• Title/Summary/Keyword: distribution of body fluid

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Study on the growth of vapor bubble in devolatilization of polymers

  • Kim, Chongyoup
    • Korea-Australia Rheology Journal
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    • v.11 no.3
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    • pp.247-253
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    • 1999
  • The growth of a spherical vapor bubble contained in a large body of upper convected Maxwell fluid is theoretically analyzed under the devolatilization condition of polymer by using a Galerkin FEM in the Lagrangian frame. Using the finite element technique, a fully explicit numerical scheme is developed both for the calculation of pressure distribution and for the tracking of bubble surface. Oscillatory behavior in bubble radius is observed during growth and the oscillatory behavior is found to be due to the interaction of mass transfer resistance and elasticity. It is found that the elasticity of fluid accelerates the growth and removal of volatile component. It is also found that the bubble growth in the devolatilization of polymers is affected by both mass transfer resistance and viscoelasticity of fluids.

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An Experimental Study on Lift Force Generation Resulting from Spanwise Flow in Flapping Wings

  • Hong, Young-Sun
    • International Journal of Aeronautical and Space Sciences
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    • v.7 no.2
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    • pp.86-103
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    • 2006
  • Using a combination of force transducer measurement to quantify net lift force, high frame rate camera to quantify and subtract inertial contributions, and Digital Particle Image Velocimetry (DPIV) to calculate aerodynamic contributions in the spanwise plane, the contribution of spanwise flow to the generation of lift force in wings undergoing a pure flapping motion in hover is shown as a function of flapping angle throughout the flapping cycle. These experiments were repeated at various flapping frequencies and for various wing planform sizes for flat plate and span wise cambered wings. Despite the previous identification of the importance of span wise fluid structures in the generation of lift force in flapping wings throughout the existing body of literature, the direct contribution of spanwise flow to lift force generated has not previously been quantified. Therefore, in the same manner as commonly applied to investigate the chordwise lift distribution across an airfoil in flapping wings, spanwise flow due to bulk flow and rotational fluid dynamic mechanisms will be investigated to validate the existence of a direct component of the lift force originating from the flapping motion in the spanwise plane instead.

Time Mean Drifting Forces on a Cylinder in Water of Finite Depths -Direct Pressure Integration Method- (유한(有限)깊이의 물에 떠있는 주상체(柱狀體)에 작용(作用)하는 시간평균표류력(時間平均漂流力) -직접압력(直接壓力) 적분법(積分法)-)

  • K.P.,Rhee;K.K.,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.22 no.2
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    • pp.27-34
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    • 1985
  • In this paper, the second order time mean forces acting on the circular cylinder floating on the free surface of a finite water depth are calculated. Under the assumption that fluid is idea and the wave the linear gravity wave, the velocity potential is calculated by the source distribution method, and the second order time mean lateral and vertical drifting forces are calculated by the direct integration of fluid pressures over the immersed body surface. The comparison of the lateral drifting forces with Rhee's results by momentum theorem shows good agreements. And it is shown that the second order time sinkage forces of a floating circular cylinder cross zero for all water depths.

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NUMERICAL METHOD IN WAVE-BODY INTERACTIONS

  • MOUSAVIZADEGAN S. H.;RAHMAN M.
    • Journal of applied mathematics & informatics
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    • v.17 no.1_2_3
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    • pp.73-91
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    • 2005
  • The application of Green's function in calculation of flow characteristics around submerged and floating bodies due to a regular wave is presented. It is assumed that the fluid is homogeneous, inviscid and incompressible, the flow is irrotational and all body motions are small. Two methods based on the boundary integral equation method (BIEM) are applied to solve associated problems. The first is a low order panel method with triangular flat patches and uniform distribution of velocity potential on each panel. The second method is a high order panel method in which the kernels of the integral equations are modified to make it nonsingular and amenable to solution by the Gaussian quadrature formula. The calculations are performed on a submerged sphere and some floating spheroids of different aspect ratios. The excellent level of agreement with the analytical solutions shows that the second method is more accurate and reliable.

