• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1410-1419
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• 2019

In this research, it is to find a method that frost does not form on the outdoor unit to develop a heat pump capable of heating in cold regions. For this reason, we produced an incubator capable of creating an environment of -25℃, and constructed an experimental apparatus so that experiments in the room were possible. However, it is necessary to grasp the characteristics of the air reaching the front of the heat pump outdoor unit installed in the experimental apparatus, and flow analysis was performed using ANSYS CFX, which is general-purpose software. As a result, the flow velocity of the air reaching the front of the outdoor unit in the outdoor unit chamber in the entire region of the simulation conditions (5.0 to 7.5 m/s) has many differences in the upper and lower portions, resulting in a natural state. It turned out that the condition can not be satisfied. Therefore, it is determined that it is necessary to additionally install a frequency divider at the front of the outdoor unit to make the flow velocity constant.

• Korean Journal of Veterinary Service
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• v.20 no.2
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• pp.143-150
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• 1997

Total viable cells and lactose non-fermenting cells were counted from animal feedstuffs (n=65). And isolation of Gram negative lactose nonfermenting enterobacteria and antibiotics susceptibility of isolates were performed. 1. The ranges of total viable cells / lactose non-fermenters in animal feedstuffs from Korean cattle were counted as 9$\times$$10^4$-1$\times$$10^7$ / 1$\times$$10^2$-6$\times$$10^3$, milking cow as 1$\times$$10^4$-2$\times$$10^8$ / 2$\times$$10^2$-8$\times$$10^3$, pig as 1$\times$$10^4$-1$\times$$10^6$ / 2$\times$$10^2$-6$\times$$10^3$, and chicken as 7$\times$$10^4$-1$\times$$10^9$ / 4$\times$$10^2$-1$\times$$10^5$ cfu/g, respectively. 2. Among the 214 isolates from feedstufs, 87 from Chinan(n=23), 66 from Changsu (n=23) and 61 from Mooju(n=19) were isolated. Of these isolates, 60 from pigs (n: 19), 51 from milking cows(n=15), 45 from chikens(n=11) and 58 from Korean cattle(20) were isolated. 3. Among the 6 genuses of Gram negative lactose nonfermenting enterobacili, Salmonella sp, Y pseudotuberculosis, Ent agglomerans and Sal choleraesuis were frequently encountered. 4. A majority of isolates were sensitive to 19 antibiotics, singly or in combination. These isolates were completely susceptible to Cp, Gm, Imp and Pi, 93% to Ak and To, 73% to Cax and Ts, 66% to Cft and Tim, 46-53% to Caz, Cf and Cz, 33-40% to Am, Azt, Cfz and Ti, and 6% to Cfx, in order, but not susceptible to Crm. 5. Among the antibiotic resistant strains, a total of 23 resistant patterns was noted, and of these Crm 40(18.7%), Am Cf Cfx Cfz Crm Ti 27(12.6%), each of Azt Ctx Crm and Azt Cax Caz Cft Cfx Crm 22(10.3% ) were frequently encountered.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.3
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• pp.207-214
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• 2015

The preliminary design of a radial inflow turbine using R134a as the working fluid at 5 kW of power for application to ocean thermal energy conversion (OTEC) is performed to obtain the trends for the efficiency and geometrical dimensions of the turbine. Using input conditions that included a turbine inlet temperature of $25^{\circ}C$, an outlet static pressure of 4.9 bar, and a mass flow rate of 1.16 kg/s, the results of a mean flow analysis show the major dimensions of the turbine, along with an angular velocity of 12,820 rpm. Based on these results, a three-dimensional turbine model is constructed for a computational fluid dynamics (CFD) analysis. The flow characteristics inside the turbine, including the volute and nozzle, are investigated using the CFD software ANSYS CFX. For a pertinent number of nozzle guide vanes, ranging from 10 to 15, the turbine efficiency was higher than 80%, with the highest efficiency shown by a nozzle with 15 guide vanes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.5
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• pp.329-339
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• 2017

