• Journal of Environmental Science International
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• v.32 no.11
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• pp.801-809
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• 2023

The purpose of this study is to predict the reflection distance following to the pulsing pressure, total air supplying, filter bag size using numercial analysis techniques and use it as an efficient operation condition and economic data for off-line type pulse air jet bag filter. In this research, filtration area 6 m² condition, calculate filter resistance coefficient for simulation through the main experiments using coke dust. Ansys fluent V19.0 apply to CFD simulation, and analysis pulsing characteristics about pulsing pressure, filtration velocity and nozzle diameter. The maximum reflecting distance of off-line type pulse air jet bag filter is 1,000 mm regardless of total air supplying at over the 42 L/m² conditions, that indicates off-line type can extend filter bag length 1,000 mm than on-line type. In order to effective primary and secondary pulsing of off-line type pulse air jet bag filter, over the 5 bar of pulsing pressure and over the 42 L/m² of total air supplying are needed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.158-164
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• 2008

In this paper, the performance of wet type filter for diesel engine combustion air has been studied with effects of air temperature, humidity, and pressure. After experiments are performed without diesel engine, it has been investigated the applicability to diesel engine. Wet type filter for diesel engine combustion air had advantages that it is not necessary to change air filter and that engine exhaust gas is environmentally friendly due to low NOx and particulate emission. Also, the filtration performance has been carried out with smoke shell.

• Journal of Technologic Dentistry
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• v.16 no.1
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• pp.5-11
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• 1994

On purpose of relative comparison of between air-vent attached pattern and non attached one, casting tests were accomplished by castability analysis unrig wax screen mesh pattern. Experimental specimens are divided Into 4groups. 1) Air-vent attached pattern with high casting pressure(coil spring type centrifugal casting machine 2.5turn). 2) Air-vent attached pattern with low casting pressure(coil spring type centrifugal casting machine 1.5turn). 3) Air vent non attached pattern with high casting pressure(coil spring type centrifugal casting machine 2.5turn). 4) Air-vent non attached pattern with low casting pressure(coil spring type centrifrgal casting machine 1.5turn). The main results are as follows : 1) The condition of high casting pressure no.1, no.3 were showed perfect castability. 2) The condition of low-casting pressure, there is a wide difference between no.2, no.4 group. Castability of no.2 group preferable to no.4 group(p<0.001). 3) Low casting pressure and complex shape cause the low-castability. So it is recommanded that use of air-vent in case of complex shaped wax pattern with low easting pressure.

• Particle and aerosol research
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• v.13 no.2
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• pp.65-77
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• 2017

In recent large-scale semiconductor manufacturing cleanrooms, the energy consumption in outdoor air conditioning (OAC) systems to heat, humidify, cool and dehumidify outdoor air(OA) represents about 40~50 % of the total cleanroom power consumption required to maintain cleanroom environment. Therefore, the assessment of energy consumption in outdoor air conditioning systems is essential for reducing the outdoor air conditioning load for a cleanroom. In the present study, an experiment with an outdoor air flow rate of $1,000m^3/h$ was conducted to compare the energy consumption in steam humidification, simple air washer, exhaust air heat recovery type air washer and dry cooling coil(DCC) return water heat recovery type air washer OAC systems. Besides, a numerical analysis was carried out to evaluate the annual energy consumption of the aforementioned four OAC systems. It was shown that the simple air washer, exhaust air heat recovery type air washer and DCC return water heat recovery type air washer OAC systems using water spray humidification were more energy-efficient than the steam humidification OAC system. Furthermore the DCC return water heat recovery type air washer OAC system was the most energy-efficient.

• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.3
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• pp.101-107
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• 2007

Indoor air quality becomes of a concern recently in view of human health. This study investigates the air diffusion performance and the air change efficiency of a classroom, when outdoor air is introduced in two different ways in addition to the heating/cooling operation of a ceiling-mounted heat pump. A CFD analysis has been performed to investigate the effect of the discharge angle of the air jets from the heat pump for both parallel and series types of outdoor air system. It is observed that the series type creates more uniform indoor environment compared to the parallel type in general. It can be concluded the discharge angle should not be larger than 40o for the parallel type, in order not to generate thermal stratification in the room.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.2
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• pp.52-58
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• 2007

This study shows a numerical method to predict automobile type air conditioner tube connector in the forming process. The simulation approach with 3-D FEM program(ABAQUS) for forming process, forming process simulation is in good agrement with it in tendency. Finally, we compared the forming result with simulation. The result of research showed thai forming process technology is promising to produce automobile type air conditioner tube connector.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.8
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• pp.1203-1210
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• 2004

It was reported recently that the pump head degradation near the best efficiency point from single-phase flow to the break-down due to air entrainment became less in a screw-type centrifugal pump than in a general centrifugal pump. In this paper, I carried out internal pressure measurements and visualizations, and investigated the various physical phenomena occurring inside a screw-type centrifugal pump operated in air-water two-phase flow. The results could give some characteristics about the degradation of pump performance on air-water two-phase flow.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.165.2-165.2
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• 2010

The objective of this study is to analyze the energy saving rate by retrofitting multi air conditioner from conventional type to high efficient type using Energyplus 4.0 which was developed for simulating a building energy by D.O.E. Generally, Multi air conditioner system was installed for both the cooling and the heating in a building. However, it was difficult to estimate the energy saving rate in the case of retrofitting multi air conditioner from conventional type to high efficient type. In the present study, annual energy consumptions of them were evaluated for same building and climate condition.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.6
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• pp.685-692
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• 2006

In a general centrifugal pump, if it is operated in a two-phase flow the activity of the impeller usually degrades and occasionally losses its function. However, the effect of break down of centrifugal pump due to entrained air has not been clarified yet. This paper shows the air-water two-phase flow characteristics of closed type and semi-open type impellers. In a sing1e-phase flow, closed-type impeller has higher efficiency and head. But in air-water two-phase flow semi-open type impeller's rates of decreases of efficiency and head are decreased.

• Journal of Biosystems Engineering
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• v.34 no.3
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• pp.167-174
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• 2009

This study was conducted to develop an agaricus bisporus washing machine which uses compressed air to remove foreign materials attached on the surface of agaricus bisporus. A prototype of the washing machine was constructed, and performance of removing foreign materials was tested. Research results are as follows: 1. Several transferring methods including PE roller rotation, brush roller rotation, PE screw rotation, vibration plate, and belt conveyor were evaluated. Roller, screw, and vibration methods caused damages on the surface of the products, but belt conveyor method caused the least damages. 2. For air jet, a stationary nozzle type and a rotational type were evaluated. The best air jet nozzle was the jet-type nozzle, and the rotational type was more effective than stationary type nozzle. 3. With the conveyer belt, box type moving method and the rotational air jet nozzle, the washing machine showed the best performance when higher than 5.4${\times}$105 Pa of air jet pressure and lower than 0.047 m/s of moving speed was used. Working performance of the system was 650 kg/h, and the damaging rate was 1.2 %.