• New & Renewable Energy
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• v.4 no.4
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• pp.30-36
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• 2008

The possibility of whether the induced wind from a vehicle traveling on highway can be used in wind power generation has been verified through computational flow analysis. The bus which is presumed to accompany relatively strong and wide range of induced wind compared to passenger vehicles because of its wide frontal area has been set as the subject of research. In order to ensure the reliability of research, the flow analysis surrounding the bus on a flat road where median strip is not installed has been compared with a preceding research while the validity of grid system and interpretation method used in this research have been assured by a qualitative method. In case of the median strip type wind power generator system, because it has been verified that a strong streamwise wind speed (5 m/s) is derived from the contraction effect of flow passage between the bus and the median strip while maintaining a relatively consistent upwind wind speed (1.4 m/s) in vertical direction in the wake area after the bus passes by although the change of wind speed is intense, it was decided as having some possibility of wind power generation. In case of the traffic sign panel type wind power generator system installed at the upper top of highway, because the wind speed of 2 m/s level has been derived for a limited time only at a section equal to the length of the bus and a faint induced wind speed less than 0.5 m/s was shown at other regions, it was decided as having almost no possibility of wind power generation.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.35-46
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• 1997

In order to satisfy customer's requirements of ride comfort and high performance, it is necessary for designers to fully understand vehicle aerodynamics and wind noise of newly produced cars because characteristics of flow and wind noise are heavily dependent on each other. In this study numerical and experimental study have been carried out to analyse the effect of flow characteristics at around of rear view mirror on wind noise and soiling on the front S/W. As a result, it's found that the spiral flow mear the front pillar is weakened and spreaded because rear view mirror obstructs the flow. It is also shown that there is abrupt change of gradient of separa- tion line, separation area, intensity of spiral flow and turbulent kinetic energy with varying shape of neck and housing of rear view mirror.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.565-568
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• 2007

The high pressure hydrogen gas refueling system is required for fuel cell vehicle. In this paper, a commercial computational fluid dynamics (CFD) code, FLUENT is adopted to investigate the gas flow characteristics inside the check valve for various refueling and tank pressures. The results showed that the choking phenomena can occur for certain refueling pressures, therefore refueling processes should be divided by multiple stages. And a design method to prevent the seal departure problem which reported in CNG usages is required.

• Tribology and Lubricants
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• v.32 no.5
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• pp.166-171
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• 2016

Electric vehicle ownership is expanding for two reasons: its technology features have enhanced fuel economy, and the number of vehicle emissions regulations is increasing. Battery performance has a large influence on the capability of electric vehicles, and even though battery thermal management has been actively researched, specific technological improvements to battery performance are not being presented. For instance, many industrial applications utilize vortex tubes as components for refrigeration machines because of their numerous intrinsic benefits. If electric vehicles incorporate vortex tubes for battery cooling, performance and efficiency advancements are possible. This study uses a counter-flow vortex tube to investigate its temperature separation characteristics, based on the back pressure of the cold air exit and the difference between the inlet and back pressures. The experiment uses a vortex tube with the following parameters: six nozzle holes, a 20 mm inner vortex diameter (D), a 14D tube length, a 0.7D cold exit orifice diameter, and a nozzle area ratio of 0.142. The measurements prove that the temperature difference between the hot air and cold air decreased because of the flow resistance of the hot air and the backflow phenomenon at the cold air exit. The flow resistance causes the temperature difference to decrease, and the back pressure of the cold air exit influences the flow resistance. The results show that the back pressure significantly influences the efficiency of temperature separation.

• Journal of the Korean Solar Energy Society
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• v.21 no.3
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• pp.33-41
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• 2001

This paper showed the a numerical analysis of the thermal and fluid flow in solar concentration absorber with tilt angle, and the purpose of this study is to obtain the optimum tilt angle of the absorber. The boundary conditions of a numerical model were assumed as flows : (1) The heat source is located at the center of absorber (3) The bottom wall is opened and adiabatic. (3) The top, right and left walls are cooled wall. The parameters for the numerical analysis are tilt angles and Rayleigh numbers i.e., tilt angle $\theta=0^{\circ},\;15^{\circ},\;30^{\circ},\;45^{\circ},\;60^{\circ},\;75^{\circ},\;90^{\circ}$ and 101 $\leq$ Ra $\leq$ 103. The velocity vectors and isotherms were dense at wall side and the heat source. The mean Nusselt number had a maximum value at $\theta=0^{\circ}$ and showed a low value as the tilt angles were increased. Finally, the decrease rate of mean Nusselt number was appeared small with tilt angle when Rayleigh numbers were increased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.21-29
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• 2014

