• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.2
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• pp.38-43
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• 2006

A turbine blade operates under high temperature, high pressure, and the loads have the characteristics that the amplitudes change. Therefore, it is important to perform a stress analysis considering thermal and pressure loads. The purpose of this study is to investigate the effects of these loads on gas turbine blade through thermal stress analysis. The analysis results shows that pressure in gas fluid flow around blade is high in leading edge part, Gas temperature is connections with pressure of flow around blade. The distribution of stress from blade is appearing as is different at suction side and pressure side.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.736-738
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• 2014

The paper deals with the accuracy comparison between two kinds of ultrasonic paths for flow rate measurement. In the Z-path, two transducers are installed on the opposite side of each other on a pipe, and the ultrasonic waves generated of one transducer propagate and arrive at the other one only through refraction. In the V-path, two transducers are installed on one side of a pipe, and the ultrasonic waves reflected at the inner wall of the pipe are received. The backgrounds were established to select one path to fit the usage by considering the advantages and disadvantages.

• Solar Energy
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• v.15 no.3
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• pp.53-58
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• 1995

The objectives of this study are to introduce the energy simulation program BLDSYM, to verify the approach, and to demonstrate the energy saving opportunities. A case study model for Hoover Middle School, OK, USA has been introduced as a base case simulation. Air-side variable air volume(VAV) and water-side variable flow hydronic(VFH) system have been recommended, modeled and simulated to quantify the energy savings compared with the base system, which is typically constant air and water flow system. More than 30% of energy savings could be obtained with the optimum variable flow system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.272-277
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• 2005

The discharge gap clearly is to order and to promote the improvement of processing feature of die-sinking electro discharge machining(EDM). If creation carbon, which generated by pyrolysis of EDM oil and processing pace power which is generated in between an electrode and a workpiece, are overproduced, they will lower the processing speed and roughness of the surface. Therefore, it is gone through the .flow analysis of EDM oil in order to improve the treatment of processing chips, which is an important problem by contriving a new flushing method. The condition of an electric discharge is not considered to be a progressing of processing. It is assumed that the flow of processing fluid is equal to the flow of processing chip, which is remaining in the discharge gap, and analyzing its correlation.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.496-501
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• 2003

Reynolds averaged Wavier-Stokes simulations based on the Reynolds stress model was performed to investigated the effect of inlet flow angle on the distributions of the Reynolds stress tensor inside tip leakage vortex of a linear compressor cascade. Two different inlet flow angles ${\beta}=29.3^{\circ}$(design condition) and $36.5^{\circ}$(off-design condition) were considered. Stress tensor analysis, which transforms the Reynolds stress into the principal direction, was applied to show an anisotropy of the normal stresses. Whereas the anisotropy was highest in the region where the tip leakage vortex collides the suction side of the blade and tip leakage flow enters between blade tip of the pressure side and the endwall, it had the lowest value at the center of tip leakage vortex. It was also found that the magnitude of maximum shear stress at design condition was greater than that of off-design condition.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.88-93
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• 1995

The purpose of this study is to introduce the energy simulation program BLDSYM, verify the approach. and demonstrate the energy saving opportunities. A case study model for Hoover Middle School, OK USA has been introduced as a base case simulation. Air-side variable air volume (VAV) and water-side variable flow hydronic (VFH) system have been recommended, modeled and simulated to quantify the energy savings compared with the base system, which is typically constant air and water flow system. More than 30 % of energy savings could be obtained with the optimum variable flow system.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.5
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• pp.1209-1215
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• 2024

In this study, fundamental research was conducted on the development of an adsorption-desorption ventilation system incorporating thermoelectric elements to improve indoor air quality (IAQ) and energy efficiency. The experiment was conducted using a thermoelectric module and silica gel as a commonly used adsorbent to evaluate the cooling and heating effects during the adsorption and desorption process. The main experimental results show that applying 3W power to the thermoelectric module reduces the outlet air temperature and improves the adsorption efficiency, while excessive power (4-5W) reduces the adsorption efficiency due to increased heat load. Additionally, when the flow rate on the adsorption side is increased, the completion time decreases. On the other hand, if the flow rate on the desorption side is increased, the completion time is also shortened. It was confirmed that as the flow rate increases, the movement of heat and moisture generated during the adsorption and desorption process becomes faster, and the reaction progresses more quickly.

• The Korean Journal of Rheology
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• v.11 no.2
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• pp.91-96
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• 1999

Semiconductive polyaniline and its derivatives such as poly(aniline-co-sodium diphenylamine sulfonate), poly (aniline-co-o-ethoxyaniline), poly (o-methylaniline), and poly (o-methoxyaniline) were synthesized, and then adopted as suspending particles of the electrorheological (ER) fluids. All suspensions of these polyaniline derivatives showed typical ER properties under high applied electric fields. However, flow behaviors are observed to be quite different depending on the polyaniline derivatives, especially in the stress plateau regions obtained at low shear rates. Using a scaling law, we also obtained universal cures of ER fluids from the flow curves at each applied electric field based on the relationship between the dynamic yield stress with the applied electric field and flow curve changes according to the electric fields.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.1
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• pp.12-24
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• 1998

The paper presents the mechanism of secondary flows and the associated total pressure losses occurring in turbine cascades with turning angle of about 127 and 77 degree. Velocity and pressure measurements are taken in seven traverse planes through the cascade passage using a prism type five hole probe. Oil-film flow visualization is also conducted on blade and endwall surfaces. The characteristics of the limiting streamlines show that the three dimensional separation is an important flow feature of endwall and blade surfaces. The larger turning results in much stronger contribution of the secondary flows to the loss developing mechanism. A large part of the endwall loss region at downstream pressure side is found to be very thin when compared to that of the cascade inlet and suction side endwall. Evolution of overall loss starts quite early within the cascade and the rate of the loss growth is much larger in the blade of large turning angle than in the blade of small turning angle.

• The KSFM Journal of Fluid Machinery
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• v.5 no.3 s.16
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• pp.33-39
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• 2002

The head-capacity corves for pumps developed by the pump manufacturer are based on tests of a single pump operating in a semi-infinite pool with no nearby walls or floors and with no stray currents. Hence, flow into the pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. However, various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found in pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface, side-wall, and back-wall due to different clearances from back-wall to vortical intake pipe. Moreover, the locations and patterns of the various types of vortices that were found in the examinations are discussed.