• 한국유체기계학회 논문집
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• 제12권3호
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• pp.13-18
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• 2009

This paper describes flow characteristics in a piping system having various duct shapes on refuse collecting system. A simulator for the refuse collecting system is designed to analyze the flow characteristics in the piping system. The simulator consists of an air intake, a waste chute, circular duct having various shapes, cyclone and turbo blower. The simulator has four different duct shapes: straight, curved, inclined and Y-shaped ducts. Three-dimensional Navier-Stokes analysis is introduced to analyze the pressure loss in the piping system. Throughout the numerical simulation, pressure loss obtained by numerical simulation has a good agreement with the results of experimental measurements. The selected length of curved and Y-ducts for the pressure loss is determined using pressure distributions on the duct. Flow and pressure characteristics in the piping system of the simulator are evaluated by numerical simulation and discussed in detail.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.425-428
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• 2006

Natural gas hydrate has been a major problem for its plugging nature in the pipeline. With the demand of deep-water production, the importance of flow assurance technology, preventing hydrate, asphaltene and wax in the pipeline becomes bigger Kinetic models combined with the flow simulator are being developed to explain the nature of hydrate plug formation in the pipeline. To simulate the hydrate plug formation, each stage including the nucleation, growth and agglomeration should be considered. The hydrate nucleation is known to be stochastic and is believed hard to be predicted. Recent publications showed hydrate growth and agglomeration can be observed rigorously using a particle size analyzer. However properties of the hydrate should be investigated to model the growth and agglomeration. The attractive force between hydrate particles, supposed to be the capillary force, was revealed to be stochastic. Alternative way to model the hydrate agglomeration is to simulate by the discrete element method. Those parameters, particle size distribution, attractive force, and growth rate are embedded into the kinetic model which is combined Into the flow simulator. When compared with the flowloop experimental data, hydrate kinetic model combined into a flow simulator showed good results. With the early results, the hydrate kinetic model is promising but needs more efforts to improve it.

• 한국정밀공학회지
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• 제33권6호
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• pp.509-516
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• 2016

A blood flow simulator is one of the experimental devices used to better understand the cardiovascular system. Time-Domain analysis is not sufficient to understand the cardiovascular system because of the effects related to pulsating flows. Even when the mean pressure and mean flow rate of the blood flow simulators are satisfied, the dynamic properties can differ from the desired performance. In this paper, the Windkessel model, a well-known mathematical model of the cardiovascular system, was employed to obtain optimized pressure using initial values. The Windkessel parameters, including flow resistance, R, are expected to lead to a better understanding of the dynamic behavior of cardiovascular systems.

• 전기학회논문지
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• 제58권10호
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• pp.1902-1910
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• 2009

This paper presents a graphical windows-based program for the education and training for novel network reduction. The object of developed simulator is to provide users with a simple and useable tool for gaining an intuitive feel for power system analysis. The developed simulator consists of the main module (MMI,GUI), the location marginal price module (LMP), the clustering module and network reduction module. Each module has a separate graphical and interactive interfacing window. The developed simulator needs with the PSS/E input data format, generator cost function, location information. Line admittances of reduced network was determined by using the power flow method(Newton-Raphson). So line flow of reduced network is almost same to original power system. Results of reduced network are compared on the window in the tabular format. Therefore, the developed simulator can be utilized as a useful tool for effective education and training for power system analysis.

• 대한의용생체공학회:의공학회지
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• 제29권4호
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• pp.323-328
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• 2008

A patient with respiratory disorders such as a sleep apnea is increasing as the obese patient increase on the modern society. Positive Airway Pressure (PAP) devices are used in curing patient with respiratory disorders and turn out to be efficacious for patients of 75%. However, these devices are required for evaluating their performance to improve their performance by the mechanical breathing simulator. Recently, the mechanical breathing simulator was studied by the real time feedback control. However, the mechanical breathing simulator by an open loop control was specially required in order to analyze the effect of flow rate and pressure after operating the breathing auxiliary devices. Therefore the aims of this study were to make the mechanical breathing simulator by a piston motion and a valve function from the characteristic test of valve and motor, and to duplicate the flow rate and pressure profiles of some breathing patterns: normal and three disorder patterns. The mechanical simulator is composed cylinder, valve, ball screw and the motor. Also, the characteristic test of the motor and the valve were accomplished in order to define the relationship between the characteristics of simulator and the breathing profiles. Then, the flow rate and pressure profile of human breathing patterns were duplicated by the control of motor and valve. The result showed that the simulator reasonably duplicated the characteristics of human patterns: normal, obstructive sleep apnea (OSA), mild hypopnea with snore and mouth expiration patterns. However, we need to improve this simulator in detail and to validate this method for other patterns.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.447-452
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• 2000

