• Journal of ILASS-Korea
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• v.19 no.3
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• pp.136-141
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• 2014

This study reports numerically the characteristics of dust scattering around the coal storage pile yards, substantially affected by the windbreak wall height. The dust scattering is closely associated with the frictional effect of wind flows as well as the pressure variation that consequently affect the dust particle behavior. In the present study, with the use of the commercial code of FLUENT, the distribution of wind velocity and pressure are predicted around coal storage pile yard for four different heights of the wind break wall. From the results, it was found that for the case 1 with the outer windbreak wall height of 3 m and inner windbreak wall height of 6 m, the amount of scattering dust for a year was estimated to be 1451 kg, whereas for the case 4 where a height of outer windbreak wall is 10 m and a height of inner windbreak wall is 16 m, the amount of scattering dust for a year was 358 kg. It shows that the dust scattering can be reduced by 75%, indicating important role of windbreak wall height on particle scattering. The numerical results would be useful in decision of the appropriate height of windbreak wall for decreasing the amount of scattering dust under various environmental conditions.

• Journal of ILASS-Korea
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• v.14 no.3
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• pp.103-108
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• 2009

This research investigated spray characteristics using LPG fuel under compression ignition to contribute to develop a high efficiency LPG fuel is an environmentally-friendly fuel since it emits lower $CO_2$ compare to other conventional fuels. In order to observe spray process, a high speed digital camera and high pressure common-rail injector were applied. Using the spray behaviors of LPG and diesel fuel from the experiment, this research analyzed the mixing process of air-fuel mixture numerically with FLUENT 6.3 when LPG and diesel fuel injected directly into the cylinder while compression stroke occurs. Spray characteristics of LPG fuel was investigated by using numerical method, in which KH-RT model was adapted for phase change. As a result of numerical analysis, this work found out that LPG spray has a wider mixing formation and uniform diffusion of air-fuel mixture compare to diesel.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.120-129
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• 2012

As the recent advancement of automobile industry, there has been a great interest in the thermal comfort of the passengers inside the cabin of an automobile. Thermal comfort is affected by temperature, velocities, and mean radiation temperature of air, thermal resistance of clothes and physical active level of human. The present study performed computational analysis to select the location of air-conditioning vent that improves thermal comfort inside the cabin. In order to do this, we considered various air vent positions, and thermal flow analysis of each case is performed using CFD for the cabin with four passengers. The thermal comfort is evaluated using the computational results and the optimum location of air vent is suggested.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.95-101
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• 2012

An electric water pump for engine cooling system has an advantage which particularly in the cold start, the use of the electric water pump saves fuel and leads to a corresponding reduction in emissions. The canned type electric water pump without mechanical sealing elements was selected to meet the requirements for operational reliability and life. However, the electric water pump for internal combustion engine generates much more heat loss than for hybrid electric vehicle since it is operated by the electric power of high current and low voltage. In this study, the fluid flow and thermal characteristics of the canned type electric water pump as an inverter integrated water pump has been investigated under the effects of heat generation. The analysis conditions such as outdoor air temperature of $125^{\circ}C$, water pump speed of 6000 rpm, coolant temperature of $106^{\circ}C$ and coolant flow rate of 120 L/min was used as a standard condition. Therefore, flow fields and temperature distribution inside the water pump were obtained. Also, we checked the feasibility of the canned type for the electric water pump in comparison with the mechanical seal type.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.111-117
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• 2008

The aim of this paper was to investigate the fluid dynamic behavior of the automotive closed type water pump with balance hole in order to evaluate and justify its overall hydraulic performance and, in particular to analyze the effects of the balance hole on the reduction of hydraulic flow force of it. The analysis has been peformed by applying the commercial computational fluid dynamics (CFD) code, Fluent, to the solution of the 3-D turbulent flow fields of automotive closed type water pump. The reliability of the employed analysis was demonstrated by the comparison between numerical result and experimental data. Although, hydraulic head of the closed type water pump with 3mm diameter of balance hole decreased by 1.1%, axial flow force was effectively reduced by 13.3%, comparison of it with no hole at design point.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.60-65
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• 2008

