• 대한조선학회 특별논문집
• /
• 대한조선학회 2006년도 특별논문집
• /
• pp.59-64
• /
• 2006

Most important factor to consider funnel performance is exhaust gas temperature and exhaust gas concentration Electric equipments on the wheelhouse top affected exhaust gas temperature. So, it is important that electric equipments keep away from high temperature. Though exhaust gas concentration is not a regulation and restraint, the exhaust 9as can cause serious problems for the on-board air quality and result in irreversible damage to the ship and people. So, we pocus on the exhaust gas concentration also. When judge whether a measured concentration is acceptable or not, criteria based on the LTEL (Long Term Exposure Limit). In this paper, we carried out the smoke simulation study. For this analysis, we used FLUENT which is commercial CFD (Computational Fluid Dynamics) code.

• Journal of Advanced Marine Engineering and Technology
• /
• 제24권3호
• /
• pp.70-78
• /
• 2000

The effects of recirculated exhaust gas on the characteristics of ;$NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The purpose of the present study is to develop the EGR control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal apparatus with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector is made up 144 nozzles with 1.0mm in diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration obtained by the intake air flow and the oxygen concentration in the recirculated exhaust gas, and the exhaust oxygen concentration measured in exhaust manifold are used to analyse and discuss the influences of EGR on NOx and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions decrease and soot emissions increase owing to the drop of intake oxygen concentration and exhaust oxygen concentration as EGR rate rises. Also, one can conclude that it is sufficient for the scrubber EGR system with a novel diesel soot removal apparatus to reduce $NO_x$ emissions, but not to reduce soot emissions.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 춘계학술대회논문집
• /
• pp.172-175
• /
• 2008

In the last five years, 45 people died and 104 were wounded because of carbon monoxide poisoning accident. CO poisoning accident is higher than any other gas accident in the rate of deaths/incidents. Most of these CO poisoning accidents were caused by defective exhaust tube in the old gas boiler and multi-use facility. In this study, the spread of CO gas released from leakage hole of exhaust tube was analyzed by computational flow modeling and concentration measuring test. CO gas leaked form exhaust tube in a building was highest concentrated near the ceiling and formed the circular currents along the walls. Through these experiments and simulation, the reasonable installation location of CO alarm was made certain and suggested.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집D
• /
• pp.115-120
• /
• 2001

The present study examined the possibility of $NO_{x}$ reduction in the high temperature industrial furnaces. duct burner of gas turbine cogeneration and two-stage gas turbine combustor. The experimental study was carried out for the diffusion flame of second stage combustor with the variations of oxygen concentration and supplying rate of hot exhaust gas from first stage combustor. It also examined the flammability range and $NO_{x}$ formation of the second stage combustor in which the fuel is supplying into the mixture of oxygen hot exhaust gas from first stage combustor. The results show that the enrichment of oxygen and increase of exhaust gas lead to increase the $NO_{x}$ up to 50 ppm with 23% $O_{2}$ condition.

• 한국자동차공학회논문집
• /
• 제16권4호
• /
• pp.56-62
• /
• 2008

A synthetic gas reformed from hydrocarbon-based fuels consists of $H_2$, CO and $N_2$. Hydrogen contained in the synthetic gas is a very useful species in chemical processes, due to its wide flammability range and fast burning speed. The ESGI (Exhaust Synthetic Gas Injection) technology is developed to shorten the light-off time of three way catalysts through combustion of the synthetic gas in the exhaust manifold during the cold start period of SI engines. Before the ESGI technology is applied to the test engine, the authors set a test rig that consists of gas temperature and composition controllers, an exhaust pulse generator and an exhaust manifold with a visualization window, in order to optimize the point and conditions of injection of the synthetic gas. Through measuring burned gas temperatures and taking photographs of synthetic gas combustion at the outlet of the exhaust manifold, the authors tried to find the optimal injection point and conditions. Analysis of burned gas composition has been performed for various $O_2$ concentrations. As a result, when the synthetic gas is injected at the port outlet of the cylinder No. 4 and $O_2$ concentration exceeds 4%, combustion of the synthetic gas is strong and effective in the exhaust manifold.

