• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.1
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• pp.9-17
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• 2015

The basic flow configuration is composed of a plane, double shear layer where relatively thin mid gas layer is sandwiched between air and fuel stream. The present study describes numerical investigations concerning the combustion enhancement according to a variation of mid layer thickness. In this case, the effect of heat release in turbulent mixing layers is important. For the numerical solution, a fully conservative unsteady $2^{nd}$ order time accurate sub-iteration method and $2^{nd}$ order TVD scheme are used with the finite volume method including k-${\omega}$ SST model. The results consists of three categories; single shear layer consists of fuel and air, inert gas sandwiched between fuel and air, cold fuel gas sandwiched between fuel and air. The numerical calculations has been carried out in case of 1, 2, 4 mm of mid layer thickness. The height of total gas stream is 4 cm. The combustion region is broadened in case of inert gas layer of 2, 4 mm thickness and cold fuel layer of 4 mm thickness compared with single shear layer.

• Journal of the Korean Solar Energy Society
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• v.37 no.6
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• pp.25-37
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• 2017

A study on factors influencing measurement error of Ground-based LiDAR(Light Detection And Ranging) system was conducted in Kimnyeong wind turbine test site on Jeju Island. Three properties of wind including inclined angle, turbulence intensity and power law exponent were taken into account as factors influencing the measurement error of Ground-based LiDAR. In order to calculate LiDAR measurements error, 2.5-month wind speed data collected from LiDAR (WindCube v2) were compared with concurrent data from the anemometer on a nearby 120m-high meteorological mast. In addition, data filtering was performed and its filtering criteria was based on the findings at previous researches. As a result, at 100m above ground level, absolute LiDAR error rate with absolute inclined angle showed 4.58~13.40% and 0.77 of the coefficients of determination, $R^2$. That with turbulence intensity showed 3.58~23.94% and 0.93 of $R^2$ while that with power law exponent showed 4.71~9.53% and 0.41 of $R^2$. Therefore, it was confirmed that the LiDAR measurement error was highly affected by inclined angle and turbulence intensity, while that did not much depend on power law exponent.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.837-842
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• 2014

A computer program is developed for the prediction of NO generation by the addition of water moisture and water electrolysis gas in LNG-fired turbulent reacting flow. This study is the first part to deal with the moisture effect on NO generation. In this study, parametric investigation has been made in order to see the reduction of thermal NO as a function of amount of moisture content in a LNG-fired flame together with the swirl and radiation effect. First of all, calculation results show that the flame separation together with the NO concentration separation are observed by the typical flow separation due to strong swirl flow. With a fixed amount of air, the increased amount of water moisture from 0 to 10% by 2% interval shows the decrease of NO concentration and flame temperature at exit are from $973^{\circ}C$ and 139 ppm to $852^{\circ}C$ and 71 ppm. The radiation effects on the generation on NO appears more dominant than swirl strength over the range employed in this study. However, for the strong swirl flow employed in this study, the flow separation cause the relatively high NO concentration observed near exit after peak concentration in the front side of the combustor.