• Journal of the Korean Society of Safety
• /
• v.15 no.2
• /
• pp.59-62
• /
• 2000

Almost accidents related with gas have started with the leakage of LPG(Liquefied Petroleum Gas) in the open air. But experimental data of LPG leak jet are difficult to find because the safety of experiment is hard to secure and its phenomenon is not steady but transitional. This study is focused on the phenomena of injection jet of liquid butane to the open air. Simple experiment shows that only liquid butane jet in the open air is possible due to the slow vaporization because of low temperature difference between the liquid and air and low vapor pressure of liquid butane. Comparing with the water, 25~40% more liquid butane flow through the tube under the same pressure difference driving.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.6
• /
• pp.961-967
• /
• 2012

The metal is frequently used in the air-conditioner frame, which must have the durability from the various external environments, but has difficulties in being manufactured for many complex shapes. On the other hand, the plastic, used as a material of injection molding, enables the realization of various shapes and the mass-production of complex ones and leads low production cost. As the air-conditioner frame becomes increasingly complex and detailed, the plastic material is highlighted as an alternative for the frame. But the product molded by plastic with a complex shape might have a noise problem. Therefore this study attempts to design the product through TRIZ in order to reduce the noise of the air-conditioner with the frame of plastic material.

• Journal of Biosystems Engineering
• /
• v.18 no.4
• /
• pp.351-357
• /
• 1993

Recently, a garlic peeler with high performance is being demanded due to increase of consumption of peeled garlic. Although the air type out of various types of garlic peelers is recommended to remove effectively skin of garlic, it has an important problem of large energy consumption. This study was performed to analyze performance of an air-type garlic peeler for its optimum design. Performance indices to represent performance of garlic peeler include peeling ratio, energy efficiency and peeling performance. The factors such as aperture of nozzle, angle and position of air injection, charge rate of garlic, peeling time and so on must be considered to design optimally an air-type garlic peeler.

• Journal of ILASS-Korea
• /
• v.8 no.4
• /
• pp.24-30
• /
• 2003

This paper presents the characteristics of lifted height and flame length from non-premixed jet flames in highly preheated air to investigate the detail combustion mechanism in the gas turbine or HCCI engine, etc. Special attention was paid to the effect of preheated air temperature, oxygen concentration and fuel injection flow rate on flame length and lifted hight. By using highly preheated air, stable flames were formed even in low oxygen concentration condition. The lifted height increased with decreasing preheated air temperature, where the flame length showed opposed phenomena. The flamelet model, which is thought to have very thin flamelet, is difficult to applicable to the present flame conditions which is formed In low oxygen concentration in highly preheated air.

• Clean Technology
• /
• v.13 no.4
• /
• pp.300-307
• /
• 2007

The combustion characteristics of diffusion flame formed in the wake of a cylindrical stabilizer with varying fuel injection angle were studied. This study was performed by measuring the flame stability limits, lengths and temperatures of recirculation zones of flames, turbulence intensity in the wake of stabilizer, and concentration distribution of combustion gas, and by taking photographs of flames. The flame stability limits are dependent on fuel injection angle and main air velocity. The length and temperature of recirculation zone are dependent on fuel injection angle. As the length of the recirculation zone is decreased, the flame shows more stable behavior. The temperature of recirculation zone has a maximum value at the condition of theoretical mixture. The flame stability is enhanced when the temperature in the recirculation zone decreases. The turbulence intensity in the wake of stabilizer is independent of the fuel injection angle, but it is affected by stabilizer itself and main air flow condition. If the stabilization characteristics of flame is good, the concentration of $C_3H_8$ is high, but the concentration of $CO_2$ is low at the boundary of recirculation zone. The combustion characteristics of diffusion flame can be controlled by changing the fuel injection angles. The appropriate fuel injection angle should be selected to get high combustion efficiency, high load power, low environmental pollution, and clean combustion condition of fuel.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.2
• /
• pp.57-62
• /
• 2000

The effect of exhaust gas recirculation(EGR) on the characteristics of exhaust gas emissions, and SFC are experimentally investigated by four-cylinder, four-cycle and direct injection marine diesel engine. In order to reduce the soot contents in the recirculated exhaust gas to intake system of the engines, a soot removal system of a cylinderical-type scrubber is specially designed and manufactured for the experimental system. (1) SFC is increased in downward convex curve style with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio. (2) NOx emission is reduced in downward convex curve style with increasing excess air ratio, it is reduced with increasing EGR rate at the same excess air ratio. (3) Soot emission is decreased in downward convex curve style with increasing excess air ratio, it is reduced with increasing EGR rate at the same excess air ratio. (4) CO emission is increased in nearly straight line style with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio. (5) HC emission is not constant tendency with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.4
• /
• pp.22-29
• /
• 2003

New high-speed depressurized circulating water channel was designed by using the CFD code. Flow in the channel has free surface and pressure in the test section can be depressed. In this study, Flow separation and bubble occurrence were considered in designing the contraction nozzle shape for better flow uniformity Tn the test section. To supplement velocity defect due to the free surface, nozzle injection system more effective in high-speed flow was installed instead of drum system. Necessary power and injection techniques were proposed. And guide vane arrangement was analyzed to reduce the flow resistance and keep quiet free surface from ´surging´. Wave absorber was devised to reduce the wave resistance and to prevent the entrainment of air to the diffuser.

• Journal of Biosystems Engineering
• /
• v.34 no.3
• /
• pp.135-139
• /
• 2009

Harmful exhaust emissions of diesel engines are recognized as main causes of air pollution in these days. But, the direct injection diesel engine is widely used for sake of minimization on energy consumption. Because biodiesel fuel is a renewable and alternative fuel for a diesel engine, its usability is expanded. To investigate the effect of biodiesel fuel(extracted from rapeseed oil) on the characteristics of performance and exhaust emissions in an agricultural diesel engine, the biodiesel fuel derived from rapeseed oil was applied in this study. Smoke emission of esterified rapeseed oil was reduced remarkably by approximately 44.5% at 1500 rpm, full load in comparison with the commercial diesel fuel. The power, torque and brake specific energy consumption of the diesel engine showed very slight differences. It was concluded that esterified rapeseed oil could be utilized effectively as an alternative and renewable fuel for agricultural direct injection diesel engines.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.7
• /
• pp.2421-2429
• /
• 1996

The objective of this research is to apply effect of the pre-mixed combustion quantity and smoke emission in diesel engine. According as air fuel ratio is increased, emission of smoke concentration is linearly reduced. As Injection timing is advanced, smoke concentration is remarkably reduced. It is considered to be the primary cause of the increase in the premixed combustible mixture during long ignition delay period with advancing injection timing. Smoke is increased with increasing engine speed, so it is considered to be the primary cause of the increase of the mass of fuel injected. Smoke is decreased according to the increase of methanol volume ratio. It is considered that the primary cause of the increase in the quantity of pre-mixed combustion.

• Journal of the Korean Society of Combustion
• /
• v.11 no.4
• /
• pp.1-8
• /
• 2006

The model cavity scramjet engine experiments are carried out using T3 free-piston shock tunnel. Upstream hydrogen fuel is injected before the cavity with different injection pressure. OH planar laser-induced fluorescence is used to investigate the combustion zone and piezoelectric pressure transducers are used to define the pressure rise due to the combustion. Main combustion region is a mixing layer which is between air and fuel. Also high OH fluorescence signal is appeared in the shear layer above the cavity in high equivalence ratio. From the OH signal in the cavity, this fuel injection system can be a role as a flame-holder.