Impingement jets have been applied in a wide variety of fields as they provide significantly high heat transfer on the impingement-jet stagnation zone. However, the crossflow in an impingement chamber developed by spent wall jets can disrupt and deflect the downstream jets in the array, leading to a decrease in the cooling performance of an array of impingement jets. A numerical analysis is made of the fluid flow and heat transfer characteristics in a corrugated structure that traps the spent air in the corrugations between impingement jets and reduces crossflow effects on downstream jets. All computations are performed by considering a three-dimensional, steady, and incompressible flow by using the ANSYS-CFX 15.0 code. The effects of the configuration parameters of the corrugated structure on crossflow reduction of the array of impingement jets are presented and discussed.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.74-81
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• 2013

In this study, the separation efficiency of wind power selector (the direction of the air flow of the air to perform gravity separation method) of municipal solid waste which was landfilled was investigated to reduce amount of waste that is designed to increase the recycling rate of wastes for the ANSYS CFX Program's numerical methods with wind through the separator. When a suction device designed to suction 1000mL of a plastic bag, the separation efficiency was 100% and when the wind speed was 0.9 m /sec or more and when the wind speed was 1.6 m / sec or more, the efficiency of plastic bottles in a mixture of 500mL and 1500mL plastic bottle waste was 100% and the aluminum screening efficiency of 250mL aluminum can was 100 % when the wind speed was 2.3 m / sec. In the last, 5mm thick compressed aluminum can efficiency was 90 % when the wind speed was 2.4 m / sec.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.11
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• pp.903-910
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• 2014

Electric fans, which consist of axial blades, are operated by the induction motor. In this paper, the objective of this study is the performance improvement of the base model fan using the design optimization. In order to aerodynamic analysis, computational simulations are performed using commercial tool ANSYS-CFX ver. 14.5. And k-${\omega}$ SST turbulence model is used for the CFD analysis. The design variables are set up as sweep and lean angles. Volumetric flow rate and torque of the fan blades are fixed to objective function. The optimized model is shown the increment of the volumetric flow rate and the reduction of the torque compared with the base model. The experimental procedure is followed KS C 9301. CFD results and experimental results are fairly well matched.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.683-687
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• 2012

The purpose of this paper is to numerically study the characteristics of the indoor air flow of a square ceiling type diffuser according to the vane angle and flow rate. The CFX of ANSYS 13.0 was used for the CFD tool. The size of the room is $6m(X){\times}6m(Y){\times}2.7m(Z)$. The exhaust diffuser was positioned diagonally to the supply diffuser. This diffuser was designed to have many holes, so the air supply had long throw patterns with low velocity decay. The characteristics of the indoor air flow was studied at volume flow rates of 5.1 CMM and 7.4 CMM, and a vane angle from $30^{\circ}$ to $60^{\circ}$, every $10^{\circ}$.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.13-18
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• 2015

Characteristics of restoring force for the wind-powered leisure boat was investigated using mathematical formulation and commercial computational method such as the ANSYS Workbench CFX-Mesh. The objective is to find the restoring moment and heel moment while boat is sailing in windy power. Conditions for angle of attack were given from $5^{\circ}$ to $90^{\circ}$. It is known that side force is larger in terms of angle of attack is higher, however critical angle is suggested to limit before over of $60^{\circ}$ for safe navigation for boat in wind. Natural results are found that stronger heel moment is observed when sail is used than no sail, and higher angle of attack is induced stronger heel moment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.855-862
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• 2013

A series of 1/5 scale-down reactor flow distribution tests had been conducted to determine the hydraulic characteristics of an APR+ (Advanced Power Reactor Plus), which were used as the input data for an open core thermal margin analysis code. In this study, to examine the applicability of computational fluid dynamics with the porous model to the analysis of APR+ internal flow, simulations were conducted using the commercial multi-purpose computational fluid dynamics software ANSYS CFX V.14. It was concluded that the porous domain approach for some reactor internal structures could adequately predict the flow characteristics inside a reactor in a qualitative manner. If sufficient computational resources are available, the predicted core inlet flow distribution is expected to be more accurate by considering the real geometry of the internal structures, especially upstream of the core inlet.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.5
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• pp.327-333
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• 2013

The purpose of this study is to predict sloshing pressure of a actual tank by using measured pressure in scaled down tank and to evaluate with structural strength of LNG Corner Block. For this purpose, we performed sloshing analysis about 138K class tank by using Ansys CFX program, and were measured both average pressure and maximum peak pressure according to scaled tank ratio. Also, measured pressure was converted to pressure of the actual tank by Froude scale law, and we conducted the evaluation of structural strength about the conner block of actual size KC-1.