• Title, Summary, Keyword: Pseudoplastic fluid

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Investigation of Heat Transfer Augmentation with Pseudoplastic Fluids in Annular Pipes (환상 파이프 내에서의 의소성 유체를 이용한 열전달 향상에 관한 연구)

  • Lee, Dong-Ryul
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.2
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    • pp.85-91
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    • 2011
  • Computational results with pseudoplastic fluid flows for fully developed non-Newtonian laminar flows have been obtained. Those consist of the product of friction factor and Modified Reynolds number and Nusselt numbers with respect to the shear rate parameter in an annular pipe. The numerical results of the product of friction factor and Reynolds numbers and the Nusselt numbers for both Newtonian region and the power law region were compared with previously published asymptotic results, respectively. In the present calculations, the product of friction factor and Newtonian Reynolds numbers for pseudoplastic fluid at power law region in annular pipe is 180% less than that for Newtonian fluid. For power law fluids with different power law flow indices, the difference of the product of friction factor and power law Reynolds number between previous and the present results at the power law region is within 0.20%. The solutions also show the effect of the shear rate parameter on the Nusselt number and about 11% increase of Nusselt number at the power region.

Investigation of Pressure Drop for a Pseudo-plastic Fluid Flow in Isosceles Triangle Pipes (이등변삼각형 단면을 갖는 파이프 내의 Pseudo-Plastic 유체유동에 대한 압력강하의 연구)

  • Lee, D.R.
    • Journal of Power System Engineering
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    • v.13 no.2
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    • pp.30-35
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    • 2009
  • Numerical Calculations for dimensionless pressure drop (friction factor times Reynolds number) have been obtained for fully developed laminar flow of MPL(Modified Power Law) fluid in isosceles triangle pipes. The solutions are valid for Pseudoplastic fluids over a wide range from Newtonian behavior at low shear rates through transition region to power law behavior at higher shear rates. The analysis identified a dimensionless shear rate parameter which for a given set of operating conditions specifies where in the shear rate range a particular system is operating, i.e., Newtonian, transition or power law region. The numerical calculation data of the dimensionless pressure drop for the Newtonian and power law regions are compared with previously published asymptotic results presenting within 0.16 % in Newtonian region and 2.98 % in power law region.

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Bionic Study of Variable Viscosity on MHD Peristaltic Flow of Pseudoplastic Fluid in an Asymmetric Channel

  • Khan, Ambreen A.;Muhammad, Saima;Ellahi, R.;Zia, Q.M. Zaigham
    • Journal of Magnetics
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    • v.21 no.2
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    • pp.273-280
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    • 2016
  • In this paper, the peristaltic flow of Psedoplastic fluid with variable viscosity in an asymmetric channel is examined. The bionic effects by means of magnetohydrodynamics (MHD) are taken into account. The assumptions of long wave length and low Reynolds number are taken into account. The basic equations governing the flow are first reduced to a set of ordinary differential equation by using appropriate transformation for variables and then solve by using perturbation method. The effect of physical parameters on the pressure rise, velocity and pressure gradient are illustrated graphically. The trapping phenomenon is analyzed through stream lines. A suitable comparison has also been made as a limiting case of the considered problem.

Study on the Rheological Properties of the Lactic acid Fermented Milk (유산균배양액의 유체역학적 성질에 관한 연구)

  • 정후길;강국희
    • Journal of Food Hygiene and Safety
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    • v.5 no.1
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    • pp.35-40
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    • 1990
  • As a link in the studies on the extracellular polysaccharide by lactic acid bacteria, the experiment was conducted to investigate the viscosity variations and rheological properties of 10% reconstituted skim milk and 12% reconstituted whole milk, respectively. 1. 10% reconstituted skim milk cultured by Str. thrennophilus 510 showed strong flow property of pseudoplastic fluid depending upon the production of exopolysaccharide. And the viscosity reached the highest value within 14% concentration. 2. 12% reconstituted whole milk cultured by lactic acid bacteria indicated flow property of pseudoplastic fluid. But there was a big difference in the viscosity as compared with 10% skim milk. 3. The maximum consistency index (k) and the minimum flow behavior index (n) of the fermented milk by Str. thermophilus 510 were 43 and 0.09, respectively. They were 35 and 0.09, in case of Lb. bulgaricus.

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Comparison of shear rate and viscosity of the commercial dental impression materials (치과진료용 인상재의 전단율과 점도의 비교)

  • Jin, Myoung-Hoon;Lee, Kwang-Rae
    • Journal of Industrial Technology
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    • v.34
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    • pp.11-14
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    • 2014
  • Viscosity and shear stress of the dental impression materials on commercial market(Imprint Garant LB(3M, U.S.A), EXAMIXFINE IT(GC, Japan), Vonflex S LB(Vericom, Korea), S-Silicone LB(Shinwon, Korea)) were measured with increasing shear rate from 50(1/sec) to 100(1/sec). The viscosity of EXAMIXFINE IT was decreased from 20,542(cP) to 14,684(cP), which is the shear thinning property of pseudoplastic as non-Newtonian fluid. Since the pseudoplastic property makes the impression material shear thinning and softly injected from cartridge, EXAMIXFINE IT might be popularly used in dentistry.

