• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.654-661
• /
• 2000

Area of greenhouse increases rapidly up to 45,265ha by the year of 1998 in Korea. Hot air heater with light oil combustion is the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat of the oil combusted in the furnace. In order to recapture the heat of this exhaust gas and to recycle for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The exhaust heat recovery system was made for space heating in the greenhouse. The system consisted of a heat exchanger made of heat pipes, ${\emptyset}15.88{\times}600mm$ located in the rectangular box of $600{\times}550{\times}330mm$, a blower and air ducts. The rectangular box was divided by two compartments where hot chamber exposed to exhaust gas in which heat pipes could pick up the heat of exhaust gas, and by evaporation of the heat transfer medium in the pipes it carries the heat to the cold compartment, then the blower moves the heat to greenhouse. The number of heat pipe was 60, calculated considering the heat exchange amount between flue gas and heat transfer capacity of heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/hr depending on the inlet air temperature of 12 to $-12^{circ}C$ respectively when air flow rate $1,100\textrm{m}^3/hr$. The exhaust gas temperature left the heat exchanger dropped to $100^{circ}C$ from $270^{circ}C$ by the heat exchange between the air and the flue gas, the temperature difference was collected by the air and the warm air temperature was about $60^{circ}C$ at the air flow rate of $1,100\textrm{m}^3/hr$. This heat pipe type exhaust heat recovery system can reduce fuel cost by 10% annually according to the economic analysis.

• Journal of Environmental Science International
• /
• v.14 no.6
• /
• pp.543-553
• /
• 2005

In recent days, photochemical smog due to the rapid industry development and vehicle increasement has become a critical pollutant in the metropolitan area and the number of ozone alarm signal has increased every year. This research was performed to evaluate VOCs emission source characteristics and concentration of VOCs in Daegu. The site average concentration was observed in the following order: industrial area > commercial area > residential area. Most of the VOCs species except toluene showed variations with higher concentration during nighttime, and lower concentration during the daytime. The major VOCs of stationary emission source were BTEX(benzene, toluene, ethylbenzene. xylene) and methylene chloride, trichloroethene and styrene. Also, those of automobile exhaust were toluene and benzene. Also, the major VOCs concentration emited by the vehicle fuel was observed in the following order: gasoline > light oil > liquefied petroleum gas (L.P.G). Correlation coefficients values were estimated between major VOCs such as toluene, ethylbenzene, m,p-xylene, o-xylene. Results showed that correlation coefficient values were significant magnitude above 0.76. Also, there showed highly significant correlations among ethyl benzene, m,p-xylene, and o-xylene concentration(Pearson correlation coefficients, r=0.868-0.982). Calculated correlation coefficients among commercial area,industrial area and residential area were 0.934-0.981, they showed high correlation. There showed highly correlation between stationary emission source and industrial area, compared with commercial area and residential area. Also, calculated correlation coefficients among commercial area, industrial area, residential area and automobile exhaust were 0.732, 0.725, 0.777, respectively.

• Journal of the korean Society of Automotive Engineers
• /
• v.7 no.1
• /
• pp.24-34
• /
• 1985

The study of unsteady gas exchange processes in the inlet and exhaust systems of the single-cylinder 4-stroke cycle spark ignition engine is presented in this paper. The generalized method of characteristics including friction, heat transfer, change of flow area and entropy gradients was used for solving the equations defining the gas exchange process. The path line calculation was also conducted to allow for calculation of the gas composition and entropy change along the path lines, and of the variable specific heat due to the change of temperature and composition. As the result of the simulation, the properties at each point in the inlet and exhaust pipe, pressure and temperature in the cylinder, and charging efficiency were obtained. Pumping loss and residual gas fraction were also computed. The effect of engine speed, exhaust and inlet pipe length on the pumping loss and charging efficiency were studied showing that the results were in agreement with what has been known from experiments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2002.10a
• /
• pp.37-40
• /
• 2002

The engine performance test was carried out to investigate the effects of breath and exhaust on the performance of a reciprocating engine for small aircraft. In this test, three valves to control flow areas of a inlet and two outlets were used, the engine manifold pressure and the static thrust of propeller were measured in nine breath/exhaust conditions. Generally, small variations on the performance were showed as the test conditions were changed. The manifold pressure was increased as flow area of the inlet or the outlet was decreased in normal condition, however it was decreased as both flow areas were decreased. The static thrust of propeller was showed similar as the manifold pressure.