In this study, the design of Free-Fall Simulator was carried out using concept of vertical wind tunnel. Free-Fall Simulator is not an experimental equipment but a training equipment. Therefore Free-Fall Simulator needs a large training section compared with test section of wind tunnel and has critical limit of height. These limits bring about the difficulty of design for a return passage. Due to small area ratio, the downstream flow of training section with high speed is not decelerated adequately to the fan section. High-speed flow leads to great losses in the small area ratio diffuser and corner. So design of diffusers and corners located between training section and fan section has a great effect on the Free-Fall Simulator performance. This study used an estimation method of subsonic wind tunnel performance. It considered each section of Free-Fall Simulator as an independent section. Therefore loss of one section didn't affect loss of other sections. Because losses of corner with vane and $1^{st}$ diffuser are most parts of overall Free-Fall Simulator, this study focused on the design of these sections.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권2호
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• pp.37-44
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• 2009

It is well known that a refrigerant-induced noise is caused by two-phase flow in the indoor unit of a heat pump air-conditioner. Especially when the flow pattern in a pipe is intermittent flow, the irregular noise occurs frequently. But it is very difficult to avoid this kind of the noise for the application of air-conditioner. Therefore, in this research, the flow patterns at two-phase flow state in a pipe of the indoor unit for the air-conditioner are researched using cycle simulator at typical cycle conditions. In order to find the relationship between refrigerant-induced noise and flow pattern, the noise patterns are investigated with respect to the estimated flow pattern from the various flow pattern maps. Base on the estimations of the flow patterns by those maps, the refrigerant-induced noise is evaluated as decreasing tube diameter, which can transit the flow pattern from slug to annular flow.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.187-189
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• 2007

This paper presents the development method of educational simulator for Power System Analysis. The developed simulator can be made the students to model, analysis of power systems by drawing the system and performing the load flow, fault analysis by themselves under window environment. The simulator has developed by using the language based on XML(extensible Markup Language). Therefore, we determine that this simulator is useful to educate the load flow and fault analysis.

• 센서학회지
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• 제8권2호
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• pp.133-138
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• 1999

In this pager, the authors have implemented a blood flow simulator and a LDF(laser Doppler flowmeter) probe using self-mixing effect of the laser diode. The purpose of the blood flow simulator is to simulate microvascular blood flow in tissue. It consists of melinex film (thickness = $123\;{\mu}m$) which has similar optical characteristics to epidermis and porous polyethylene filter (Vyon, porosity 35%, mean pore size $50\;{\mu}m$, thickness=1 mm) which has similar optical characteristics to dermis. The blood flowmeter probe consists of laser diode(5 mW, 780 nm wavelength), CD lens(focal length 12 mm). current-to-voltage converter, highpass filter, and premplifier. It doesn't need optical fiber, therefore, implementation of the probe is simpler than conventional probe using optical fiber.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.52-59
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• 2014

Operator training simulator, within a training environment designed to understand the principles and behavior of the railway system with respect to operator's entries and predefined scenario, can provide a very strong benefit in facilitating operators' handling undesired operations. This simulator consists of computer system and applications, and the purpose of applications is to generate the power and voltage and analyze the AC substation and DC railway, respectively. This paper describes a novel approach to the new techniques for AC/DC hybrid simulation for the operator training simulator in the railway system. We first propose the structure the database of railway system. Then, topology processing and power flow using a linked-list method based on the proposed database, full or decoupled newton-rapshon methods are presented. Finally, the interface between the analysis for AC substation using a newton-rapshon method and the analysis for DC railway system using a time-interval power flow method is described. We have verified and tested the developed algorithm through the extensive testing for the proposed test system. To demonstrate the validity of the developed algorithm, comparative simulations between the proposed algorithm and PSS/E for the test system were conducted.