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Fluid Properties and Quality of Agar Solution from Cheju Seaweed, Gellidium amansii (제주산 우뭇가사리로 부터 추출한 한천의 품질 및 용액 특성)

  • KANG Hoon-I;KO Moon-Sub;KIM Hyeon-Ju;KIM Sung-Woo;BAE Tae-Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.29 no.5
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    • pp.716-721
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    • 1996
  • To bring out the functional properties of Agar-agar extracted with 0.01N $H_2SO_4$ from Gellidium amansii produced in Che-ju Udo and its fluid properties were investigated. The yield of agar from Gellidium amansii produced was $32.7\%$, the content ratio of agarose and agaropectin was 79 to 21, gelation ability was $0.19\%$ and jelly strength was $413.8\;dyne/cm^2$. Agar-agar solution showed the movement of non-Newtonian fluid and pseudoplastic property was emerged as its concentration go higher. The yield stresses in the range of $0.5\~5\%$ agar-agar solution were $0.09\~1.21\;dyne/cm^2\;at\;80^{\circ}C,\;0.12\~5.29\;dyne/cm^2\;at\;60^{\circ}C\;and\;4.84\~58.37\;dyne/cm^2\;at\;50^{\circ}C$.

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Rheological Properties of Biopolymer Produced by Bacillus coagulans CE-74 (Bacillus coagulans CE-74가 생산하는 Biopolymer의 물성)

  • Lee, Seon-Ho;Son, Gyu-Mok;Choi, Cheong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.2
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    • pp.198-203
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    • 2000
  • A highly viscous biopolymer from Bacillus coagulans CE-74 was purified and its rheological properties were studied The rheological properties of biopolymers produced by Bacillus coagulans CE-74 were studied at the temperature ranges with 20~8$0^{\circ}C$, at the concentration of 0.5~4.0%, at the pH ranges from 3 to 1 and at the shear rate fo 7.34~73.38 sec-1. The apparent viscosity of biopolymer was decreased with increasing shear rate, and thereby biopolymer showed pseudoplastic characteristics. Biopolymer solution showed a characteristic of non-Newtonian fluid properties. At the concentration of 1%, the consistency index and the flow behavior index were shown at 2.64 poise. sec11 and 0.8571, respectively. All dispersions were pseudoplastic fluids described accurately by Herschel-Bulkley model. The change of the biopolymer viscosity on pH showed the highest value at the pH 7.0 and it showed lower at acidic conditon that at alkaline condition comparatively.

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Rheological Properties of Garlic Juice and its Concentrate (마늘 착즙 및 농축액의 Rheological Properties)

  • Kim, Byeong-Sam;Park, Noh-Hyun;Park, Moo-Hyun;Han, Bong-Ho;Bae, Tae-Jin
    • Korean Journal of Food Science and Technology
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    • v.22 no.6
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    • pp.646-650
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    • 1990
  • To develop a new form of spice material by concentration of garlic juice, its rheological properties were investigated. In the temperature range of $15\;to\;65^{\circ}C$, the garlic juice with the solid content of $32\;to\;60^{\circ}Brix$ was considered as a pseudoplastic fluid. Flow and consistency indices of the juice interpreted by power-law equation varied from $0.9937\;to\;0.6130\;and\;0.0041\;to\;3.1886Pa{\;s^n$, respectively. Apparent viscosity was lineally decreased as shear rate was increased. Activation energy for the flow of the garlic juice changed in the range of 11,216 to 23,195 kJ/kg mol.

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The Effects of a Type and Concentration of Coal and Additive on the Rheological Characteristics of CWM (석탄의 종류, 농도 및 첨가제가 석탄-물 혼합연료의 유동특성에 미치는 영향)

  • Kim, Soo-Ho;Hwang, Kap-Sung;Hong, Song-Sun
    • Applied Chemistry for Engineering
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    • v.8 no.4
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    • pp.640-644
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    • 1997
  • We investigated that how both the type and the concentration of coal and the surfactant and the electrolyte added to increase the fluidity of CWM influence rheological characteristics. According to the type of coal, the viscosity of CWM was increased with increasing O/C ratio. Also, the CWM was represented the property of non-Newtonian fluid, having yield stress which was linerarly increased with increasing coal concentration. According to the surfactant used as an additive, the rheological characteristics of CWM was represented the pseudoplastic property as n<1 without relating to the concentration of added surfactants. Also, according to the increase of the amount of electrolyte, n was nearly approached 1. Therfore, we found that CWM opproched Newtonian fluid and that when more than 0.05wt.% of electrolyte were added, yield stress was not shown up.

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A Study on Compression Molding Process of Long Fiber Reinforced Plastic Composites -Effect of Needle Punching on Viscosity- (장섬유강화 플라스틱 복합재의 압축성형 공정에 관한 연구 -점도에 미치는 니들펀칭의 영향-)

  • 송기형;조선형;이용신
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.184-187
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    • 2002
  • Compression molding was specifically developed for replacement of metal components with composites. As the mechanical properties of the products are dependent on the separation and orientation, it is important to research the fiber mat structure and molding conditions. In this study, the effects of the fiber mat structure(NP: 5, 10, 25punches/$\textrm{cm}^2$) and the mold closure speed($\dot{\textrm{h}}$=0.1, 1, 10mm/min) on the viscosity of composites were discussed. The composites is treated as a Non-Newtonian power-law fluid. The parallel-plate plastometer is used and the viscosity is obtained from the relationship between the compression load and the thickness of the specimen.

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