• Title, Summary, Keyword: pseudoplastic

Search Result 134, Processing Time 0.104 seconds

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
    • /
    • v.13 no.2
    • /
    • pp.85-91
    • /
    • 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.

Studies on the Steady Shear Flow Properties of Sea Mustard Aqueous Extracts (열수 추출 미역액의 정상유동특성에 관한 연구)

  • 최희숙;오성훈
    • The Korean Journal of Food And Nutrition
    • /
    • v.13 no.1
    • /
    • pp.78-82
    • /
    • 2000
  • For the purpose of investigation of the food processing fittness of the sea mustard aqueous extracts, the steady shear flow have been measured over a wide range of shear rate using a Brookfield digital viscometer(SPDL21). The rheological behaviors of the sea mustard aqueous extracts which were extracted at 10$0^{\circ}C$ for 2 hours exhibited pseudoplastic behavior with yield stress. In the test of the relationship between temperature and apparent viscosity of samples at 10 rpm decreased along with the increment of temperature. The sea mustard aqueous extracts appeared greatly temperature dependent characteristics(Ea=1.51 ㎉/mole).

  • PDF

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 the Korea Society For Power System Engineering
    • /
    • v.13 no.2
    • /
    • pp.30-35
    • /
    • 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.

  • PDF

Effects of Particle Size Distribution of Alumina on Behaviors of Tape Casting (테이프 케스팅 거동에 미치는 알루미나의 입도분포의 영향)

  • 윤원균;김정주;조상희
    • Journal of the Korean Ceramic Society
    • /
    • v.34 no.11
    • /
    • pp.1173-1181
    • /
    • 1997
  • Effects of particle size distribution of alumina ceramics on behaviors of tape casting were investigated with emphases on the rheological characteristic of slurry, green density, green sheet strength, and sintering density. For the control of particle size distribution of alumina, the commercial grade low soda alumina, which had different mean particle size of 3.58 ${\mu}{\textrm}{m}$ and 0.42 ${\mu}{\textrm}{m}$, were chosen and blended together. As results, the mixing of 80 wt% fine powder and 20 wt% coarse powder(designated to FC20) led to the increase of packing density and strength of green sheet, and made it easy to handle during processing without lowering of sintering density. Besides, the pseudoplastic behavior of slurry decreased with increase of the fraction of coarse alumina powder.

  • PDF

Solution Properies of Algin Affected by Various Food Additives (여러 가지 식품처가제에 의한 Algin 용액의 유동특성)

  • 박명한
    • The Korean Journal of Food And Nutrition
    • /
    • v.12 no.2
    • /
    • pp.204-208
    • /
    • 1999
  • In order to obtain data for use of algin in drink making process solution properties of algin have been investigated at various condition of algin concentration temperature pH and various food additives. At same revolution velosity viscosities of algin were increased as algin concentration raised. Algin solution showed dilatnat type flow in concentration of 0.25% to 0.4% but pseudoplastic type flow in above 0.5% showed dilatant type flow in concentration of 0.25% to 0.4% but pseudoplastic type folw in above 0.5% A maximum viscosity of algin was observed at pH 5.5 and its viscosities were also decreased as the tem-perature increased and heating at 8$0^{\circ}C$ above. Organic acids affected on the viscosity of algin with pH dependently and gel formed in pH below 3.0 Sweetners have no effect to the viscosity of algin. How-ever addition of NaCl and KCL upto 1.0% decreased a little its viscosity and CACl2 MgCl2 and FeCl3 increased the viscosity of algin Glutamic acid decreased the viscosity of algin.

  • PDF

Flow Properties of Sulfated Polysaccharides in the Tunic of the Ascidin Halocynthia roretzi (우렁쉥이 껍질 유래 황산다당의 유동 특성)

  • Son, Byoung-Yil;Hong, Byeong-Il;Ahn, Jong-Woong
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.40 no.2
    • /
    • pp.68-72
    • /
    • 2007
  • The flow properties of sulfated polysaccharides purified from the ascidian Halocynthia roretzi tunic were investigated. The sulfated polysaccfarides produced aqueous solutions of low apparent viscosity with pseudoplastic flow behavior. The respective activation energies of TCA-treated and TCA-nontreated solutions were $2.2248{\times}10^4\;and\;1.442{\times}10^4J/kg{\cdot}mol$ at a 150L/s shear rate. The viscosity of the sulfated polysaccharides solution was increased by the addition of sugar, while it was not changed by the addition of NaCl.

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
    • /
    • v.34
    • /
    • pp.11-14
    • /
    • 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.

  • PDF

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
    • /
    • v.21 no.2
    • /
    • pp.273-280
    • /
    • 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.

Effects of Extractants on the Characteristic of Soluble Dietary Fiber from Apple Pomace (추출용매가 수용성 사과박 식이섬유의 특성에 미치는 영향)

  • Kim, Hyo-Joong;Hur, Jae-Kwan;Huh, Chul-Sung;Baek, Young-Jin
    • Korean Journal of Food Science and Technology
    • /
    • v.33 no.2
    • /
    • pp.161-165
    • /
    • 2001
  • The dietary fiber was extracted from apple pomace with various concentrations of acidic, alkaline solvents and water in $24.4{\sim}29.3%$ yield. The extractions of water-soluble dietary fiber with acidic(6.85%) and alkaline solvent(6.55%) were more effective than the water extraction(6.0%). The higher extraction yield was obtained with increased concentration of acidic or alkaline solvents. The content of galacturonic acid was higher in the order, 0.01 M HCl(77.5%)>0.05 M HCl(76.8%)>$H_2O(76.1%)$>0.05 M NaOH(73.8%)> 0.01 M NaOH(69.0%) and the extraction with acidic solvent showed the highest pectin yield. The color value increased by extraction with solvent in higher concentration. And at equal concentration, the color value of alkaline extract was higher than that of acidic exctract. There was no relationship between the color value and the extraction yield of dietary fiber. In the investigation on the rheological properties, the shear stress increased in proportion to galacturonic acid contents. While water-soluble dietary fiber extracted with acid and water represented Newtonian rheological properties, the alkaline extract was inclined to have converting property from pseudoplastic to Bingham pseudoplastic with increment of alkaline concentration. In the studies on the time-dependence of apparent viscosity, the thixotropic property with hysteresis loop was observed in alkaline extract.

  • PDF

The Change of Rheological Properties of Nutritional Beverage Base by the Soy Protein Isolate (분리대두단백의 첨가에 따른 영양음료 Base의 Rheology 특성 변화)

  • Shin, Je-Ho;Seo, Jong-Kyo;Lee, Seok-Ki;Sim, Jae-Hun;Kim, Sang-Kyo;Baek, Young-Jin
    • Korean Journal of Food Science and Technology
    • /
    • v.31 no.3
    • /
    • pp.638-643
    • /
    • 1999
  • In this study we prepared 5 types of nutritional beverage base samples containing various ratios of soy protein isolate (SPI) and sodium caseinate as protein source. The rheological properties of each sample were measured and the results were as followes; Samples changed their rheological properties with the ratio of SPI. Samples represented newtonian property with low ratio of SPI, pseudoplastic property with the increment of SPI, and bingham pseudoplastic property with higher increment of SPI (80% as protein source). In this result we conjectured that the more was the SPI, the more was the formation of progel during heat treatment, which could be the reason of the rheological changes. In the test of the relationship between temperature and apparent viscosity, apparent viscosity of samples decreased along with the increment of temperature. In observing the relationship between time and apparent viscosity, we found sample, containing high ratio of SPI (80%), represented thixotropic property clearly with the hysteresis loop.

  • PDF