šค์˜ ์˜จ๋„๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค., ๋งค๋‹ˆ

ํด๋“œ์˜ ์˜จ๋„๋Š” 493oK ์ •๋„๋กœ ๋ถ„ํฌ๋˜์–ด ์žˆ๊ณ , ํ”„๋ฆฌ๋žœ๋“œ

์—์„œ ๋‹ค์ด๋žœ๋“œ ๊นŒ์ง€๋Š” 496oK์ •๋„๋กœ ์•ฝ 3oK ์ •๋„ ์ƒ์Šน

ํ•˜์˜€๋‹ค. ๊ทธ๋ฆฌ๊ณ  ๋‹ค์ด์Šค ์ถœ๊ตฌ์—์„œ์˜ ์˜จ๋„๋ถ„ํฌ๋Š” 496oK

์˜ ๊ท ์ผ ๋ถ„ํฌ๋กœ ์ด๋ฃจ์–ด์ ธ ์žˆ๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋‹ค์ด

์Šค ์ž…๊ตฌ์™€ ์ถœ๊ตฌ์˜ ์˜จ๋„ ์ฐจ์ด๋Š” 3oK๋กœ Fig. 11๋ณด๋‹ค ๊ฐ์†Œ

ํ•˜์˜€๋‹ค. ์—ฌ๊ธฐ์„œ ์•Œ ์ˆ˜ ์žˆ๋Š” ๊ฒƒ์€ ๋‹ค์ด์Šค ์ž…๊ตฌ์˜ ์••๋ ฅ์ด

์ฆ๊ฐ€ํ•˜๋ฉด ๋‹ค์ด๋žœ๋“œ ์˜์—ญ์˜ ์˜จ๋„๋ณ€ํ™”์˜ ๊ธฐ์šธ๊ธฐ๊ฐ€ ๊ฐ์†Œ

ํ•œ๋‹ค๋Š” ์ ์ด๋‹ค. ์ด๊ฒƒ์€ ์šฉ์œต์ˆ˜์ง€์˜ ์œ ๋™์„ฑ์ด ์ฆ๊ฐ€๋œ ๊ฒƒ

์— ๊ธฐ์ธํ•œ ๊ฒƒ์œผ๋กœ ์—ฌ๊ฒจ์ง„๋‹ค.

Fig. 13์€ ๋‹ค์ด์Šค ์ž…๊ตฌ์˜ ์••๋ ฅ์ด 40 kgf/cm2์ผ ๋•Œ์˜

Fig. 10. Velocity with length of dies edge.

Fig. 11. Temperature distribution in dies(S1).

Fig. 12. Temperature distribution in dies (S2).

Page 6: An Analysis of the Polymer Melt Flow in Extruder Dies

24 ์ตœ๋งŒ์„ฑยท๊น€๊ด‘์„ 

๋ฐ˜๋„์ฒด๋””์Šคํ”Œ๋ ˆ์ด๊ธฐ์ˆ ํ•™ํšŒ์ง€ ์ œ12๊ถŒ ์ œ2ํ˜ธ, 2013

๊ฒฝ์šฐ์— ๋Œ€ํ•œ ๋‹ค์ด์Šค์˜ ์˜จ๋„๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค.

Fig. 11 - Fig. 13๊นŒ์ง€ ๋‚ด์šฉ์„ ์‚ดํŽด๋ณด๋ฉด, ๋‹ค์ด์Šค ์ž…๊ตฌ์˜

์••๋ ฅ์ด ์ฆ๊ฐ€ํ•˜๋ฉด ๋‹ค์ด๋žœ๋“œ ์˜์—ญ์˜ ์˜จ๋„ ๋ถ„ํฌ๊ฐ€ ๊ฑฐ์˜

๊ฐ™์•„์ง„๋‹ค๋Š” ์ ์ด๋‹ค. ๋”ฐ๋ผ์„œ ๋‹ค์ด์Šค ์ž…๊ตฌ์••๋ ฅ์ด ์ฆ๊ฐ€ํ• 

์ˆ˜๋ก ๋”์šฑ ์•ˆ์ •๋œ ์šฉ์œต ์ˆ˜์ง€์˜ ๊ท ์ผ์œ ๋™์„ ์–ป์„ ์ˆ˜ ์žˆ

์Œ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

Fig. 14๋Š” ๊ณ ๋ถ„์ž์••์ถœ๊ธฐ์˜ ๋‹ค์ด์Šค๋ฅผ ์ ์™ธ์„  ์นด๋ฉ”

๋ผ์˜ ๊ฐ€์‹œ๊ด‘์„ ์œผ๋กœ ์ดฌ์˜ํ•œ ์‚ฌ์ง„์ด๋‹ค.