Evaluation of Design Safety for Butterfly Valve (버터플라이 밸브의 설계 안전도 평가)

  • Lee, Seung-Pyo;Kim, Kwang-Suk;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.18 no.1
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    • pp.29-35
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    • 2009
  • Butterfly valve is a kind of rotational valve which opens and closes the flow of fluid on rotating the disk 90 degrees in the valve body. In this paper, butterfly valve design safety evaluation which is based on the international valve specifications is investigated. Both body and disk of the butterfly valve are considered under the normal and pressurized operating conditions. A finite element analysis is carried out to compute the distribution of the displacement, stress and safety factor by using ANSYS. On the basis of calculated design safety we offer the design modification and compare with them.

Cavitating-Flow Characteristics around a Horn-Type Rudder (혼 타 주위의 캐비테이팅 유동 특성에 대한 연구)

  • Choi, Jung-Eun;Chung, Seak-Ho;Kim, Jung-Hun
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.3 s.153
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    • pp.228-237
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    • 2007
  • The flow characteristics around a horn-type rudder behind an operating propeller of a high-speed large container carrier are studied through a numerical method in fully wetted and cavitating flow conditions. The computations are carried out in a small scale ratio of 10.00(gap space=5mm) to consider the gap effects. The Reynolds averaged Navier-Stokes equation for a mixed fluid and vapor transport equation applying cavitation model are solved. The axisymmetry body-force distribution technique is utilized to simulate the flow behind an operating propeller. The gap flow, the three-dimensional flow separation, and the cavitation are the flow characteristics of a horn-type rudder. The pattern of three-dimensional flow separation is analyzed utilizing a topological rule. The various cavity positions predicted by CFD were shown to be very similar to rudder erosion positions in real ship rudder. The effect of a preventing cavitation device, a horizontal guide plate, is also investigated.

Thermal-flow Analysis of the Cooling System in the Medicated Water Electrolysis Apparatus (냉이온수기 냉각시스템에 관한 열유동 해석)

  • Jeon, Seong-Oh;Lee, Sang-Jun;Lee, Jong-Chul;Kim, Youn-Jea
    • The KSFM Journal of Fluid Machinery
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    • v.14 no.3
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    • pp.33-38
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    • 2011
  • Medicated water electrolysis apparatus, which electrolyzes water into acidic water and alkaline water, was in the spotlight as becoming known the effect of alkaline water. It is known as good for health as removing active oxygen in the human's body and promoting digestion. But, the customers could not get that desired water temperature because these apparatuses are directly connected with a water pipe. So, the cooling system was developed for controlling the temperature of the alkaline water. One of the typical way is to store water in water tank and control the temperature. But, in this way, storing water can be polluted impurities coming from outside. For protecting this pollution, the cooling system based on indirect heat exchange method through phase change between water and ice was developed. In this study, we have calculated efficiency of the cooling system with phase change by experiment and commercial CFD(Computational Fluid Dynamics) code, ANSYS CFX. To consider the effect of latent heat that is generated by melting ice, we have simulated two phase numerical analyses used enthalpy method and found the temperature, velocity, and ice mass distribution for calculating the efficiency of cooling. From the results of numerical analysis, we have obtained the relationship between the cooling efficiency and each design factor.

