• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.879-884
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• 2003

This paper is to experimentally investigate the effect of the through-flow and grazing-flow on the absorption performance of a perforated plate system. The experiment is performed through the systematic change of the through-flow velocity, grazing-flow velocity, incident sound pressure level, and the geometrical parameters such as the porosity and hole diameter. From the experimental results, it is found that for the nonlinear relationship between the acoustic resistance and incident sound pressure level there is no influence of the through-flow on the absorption performance, but fur the linear relationship between them there is a strong dependence of the absorption performance on the through-flow velocity. It is also shown that the absorption performance is controllable by changing the porosity and hole-diameter in size.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 춘계 학술대회논문집
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• pp.214-219
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• 2004

The HANARO, a multi-purpose research reactor of 30 MWth, open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. The HANARO is composed of inlet plenum, grid plate, core channel with flow tubes and chimney. The reactor core channel is located at about twelve m (12 m) depth of the reactor pool and cold by the upward flow that the coolant enters the lower inlet of the plenum, rises up through the grid plate and the core channel and exit through the outlet of chimney. A guide tube is extended from the reactor core to the top of the reactor chimney for easily un/loading a target under the reactor normal operation. But active coolant through the core can be Quickly raised up to the top of the chimney through the guide tube by jet flow. This paper is described an analytical analysis to study the flow behavior through the guide tube under reactor normal operation and unloading the target. As results, it was conformed through the analysis results that the flow rate, about fourteen kilogram per second (14 kg/s) suppressed the guide tube jet and met the design cooling flow rate in a circular flow tube, and that the fission moly target cooling flow rate met the minimum flow rate to cool the target.

• Journal of Advanced Marine Engineering and Technology
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• 제23권2호
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• pp.124-130
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• 1999

Flow characteristics of a compressible gas flow through a rotating disc-type rotary valve are investigated experimentally under various conditions. It is known that the mass flow rate through poppet valves of 4-stroke cycle engines and through piston valves of 2-stoke cycle engines decrease with increase in engine speed. Rotary valve is one means by which air may be made to flow inter-mittently through a pipe. In this paper an exhaust system simulator of engine was used to experi-mentally analyze the decrease in flow rate at high rotation speeds and to determine what variables other than rotational speed give rise to the observed behaviour. These variables have been included in an empirical equation which is representative of the measured flow characteristics.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.900-904
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• 1991

It is important and difficult to control the steam temperature in the once through boiler. Generally, steam temperature of once through boiler not only is controlled by boiler spray water flow, but also is influenced by feed water flow and fuel flow. So we have to make the same gain of fuel flow controller and feed water flow controller. This paper is shown the design and test of steam temperature and feed water flow control system for once through boiler in pusan thermal power plant.

• 한국안전학회지
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• 제15권3호
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• pp.52-56
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• 2000

The finite control volume method was utilized to investigate the effects of flow through openings on convection in an enclosure. Flow patterns and temperature distribution were compared for non-dimensional inflow velocity U=20, 40, 60 at Ra=$10^4$ and $5\times10^4$, respectively. The inflow velocity influenced temperature distribution in the enclosure significantly and lowered temperature on the top wall. The flow through openings forced the position of the highest temperature on the top wall to move toward the outflow opening.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.163-167
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• 2003

This paper is to experimentally investigate the effect of the through-flow on the absorption performance of a perforated plate system. The experiment is performed through the systematic change of the through-flow velocity, incident sound pressure level, and the geometrical parameters such as the porosity and hole diameter. From the experimental results, it is found that fur the nonlinear relationship between the acoustic resistance and incident sound pressure level there is no influence of the through-flow on the absorption performance, but for the linear relationship between them there is a strong dependence of the absorption performance on the through-flow velocity. It is also shown that the absorption performance is controllable by changing the porosity and hole-diameter in size.

• 설비공학논문집
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• 제11권4호
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• pp.492-498
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• 1999

Mass flow rates of R407C and R290 through capillary tubes were measured with various capillary tube geometries and flow conditions. For all refrigerants tested in the present study, mass flow rate through the capillary tube was strongly dependent on the condensing pressure, subcooling and capillary length and diameter. The flow rate of R407C was 5~10［%］ higher than that of R22 at the same condensing temperature and degree of subcooling, while flow rate for R290 was 40［%］ lower than that for R22. Based on experimental results, an empirical correlation was developed using Pi theorem to predict the mass flow rate through capillary tubes. The predicted flow rates using the model were consistent with the experimental data within ${\pm}$10[%］.

• Journal of Mechanical Science and Technology
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• 제20권3호
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• pp.391-398
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• 2006

This work involves a method for modeling the flow distribution in the stack of a solid oxide fuel cell. Towards this end, a three dimensional modeling of the flow through a Solid Oxide Fuel Cell (SOFC) stack was carried out using the CFD analysis. This paper examines the efficacy of using cold flow analysis to describe the flow through a SOFC stack. It brings out the relative importance of temperature effect and the mass transfer effect on the SOFC manifold design. Another feature of this study is to utilize statistical tools to ascertain the extent of uniform flow through a stack. The results showed that the cold flow analysis of flow through SOFC might not lead to correct manifold designs. The results of the numerical calculations also indicated that the mass transfer across membrane was essential to correctly describe the cathode flow, while only temperature effects were sufficient to describe the anode flow in a SOFC.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.346-352
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• 2002

This paper is the experimental study to estimate the influence of various design parameters on the performance of mufflers with perforated tubes and through-flow partitions. Muffler types considered in the present work include through-flow chamber, through-flow chamber with partition, and cross-flow chamber. The influences of the design parameters on the performance of the mufflers can be outlined as follows. In the case of the through-f]ow type mufflers, increasing the tube thickness and the hole diameter of the perforated tubes does not change the maximum value of the transmission loss but decrease the cutoff frequency. In the case of the through-flow with partitions type mufflers, it is shown that combining a fe w short chambers and long chambers can modify the frequency locations of the resonance frequencies to optimize the performance of the mufflers. For the case of the cross-flow type mufflers, it is shown that the transmission loss of the mufflers is mainly affected by the lower porosity when the porosities are different in both sides of the plug. Overall, it is shown that performance of the through-flow type with partition type mufflers is excellent in the lower frequency region, where the cross-flow type mufflers have better performance in the higher frequency region.

• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.372-380
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• 1997

This paper describes experimental investigations of helium-air exchange flows through parti¬tioned opening and two-opening. Such exchange flows may occur following rupture accident of stand pipe in high temperature gas cooled reactor. A test vessel with the two types of small open¬ing on top of test cylinder is used for experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. A technique of flow visualization by Mach-Zehnder interferometer is provided to recognize the exchange flows. In the case of exchange flow through the partitioned opening, flow passages of upward flow of the helium and downward flow of the air within the opening are separated by vertical partition, and the two flows interact out of entrance and exit of the opening. Therefore, an experiment of the exchange flow through two-opening is made to investigate effect of the fluids interaction of the partitioned opening sys¬tem. As a result of comparison of the exchange flow rates between the two types of the opening system, it is found that the exchange flow rate of the two-opening system is larger than that of the partitioned opening system due to absence of the effect of fluids interaction. Finally, the fluids interaction between the upward and downward flows through the partitioned opening is found to be an important factor on the helium-air exchange flow.