• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.279-283
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• 2002

The effects of finite gap at the tip of turbomachinery blades have long been topics of both theoretical and experimental research because tip clearance degrades turbomachinery performance. This paper presents an analytical study of radial flow redistribution in a high speed compressor stage with axisymmetric tip clearance. The flow is assumed to be inviscid and compressible. The stage is modeled as an actuator disc and the analysis is carried out in the meridional plane. Upon going through the stage, the radially uniform upstream flow splits into the tip clearance and passage flows. The tip clearance flow is modeled as a jet driven by blade loading, or pressure difference between the pressure and suction sides. The model takes into consideration the detached shocks which occur in the rotor passage at the design point. This shock model is used to calculate the density ratio across the stage. Thus, the model is capable of predicting the kinematic effects of tip clearance in the high speed compressor flow field.

• Culinary science and hospitality research
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• v.8 no.3
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• pp.147-168
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• 2002

This research made an alternative plan about tour experience program development utilizable cooking peculiar of an Andong locality. First currently Andong region have an Andong bass fishing great meeting, an Andong international mask dance, an Andong apple expo, an Andong Korean beef miss choice meeting, an Andong Hahoe folk village dabbling in water festival, but Andong didn't have about food festival. This region will mask a planning about food festival after this. Second, an Andong have a rich tradition of confucianism and buddhism. For example, there are Bongieong temple and Dosan private school. Therefore it is necessary tour experience program development can join of food and culture. Third, in term original locality of mask dance, we can tour experience development program out of the traditional food festival and mask dance performance. Fourth, Andong have a traditional food (a bluff memorial service rice, Andong fermenting rice, Gunjin noodle) and a traditional Korean-style house(sueding, chirye artists). It is necessary the development of board and loading experience program.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.71-75
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• 2005

For the damage tolerance improvement of conventional laminated composites, stitching process have been utilized for providing through-thickness reinforcements. 2D preforms were stacked with S-2 glass plain weave and S-2 glass MWK (Multi-axial Warp Knit) L type. 3D preforms were fabricated using the stitching process. All composite samples were fabricated by RTM (Resin Transfer Molding) process. To examine the damage resistance performance the low speed drop weight impact test has been carried out. For the assessment of damage after the impact loading, specimens were examined by scanning image. CAI (Compressive After Impact) tests were also conducted to evaluate residual compressive strength. Compared with 2D composites, the damage area of 3D composites was reduced by 20-30% and the CAI strength showed 5-10% improvement.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.304-309
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• 1997

Elastic elements, at first, were extensively used in suspensions as vibration isolators at joints. Nowadays they are used to improve stability and handling. The design of these elements has become a very important matter since the loading condition of the mechanism gives a mew suspension geometry without any modification. This paper presents an analysis of forces and moments of joints with elastic elements in the McPherson suspension mechanism to evaluate accurately the elastic deformation using the displacement matrix method in conjunction with the equilibrium equations. First the suspension is modeled as a multi-loop spatial rigid-body guidance mechanism which has elastic elements at the hardpoints of the suspension. Then a method and design euqations are developed to analyze the suspension characteristics by the various tire load. Also the displacement matrices and constraint equations for links are appllied to determine the sensitivity of the suspension mechanism. Finally this approach may conduct a realistic design of suspension mechanisms with elastic elements to improve the performance of the automobile under various driving conditions.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.55-67
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• 1993

In this study, the thermal behavior characteristics of the cylinder block of a small 3-cylinder, 4-stroke gasoline engine were analyzed, using the 3-dimensional finite element method. Before numerical analyses were conducted, the performance test and the heat transfer experiment of the engine were carried out in order to prepare the input data for the computations. Engine cycle simulation was performed to obtain the heat transfer coefficient and the temperature of the gas and the mean heat transfer coefficient of coolant. Temperature fields as a result of steady-state heat transfer were obtained and compared with experimental results measured at specific points of the inner and the outer walls of the cylinder block. The thermal stress and deformation characteristics resulting from the nonuniform temperature distributions of the block were investigated. The effects of the thermal behaviors of the cylinder block on the engine operations and the unfavourable aspects of excessive thermal loading were examined on the basis of the calculated results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.63-68
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• 2007

This paper presents vibration control performance of an active hybrid mount featuring piezostack actuators. The proposed hybrid mount is devised by adopting piezostack as an active actuator and rubber as a passive element. After experimentally identifying actuating force characteristics of the piezostack and dynamic characteristics of the rubber, the hybrid mount was designed and manufactured. Subsequently, a vibration control system with a specific mass loading is constructed, and its governing equations of motion are derived. In order to actively attenuate vibration transmitted from the base, a feedforward controller is formulated and experimentally realized. Vibration control responses are then evaluated in time and frequency domains.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1054-1059
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• 2007

This paper summarized a solution procedure for a large cylindrical structure mounted underneath a ship as a sonar. Vibration analysis of the water loaded structure is required to enhance the structural reliability as well as acoustic performance of the sonar. It is, however, often very difficult to solve such structures since they have many DOFs, considering the frequency of interest and the waterloading. The cyclic symmetric method is firstly reviewed to show how the eigen properties of the full model can be obtained from the representative segment model. The mode mapping method is then proposed and verified to take into account the waterloading with the minimum DOF for the analysis. The solution procedure is finally proposed and applied for a waterloaded cylindrical array structure.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.411-417
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• 2014

The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.238-240
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• 2006

For the method of train position detection, ground-based train position estimation mainly has been applied so far. Ground-based position detection is the way to detect train current positions by installing train position equipments on railroad lines. However, the ground-based methods should install detection equipments on each section, and can only be able to detect train positions from main command center. So this method has several disadvantages such as an discontinuous position detection, an increment in cost of installation and maintenance. To make possible continuous train position detection, and to minimize amount of the cost, the vehicle-based position detection method should be chosen to determine train positions by loading position equipments on vehicles. In this paper, to realize the vehicle-based train position detection method, configuration scheme of train position detection equipment is suggested by using GPS, inertial sensor, speed sensor and its performance is verified by simulations.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.487-492
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• 2002

The interior portion of Gerber's beam are constructed with post-tensioned segmental composite beams in this study. A precast concrete member which is larger than the limits of domestic transportation regulation in weight, length, and volume is divided into three parts, transported separately, and erected with a composite member by post-tensioning in site. Static flexural loading tests are performed on Gerber's type frames which are consisted with 2.5m overhangs and 5m interior beams composited from three pieces. The connection of overhang to interior composite beam and beam to beam, and flexural performance of interior portion of Gerber's beam are examined thoroughly. All of the tests are ended with a compression failure of the interior composite beams over the design strength of homogeneous beams. The brittle connection failures or tensile failures with the failure of lower strand was not observed in any test frames.