• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.35-38
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• 2002

Variations of temperature and velocity fields in a Hele-Shaw Convection Cell (HSC) were measured using a holographic interferometry and PIV technique with varying Rayleigh number. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow at high Rayleigh numbers. Two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed to measure the temperature field variations of HSC convective flow. In the double-exposure method, unwanted waves can be eliminated and reconstruction images are clear, but transient flow structure cannot be observed clearly. On the other hand, transient flow can be observed and reconstructed well using the real-time method. PIV results show that flow inside the HSC is periodic and the oscillating state is well matched with the temperature field results. The holographic interferometry and PIV techniques employed in this study are useful for analyzing the unsteady convective thermal fluid flows.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2713-2717
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• 2008

Whole flow fields of a room air conditioner (RAC) have been visualized by a Particle Image Velocimetry (PIV) technique to analyze the flow structure with various inlet and outlet angles, and to control an eccentric vortex which affects an efficiency and noise of the RAC. A test model with 5 stages of a cross flow fan has been manufactured and a transparent acryl has been installed at the side of the test model for the PIV experiment. The inlet and outlet flows and the flow inside the cross flow fan have been analyzed by varying the inlet grill angles and outlet blade angles. The movement of the eccentric vortex has been investigated experimentally by developing the measurement technique for the inner flow field of the cross flow fan. From the visualization of the inner flows, the origins of the noise inside the RAC and the condensation points around the outlet parts of the cold air have been observed and the solution of the problems can be proposed in this study.

• Journal of computational fluids engineering
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• v.11 no.3 s.34
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• pp.37-45
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• 2006

In this study we present the numerical methods that can be used in visualization of the flow and mixing patterns in a cavity driven by a top lid. The basic flow field within the cavity has been obtained by using a simple numerical scheme. The invariant manifold also called unstable manifold was then attained to represent the mixing pattern within the cavity. It was shown that care must be taken in calculating the trajectories of the fluid particles especially near corners of the cavity. The numerical results show excellent agreement with those obtained experimentally by other research group.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.134-141
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• 2000

In this study, a scaled model chamber was built to investigate ventilation characteristics of the Under floor Air-conditioning System. Experimental study was performed in model for cargo-oil pump room with inlet and outlet by visualization equipment with laser apparatus. Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system(CACTUS'2000) which adopted two-frame grey-level cross correlation algorithm. The flow pattern reveals the large scale counterclockwise forced-vortex rotation from upside louver to lower scupper toward diagonal corner and also found small eddies at bottom layer

• Journal of the Korean Society of Visualization
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• v.3 no.2
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• pp.79-87
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• 2005

Two engines, one is conventional DOHC 4 valve and the other is narrow valve angle, were used to compare the characteristics of swirl motion generation in the cylinder. One intake port is deactivated to induce swirl flow. A PIV (Particle Image Velocimetry) was applied to measure in-cylinder velocity field according to inlet valve angle during intake and compression stroke. The results show that the flow patterns of narrow valve engine are much more stable and well arranged compared with the normal engine over the entire intake and compression stroke except early intake stage, and very strong swirl motion is generated at the end of compression stage in this engine nevertheless using straight port which is unfavorable for swirl generating. In the normal engine, however, strong swirl motion induced during intake stroke is destroyed as the compression progresses.

• 한국가시화정보학회:학술대회논문집
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• 2003.11a
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• pp.91-94
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• 2003

The present study addresses experimental results to investigate the details of the near field flow structures produced in the under-expanded, dual, coaxial, swirling, jet. The sonic swilling jets are emitted from a sonic inner nozzle and the outer annular nozzle produces the co/counter swirling streams against the primary swirling jet, respectively. The interactions between both the secondary annular swirling and primary inner supersonic swirling jets are quantified by the pilot impact and static pressure measurements, and visualized by using the Schlieren optical method. The experiment has been performed fur different swirl intensities and pressure ratios. The results obtained show that the secondary co-swirling jet significantly changes the inner under-expanded swirling jet, such as the recirculation zone, pressure distribution, through strong interactions between both the swirling jets, and the effect of the secondary counter-swirling jet on the primary inner jet is similar to the secondary co-swirl jet case.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.56-62
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• 2020

The purpose of this study is to observe the visualization of the flow field for air flow distributed in the car from the ventilation fan installed in the ceiling of the passenger elevator car through the numerical analysis using computational fluid dynamics. STAR-CCM+, which is a code used for the numerical analysis, was used to predict the airflow distribution inside the elevator car. The numerical analysis of the distribution of the air current in the elevator was carried out. As a result, the analysis results for each point and the visualization of the air current distribution and the temperature distribution in the elevator car and were obtained. It was found that heat transfer was actively occurring inside the car due to the influence of the flow field discharged from the ventilation vent installed in the ceiling in the elevator car, and especially the convection heat transfer of Model-2 was more active than that of Model-1. As a result, the temperature distribution inside the car was found to be relatively low. In addition, the temperature distribution at a cross-section of 1700mm height in the elevator car shows that Model-2 is the location of the ventilation vent which makes people feel more comfortable.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.89-92
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• 2007

In the present study, the flow field in a square container with various comer rounding is studied to investigate drain flow characteristics. An attempt has been made to understand the mechanism that is responsible for vortex suppressing by the different radius of rounding at the comer. For this purpose, flow visualization studies using PIV (Particle Image Velocimetry) are employed to determine the flow patterns in a square tank. Results are obtained when there is no draining and with draining. The flow field is visualized both in horizontal and vertical planes.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.152-153
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• 2012

While engine room arranging pipe which is used from the vessel, It measured the internal flow of 90 degree elbow which is used from the main condenser. Fluid flow in elbow of 90 degree is measured by PIV and Dewetron system. The Reynolds number adopts 50000 and experimental study of flow field in the elbow.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.183-196
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• 1997

Gas flow field within the cylinder which is called a tumble flow is important factor in improving lean combustion stability. In this study, steady state flow tests were performed to quantify tumble ratio of flowfields generated by a tumble intensifying valve(TIV). In addition, velocity and fluctuation profiles in an intake port and flowfields in th cylinder were inspected using a hotwire anemometer and a laser light sheet method with various TIV configurations. These experimental results show that installated TIV has a great effect on flow field distribution in an intake port and test effects enhance a tumble flow in the cylinder.