• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.896-901
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• 2009

In this study, in order to apply the air and pure oxygen in the Jet Loop Reactor (JLB) in which the oxygen transfer rate is high, differentiate the operation mode according to each air flowrate and liquid flowrate and investigate the oxygen transfer characteristic, an experiment was carried out. The oxygen concentration with the air flowrate ($Q_g$) and liquid flowrate ($Q_L$) was identical but the oxygen transfer coefficient ($K_L{\cdot}a$) is linear depending on degree of two factors. The width of an increase is small in $0.1min^{-1}$ when the air flowrate is 0.2 L/min with increasing the liquid flowrate. Whereas, the increment was exposed to be very high for $1.5min^{-1}$ when the air flowrate was 5 L/min. In the experiments using the pure oxygen, it was 30 mg/L of oxygen concentration finally and it was 3.5 times than using the air. But the time reached the saturated concentration was similar to using the air, and $K_L{\cdot}a$ was similar to using the air too. Analysis between two independent variable and oxygen transfer of the correlation is the same model like $K_L{\cdot}a={0.0161Q_L}^{1.5371}{Q_g}^{0.5433}$ using with coefficient non linear regression analysis. It was resulted that the liquid flowrate were approximately three times than air flowrate on effect to oxygen transfer rate.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.402-407
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• 2008

This study is performed to investigate heat transfer characteristics for thermal performance of fin-and-tube sensible heat exchangers under the low air flowrate according to fin geometry combination and coolant flowrate control. Fins and tubes of samples were separated between front row and rear row. Experiment results are plotted heat transfer rate of each row, heat transfer coefficient and sensible heat ratio against water flowrate control of each row. It is observed that thermal performance can be enhanced by fin geometry combination and water flowrate control of each row under the low air flowrate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.2
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• pp.116-122
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• 1992

The purpose of this paper is to determine the cut off flowrate regions of the overflow valve in using L.P gas vassels. The experimental methods were employed to measure the cut off flowrate in the state of constant pressure by using the $N_2$ gas. 1) To determine the optimum cut off flowrate regions, Hose length are required 0.5 meters. 2) Cut off fowrate regions about the each pressure can be suggested as follows. A) Cut off flowrate rigions are $2.0-4.0m^3/hr$ at the pressure of the $1Kg_f/cm^2$. B) Cut off flowrate rigions are$7.0-10.0m^3/hr$ at the pressure of the $10Kg_f/cm^2$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.1018-1027
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• 2003

This study treats the analysis of the performance and the design of plume abatement wet/dry cooling tower with dry type heat exchanger using a numerical method. A two-dimensional analysis is performed using the finite volume method for mechanical draft counterflow and crossflow tower. For a coupling problem between water and air system, a turbulent two phase flow is considered. Effectiveness-NTU method is used for modeling of the dry type heat exchanger. The parameter change simulations of the outer wall shape, the relative flowrate of air, and attachment of an air mixer are performed to examine the effect on plume abatement. It is found that if the relative air flowrate ratio and the adequate air mixer type are chosen well in addition to the ratio of water to air flowrate, the loss of the cooling capacity and the additional cost are reduced and the plume is abated.

• International Journal of Air-Conditioning and Refrigeration
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• v.13 no.2
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• pp.61-70
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• 2005

This study treats the numerical analysis of performance and design for plume abatement wet/dry cooling tower with a dry type heat exchanger. A two-dimensional analysis is performed using the finite volume method for mechanical draft counterflow and crossflow tower. For a coupling problem between water and air system, a turbulent two phase flow is considered. The Effectiveness-NTU method is used for modeling of the dry type heat exchanger. The parametric simulations such as the relative flowrate of air and attachment length of an air mixer are performed to examine the effect on plume abatement. It is found that if the relative air flowrate ratio and the adequate air mixer type are chosen well in addition to the ratio of water to air flowrate, the loss of cooling capacity and the additional cost are reduced and the plume is abated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.251-262
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• 1995

The goal of this study is to provide fundamental information on the design of a new diesel injector system. The cylindrical disk spray was made by an impinging disk insited below the exit of air-assist atomizor. The disintegration processes on a twin-fluid atomization by air-assist atomizor were investigated. Liquid jet was disintegrated at the condition that wavelength was equal and longer than the circumference of the liquid jet, .lambda. .geq. .pi.do. However, the wavelength and the diameter of the liquid jet were decreased according to the increasing of air velocity. The relative density distribution of droplets and pattern of spray by impinging disk were investigated with a C-CCD. Optimum design conditions for cylindrical disk spray were also achieved. The pattern of cylindrical spray can classified according to the size of the disk and the distance from the nozzle tip to the disk. When the space of the disk and the nozzle tip was narrow and the diameter of the disk was larger than that of the air orifice of the nozzle exit, the good distribution of spray could be achieved. When the air flowrate was constant, the spray width was decreased according to the increasing of the liquid flowrate. When the liquid flowrate was constant, the spray width was decreased according to the increasing of the air flowrate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.5
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• pp.359-364
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• 2002

A popular type of residential air conditioner is the split system which has two separate units: indoor and outdoor units During field installation of the split system, the potential exists for not setting the charge exactly to the manufacturer´s specifications. The objective of this study is to investigate the effects of the refrigerant charge on the performance of the air conditioner. An air conditioner with capillary tube expansions was tested for various refrigerant charges. The results indicated that the more charge resulted in the more flowrate of the refrigerant. The flowrate of the refrigerant was one of the most important factors to understand the e(sects of the charge on the performance of the air conditioner with capillary tube expansions. Under-charge results in wide region of superheated vapor of the refrigerant in the evaporator, while over-charge results in high temperature of the liquid refrigerant in the evaporator.

• Journal of Advanced Marine Engineering and Technology
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• v.9 no.4
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• pp.339-347
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• 1985

Precise measurement of flowrate is considered as an important measuring factor in mechanical and chemical experiment. Although there are many methods to measure flowrate, Float type flowmeter is widely used because of its easy attachment to piping and high measuring precision. To design the precise float type flowmeter, much design information such as tapered-tube dimensions, float size, float shape and float material is required. In this paper, fundamental design theory for float type flowmeter according to the given flowrate range is suggested and compensation coefficients of volumetric and weight flowrate for water, R-113 and air are calculated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.933-942
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• 1992

The effects of the folwrate on the dropsize from the two-phase coaxial nozzle are investigated by using the direct photographic method and the empirical equation is obtained. For the photography, the light source which the life time is the order of 100ns is fabricated and the lens is the zoom lens which has the MICRO function with a teleconvertor. The distillated water and the compressed air of the surrounding temperature are injected and atomized. For the purpose of the exact adjustment and measurement of the flowrates, the two rotameters are used. As a result of this study, the sauter mean diameter of droplets has a tendency for a logarithmic function with air flowrate and for a exponential function with water flowrate.

• Fire Science and Engineering
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• v.17 no.4
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• pp.105-110
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• 2003

In Part II, the temperature and smoke particle distributions of the extraction system, which yielded the best smoke removal performance among the three smoke control systems in Part I, for extraction flowrates of 0.6∼2.4 ㎥/s and two fire sizes of 200 ㎾ and 2 ㎿ were presented. The same numerical method was utilized to the same computational domain and configurations as Part I. It was shown that the extraction flowrate affects the smoke control performance significantly, and that a similar trend in improving the smoke removal performance with the increasing extraction flowrate between the two fire sizes. An extraction flowrate of 2.4 ㎥/s or higher was required for the temperature in the escape route less than $^{\circ}C$ for the given situations.