In this paper examine the characteristics of the generator supplying the most significant electrical energy in some parts required to drive the vehicle, and it is focused on to fabricate a performance evaluation unit for developing alternator with better performance. Through performance tests in accordance with the electrical load of alternators that is made in Valeo Corp. and Denso Corp., which are currently applied by H Corp., the fabricated performance evaluation unit has measured the power generation amount of the electrical energy supplied from the alternator, and it was analyzed. On the basis of this result, and to understand the flow of electrical energy of the vehicle, furthermore, it is intended to verify the usefulness of the performance evaluation unit which is designed in this paper. In this paper, based on the mechanism of the proposed performance evaluation unit, it will try to learn the convergence technology that can be applied to the design of the performance evaluation unit of other components of the vehicle.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.159-163
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• 2020

In this study, the flow analyses around according to the existence or non- existence of the trailer's deflector and the shapes were carried out. In the absence of a deflector, the kinetic energy of the turbulence behind the container also generates higher kinetic energy in a wider area than in the presence of a deflector, which adversely affects the vehicle's driving performance. As a trailer's wind deflector-free model has unstable flow rates around the trailer and high kinetic energy of turbulence than a model with a deflector, it can be thought that the increase of fuel economy can be expected by installing a deflector in the trailer. By applying the study result on flow analysis near trailer due to shape of wind deflector, this study is seen to be suitable for the aesthetic convergence.

• Journal of Auto-vehicle Safety Association
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• v.14 no.1
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• pp.55-61
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• 2022

Along with global environmental issues, the size of the electric vehicle market has recently skyrocketed. Various efforts have been made to extend mileage, one of the biggest problems of the electric vehicles, and development of batteries with high energy densities has led to exponential growth in mileage and performance. However, proper thermal management is essential because these high-performance batteries are affected by continuous heat generation and can cause fires due to thermal runaway phenomena. Therefore, thermal management of the battery is studied through the optimal design of the guide vanes, while utilizing the existing battery casing to ensure the safety of the electric vehicles. A battery from T-company, one of a manufacturer of the electric vehicles, was used for the research, and the commercial CFD software, ANSYS CFX V20.2, was used for analysis. The guide vanes were derived through optimal design based on a genetic algorithm with flow analysis. The optimized guide vanes show improved heat removal performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.6
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• pp.895-902
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• 2018

Energy consumption in buildings is close to 40% of the total national energy consumption in developed countries such as US and Japan, and Korea accounts for 24% of total energy consumption. In buildings, HVAC can't freely control the cooling flow rate according to the required calorie, so energy is not used efficiently. Therefore, by using the energy saving valve, the flow rate can be controlled by the required amount of heat and the energy can be saved. In this paper, we define basic conditions and develop control and monitoring boards for building energy saving valves based on PIC processor with low power and high cost-effectiveness. The designed board displays and transmits in real time information about two temperature values, flow values and calculated calories for temperature difference measurement. The developed board will be useful for real - time monitoring of the state of the valve in the future and development of the valve for the offshore.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.129-143
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• 2015

Increasing concerns on climate change and energy security accelerated policies to reduce green-house gas emission, especially from the transportation sector. Electric vehicle (EV) has been on the spotlight to deal with such environmental issue and V2G (Vehicle-to-Grid) technology began to draw attentions as an alternative to reduce ownership costs while contributing to an efficient and decentralized power grid. This study conducts a scenario analysis on total cost of ownership of EV under V2G scheme and compare with non-V2G EV and Internal Combustion Engine (ICE) vehicle. As result, V2G service is expected to provide an annual average profit of $210 to EV users willing to reverse flow its residual power in the battery. The profit from V2G service leaves a margin of $4,530 over operational lifetime, compared with $2,420 cost of charge for non-V2G EV. In summary, total cost of ownership of V2G-capable EV was 6.2% less than non-V2G EV and 10.2% higher than ICE vehicle. The results confirm a comparative economic advantage of operating EV under V2G scheme. Increased number of EVs with V2G service has shown to provide positive effects to power industry for valley filling in load distribution, thus, favorably increasing the overall economic feasibility.