• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.9 no.2
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• pp.45-53
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• 2005

This paper investigates the influence of thermal conductivity and variable viscosity on the problem of micropolar fluid in the presence of suction or injection. The fluid viscosity is assumed to vary as an exponential function of temperature and the thermal conductivity is assumed to vary as a linear function of temperature. The governing fundamental equations are approximated by a system of nonlinear ordinary differential equations and are solved numerically by using shooting method. Numerical results are presented for the distribution of velocity, microrotation and temperature profiles within the boundary layer. Results for the details of the velocity, angular velocity and temperature fields as well as the friction coefficient, couple stress and heat transfer rate have been presented.

• Journal of computational fluids engineering
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• v.8 no.2
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• pp.49-56
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• 2003

Three-dimensional endwall flow within a linear cascade passage of high performance turbine blade is simulated with a 3-D Navier-Stokes CFD code (MOSA3D), which is based on body-fitted coordinate system, pressure-correction and finite volume method. The endwall flow characteristics, including the development and generation of horseshoe vortex, passage vortex, etc. are clearly simulated, consistent with the generally known tendency. The effects of both turbulence model and convective differencing scheme on the prediction performance of endwall flow are systematically analyzed in the present paper. The convective scheme is found to have stronger effect than the turbulence model on the prediction performance of endwall flow. The present simulation result also indicates that the suction leg of the horseshoe vortex continues on the suction side until it reaches the trailing edge.

• Journal of computational fluids engineering
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• v.8 no.3
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• pp.1-6
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• 2003

Three-dimensional endwall flow within a linear cascade passage of high performance turbine blade is simulated with a 3-D Wavier-Stokes CFD code (MOSA3D), which is based on body-fitted coordinate system, pressure-correction and finite volume method. the endwall flow characteristics, including the development and generation of horseshoe vortex, passage vortex, etc. are clearly simulated, consistent with the generally known tendency The effects of both turbulence model and convective differencing scheme on the Prediction performance of endwall flow are systematically analyzed in the present paper. The convective scheme is found to have stronger effect than the turbulence modei on the prediction performance of endwall flow. The present simulation result also indicates that the suction leg of the horseshoe vortex continues on the suction side until it reaches the trailing edge.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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• pp.406-414
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• 2004

In Gerotor pump, the pressure pulsations which occur due to the pump geometry result in vibration and noise of pump elements as well as cavitation in hydraulic system when the chambers of gerotor enter the delivery port and leave the suction port. Therefore it is important to study on the pressure pulsations before design and analysis of characteristics in Gerotor pump. In this paper, to reduce the unnecessary pressure pulsations, the port plate of Gerotor pump is designed based on the notch of the vane pumps and the relief grove of the piston pumps. The theoretical analysis of the pressure pulsations is performed in consideration of design parameters of the port plate which include each port positions and groove width and operating conditions which include rotational velocity and delivery pressure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.687-692
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• 2007

Vacuum cleaner, one of those household articles, have easily used in our life. Recently vacuum cleaner tends to be compact and portably with high suction power and low noise. As increasing this suction power, the vibration and noise of vacuum cleaner become important problem. To reduce noise efficiently, it is important to identify the noise and the vibration. This pater is to characterize the noise and vibration of a vacuum cleaner.

• Journal of computational fluids engineering
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• v.8 no.1
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• pp.8-15
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• 2003

Three-dimensional endwall flow within a linear cascade passage of high performance turbine blade is simulated with a 3-D Wavier-Stokes CFD code (MOSA3D), which is based on body-fitted coordinate system, pressure-correction and finite volume method. The endwall flow characteristics, including the development and generation of horseshoe vortex, passage vortex, etc. are clearly simulated, consistent with the generally known tendency. The effects of both turbulence model and convective differencing scheme on the prediction performance of endwall flow are systematically analyzed in the present paper. The convective scheme is found to have stronger effect than the turbulence model on the prediction performance of endwall flow. The present simulation result also indicates that the suction leg of the horseshoe vortex continues on the suction side until it reaches the trailing edge.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.385-385
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• 2000

In this paper, We presents the development of an automatic fog water collector that operates during fog events. This collector consists of fraction collectors, a wind hall and a fog sensor. If a fog event occurred, then the fog sensor wouldjudge whether it is a fog or not. If the fog sensor judged the fug, then the fog in the air would be rucked by suction fans. At the same time, the wind direction, the wind velocity, the atmospheric temperature and the atmospheric pressure would be measured and recorded. We are also developing a wireless communication system for the remote control and the remote data analysis in order to collect, store and process the data collected in the automatic fog water collector.

• The Journal of Korea Robotics Society
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• v.5 no.3
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• pp.177-185
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• 2010

In this paper, a wall climbing robot, called LAVAR, is developed, which is using an impeller for adhering. The adhesion mechanism of the robot consists of an impeller and two-layered suction seals which provide sufficient adhesion force for the robot body on the non smooth vertical wall and horizontal ceiling. The robot uses two driving-wheels and one ball-caster to maneuver the wall surface. A suspension mechanism is also used to overcome the obstacles on the wall surface. For its design, the whole adhering mechanism is analyzed and the control system is built up based on this analysis. The performances of the robot are experimentally verified on the vertical and horizontal flat surfaces.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.12
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• pp.931-937
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• 2008

A high motive pressure thermal vapor compressor(TVC) for a commercial multi-effect desalination(MED) plant is designed to have a high entraining performance and its robustness is also considered in the respect of operating stability at the abrupt change of the operating pressures like the motive and suction steam pressure which can be easily fluctuated by the external disturbance. The TVC having a good entraining performance of more than entrainment ratio 6.0 is designed through the iterative CFD analysis for the various primary nozzle diameter, mixing tube diameter and mixing tube length. And then for a couple of TVC having a similar entrainment ratio, the changes of the entrainment ratio are checked along the motive and suction pressure change. The system stability is diagnosed through the analyzing the changing pattern of the entrainment ratio.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.144-149
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• 2019

This paper describes the results of a study on the unmanned maintenance robot that simultaneously performs the cleaning and inspection of the photovoltaic panels. The robot has a special adsorptive device, an infrared sensor, a vacuum level sensor and a camera. The robot uses two SSC (Sliding Suction Cup) adsorptive devices to move up and down the slope. First, the forces generated when the robot moves up the slope are mechanically analyzed, and the required design and control of the adsorption system are suggested. The robot was designed and manufactured to operate stably by using the presented results. Next, the normal force between the panel and the wheel was measured to confirm that the robot was manufactured and operated as intended, and the robot motion was tested on the inclined panel. It has been proven that robots are well designed and built to clean and inspect sloped panels.