• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제16권3호
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• pp.181-192
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• 2012

Here in this paper, the steady paint film flow on a vertical wall of a non-Newtonian pseudo plastic fluid for drainage problem has been investigated. The exact solution of the nonlinear problem is obtained for the velocity profile. Also the average velocity, volume flux, shear stress on the wall, force to hold the wall in position and normal stress difference have been derived. We retrieve Newtonian case, when material constant ${\mu}_1$ and relaxation time ${\lambda}_1$ equal zero. The results for co-rotational Maxwell fluid is also obtained by taking material constant ${\mu}_1$ = 0. The effect of the zero shear viscosity ${\eta}_0$, the material constant ${\mu}_1$, the relaxation time ${\lambda}_1$ and gravitational force on the velocity profile for drainage problem are discussed and plotted.

• 동의생리병리학회지
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• 제30권1호
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• pp.40-46
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• 2016

Many medicinal plants have been used for the treatment of edema, jaundice, and gonorrhea in traditional Oriental medicine. This screening study was designed to search the positive inotropic effects of herbal extracts in beating rabbit atria. Aquarius extracts of twenty six herbs were examined in atrial mechanical dynamics such as pulse pressure and stroke volume and atrial natriuretic peptide (ANP), one of the main hormones involved in the regulation of the body fluid and blood pressure homeostasis in perfused beating rabbit atria. Sophora flavescens Ait., Rheum officinale Baill., Acorus gramineus Sol., Chelidonium majus L., Pulsatilla koreana Nakai., Reynoutria japonica Houtt., Euphorbia lathyris L., Pyrrosia lingua (Thunb.) Farwell, Poncirus trifoliata Rafin., Anemarrhena asphodeloides Bunge, Kochia scoparia Schrad. significantly increased stroke volume and pulse pressure. However, those herbal extracts were not induced ANP secretion. We clarified the eleven herbal extracts for the positive inotropic effect independent of ANP secretion in beating rabbit atria. Thus these results provide a beneficial data for the treatment of the impairment of body fluid and blood pressure in traditional Oriental medicine.

• 한국유체기계학회 논문집
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• 제17권6호
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• pp.77-83
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• 2014

The vessel of integral reactor contains its major primary components such as the fuel and core, pumps, steam generators, and a pressurizer, so its size is proportional to the required space for the installation of each component. The steam generators take up the largest volume of internal space of reactor vessel and their volumes is substantial for the overall size of reactor vessel. Reduction of installation space for steam generators can lead to much smaller reactor vessel with resultant decrease of overall cost for the components and related facilities. A printed circuit heat exchanger is one of the compact types of heat exchangers available as an alternative to conventional shell and tube heat exchangers. Its name is derived from the procedure used to manufacture the flat metal plates that form the core of the heat exchanger, which is done by chemical milling. These plates are then stacked and diffusion bonded, converting the plates into a solid metal block containing precisely engineered fluid flow passages. The overall heat transfer area and pressure drops are evaluated for the steam generator based on the concept of the printed circuit heat exchanger in this study. As the printed circuit heat exchanger is known to have much larger heat transfer area density per unit volume, we can expect significantly reduced steam generator compared to former shell and tube type of steam generator. For the introduction of new steam generator, two design requirements are considered: flow area ratio between primary and secondary flow paths, and secondary side parallel channel flow oscillation. The results show that the overall volume of the steam generator can be significantly reduced with printed circuit type of steam generator.

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1211-1214
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• 2003

The anomalies that appear at every multiple of 15 ℃ in the viscosity of a thin liquid film of water and of water near solid interfaces are explained in this paper by comparing the thermal wavelength and molecular free volume of water, and quantum numbers are found. The possibility that these anomalies are related to the preferred and/or lethal temperatures of organisms is considered. The toxicity of heavy water (D₂O) can also be explained with this approach.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.137-143
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• 1998

Numerical simulation is conducted to clarify the heat transfer and fluid flow characteristics of traction motor for electric car SIMPLE algorithm based on finite volume method is used to make linear algebra equation. The governing equations are solved by TDMA(TriDiagonal Matrix Algorithm) with line-by-line method and block correction. From the results of simulation, the characteristics of cooling pattern is strongly affected by the size of hole in stator core. In the case of high rotational speed of rotor, temperature difference along the axial direction is more decreased than that of low rotational speed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 춘계 학술대회논문집
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• pp.48-57
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• 1999

This paper deals with the numerical simulation of the behavior of single bubble rising near the free surface. Volume fraction of fluid (VOF) method with continuum surface force (CSF) model, the well known method for two phase flow simulation is adopted. A bubble of spherical shape positioned beneath the free surface is assumed at the initial stage. The difference according to the fluid properties of surrounding medium is examined. Simulation results are depicted and explained with the time history of bubble shape, velocity field and vorticity distribution.

• Tribology and Lubricants
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• 제14권4호
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• pp.95-99
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• 1998

The electrorheological (ER) behavior of chitosan suspension in the silicone oil was investigated. Chitosan suspension showed a typical ER response, Bingham flow behavior upon application of an electric field due to the polarizability of the branched amino group of the chitosan particles. The shear yield stress exhibited a linear dependence on the volume fraction of particles and the squared electric field. On the basis of the experimental results, chitosan suspension has been correlated with the conduction models for ER response and found to be an ER fluid.

• Tribology and Lubricants
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• 제17권2호
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• pp.124-129
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• 2001

The electrical and rheological behaviors of the cellulose phosphate ester suspension in the silicone oil were investigated. Cellulose phosphate ester suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the cellulose phosphate ester suspension exhibited a linear dependence on the volume fraction of particles and a square power of the electric field. On the basis of the experimental results, cellulose phosphate ester suspension correlated with the conduction model of Tang et al, and found to be an ER fluid.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 추계 학술대회논문집
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• pp.102-107
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• 1998

Axisymmetric flows in an optical fiber coating applicator were computed by using structured finite volume solver FLUENT. The numerical computations were performed for various draw speeds from 900m/min to 1,200m/min. The physical phenomena in the coating applicator is the main topic of this paper. The results of the simulations covering streamline, pressure, temperature, and fluid-fluid interface are shown in this paper.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.243-248
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• 2007

A three-dimensional (3D) unstructured hydrodynamic solver for transient two-phase flows has been developed. A two-fluid three-field model was adopted for the two-phase flows. The three fields represent a continuous liquid, an entrained liquid, and a vapour field. The hydrodynamic solver is for the 3D component of a nuclear system code and the component-scale analysis tools for transient two-phase flows. The finite volume method and unstructured grid are adopted, which are useful for the flows in a complicated geometry. The semi-implicit ICE (Implicit Continuous-fluid Eulerian) numerical scheme has been adapted to the unstructured non-staggered grid. This paper presents the numerical method and the preliminary results of the calculations. The results show that the numerical scheme is robust and predicts the phase change and the flow transitions due to boiling and flashing problems well.