• 한국입자에어로졸학회지
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• 제9권3호
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• pp.139-147
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• 2013

The performances of indoor air cleaners including particle cleaning capacity and collection efficiency are usually tested at the condition of the maximum air flow rate of the air cleaners. However, the power consumption of the air cleaners is highly dependent on the air flow rate of the individual air cleaners. Therefore, there seems to be an optimized air flow rate for the air cleaning capacity considering power consumption. In this study, clean air delivery rate(or standard useful area as suggested room size) and power consumption have been investigated for different maximum air flow rates of 15 air cleaners and then compared those for different air flow rate modes of the individual 5 air cleaners selected from the 15 cleaners. For the maximum air flow rate conditions of 15 air cleansers, the power consumption per unit area was less related to the maximum air flow rate. However, for the different air flow rate modes of the selected 5 air cleaners, the lower power consumption per unit area was corresponding to the lower air flow rate mode of the individual air cleaners. When considering the operation time to the desired particle concentrations, there was an optimized one in the medium air flow rate modes for the individual air cleaners. Therefore, not only the maximum air flow rate but also lower air flow rates of individual air cleaners should be considered for estimating air cleaning capacity based on energy consumption per unit area.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.92-101
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• 1996

In a gasoline engine, the characteristics of air flow is very important not only for the design of the intake system geometry bout also for the accurate measurement of the induction air mass. In this study, an air flow rate measurement of the induction air mass. In this study, an air flow rate measurement was conducted by using the hot wire flow meter at the upstream of the intake port and the throttle. At the upstream of the throttle, the overshoot phenomena of the air flow rate by fast throttle opening were analyzed with choked flow. At the upstream of the intake port, the cylinder variation of the air flow rate and the difference between fast throttle opening and closing were showed during the unsteady state by the throttle step change. The results of this study can be used for the design of the throttle valve geometry and cylinder by cylinder control.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.1-12
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• 1997

In an SI engine, the characteristics of the air flow is important not only for the design of the intake system geometry but also for the accurate measurement of the induction air mass. In this study, an air flow rate measurement using the ultrasonic flow meter and hot wire flow meter was conducted at the upstream of the intake port and the throttle. At the upstream of the intake port, the pulsating flow into the cylinder affected by the pressure wave was detected directly with the flow meters instead of pressure sensors. At the upstream of the throttle, the reverse flow phenomena were showed by comparing the flow pattern measured by the hot wire air flow meter and the ultrasonic air flow meter. The results of this study can be used for the analysis of the tuning effect in the intake manifold and estimation of the error in real time measurement for the air flow rate.

• 대한기계학회논문집B
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• 제27권4호
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• pp.511-517
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• 2003

An experiment is conducted to investigate the effect of air and water mass flow rates on cooling characteristics of mist impinging jet on a flat plate. The air mass flow rate ranges from 0.0 to 3.0 g/s, and water mass flow rates from 5.0 to 20.0 g/s. An air-atomizing nozzle is used fur the purpose of controlling air and water mass flow rates. The test section is designed distinctively from previous works to obtain local heat transfer coefficient distributions. Heat transfer characteristics of the mist impinging jet are explained with the aid of flow visualization. Surface temperature and heat transfer coefficient distributions become more uniform as air mass flow rate increases. The water flow rate provides substantial contribution to enhancement of cooling performance. On the other hand, The air mass flow rate weakly influences the averaged heat transfer rate when the water mass flow rate is low, but the averaged heat transfer rate Increases remarkably with the air mass flow rate in case of the high water mass flow rate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2291-2296
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• 2007

Thermal transport from vertical heated surface to falling liquid film in a channel has been investigated experimentally. Air-flow is introduced into channel to make a counter flow against falling liquid film. This problem is of particular interest in the design of direct contact heat exchange system, such as cooling tower, evaporative cooling system, absorption cooling system, and distillation system. The effects of channel width and air flow rate on the heat transfer to falling liquid film are studied in detail. The results obtained indicate that heat transfer rate is gradually decreased with an increase in the channel width without air flow as well as with air flow in a channel. It is also found that heat transfer rate of air-flow is increased while heat transfer rate of falling liquid film is decreased with an increase in the air flow rate at a given channel width. However, total heat transfer rate form the heated surface is increased as the air flow rate is increased.