Fig. 15๋Š” ๋‹ค์ด์Šค์˜ ํ‘œ๋ฉด์˜จ๋„๋ฅผ ์ธก์ •ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ

Fluke์‚ฌ (๋ชจ๋ธ๋ช…, Ti25)์˜ ์นด๋ฉ”๋ผ ์ ์™ธ์„ ์˜จ๋„์ธก์ •๊ธฐ๋ฅผ

์‚ฌ์šฉํ•˜์—ฌ ๋‹ค์ด์Šค ํ‘œ๋ฉด์˜จ๋„๋ฅผ ์ธก์ •ํ•œ ์‚ฌ์ง„์ด๋‹ค. ์ดฌ์˜์กฐ

๊ฑด์œผ๋กœ๋Š” ๋ฐฉ์‚ฌ์œจ์ด 0.9์ด๋‹ค. ์ด๋ฏธ์ง€ ๋ฒ”์œ„๋Š” 422oK์—์„œ

512oK์ด๊ณ , ํ‰๊ท  ์˜จ๋„๋Š” 486oK์ด๋‹ค. ์ด๊ฒƒ์€ ํ•ด์„ํ•œ ๊ฒฐ

๊ณผ์™€ ์˜จ๋„๋ฒ”์œ„์™€ ๋งค์šฐ ์œ ์‚ฌํ•จ์„ ๋ณด์—ฌ์ค€๋‹ค.

Fig. 16์€ ์ž…์ฒด ์ด๋ฏธ์ง€์˜ ํ”ฝ์…€ ์˜จ๋„๋ฅผ 3์ฐจ์› ์ด๋ฏธ์ง€

๋กœ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. X์ถ•๊ณผ Y์ถ•์€ ์ด๋ฏธ์ง€์˜ ํ”ฝ์…€ ์œ„์น˜

๋“ค๋กœ ๊ตฌ์„ฑ๋˜๋ฉฐ, Z์ถ•์€ ์ด๋ฏธ์ง€์—์„œ ํ•ด๋‹น (X,Y) ์œ„์น˜์˜

์˜จ๋„ ๊ฐ’์ด๋‹ค. ์ด ๊ทธ๋ฆผ์—์„œ ๋ณผ ๋•Œ, ํ‘œ์ธต๋ถ€๋ถ„์˜ ์˜จ๋„๋ถ„ํฌ

๋Š” ๊ฑฐ์˜ ๋“ฑ์˜จ๋ถ„ํฌ๋ฅผ ํ•œ๋‹ค๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ์ด๋•Œ์˜

์‹คํ—˜์กฐ๊ฑด์€ ์‹ค๋ฆฐ๋” ์˜จ๋„ 213oK, ์—ฐ์‹ ์†๋„ 400 rpm, ๋ƒ‰

๊ฐ๋กค ์˜จ๋„ 293oK, ์—ฐ์‹ ๋น„ 3.0 : 1, ์—ฐ์‹ ๋กค ์˜จ๋„๋ฅผ 373oK

๋กœ ํ•˜์˜€๋‹ค.

4. ๊ฒฐ ๋ก 

Solid Works 2010์„ ์‚ฌ์šฉํ•˜์—ฌ ๊ณ ๋ถ„์ž ์••์ถœ๊ธฐ์˜ ๋‹ค์ด

์Šค๋ฅผ 3์ฐจ์›์œผ๋กœ ๋ชจ๋ธ๋งํ•˜๊ณ , STAR- CCM+์„ ์‚ฌ์šฉํ•˜

์—ฌ ๋‹ค์ด์Šค ๋‚ด์—์„œ ์šฉ์œต์ˆ˜์ง€์˜ ํ๋ฆ„์— ๋Œ€ํ•œ ์œ ๋™ํ•ด์„์„

3์ฐจ์› ์œ ํ•œ์š”์†Œ๋ฒ•์œผ๋กœ ํ•ด์„ํ•˜์˜€๋‹ค.

ํ•ด์„๊ฒฐ๊ณผ์— ๋”ฐ๋ฅด๋ฉด ๋‹ค์ด์Šค์ž…๊ตฌ์˜ ์••๋ ฅ์ด ์ฆ๊ฐ€ํ•จ์—

๋”ฐ๋ผ ์šฉ์œต์ˆ˜์ง€์˜ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๊ณ , ๋‹ค์ด์Šค

์ž…๊ตฌ ์••๋ ฅ์ด ๋‹ค์ด์Šค ์ถœ๊ตฌ ์†๋„์— ์˜ํ–ฅ์„ ๋ฏธ์นœ๋‹ค๋Š” ๊ฒƒ

์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋˜ํ•œ ๋‹ค์ด์Šค์ž…๊ตฌ ์••๋ ฅ์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก

๋‹ค์ด์Šค์ถœ๊ตฌ์˜ ์œ ๋™์†๋„ ๋ณ€๋™์ด ์‹ฌํ•ด์ง€๋ฏ€๋กœ ์••์ถœ์˜ ์ƒ

์‚ฐ์„ฑ๊ณผ ํ•„๋ฆ„์˜ ๋‘๊ป˜๋ณ€๋™์„ ๊ณ ๋ คํ•œ ๊ณต์ •์กฐ๊ฑด์„ ๊ฒ€ํ† ํ• 

ํ•„์š”๊ฐ€ ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์˜จ๋„๋ถ„ํฌํ•ด์„์„ ํ†ตํ•˜์—ฌ ํ•ด์„ํ•ด ๋ณผ

