• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.6
• /
• pp.658-665
• /
• 1998

This paper investigates local exhaust effectiveness in a room with a supply and an exhaust slots on the ceiling. The mean age of air is an indicator of supply effectiveness, while the mean residual life time can be used as an indicator of exhaust effectiveness. The distribution of local mean residual life time in a space is calculated by four different numerical procedures. The reverse-flow calculation method has been proved to show quite accurate results while it can save considerable amount of computation time and efforts, compared to the method by its original definition. It is concluded that the diffusion term in the equation of mean residual life time can be neglected. The spatial and temporal diffusion characteristics of the contaminant are also discussed.

• 유체기계공업학회:학술대회논문집
• /
• 2004.12a
• /
• pp.297-302
• /
• 2004

CFD analysis has been performed to investigate flow behavior in LP exhaust hood of steam turbines and evaluate exhaust loss, which is directly related to the steam turbine performance, in it. Development of the optimum shape of LP exhaust hood has been done with an improved shape of steam guide, which plays a key role in terms of cost as well as performance. The newly developed LP exhaust hood will be applied for a large USC steam turbine having a capacity of 1,000 MW.

• Journal of Energy Engineering
• /
• v.23 no.2
• /
• pp.114-118
• /
• 2014

The need to maximize the exhaust pipe inside surface and to minimize exhaust resistance And Find the best point between the exhaust and the duration of contact between the two surfaces. Exhaust gas mass flow On the whole cross section of catalytic converters more uniform distribution will contribute to its usability. Based on the flow rate of fluid traces given color, Exhaust fluid resistance in the porous catalyst can be estimated, from the efficiency of the catalytic converter that is very important.

• Journal of computational fluids engineering
• /
• v.11 no.3 s.34
• /
• pp.52-58
• /
• 2006

A numerical investigation is made of air flow in a spinner equipment used for cleanning and drying flat display panels. A unique feature of the spinner under question is the placement of a torus plate cover over the rotating plate. The turbulent flow is driven by rotation of a large disk and suction by the exhaust system connected to vacuum chamber. The flow is modelled as an axisymmetric two-dimensional flow and computation is conducted by using the FLUENT package with a version of k-$\varepsilon$ turbulence model. The required capacity of the exhaust system is assessed numerically. The usefulness of the cover in controlling air flow circulation is examined. A computational trouble shooting is attempted to resolve the problem of panel rising which occurred in real experiment.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.5
• /
• pp.55-65
• /
• 1998

A numerical and experimental study of three-dimensional steady incompressible non-reacting flow inside various dual-monolith catalytic converters has been conducted for achievement of performance improvement, reduction of light-off time and longer service life by improving the flow uniformity within the monolith. In this study, the effects of curvature of inlet exhaust pipe and monolith brick length on the flow uniformity and pressure drop within monolith were numerically investigated. The computations are confirmed by measurements of steady flow. The agreement between computations and experiment was relatively good. The result of this study shows that curvature of inlet exhaust pipe and monolith brick length gave a great effect on the flow uniformity and the shorter the brick length, the lower flow uniformity and the less pressure drop.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.802-805
• /
• 2007

The exhaust system, including a muffler, is one of the major sources to generate the radiated noise of construction equipment. The muffler is generally known that it reduces the exhaust noise level, but it sometimes increases the noise level because of the flow effect inside a muffler. So, it is required to consider the flow effect inside a muffler to reduce the exhaust noise level of construction equipment. In this paper, an experimental method to consider a quantitative flow effect inside a muffler was set up through a series of tests. Finally, the experimental result was verified through the flow noise analysis using CFD analysis result. These results make it possible to understand the dynamic characteristics of the flow noise and to design the low noise muffler for the construction equipment.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.3
• /
• pp.182-188
• /
• 2008

In order to improve scavenging performance of free piston hydrogen fueled engine, this study estimate compatibility of uni-flow scavenging. The scavenging flow characteristics in the cylinder is investigated by flow visualization and PIV method. Consequently it has been found that the scavenging performance decreased with abnormal expansion of piston and delay of the exhaust valve opening timing. And the scavenging performance of exhaust valve located center in cylinder head is better than that of exhaust valve located side in cylinder head.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.684-689
• /
• 2004

In this study, a experimental method has been introduced for the various exhaust pipe geometry of 4-stroke single cylinder engine. The main experimental parameters are the variation of exhaust pipe diameters and lengths, to measuring the pulsating flow when the intake and exhaust valves are working. As the results of experimental test, the various exhaust geometry were influenced strongly on the exhaust pressure. As the exhaust pipe diameter was decreased, the amplitude and the number of compression wave in exhaust pressure was increased. According to decreasing pipe diameter, the number of compression wave in exhaust pressure was decreased. When the pipe diameter was increase, the second amplitude was increased.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.10a
• /
• pp.461-462
• /
• 2009

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.3
• /
• pp.115-125
• /
• 2008

Recently, Exhaust Gas Recirculation (EGR) system which re-flow a cooled exhaust gas from vehicles burning diesel as fuel to a combustion chamber of engine has been used to solve the serious air pollution. For the design and mass production of EGR system, it is essential to ensure structural integrity evaluation. The EGR system consisted of ten dimpled oval core rectangular tubes, two fix-plates, two coolant pipes, shell body and two flanges in this study. To confirm the safety of the designed system, finite element modeling about each component such as the dimpled oval core tube with the dimpled shape and others was carried out. The reliability of EGR system against exhaust gas flow with high temperature was investigated by flow and pressure analysis in the system. Also, thermal and strength analysis were verified the safety of EGR system against temperature change in the shell and tubes. Furthermore, modal analysis using ANSYS was also performed. From the results of FE analysis, there were confirmed that EGR system was safe against the flow of exhaust gas, temperature change in EGR system and vibration on operation condition, respectively.