• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.102-111
• /
• 2001

To describe the air flow characteristics within an air cleaner cover and mass air flow sensor (MAFS) entry region installed in a 3.0L engine air induction system, flow visualization, velocity and turbulence intensity measurements were taken in several view planes. A detailed knowledge of the interaction between the design parameters and the flow structures will enhance our understanding of the motions within the flow field and enable engineers to optimize the induction system and reduce the signal-to-noise ratio in the MAFS output. Emphasis is placed on the analysis of coherent motions and the controlling parameters which affect the air flow in the MAFS entrance region over a flow rate of 13-240 kg/hr. The high speed motion pictures illustrated that the air flow generated within the air cleaner cover under steady state condition is quite complex. In both axial and radial planes of the main passage it was found that the flow pattern is remarkably influenced by the air cleaner cover and main passage configuration. A comparison of the flow patterns and measurements in the original and modified air cleaner cover is presented. Measurements from the MAFS indicated an significant reduction in pressure drop and signal noise for the modified cover as compared with the original cover, over an air flow rate of 13-240 kg/hr.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.3
• /
• pp.214-220
• /
• 2002

A small air conditioner using thermoelectric module has been designed and built. Three types of cooling methods, such as air cooling, closed-loop water cooling, and evaporative cooling, for hot side of thermoelectric module have been investigated. Among three types of cooling method, the evaporative cooling method is seen to be the most effective to achieve the steady state operation of a thermoelectric air conditioner The system performance with evaporative cooling method are also studied in detail for several oprating parameters, such as input power to the thermoelectric module, water or air flow rate at the hot side, and air flow rate at the cold side. The results obtained indicate that the cooling capacity of a system is increased with an increase in the input power to the thermoelectric module while the system COP is decreased. It is also found that the optimal air flow rate as well as water flow rate at the hot side is needed for the best system performance at a liven operating condition. Both the system COP and cooling capacity are increased as the air flow rate at cold side is increased.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.5
• /
• pp.325-331
• /
• 2011

A numerical analysis of reactive flow in a MILD(Moderate and Intense Low oxygen Dilution) combustor is accomplished to elucidate the characteristics of combustion phenomena in the furnace with the change of fuel and air nozzle position and air mass flow rate. For the case with the fuel nozzle located near center position of combustor, the reaction zone started at the fuel nozzle and had inclined shape toward combustor wall when the air mass flow rate was relatively smaller. On the other hand, the end of reaction zone moved toward center of combustor from combustor wall when the air flow rate was relatively larger. For the case with the air nozzle located near center position of combustor, the reaction zone started at the fuel nozzle and had inclined shape toward combustor wall when the air mass flow rate was relatively small, which was similar as the previous case with smaller air mass flow rate. On the other hand, the end of reaction zone moved toward combustor wall when the air flow rate was relatively larger. The maximum temperature increased as the air mass flow rate increasing for both cases, and the concentration of thermal NOx increased also from the previous reason of temperature characteristics. The concentration of NOx for the case with the air nozzle located near center position of combustor was considerably smaller than that for the case with the fuel nozzle located near center position of combustor. From the present study, the case with the air nozzle located near center position of combustor and theoretical air flow rate was the most effective condition for the NOx reduction and perfect combustion.

• Proceedings of the KSR Conference
• /
• 2003.10c
• /
• pp.345-350
• /
• 2003

The inside of EMU is supplied with the cooling air from air-conditioner and the fresh air from exterior through the air-conditioner duct which is one of the air conditioning system. The shape of air-conditioner duct is a major factor in determining the air-conditioning efficiency, thermal comfort and energy efficiency. Therefore, this study is to understand the flow characteristics in the air-conditioner duct by three dimensional numerical simulation. The air-conditioner duct was calculated for the design volume flow rate, $2,726\;m^3/h/unit$. From the result of calculation and measurement, the velocity at diffuser outlet presented good agreement in general. [n this present study, the calculation was also performed for three volume flow rate(1,800, 2,200, 3,000 $m^3/h/unit$) and total pressure characteristic curve with volume flow rate was presented.