• 대한기계학회논문집B
• /
• 제24권5호
• /
• pp.660-667
• /
• 2000

In order to investigate the exhaust structure and secondary oxidation of unburned hydrocarbon (HC) in the exhaust port, concentrations of individual HC species were measured in exhaust process, the degree of oxidation were obtained. Using a solenoid-driven fast sampling system on single-cylinder research engine fueled with 94% propane, the profiles of unburned hydrocarbons (HCs) and non-fuel HCs with a propane fueled engine were obtained from several locations in the exhaust port during the exhaust process. The sampled gases were analyzed using a gas chromatography of HC species with 4 or lesser carbon atoms. The change of total HC concentration and HC fractions of major components through the exhaust port were discussed. The results showed that non-uniform distribution of HC concentration existed around the exhaust valve and changed with time, and that the exhaust gas exhibited nearly uniform concentration profile at port exit, which was due to mixing and oxidation. Also it could be known that bulk gas with relatively high HC concentration came out through the bottom of the exhaust valve. To estimate the mass-based degree of HC oxidation in the exhaust port from measured HC concentrations, a 3-zone diagnostic cycle simulation and plug flow modeling were used. The degree of oxidation ranged between 26 % and 36 % corresponding to the engine operation conditions.

• 동력기계공학회지
• /
• 제19권4호
• /
• pp.82-88
• /
• 2015

The purpose of this study is to investigate the effect of the impinging plate on combustion process in Diesel engine. Especially, the variation of exhaust emission and engine performance by the change of fuel injection timing and fuel injection pressure between the trial engine with impinging plate and the prototype engine were examined. The nitrogen oxide concentration of the trial engine decreased more than 50% compared to the prototype engine, however, smoke concentration of the trial engine indicated higher degree than the prototype engine. The smoke concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection timing become faster, whereas the nitrogen oxide concentration decreased as the fuel injection timing is retarded. The nitrogen oxide concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection pressure become lower. But smoke concentration decreased as the fuel injection pressure become higher.

• 대한기계학회논문집B
• /
• 제24권9호
• /
• pp.1247-1254
• /
• 2000

The effects of recirculated exhaust gas on the characteristics of $NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The simultaneous control of $NO_x$ and soot emissions in diesel engines is targeted in this study. The EGR system is used to reduce $NO_x$ emissions, and a novel diesel soot removal device with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector has 144 nozzles in 1.0 mm diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration and the mean equivalence ratio calculated by the intake air flow and fuel consumption rate, and the exhaust oxygen concentration measured are used to analyse and discuss the influences of EGR rate on $NO_x$ and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions are decreased and soot emissions are increased owing to the drop of intake oxygen concentration and exhaust oxygen concentration, and the rise of equivalence ratio as the EGR rate rises.

• 한국표면공학회지
• /
• 제55권6호
• /
• pp.433-440
• /
• 2022

Environmental pollution caused by power plant exhaust gas is highlighted and eco-friendly regulations are being strengthened. However, due to the abundant reserves and low prices of coal, still the most used for power generation in the world. Therefore, flexible operation of coal-fired power plants to reduce emissions has become an inevitable option. However, lowering the output increases the possibility of acid dew point corrosion as the exhaust gas temperature decreases. The dew point corrosion occurs when condensable gases such as SO₃, HCl, NO₂ and H₂O cools below the saturation temperature. SO₃ is already well known to cause severe low- temperature corrosion in coal-fired power plants. Therefore, this study aims to prevent damage that may occur during operation by analyzing the dew point and corrosion resistance with exhaust gas temperature and sulfuric acid concentration of the power plant economizer tube.

• 한국자동차공학회논문집
• /
• 제17권1호
• /
• pp.43-49
• /
• 2009

A catalyzed diesel particulate filter (CDPF) causes the progressive increase in back pressure of an exhaust system due to the loading of soot particles. To minimize pressure drop which is generated by CDPF, the filter should be regenerated when it collects a certain quantity of soot. It is important to know characteristics of regeneration of CDPF with various of exhaust gas temperatures and compositions. The oxidation of HC in DOC leads to increase gas temperature of DOC downstream. The increased gas temperature by DOC has an positive effect on CDPF regeneration. This study presents characteristics of regeneration of CDPF with DOC according to various gas composition, such as HC and $O_2$ concentration. The test-rig is used to control each gas composition and temperature during regeneration of CDPF. Experimental results indicate that the increased concentration of $O_2$ regenerates DPF more actively. With increasing HC concentration, the gas temperature of CDPF upstream increased due to more oxidation of HC. But excessive supply of HC leads to decrease of $O_2$ concentration in the CDPF, which makes it hard to regenerate CDPF.