• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.126-126
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• 2002

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.48-48
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• 1996

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.1
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• pp.8-15
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• 2004

Supersonic jets impinging on $60^{\cire}$ wedge were investigated to obtain fundamental design data for jet deflector It was of interest to study flow phenomena such as shock interaction and separation induced by shear layer. Experiments using supersonic cold flow system were conducted for Schlieren flow visualization and measurement of surface pressure. Numerical results were compared with the experimental results. The major parameters are underexpansion ratio, distance from nozzle to apex and design Mach number. Flow conditions were obtained for the wedge shock to attach on or detach from the wedge. The dominant feature of flow-field is shock pattern induced by the Interaction between the wedge shock and the barrel shock.

• Fire Science and Engineering
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• v.16 no.1
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• pp.77-83
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• 2002

The objective of this study is to propose a method to prevent the possible stress corrosion cracking of a horizontal side-wall sprinkler head deflector in the same atmosphere of ammonia gas as it regulated in the UL (Underwriters Laboratory). A corrosion test is carried out for three types of specimen according to post-forming treatment, one of which is annealing, another sand blasting and the other no treatment. The observation of the test specimens with a metal micro-scope says that the tensile residual stress is a major factor causing corrosion cracking, and that a proper heat treatment can remove or reduce the residial stress and prevent a crack from occurring even in a severe corrosive atmosphers.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.89-95
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• 2011

In this study, We modeled the deck house of the container ship like the representative bluff body and made the model ship. By using the PIV technique, the exhaust gas anti-reflux effect of the deck house backward according to open and close of the Sunken Deck and installation of the deflector in deck house side were measured in circulating water channel. The experiment system consists of hi-speed camera, laser, image board, host computer. The mean velocity vector and time mean axial velocity were found in deck house backward and the results were compared each case.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.266-269
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• 2003

During liquid rocket engine combustion, the resulting combustion gas has flow characteristics of high temperature and high velocity. An experimental study was performed to obtain basic data for a flame deflector design that is endurable under such flow characteristics. While the injected-water cools down the combustion plume, temperature and pressure of the plume was measured. As the experiment is being performed, gas temperature was measured using infrared cameras, and the gas temperature data was compared with the temperature data from the sensor in the plume. With the results of this experiment, we were able to obtain applicable temperature data for flame deflector design and predict the performance and structural strength required for installation of water injector.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.26-31
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• 2003

In this paper, supersonic jets impinging on axisymmetric cone were investigated to obtain fundamental design data for jet deflector case of example being VTOL/STOL or rocket launch. It was of interest to study flow phenomena such as shock interactions and separation induced by shear layer. Experiments were conducted to obtain schlieren flow visualization and measurement of surface pressure. Numerical results are compared with the experimental result. The dominant feature of the flow is the shock pattern induced by the interaction between the cone shock and the barrel shock. This pattern can take a wide variety of forms depending on the structure of the free jet and strongly influences the form of the surface pressure distributions.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.210-217
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• 2011

In results of accomplishing fundamental study to improve the flocculant-mixing of the Flash-Mixer in Onsan Water-Treatment Plant at the small cost, We obtained 8.9% of mixing-efficiency from the field data and 3.2% of the characteristic flow-ratio as the available maximum volume-ratio in this Water-Treatment Plant. The optimum elements with the deflector diameter of 400 mm and deflector angle of $145^{\circ}$ at the flow ratio of 3.2% could be obtained from the expanded study on the ground of the fundamental study. Finally, the efficiency could be improved about 510% from 8.9% to 45.4% and the average turbidity could be improved about 14%.

• Korean Chemical Engineering Research
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• v.62 no.2
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• pp.191-199
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• 2024

A study was conducted on a tubular heat exchanger to improve its heat transfer rate by using a novel baffle plate design with discontinuous swirling patterns. The design consisted of perforated baffle plates with rectangular air deflectors positioned at varying angles. The tubes in the heat exchanger were arranged in a consistent alignment with the airflow direction and exposed to a uniform heat flux on their surfaces. Each baffle plate included sixteen deflectors inclined at the same angle and arranged in a clockwise pattern. This arrangement induced a swirling motion of the air inside a circular duct where the heated tubes were located, leading to increased turbulence and improved heat transfer on the tube surfaces. The spacing between the baffle plates was adjusted at different pitch ratios, and the Reynolds number was controlled within a range of 16,000 to 29,000. The effects of pitch ratios and inclination angles on the heat exchanger's performance were analyzed. The results indicated that using a baffle plate with rectangular deflectors inclined at 30° and a pitch ratio of 1.2 resulted in an average increase of 1.29 in the thermal enhancement factor.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.276-278
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• 2012

This study was performed to investigate wake flow and unsteady flow characteristics using a model for actual shape of a wind breaker and visualization of flow through the particle image velocity. three control angle of flap were selected and instantaneous velocity distributions and flow characteristics were experimently investigated. It is found that as the control angle increase, the flows are characterized by the appearance of the growth of recirculation region.