• Journal of the korean Society of Automotive Engineers
• /
• v.15 no.1
• /
• pp.55-66
• /
• 1993

The characteristics of the flow processes in the cylinder of the two-stroke cycle engines have become the subject of increasing and attention owing to the simplicity and the higher power per unit weight of the two-stroke cycle engine. Among the many factors which influence on the scavenging flow, the port angle is important factor. Hence, four different type models with one inlet-port and two side-ports are studied to show the effect of port angle on the laminar scavenging flow. When the inlet-port axial is relatively larger than the side-port axial angle, it is showed that the fresh charge penetrate into the burned gas and displace it first toward the cylinder head and then toward the exhaust port. When the inlet-port axial angle is much less than the side-port axial angle, the fresh charge through the inlet-port directly move toward the exhaust port. The result showed that the model A may suppress the generation of vortices in the vicinity of inlet and side prots which restrict the sufficient supply of fresh charge and obstruct the perfect displacement of all combustion products.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.2
• /
• pp.9-18
• /
• 2000

Combustion and emission characteristics in a direct injection diesel engine is closely related to the intake port system. It is therefore important to understand the swirl flow characteristics formed by a helical intake port. However there are still many uncertainties. The purpose of this experimental study is to investigate the effects of the valve eccentricity ratio and the inlet flow conditions of a helical intake port on the characteristics of an in-cylinder swirl flow. A steady state flow test rig consisted of ISM(impulse swirl meter), LFM(laminar flow meter) and cylinder head with a helical intake port was used. The swirl ratio(Rs) and mean flow coefficient(Cf(mean)) with inlet flow conditions were measured. The results of these experiment can be summarized as follows. Swirl flow characteristics of a helical intake port are affected by the inlet flow conditions, and especially they are much affected by the length of a manifold runner and the rotational angle of a curved manifold runner.

• Tribology and Lubricants
• /
• v.23 no.1
• /
• pp.1-8
• /
• 2007

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed to overcome the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. Therefore, in this study, the effects of the type of inlet oil port, inlet temperature and the sort of engine oil on the performance of a turbocharger bearing are to be investigated. It is found that the type of oil inlet ports, the control of inlet oil temperature and the selection of engine oil type play important roles in determining the temperature and pressure, then the friction and load of a turbocharger journal bearing at high speed operation.

• Journal of the Korea Convergence Society
• /
• v.11 no.5
• /
• pp.159-164
• /
• 2020

In this study, the flow analysis of air in the inner side of vehicle due to the position on inlet port of air at car was carried out. Under the comfortable condition as the inlet port in which the air flows, it was possible to confirm that the inlets became the upper and middle sides or the forward side of the vehicle. If the air flow is not evenly distributed within the vehicle, the lower position of the vehicle is the lowest condition among all conditions. The results of this study will help to keep the inner state of the vehicle pleasant by adjusting the location of the inlet to suit the passenger's taste or situation. The design and analysis results of this study can be effectively applied at adjusting the location of the inlet at car. By applying the flow analysis according to the inlet port of air at car, this paper is seen as the convergence study that conforms to aesthetic design.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.7
• /
• pp.549-556
• /
• 2001

Heat flow characteristics during hot water extraction process was studied experimentally. Data were taken at various outlet port type for the fixed inlet port type, inlet-outlet temperature differences and mass flow rates. In this study, the temperature distribution in a storage tank and an outlet temperature were measured to predict a flow pattern in the storage tank, and a hot water extraction efficiency was analysed with respect to the variables dominating a extraction process. Experimental results show that the extraction efficiency is high in a low flow rate in case of using modified distributor I(MDI) as a outlet port type.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.7
• /
• pp.1408-1418
• /
• 1992

The valve timing and intake system in SI engine is chosen in order to get the maximum performance at the target rpm. This is a compromise and the performance reduction is expected in a certain rpm range. Therefore, to accomplish the possible engine capacity all over the operation ranges, it is required to investigate the effects of intake system and valve timing on engines more thoroughly. In this paper, it was attempted to examine closely the combined effects on the torque and the volumetric efficiency due to the change of valve timing and intake system dimensions. For this, the inlet port pressure was chosen as a primary parameter to represent engine performance characteristics together with surge tank pressure and induction pressure as secondaries. The inlet port pressure was analyzed in connection with both the secondaries and the performance data. Especially the relation between the inlet port pressure and the torque and volumetric efficiency was investigated on the operating conditions. In this experiment, it was acquired that the performances at specific rpm range could be improved by the combinations of valve timing and intake system. Then it was verified that pressure at a intake system contained useful data for the engine performance. By the analysis of inlet port pressure with the others, it was obtained that the properties of the torque and the volumetric efficiency due to the change of valve timing and intake conditions were able to be defined by the average and the maximum inlet port pressures, the pressure near before the intake valve closing(IVC) point as well as the pressure at IVC point during the intake valve opening duration. These results could be applied to almost all over the experimental conditions.

• KSTLE International Journal
• /
• v.7 no.2
• /
• pp.35-44
• /
• 2006

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure, then the friction and load of journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• Tribology and Lubricants
• /
• v.23 no.5
• /
• pp.207-218
• /
• 2007

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure distribution, then the friction in a journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• Journal of Power System Engineering
• /
• v.17 no.4
• /
• pp.51-57
• /
• 2013

The length and position of the inlet port on the double tube heat exchanger is analyzed by CFX ver.11 for studying the characteristic of its flow distribution. When the boundary conditions of the inlet temperature and mass flow rate were each $20^{\circ}C$ and 10 ~ 50 kg/min, 3 models that are based on the distance between the inlet port and the center of the heat exchanger(0, 5.025, 10.05 mm) were analyzed to find the uniformity of the flow rate. Based on the flow rate, 4 lengths (23.723, 33.890, 44.057, 57.274 mm) were used to study the flow distribution according to Reynolds Number. The results show that, when the distance from the inlet to the position of the center of the heat exchanger is 10.05 mm and the length is 57.274 mm, the flow distribution is the most unified.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.2
• /
• pp.385-393
• /
• 2022

Hydrogen has reduced greenhouse gas (GHG) emissions, the main cause of global warming, and is emerging as an eco-friendly energy source for ships. Hydrogen is a substance with a lower flammability limit (LFL) of 4 to 75% and a high risk of explosion. To be used for ships, it must be sufficiently safe against leaks. In this study, we analyzed the effect of changes in the area of the air inlet / vent port on the ventilation performance when hydrogen leaks occur in the hydrogen tank storage room. The area of the air inlet / vent port is 1A = 740 mm × 740 mm, and the size and position can be easily changed on the surface of the storage chamber. Using ANSYS CFX ver 18.1, which is a CFD commercial software, the area of the air inlet / vent port was changed to 1A, 2A, 3A, and 5A, and the hydrogen mole fraction in the storage chamber when the area changed was analyzed. Consequently, the increase in the area of the air inlet port further reduced the concentration of the leaked hydrogen as compared with that of the vent port, and improved the ventilation performance of at least 2A or more from the single air inlet port. As the area of the air inlet port increased, hydrogen was uniformly stratified at the upper part of the storage chamber, but was out of the LFL range. However, simply increasing the area of the vent port inadequately affected the ventilation performance.