• Journal of the Korean Society of Safety
• /
• v.21 no.6 s.78
• /
• pp.1-6
• /
• 2006

Subway platform is divided into Side-platform type and Center-platform type. In this study does quantitative fire risk assesment of subway platform types in numerical analysis by using CFD model. From the result of this study, 1) All exhaust mode was low-end result it seems most fire risk at Side-platform station. 2) All exhaust mode was low-end result it seems most fire risk at Center-Platform station. 3) When comparing same type exhaust mode of Side-platform and Center-platform that last thing was visible $9.1{\sim}72.34%$ low-end fire risk. Center-platform is more opera-tive than Side-platform that reduce fire risk when that was same dimension and external environment. Designer look upon a fire characteristic of subway platform types when he make smoke control air volume and platform area design.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.9
• /
• pp.868-877
• /
• 2001

This study is to present the typical energy consumption criteria and $CO_2$ exhaust rate in multi-family housing complex by analyzing the energy consumption characteristics. The contents and methodology of this study are as follows; -Examining the documents of maintenance accounts, investigate the cost and its items expended by the annual maintenance in multi-family housing complex. -Survey each consumption of energy sources, maintenance area, location of multi-family housing complex, heating type, and so forth. -After classifying with heating type of multi-family housing complex investigated, Scrutinize the energy consumption by each source. -Analyze the characteristics of energy consumption and $CO_2$ exhaust through multiple regression analyses of maintenance property. -Suggest the typical energy consumption criteria (Mcal/$m^2$.year, Mcal/house.year) and $CO_2$ exhaust rate (kg-c/$m^2$.year, Kg-c/house.year) in multi-family housing complex. the results will come into basic data for estimating energy consumption in multi-family housing complex according to maintenance characteristics.

• Journal of the Korean Chemical Society
• /
• v.57 no.6
• /
• pp.691-696
• /
• 2013

Black carbon contributes to global warming and melting of polar ice as well as causing respiratory diseases. However, it is also an inexpensive, easily available carbon nano material for elementary chemistry experiments. In this study, black carbon samples collected from candle light and automobile exhaust pipes have been investigated to examine their compositions and surface characteristics. The observed broad G and D bands and amorphous $sp^3$ band in their Raman spectra as well as the high intensity of the D (defect) band reveal that black carbon is principally made of amorphous graphite. The black carbon deposits in automobile exhaust pipes are apparently more amorphous, probably due to the shorter time allowed for formation of the carbonaceous matter. An exceptionally large water contact angle ($159.7^{\circ}$) is observed on black carbon, confirming its superhydrophobicity. The surface roughness evidently plays an important role for the contact angle much larger than that of crystalline graphite ($98.3^{\circ}$). According to the Sassie-Baxter equation, less than 1% the area actually in contact with the water drop.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.2
• /
• pp.65-73
• /
• 2007

The use of an Exhaust Gas Recirculation(EGR) for a diesel engine with variable geometry turbocharger(VGT) has confronted how to obtain the amount of EGR for NOx reduction requirement at wide operating range and less side effect. Through a combined effort of modeling(wave action simulation) and experiment, an investigation into the effect of EGR area ratio and pipe length on EGR characteristics of common rail diesel engine with VGT has been performed. For accurate computation, calibration of constants involved in empirical and semi-empirical correlations has been performed at a specific operating point, before of its use for engine simulation. From the results of this study, it was found that EGR rate is sharply increased with increasing EGR area ratio until area ratio of 0.3. However, the effect of EGR area ratio on EGR rate is negligible beyond this criteria. This study also investigates the effect of EGR pipe length on a EGR amount and pulsating flow characteristics at EGR junction. The results showed that the longer EGR pipe length, the lower EGR amount was achieved due to the flow loss resulting in lower amplitude of pressure wave.

• 한국전산유체공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.281-285
• /
• 2005

Viscous solutions of supersonic jet impinging on a flat wall in a confined plenum are simulated using three-dimensional Navier-Stokes solver. A confined plenum was designed for simulating the missile launch and analyzing the behavior of the exhaust plume, which were accompanied by complex flow interactions with shock and boundary layer. Concerns of this paper are to show accurate simulation of internal flow in confined plenum and to demonstrate the jet flow structure when the jet interacts with a small opening on the side. Objectives of this numerical simulation are to understand the effect of changing the plume exit area of the plenum. Pressure and temperature rise at certain position in the plenum are traced and compared with test data.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2017.10a
• /
• pp.54-58
• /
• 2017

The vessels which are operated in ECA (Emission Control Area) after $1^{st}$ January 2016 shall be complied with revised NOx emission requirement (Tier III). Effective solutions for NOx emission requirement are SCR (Selective Catalytic Reduction), EGR (Exhaust Gas Recirculation) and Installation of LNG Dual Fuel Engine. This study is considered the design modification as per application of LNG Ready notation. In case of LNG Ready - S notation, the vessel shall be retrofitted the Main engine with Dual fuel engine and LNG Fuel system after delivery. On this paper, the entire process for design modification was explained to meet the requirement for LNG Ready notation.