๋•Œ, ๋‹ค์ด์Šค ์ž…๊ตฌ์••๋ ฅ์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ๋”์šฑ ์•ˆ์ •๋œ ์šฉ์œต์ˆ˜

์ง€์˜ ์˜จ๋„๋ถ„ํฌ๋ฅผ ์–ป์„ ์ˆ˜ ์žˆ๋‹ค. ์ด๊ฒƒ์€ ํ•„๋ฆ„์˜ ์—ด๋ณ€

ํ˜•์— ์˜ํ•œ ๋‘๊ป˜๋ณ€๋™์„ ๊ณ ๋ คํ•  ๋•Œ ๊ฐ€๋Šฅํ•˜๋ฉด ์ž…๊ตฌ์••๋ ฅ์„

๋†’์ด๋Š” ๊ฒƒ์ด ๋ฐ”๋žŒ์งํ•œ ๊ฒƒ์œผ๋กœ ๋ณด์ธ๋‹ค. ๊ฒฐ๋ก ์ ์œผ๋กœ ์ตœ

์ ํ™”๋œ ๊ณ ๋ถ„์ž์••์ถœ์˜ ๋‹ค์ด์Šค๋ฅผ ์‚ฌ์šฉํ•˜๋”๋ผ๋„, ๋‹ค์ด์Šค

์ž…๊ตฌ์˜ ์••๋ ฅ์„ ์ƒ์‚ฐ์„ฑ๊ณผ ๋‘๊ป˜ ํŽธ์ฐจ๋ฅผ ๊ณ ๋ คํ•œ ์ตœ์ ๊ณต์ •

์กฐ๊ฑด์„ ์ •ํ•˜๋Š” ๊ฒƒ์ด ๋ฐ”๋žŒ์งํ•˜๋‹ค.

Fig. 13. Temperature distribution in dies (S4).

Fig. 14. Photo of polymer extruder dies by a visible ray.

Fig. 15. Surface temperature on extruder dies.

Fig. 16. The 3D. IR surface temperature on dies.

Page 7: An Analysis of the Polymer Melt Flow in Extruder Dies

๊ณ ๋ถ„์ž์••์ถœ ๋‹ค์ด์Šค์˜ ์œ ๋™ํ•ด์„ 25

Journal of KSDT Vol. 12, No. 2, 2013

์ฐธ๊ณ ๋ฌธํ—Œ

1. C. Rauwendaal, โ€œPolymer Extrusionโ€, 4th Edition,

Hanser Publishers, 2001

2. Y. Wang, โ€œThe flow distribution of molten polymers

in Slit Dies and Coat Hanger Die through Three-

Dimensional Finite Element Analysisโ€, In Polymer

Engineering and Science, pp. 204-212, 1991

3. S. Puissant, Y. Demay, B. Vergnes, โ€œTwo-Dimen -

sional Multilayer Co-extrusion Flow in a Flat Coat

-hanger Die. Part Iโ€, Modeling, Polym. Eng. Sci., Vol.

34, pp. 201-208., 1994.

4. D.E. Smith, D.A. Tortorelliav, C.L. Tucker, โ€œOptimal

Design for Polymer Extrusion. Part I: Sensitivity

Analysis for Nonlinear Steady-State Systemsโ€, Com-

puter. Methods Appl. Mech. Eng., pp. 283-302.,

1998.

5. D.E. Smith, โ€œAn Optimization-Based Approach to

Compute Sheeting Die Designs for Multiple Operat-

ing Conditionsโ€, SPE ANTEC Technical Papers, pp.

315-319, 2003.

6. P. Hurez, P.A. Tanguy, D. Blouin, โ€œA New Design

Procedure for Profile Dieโ€, Polym. Eng. Sci. Vol. 36,

pp 626-635, 1996.

7. J.Z Liang, โ€œPressure Effect of Viscosity for Polymer

Fluids in Die Flowโ€, Polymer Vol. 42 pp. 3709-3712,

2001.

8. M. S. Choi, K. S. Kim, โ€œAn Analysis of a Thermo-

Plastic Melt Flow in the Metering Zone of a Polymer

Extruderโ€, J, of the Semiconductor & Disp. Tech.,

Vol. 11. No. 4, 2012.

9. C. Chen, P. Jen, F. S. Lai, โ€œOptimization of the Coat

Hanger Manifold via Computer Simulation and

Orthogonal Array Method,โ€ In Polymer Engineering

and Science, , pp. 188-196, 1997

10. Y. W. Yu, T. J. Liu, โ€œA Simple Numerical Approach

for the Optimal Design of an Extrusion Die,โ€ In:

Journal of Polymer Research, pp. 1-7, 1998.

11. CD-Adapco, STAR-CCM User Guide ver. 6.04.,

2011.

์ ‘์ˆ˜์ผ: 2013๋…„ 5์›” 21์ผ, ์‹ฌ์‚ฌ์ผ: 2013๋…„ 6์›” 11์ผ,

๊ฒŒ์žฌํ™•์ •์ผ: 2013๋…„ 6์›” 17์ผ


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