• 한국연소학회:학술대회논문집
• /
• 1999.10a
• /
• pp.129-138
• /
• 1999

In this paper, our main issue is that establishing the control procedure of continuous gas flow rate according to combustion fan RPM. For this, first, we decide the optimum operating condition of gas swirl burner through analysis of combustion characteristics - thermal efficiency, combustion efficiency and exhaust gases such as CO, $CO_{2}$, $O_{2}$, $NO_{x}$ and THC. Second, fuel gas flow rate of gas valve is decided with considering excess air ratio and combustion fan RPM is decided by the target of combustion air flow rate. Finally, experimental operating equation is acquired by regression for gas valve and combustion fan. This equation is the control equation of continuous gas flow rate and always gas flow rate is decided by combustion fan operating RPM.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.11
• /
• pp.599-605
• /
• 2009

This paper presents a numerical evaluation of the flow rate of air conditioner outdoor unit by investigating the effects of fan location and shroud shape. To determine optimal design parameters, we investigated the exhaust flow rate by changing shroud height, fan height, fan guide height, and fan width. The 3rd order central composite design was performed to select three most important parameters affecting the exhaust flow rate. According to the result of response surface method, the exhaust flow rate of the optimum model increased by 6.25% compared to that of the base model.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.4
• /
• pp.247-253
• /
• 2003

The new shape of louver-fin has been applied to a parallel flow condenser to enhance air-side heat transfer rate lot an automotive air-conditioner R- l34a is employed as a refrigerant inside the flat tube of the condenser, This problem is of particular interest in reducing the geometric size of the automotive air conditioner The effect of air flow rate on pressure drop as well as heat transfer in air side are studied in detail. Comparison of the performance is also made with that of a conventional parallel flow condenser, which is available in the market. The results obtained indicate that the total pressure drop through the pre sent condenser is not changed, while the heat transfer rate is increased by 24% at high veto city of air flow, compared with those of the conventional condenser. The parallel flow condenser with a new shape of louver-fin could be reduced in size by 20% for the equivalent condenser capacity, compared with the conventional parallel flow condenser.

• Journal of Biosystems Engineering
• /
• v.20 no.4
• /
• pp.333-342
• /
• 1995

The resistance to air flow through fruits and vegetables in bulk was an important consideration in the design of the pressure cooling system. The amount of resistance to air flow through produce in bulk normally depended upon air flow rate, stacking depth, porosity, stacking patterns and shape and site of product. But, there was not enough information relating the effects of those factors on air flow resistance. The objectives of this study were to investigate the effect of stacking depth, stacking patterns, porosity and airflow rate on airflow resistance and to develop a statistical model to predict static pressure drop across the produce bed as a function of air flow rate, stacking depth, bed porosity, and product size. Mandarins and tomatoes were used in the experiment. The airflow rate were in the range of 0.1~1.0 ㎥/s.$m^2$, the porosity were in the range of 0.25~0.45, the depth were in the range of 0.3~0.9m and the equivalent diameters were 5.3cm and 6.3cm for mandarins, and 6.5cm and 8.5cm for tomatoes. Three methods of stacking arrangement were used i.e. cubic, square staggered, and staggered stacking arrangement. The results were summarized as follows. 1. The pressure drops across produce bed increased in proportion to stacking depth and superficial air velocity and decreased in proportion to porosity. 2. The increasing rates of pressure drop according to stacking patterns with the increase of superficial air velocity were different one another. The staggered stacking arrangement produced the highest increasing rate and the cubic stacking arrangement produced the lowest increasing rate. But it could be assumed that the stacking patterns had not influenced greatly on pressure drops if it was of equal porosity. 3. The statistical models to predict the pressure drop across produce bed as a function of superficial air velocity, stacking depth, porosity, and product diameter were developed from these experiments.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.12
• /
• pp.1227-1233
• /
• 2004

Air handling unit (AHU)'s air filter pressure difference is important for energy consumption and indoor air quality. Both energy Performance data and air filter differential pressure of AHU in real office buildings were monitored and analyzed to investigate quantitatively energy impact as dust buildup level on air filter grows. We also modeled and simulated CAV system using HVACSIM＋ program to examine the energy effect of dust buildup on filters. Through analysis of time series pressure drop data, the filter pressure difference rate has been increased due to cumulative supply air flow rate increase. As filter pressure drop increased to 1 inch water column, it is found that the supply air flow rate was decreased by 10%, the chilled water flow rate was increased by 5.9% and the pump energy consumption was increased to 5.9%.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.379-384
• /
• 2003

Coal-burning utilities are facing a major NOx control compliance challenge due to the heavy emission regulation. In response to this challenge, some applicative technologies to effectively reduce NOx are developed and applied in the pulverized coal power plants. One of these is low NOx burner(LNB) equipped with multi-staged air register. In this study, NOx emission rate and flame shapes are investigated with secondary and tertiary air flow conditions in air staged coal burner, and the optimal windows of flow conditions to minimize NOx emission rate are found out. The test conditions treated in this study are the flow rate, swirl direction and intensity and throat injection velocity of secondary and tertiary air.