The Effect of Concentrated Onion Juice in a Body Composition, Serum Electrolytes and Lipids Levels on Hyperlipidemia (양파 농축액이 고지혈증 성인 남자의 체성분, 혈장 전해질 및 지질 성분에 미치는 영향)

  • 황금희;정난희;조남철;유영균;박평심;노영희;서희숙;노인옥
    • The Korean Journal of Food And Nutrition
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    • v.16 no.1
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    • pp.36-45
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    • 2003
  • It is known as that onion is antioxidation effect, antibiotic effect, blood pressure decreasing effect and reducing serum cholesterol levels. This research about effect that onion concentrate gets blood cholesterol levels and body composition. Subject was 17 adult men of hyperlipidemia. Age distribution of investigation subjects were average 49.4 years old by 40~56 years old, and average height and weight were 167.6cm and 75.5kg each, BMI was 26.9kg/$m^2$, and BMR was 1,460.6$\pm$87.5㎉, and AMC was 25.0$\pm$1.05cm, and BCM was 41.0$\pm$2.79cm. In the meantime, the body muscle was 53.7$\pm$3.7kg, and fat mass was 18.7$\pm$3.8kg, and intracellular fluid was 26.6$\pm$1.8kg, and extracellular fluid was 12.8$\pm$0.9kg. The % body fat was 24.6$\pm$3.8%, and fat distribution was 0.9$\pm$0.0%, and the obesity degree was 125.4$\pm$8.2%. Vegetables, seaweeds, fruits and juices increased by change of dietary life and greasy foods, instants, breads, rices etc. decreased or there was no change, fast foods and eggs were no change. Also, subject previewed that guidance about stress, smoking, drinking and beverage intake need. If compared the nutrient intake amount with before onion concentrate allowance, it was similar level almost without significant. Energy, calcium and riboflavin are lower than the RDA for koreans. After 3 months, the levels of plasma total cholesterol, triglycerides had decreased significantly : 15.0%, 31.2% respectively. And the HDL-cholesterol and LDL-cholesterol levels also showed a marked reduction of 6.8%, 8.7% respectively. Plasma lipid level change by onion concentrate supplement would can know that case of triglyceride more greatly than plasma cholesterol. The pH and Na+ level of plasma were low significant since 8 weeks after, and $K^{+}$ level increase significant. While $Ca^{++}$ level was low significant after 1 month, there was no change since 2 months after, but nC $a^{++}$ level was low significantly. Plasma $Mg^{++}$ level was no change and nM $g^{++}$ level was low significant after intake.e.e.e.e.e.

Bearing Hydrodynamic Lubrication Analysis with Fluid-Multi Body Dynamics Coupling (유체-다물체 동역학 연성해석을 통한 베어링 윤활해석)

  • Lee, J.H.;Kim, J.H.;Kim, C.W.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.430-435
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    • 2008
  • This research deals with the implementation hydrodynamic (HD) lubrication system with an integration of multibodydynamics (MBD) in order to analyze bearing lubrication characteristics such as pressure distribution and oil film thickness dynamically. The HD solver developed newly will transmit force and torque data to MBD solver, and receive position and velocity data from it continuously. After an analysis, we will verify the result with existing commercial software. Moreover, other functions like adjusting size of mesh grid, setting oil hole & groove effects, and consideration of thrust force will be introduced.

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A Study on Hydraulic Modifications of Low-Pressure Membrane Inlet Structure with CFD and PIV Techniques (CFD와 PIV 기법을 이용한 저압막 유입부 수리구조 개선에 관한 연구)

  • Oh, Jeong Ik;Choi, Jong-Woong;Lim, Jae-Lim;Kim, Donggil;Park, No-Suk
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.11
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    • pp.607-618
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    • 2015
  • This study was conducted to suggest hydraulic modification for improving evenness of inlet flow distribution into side stream type low-pressure MF (microfiltration) module using CFD (computational fluid dynamics) simulation and PIV (particle image velocimetry) techniques. From the results of CFD simulation for various typed inlet structure, it was investigated that installing internal orifice baffle in inlet the distribution channel could improve the evenness of inlet flow distribution over about 40%. Also, from the results of PIV measurements which were carried out for verifying the CFD simulation, it was observed that the momentum of the water body coming from the opposite side of the inlet was relatively larger. This momentum would generate strong shear force in the near of inlet side wall. On the other hands, occurrence of dead zone and eddy flow was confirmed in the opposite side.