A typical louvered-fin oil cooler can be easily contaminated under dusty environment hence resulting in poor performance of a heat exchanger. Thus, in this study, a dust-proof oil cooler has been studied with a unique shape of a 3-dimensional wavy fin since non-louvered fins could have better performance under dusty environment compared to louvered fins. Recently, they have been introduced to commercial and constructional vehicles in Japan. At first numerical analysis has been done to optimize the angle of the wavy fin so that the oil cooler developed can satisfy the target performance. The wavy fin has been then made with roll-forming and roll-pitch stands, and a prototype of an oil cooler with the wavy fin has been finally built with brazing. The performance test showed that the heat release rate of the oil cooler was well beyond the target, 4.94kW and the air-side pressure drop was below the criterion, 0.19kPa. In addition, the results showed that the numerical prediction was effective enough to design the dust-proof oil cooler that satisfies the performance criteria.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.2
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• pp.145-150
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• 2017

Air brake valves are widely used in automotive braking systems and the Korean automobile industry depends on importing them. Therefore, we should develop the technical expertise for their domestic production. In this study, air brake valves were analyzed that can be used in a variety of automobiles. Computational fluid dynamics analysis, static structural analysis, and hyper-elastic analysis were carried out. Before production of an air brake valve system, the performance of different parts has to be evaluated, for instance by using finite element analysis. The structural stability of the product can be determined using static dynamics. The compression behavior of the O-ring is predictable by nonlinear hyper elastic analysis, although errors are possible due to one-way loading. This simulation study can both save time and reduce costs compared to the development of experimental prototypes.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.927-935
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• 2016

A gerotor is suitable for miniature manufacturing because it has a high discharge per cycle and a simple structure, while also being widely used as lubrication oil of engines and the hydraulic source of automatic transmission. In the automobile industry, it has been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor design. In this study, to obtain an optimal gerotor with an ellipse-elliptical involute-ellipse combined lobe shape, an automatic program was developed for calculating performance parameters and drawing a gerotor profile. An oil pump was assembled with the optimal gerotor together with the port used at the actual field and CFD analysis was performed on this assembly using Ansys-CFX. A performance test for the oil pump was carried out and showed good agreement with the results obtained from the theoretical analysis and the CFD analysis.

• Journal of Power System Engineering
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• v.14 no.3
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• pp.25-32
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• 2010

전 세계적으로 급속도로 인기가 더해가고 있는 수소에너지는 높은 전환 효율성, 재생성, 친환경적인 특징을 가지며 미래의 주 에너지가 될 것이다. 왕복동식 압축기를 통과한 후의 수소 가스의 압력은 높은 맥동압을 가진다. 스너버는 압축기의 한 구성품으로 맥동압을 낮추고 수소가스의 불순물을 제거하기 위해 사용된다. 이 연구에서의 실험은 스너버 시스템에 사용된 강관의 맥동에 관해 조사하기 위해서 수행되었다. 맥동압은 12 Hz ~ 60 Hz의 모터속도에서 RMS값을 기준으로 0.1625% ~ 0.5305% 그리고 평균압력을 기준으로 0.1621% ~ 0.5277% 감소하였다. 압력손실은 RMS값을 기준으로 0.1092% ~ 1.4419%, 평균압력을 기준으로 0.1493% ~ 1.7507%로 측정되었다. CFD를 이용한 수치해석값은 실험값이 거의 비슷한 결과를 나타내고 강관 관로 내부 가스의 자세한 압력을 설명하기 위한 중요한 역할을 수행한다.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.130-135
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• 2016

The thermal performance of amorphous steel fibers mixed floor heating system was evaluated. Analysis of results, depending on the hot water supply temperature changes, the average temperature of the bottom of the hot water supply temperature is an amorphous steel fiber floor heating system is about 2~4% higher. The average temperature of the floor surface to 1.5m air amorphous steel fiber system is 1~2% higher. The amount of heat supplied to indoor air (1.5m) from the bottom surface of amorphous steel fiber floor heating system is about 7~8% higher