• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.69-74
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• 2002

The following results are achieved from a mortar flow test depending on stainless steel slag fineness, replacement ratio, and a research on material age compressive strength, strength activity index. 1. Flow is proportional to the stainless steel slag fineness within the limits of 4000~8000$\textrm{cm}^2$/g, but in the case of fineness 20000$\textrm{cm}^2$/g flow decreases at all conditions except the case of replacement ratio 10%. 2. As stainless steel slag replacement ratio increases, Mortar of flow somewhat decreases. 3. As stainless steel slag blends, compressive strength decreases, but in proportion to the increase of age, compressive strength increases. 4. As stainless steel slag replacement ratio, compressive strength decreases. 5. In the case of stainless steel slag fineness 6000$\textrm{cm}^2$/g and 20.000$\textrm{cm}^2$/g, compressive strength of revelation ratio has the maximum value when it's replacement ratio is 10%.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.13-21
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• 2007

This paper presents characteristics of steady flow by variation of a combustion chamber and an intake port. Gas flow field inside a combustion chamber is the important factor in improving combustion stability and reduction of emission level. The flow characteristics such as flow coefficient, tumble ratio and swirl ratio are measured by the steady flow rig test with an impulse meter in this study. In the measuring, the valve lifts are varied between 1mm to 10mm. The three combustion chambers and two intake ports were applied to the steady flow apparatus in order to investigate the effect of swirl and tumble on the in-cylinder flow. As a result, tumble ratio were found to be different by variation of the combustion chambers and the intake ports. The data from the present study can be applied to design of a similar engine as basic data.

• Journal of Mechanical Science and Technology
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• v.20 no.5
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• pp.717-727
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• 2006

The present study experimentally investigated the effect of flow direction and other flow parameters on two-phase flow distribution of refrigerants at a T-junction, and also suggested a prediction model for refrigerant in a T-junction by modifying previous model for air-water flow. R-22, R-134a, and R-410A were used as test refrigerants. As geometric parameters, the direction of the inlet or branch tube and the tube diameter ratio of branch to inlet tube were chosen. The measured data were compared with the values predicted by the models developed for air-water or steam-water mixture in the literature. We propose a modified model for application to the reduced T-junction and vertical tube orientation. Among the geometric parameters, the branch tube direction showed the biggest sensitivity to the mass flow rate ratio for the gas phase, while the inlet quality showed the biggest sensitivity to the mass flow rate ratio among the inlet flow parameters.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.25-30
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• 2011

Flow control of flow field is essential to design efficient elements relating to fluid machineries. In this study, flow characteristics of rectangular prism with center gap through-flow at different aspect ratio was investigated to flow control. It was used a FLUENT 6.3 version to study flow field. It was found that the through-flow disturbs the development of vertical velocity component and decreased the vortex size and critical value of a rapid change in pressure coefficient distribution.

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.879-887
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• 2003

The flow in a parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V$\_$i/ / V$\_$o/ : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photographs showing fluid motion inside and around the test channel are also presented and discussed.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.27-35
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• 2006

It has been observed in experiments that combustion instability of low frequency (${\sim}$ 10Hz) results form the modulation of equivalence ratio at fuel injection hole when a pressure fluctuation propagates upwards along the channel of the burner under an unchoked fuel flow condition. In this study, a commercial program was used to determine how the fuel flow rate changed with respect to the pressure, velocity of the fuel flow and the mass fraction in a choked and an unchoked condition. The calculation focus on the upstream of the dump plane to know how the forced pressure with the fuel injection conditions affects the modulation of the equivalence ratio. Therefore, it is found that pressure fluctuation leads to oscillation of mass flow rate and then results in equivalence ratio modulation under the unchoked fuel flow condition.

• Wind and Structures
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• v.27 no.2
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• pp.111-121
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• 2018

Experiments were conducted in a large-scale Ward-type tornado simulator to study tornado-like vortices. Both flow velocities and the pressures at the surface beneath the vortices were measured. An interpretation of these measurements enabled an assessment of the mean flow field as well as the mean and fluctuating characteristics of the surface pressure deficit, which is a manifestation of the flow fluctuation aloft. An emphasis was placed on the effect of the aspect ratio of the tornado simulator on the characteristics of the simulated flow and the corresponding surface pressure deficit, especially the evolution of these characteristics due to the transition of the flow from a single-celled vortex to a two-celled vortex with increasing swirl ratio.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.441-448
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• 2006

In-cylinder flows such as tumble and swirl play an important role on the engine combustion efficiencies and emission formations. The tumble flow, which is dominant in current high performance gasoline engines, is able to effect fuel consumptions and emissions under a partial load condition in addition to the volumetric efficiency under a wide open throttle condition. Therefore, it is important to optimize the tumble ratio of a gasoline engine for better fuel economy, lower emissions, and maximum volumetric efficiency. First step for optimizing a tumble ratio is to measure a tumble ratio accurately. For a tumble ratio measurement, many different methods have been developed and used such as steady flow rig, PIV, PTV, and LDV. However, it is not well known about the relations among the measured tumble ratios using different methods. The purpose of this research is to correlate the tumble ratios measured using three different methods and find out merits and demerits of each measurement method. In this research the tumble flow was measured, compared, and correlated using three different measurement methods at the same engine: steady flow rig; 2-dimensional PIV; and 3-dimensional PTV water flow rig.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.267-274
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• 2016

Sewerage supply in rural community is the important for water quality protection of water system such as river, lake and wetland. And characteristic of small scale wastewater system that have wide range of inflow and concentration in sewage should be considered for stable operation of small scale wastewater treatment plant. In this research, characteristics of flow ratio (flow / designed flow), effect on treatment efficiency of small scale wastewater treatment plant and assessment of optimal flow ratio were conducted through analysis on operation result of 18 small scale wastewater treatment plant in Bong-hwa gun. As a result, flow ratio shows the higher value during summer. However pollutants concentration in sewage was shown the higher concentration during autumn and winter. Treatment of small scale wastewater treatment plant is increased when flow ratio increased, and nutrient treatment efficiency is more sensitive to change of flow ratio than organic compound and suspended solids. According to this research result, it need to be maintained flow ratio 0.8 over value for stable treatment efficiency of small scale wastewater treatment plant.

• Journal of Environmental Science International
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• v.7 no.4
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• pp.451-460
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• 1998

The objectives of this study Is to evaluate the total runoff yield, peak flow and peak flow travel time depending on the urbanization, return period and rainfall patterns at the downstream of Manchon urban watershed in TaeGu City. SWM(Storm Water Management Model) is used for runog analysis based on 5 different steps of urbanization and 4 different types of Hufrs quartile according to 8 return periods. It is analyzed that the order of total runoff yield according to raiun patterns is Huffs 4, Huffs 2. Huffs 3 and Huffs 1 quartile, that of peak flow magnitude is Huffs 2, Huffs 1, Huffs 4 and Huffs 3 quartile at present development ratio. under the 60, 70, 80 and 90ft of urbanization to the 50% of urbanization by means of the rainfall patterns, the mean Increasing ratio of total runoff yield for each case is 4.55, 11.43, 16.07 and 20.02%, that of peak flow is 5.82, 13.61, 17.15 and 18.83%, the mean decreasing ratio of peak flow travel time Is 0.00, 2.44, 5.07 and 6.26%, the mean increasing ratio of runoff depth Is 4.51, 11.42, 16.02 and 20.05% respectively. the mean increasing ratio of total runoff yield by means of each and 19.71%. Therefore, as the result of this study. it can be used for principal data as to storm sewage treatment and flood damage protection planning in urban small watershed.