• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.337-342
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• 2023

Since the electric vehicle uses an electric motor, problems have arisen as the driver hears the inherent noise of the motor or external noise, which was not a problem in the past, due to the overall lower noise environment than when using an internal combustion engine. Therefore, the purpose of this paper is to reduce the noise and vibration of electric motors for electric vehicles, and recently, to increase the speed of high-power, high-efficiency electric motors in a small size, and to develop low-noise motors, IPM motors are applied to produce 35KW electric motors for electric vehicles. A motor for low noise was designed and implemented. N-T Curve and efficiency map were confirmed as the final result of developing a 35KW low-noise motor for electric vehicles by applying the IPM motor applied in this paper. Based on 3500 rpm, Max Torque [Nm]: 121.15, Max Power [KW]: 44.04, and Max Efficiency [%]: 97.65, showing high efficiency.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.53-62
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• 2010

An airbag is composed of housing assembly, door assembly, cushion assembly, and an inflator. The inflator is the essential part that generates gas for airbag. When an airbag is activated, it effectively absorbs the crash energy of the passenger by inflating a cushion. In this study, tank tests were performed with newly synthesized propellants with various compositions, and the results are compared with the numerical results. In the simulation of inflator, a zonal model has been adopted which consisted of four zones of flow regions: combustion chamber, filter, gas plenum, and discharge tank. Each zone was described by the conservation equations with specified constitutive relations for gas. The pressure and temperature of each zone of the inflator were calculated and analyzed and the results were compared with the tank test data. In the zone of discharge tank the pressure quickly rose, the pattern of pressure curve was very similar to the pressure curve of real test. And in zone 1 & 2 & 3 the mass of products was increased and decreased with time. In zone 4, the mass of products was increased with time like real inflator. From the similarity of pressure curve in zone 4 and closed bomb calculation the modeled results are well correlated with the experimental values.

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.163-173
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• 1997

This article presents an application of a large-scale structural mixing model (Broadwell et al. 1984) to the blowout of turbulent reacting jets discharging perpendicularly into an unconfined cross air-flow. In an analysis of a common stability curve, a plausible explanation can be made that the phenomenon of blowout is related only to the mixing time scale of the two flows. The most notable observation is that the blowout distance is traced at fixed positions at all times according to the velocity ratio R. Measurements of the lower blowout limits in the liftable flame agree qualitatively with the blowout parameter ${\varepsilon}$, proposed by Broadwell et al. Good agreement between the results calculated by a modified blowout parameter ${\varepsilon}^'$ and experimental results confirms the important effect of a large-scale structure in specifying the stabilization feature of blowouts.

• Journal of the Semiconductor & Display Technology
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• v.14 no.1
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• pp.13-17
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• 2015

$YAlO_3:Tb{_x}^{3+}$ has been synthesized by a combustion process and the concentration x of Tb was varied from 0.001 and 0.05 mol% per mole of YAlO3. The energy transfer of $^5D_3{\rightarrow}^7F_6$(385nm) and $^5D_4{\rightarrow}^7F_5$(544nm) transitions on the $YAlO_3:Tb{_x}^{3+}$(x =0.001, 0.05) have been investigated by using decay curves. The energy transfer mechanism was explained by Inokuti and Hirayama model. The results of calculation and fitting showed that values of n are 6.11(x=0.01) and 6.13(x=0.005). These indicate that the energy transfer mechanism between $Tb^{3+}$ ions is dipole-dipole interaction.

• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.47-58
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• 2000

The relationship among the flame radiation, NOx emissions, residence time, and global strain rate are examined for turbulent non-premixed jet flames with wide variations in coaxial air conditions. Measurements of NOx emission, flame geometry and flame radiation were made to explain the NOx emission scaling based on global parameters such as flame residence time, global strain rate, and radiant fraction. The overall 1/2-power scaling is observed in coaxial air flames, irrespective of coaxial air conditions, but the degree of deviation from the l/2-slope curve in each case differs from one another. From the comparison between the results of pure hydrogen flames and those of helium diluted hydrogen flames, it is observed that flame radiation plays a significant role in pure hydrogen flames with coaxial air and the deviation from 1/2-power scaling may be explained in two reasons: the difference in the flame radiation and the difference in jet similarity in coaxial air flames. From the radiation measurements, more detailed explanations on these deviations were suggested.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.259-261
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• 2012

The effect of fuel composition and coaxial air on the nitrogen oxide emission index was studied in a non-premixed turbulent jet flame. Validity of experimental setup and methodology is checked. The NOx emission trend is similar with previous works in hydrogen flame, but it's not well in $H_2/CO$ flame. Normalized EINOx scaling with modified $S_G$ applying near-field concept was conducted. Experimental data don't collapse single correlation curve, but partially same trend is observed in all cases.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.113-114
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• 2014

Though polymer cement mortar is widely used to repair or reinforce concrete as it has superior adhesion, dense internal structure, chemical resistance, and workability in comparison to those of general cement mortar, studies on its behaviors in high temperature environment such as fire is urgently required. Accordingly, in this experiment, the degrees of reduction in the compressive strength at different temperatures was grasped applying ISO834 Heating Curve, and the effect of polymer content and type on compressive strength could be determined. As a result of this experiment, it is found that polymer type and content have a big effect on reduction of compressive strength in high temperature range, and not only the dynamic characteristics but also the combustion characteristics in high temperature range are required to be studied considering occurrence of a fire in the future.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.10-16
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• 1995

In this study, the optimum design is carried out upon the crankshaft of in-line 6-cylinder internal combustion diesel engine with the mechanical analysis for the layout design, which is standard calculation whose process contains quadratic curve fitting method and quasi newton method about cost function, design variables and constraint conditions, Without finite element analysis, this process in wich mechanical analysis is performed upon the most critical part in crankshaft gives necessary and satisfied output in layout design and saves time and cost in developing a new diesel engine. In this study, also, the 3-dimensional finite element method is used in confirming the standard calculation for the optimization of crankshaft and the shape optimization in crankweb is obtained.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.15-18
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• 2008

This study fulfilled analysis of startup characteristics of Turbo pump unit-Gas generator open loop test from the viewpoint of simulation. The test results were investigated and the calculated results were compared to test results. The curve for RPM developing predicted by simulation agreed well with test result. The slope of transient combustion pressure of gas generator correspond with test result.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.19-22
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• 2008

This study fulfilled analysis of startup characteristics of Turbo pump unit-Gas generator closed loop test from the viewpoint of simulation. The test results were investigated and the calculated results were compared to test results. The curve for RPM developing predicted by simulation agreed well with test result. The slope of transient combustion pressure of gas generator correspond with test result.