• 대한기계학회논문집B
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• 제32권5호
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• pp.335-341
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• 2008

Thermal transport from vertical heated surface to falling liquid film in a channel has been investigated experimentally. Air-flow is introduced into channel to make a counter flow against falling liquid film. This problem is of particular interest in the design of direct contact heat exchange system, such as cooling tower, evaporative cooling system, absorption cooling system, and distillation system. The effects of channel width and air flow rate on the heat transfer to falling liquid film are studied in detail. The results obtained indicate that heat transfer rate is gradually decreased with an increase in the channel width without air flow as well as with air flow in a channel. It is also found that heat transfer rate of air-flow is increased while heat transfer rate of falling liquid film is decreased with an increase in the air flow rate at a given channel width. However, total heat transfer rate from the heated surface is increased as the air flow rate is increased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.528-533
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• 2001

An experimental study is carried out to investigate the effects of air and water mass flow rates on cooling characteristics of mist impinging jet on a flat plate. Experiments are conducted with air mass flow rates from 0.0 to 3.0 g/s, and water mass flow rates from 5.0 to 20.0 g/s. An air-atomizing nozzle is used for the purpose of controlling air and water mass flow rates. In this study, a new test section is designed to obtain local heat transfer coefficient distributions. Heat transfer characteristics of the mist impinging jet are explained with the aid of flow visualization. Surface temperature and heat transfer coefficient distributions become more uniform as air mass flow rate increases, and that the increases in water flow rate mainly enhance cooling performance. Air mass flow rate weakly influences averaged heat transfer coefficient when water mass flow rate is low, but averaged heat transfer coefficient increases remarkably as air mass flow rate in case of high water mass flow rate.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1191-1196
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• 2009

The T-s chart of air displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. In previous study, the software analyzing 31 kinds of values in water system and 32 kinds of values in air-conditioning system were developed. In this study, the software drawing 13 kinds of quantity of state on air properties as ideal gas and analyzing 25 kinds of values in any air system was developed. The 13 kinds of quantity of state on air properties are temperature, pressure, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, and velocity of sound, and the 25 kinds of values including 13 kinds are mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, reversible work, lost work, and relative humidity. The developed software can draw any range of chart and analysis any state or process on air system. Also, this supports various document-editing functions such as power point. We wish to this chart is a help to design, analysis, and education in air system field.

• Journal of Advanced Marine Engineering and Technology
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• 제31권8호
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• pp.954-960
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• 2007

The purpose of this paper is to obtain design method of air-distribution system. Air-distribution system is composed of blower, duct, diffusers and measuring equipment. The air-flow rate from each diffuser is not equal. The air-flow rate is calculated with the combined equations which are Bernoulli's equation, continuity equation and minor loss equations. Inlet condition and outlet condition are adapted in each duct system. Then square difference between function of maximum air-flow rate and minimum air-flow rate is used as an object function. Area of diffuser and velocity are established as constraints. To minimize the object function, the optimization method is used. After optimization the design variables are selected under satisfaction of constraints. The air-distribution system is calculated again with the result of optimized design variable. It is shown that the air-distribution system has the equal air-flow rate from diffusers.

• 한국기계가공학회지
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• 제12권3호
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• pp.21-27
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• 2013

This study is investigated on flow analysis according to grill configuration of radiator. The stream of flow which pass through radiator grill in car body and the contour of pressure distribution are estimated by the basis. As the magnitude of resistance force which flow affects the car body is investigated so that the power reduction can be reduced. As the pressure inside radiator grill is assessed, more efficiency can be investigated in order that the flow rate inside car body can be increased. Model 2 has the most air resistance and model 1 has the least among model 1, 2 and 3. Model 1 has the most air flow rate at inside. There are model 3 and 2 simulated according to flow rate. As the curved surface at radiator grill configuration increases in number, air flow rate becomes distributed uniformly. By considering the effect on air resistance and air flow rate at radiator grill, model 3 becomes the most effective configuration.