낙구식 점도계와 모세관 점도계를 이용한 점탄성유체의 점성과 특성시간의 측정

전찬열; 황태성; 유상신

Korean Journal of Rheology, Vol.2, No.2, 19-27, December, 1990

Measurements of Viscosity and Characteristic Times of Viscoelastic Fluids with the Falling Ball Viscometer and Capillary Tube Viscometer

전찬열, 황태성, 유상신

초록

레이저와 타이머장치를 설치한 낙구식 접도계에서 구와 니들이 주어진 구간을 통과하는 시간을 측정하여 종말속도를 정확히 결정하였고 점성이 작은 유체의 낮은 전단률 점성과 영 전단률 점성은 속이 빈 알루미늄 구와 니들을 이용하여 측정하였다. 알루미늄 구와 니들의 속에 철분을 삽입하여 밀도를 다양하게 변화시켰다. 낙구식 점도계에서 측정한 낮은 전단률 점성과 영 전단률 점성, 그리고 모세관 점도계에서 측정한 높은 전단률 점성과 무한 전단률 점성을 이용하여 점탄성 유체의 특성이완시간을 결정하였다. 실린더 속의 시험용 유체를 교란시키지 않고 밑면에 떨어진 구를 회수하는 장치를 설치하였다. 이 장치는 하나의 구로써 점탄성유체의 특성확산시간을 측정하는데 대단히 효과적이었다. Polyacrylamide Separan AP-273 용액(농도 500-2000wppm)의 특성이완시간과 특성확산시간을 낙구식 점도계와 모세관 점도계의 실험결과를 이용하여 결정하고 폴리머 용액의 퇴화 현상을 실험적으로 분석하였다.

Terminal velocities of balls and needles are determined by the measured passing times of a given interval with the laser and timer system installed in the falling ball viscometer. Viscosity at low rate of shear and zero-shear-rate viscosity of low viscous fluids are measured by hollow aluminium balls and needles are varied by inserting some iron powder depending on the density required. Measured viscosity at low rate of shear and zero-shear-rate viscosity with the falling ball viscometer and viscosity at high rate of shears and infinite-shear-rate viscosity with the capillary tube viscometer are used to calculate the relaxation times of viscoelastic fluids. Ball removal device is installed to remove the dropped ball from the bottom of the cylinder without disturbing the sample fluids in the cylinder. It is that the device is very effective in measuring the characteristic diffusion time of viscoelistic fluids with a single ball. Characteristic relaxation time and characteristic diffusion time of Ployacrylamide Separan AP-273 with concentrations of 500-2000 wppm are determined by the experimental results of the falling ball viscometer and capillary tube viscometer, and degradation phenomena of polymer solutions is investigated experimentally.

Keywords:Viscoelastic fluid;characteristic relaxation time;characteristic diffusion time;hollow ball;needle;zero-shear-rate viscosity;infinite-shear-rate viscosity;degradation

[References]

Cho YI, Ph.D. Thesis, University of Illinois, Chicago Circle (1979)
Cho YI, Hartnetr JP, Letters in Heat and Mass Transfer, 6, 335-342 (1979)
황태성, 박사학위논문, 단국대학교 대학원 (1988)
엄정섭, 박사학위논문, 단국대학교 대학원 (1989)
전찬열, 유상신, 대한기계학회 논문집, 제 14권 제 1호, 241-250 (1990)
Kanchanalakshana D, Ghajar AJ, Int. Commun. Heat Mass Transf., 13, 219 (1986)
Cho YI, Hartnett JP, Lee WY, J. Non-Newton. Fluid Mech., 15, 61 (1984)
Park NA, Ph.D. Thesis, Mechanical Engineering Dept., State University of New York at Stony, Brook (1984)
Park NA, Cho YI, J. Non-Newton. Fluid Mech., to be published
Robert HP, Cecil HC, "Chemical Engineering Handbook," Fifth Edition, McGraw-Hill, New York, 3-87 (1973)
Chang HD, Darby R, AIChE J., 30, 274 (1984)
Cho YI, Hartnett JP, Handbook of Heat Transfer Applications, McGraw-Hill, New York, 2-5-19 (1986)
Yoon HK, Ghajar AJ, Proc. 8th Int. Heat Transfer Conf., McGraw-Hill, New York, 937-942 (1986)

[1] Cho YI, Ph.D. Thesis, University of Illinois, Chicago Circle (1979)

[2] Cho YI, Hartnetr JP, Letters in Heat and Mass Transfer, 6, 335-342 (1979)

[3] 황태성, 박사학위논문, 단국대학교 대학원 (1988)

[4] 엄정섭, 박사학위논문, 단국대학교 대학원 (1989)

[5] 전찬열, 유상신, 대한기계학회 논문집, 제 14권 제 1호, 241-250 (1990)

[6] Kanchanalakshana D, Ghajar AJ, Int. Commun. Heat Mass Transf., 13, 219 (1986)

[7] Cho YI, Hartnett JP, Lee WY, J. Non-Newton. Fluid Mech., 15, 61 (1984)

[8] Park NA, Ph.D. Thesis, Mechanical Engineering Dept., State University of New York at Stony, Brook (1984)

[9] Park NA, Cho YI, J. Non-Newton. Fluid Mech., to be published

[10] Robert HP, Cecil HC, "Chemical Engineering Handbook," Fifth Edition, McGraw-Hill, New York, 3-87 (1973)

[11] Chang HD, Darby R, AIChE J., 30, 274 (1984)

[12] Cho YI, Hartnett JP, Handbook of Heat Transfer Applications, McGraw-Hill, New York, 2-5-19 (1986)

[13] Yoon HK, Ghajar AJ, Proc. 8th Int. Heat Transfer Conf., McGraw-Hill, New York, 937-942 (1986)