• Journal of the Korean Institute of Gas
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• v.23 no.5
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• pp.24-34
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• 2019

In this study, the experimental studies were conducted to analyzing characteristics of combustion and flame stabilizing according to with and without water tube in boiler. The burner has consisted of SiC foam where has the location of submerged flame between a ceramic board acting as flash-back arrestor. Porous burner is also insulated to minimize heat loss in the radial direction. In the condition of fixed equivalence ratio, the flame mode was divided into three stability zones by the flow rate. The main factor for blow-off and flash-back depends on mixture flow rate. Consequently, the case of burner with water-tube has higher NOx emissions than without case. This result explains that the presence of water-tube makes the heat loss resistant to ambient temperature with increasing of NOx. This tendency was proved by predicting the relationship between O₂ emission and NO production rate, and by analysing temperature profiles.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.21-27
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• 2019

Composite motor cases fabricated by the filament winding method are structurally weak in the dome when they are required to withstand the internal pressure of the combustion gas. In this study, a finite element analysis is conducted to compare the burst pressure of a composite dome according to the variation of the pressure distribution ratio(PDR). The performance of the composite motor case was compared quantitatively by calculating the stress on the inner and outer dome surfaces and metal boss volume. As a result, the critical point of the failure mode was observed at a PDR between 2.5 and 3.0. A design at a PDR of 2.5­-3.5 can reduce the weight of metal boss without fluctuation in the burst pressure of the combustion motor case. Moreover as the design reference value changes according to the dome shape and opening size, further analysis and testing are necessary.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.2
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• pp.66-78
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• 2021

In this study, the effect of Symmetry Breaking was compared according to the equivalent ratio condition and the number of nozzles where combustion instability occurs in an annular combustor. Generally, due to the relatively short combustor length, a longitudinal instability was less likely to occur in the annular combustor, but the combustion instability sometimes happens when ducts such as transition piece in gas turbine power station are present. In this case, due to the duct, only the longitudinal instability mode is observed. The characteristics of Symmetry Breaking were investigated according to the number of five lean nozzles and the equivalent ratio combination, and as the equivalent ratio decreased, the effect of Symmetry Breaking rapidly occurred, and the instability was dramatically disappeared and the amplitude was greatly reduced. In addition, it was confirmed that as the number of lean nozzles increased, a phenomenon such as a reduction in the equivalent ratio appeared.

• Fire Science and Engineering
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• v.26 no.6
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• pp.92-98
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• 2012

In this sturdy, large experimental (ISO 13785-2) was performed to analyze the building materials used in fire retardant materials for aluminum composite panel and in general properties. As a results, maximum temperature in the case of the general materials was measured in 210 seconds $1,021^{\circ}C$, the retardant materials was measured in 1,200 seconds early $1,190^{\circ}C$. The retardant material of aluminum composite panel, Fire behavior if the ignition is slow and the general materials in aluminum composite panel, fire ignition and combustion at the same time was growing rapidly. The general materials and flame-retardant material of aluminum composite panel was an obvious difference to the combustion ignition but after ignition combustion mode showed a similar pattern of the rapidly vertical spread of flame. The results of this study, in order to reduce the risk of aluminum composite panels for fire and the retardant materials used for ignition the slow should be actively encouraging. Also after the ignition, there is an urgent need to put out a fire in exterior materials for extinguishing facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.662-668
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• 2018

Most electric rooms are located in the underground spaces of buildings. When a fire occurs in electrical equipment, the fire expands to cable insulation material, resulting in toxic smoke and combustion products. If the smoke and combustion products quickly move vertically and horizontally, the evacuation of occupants and firefighting activities will be hindered. Therefore, it is necessary to design optimal equipment for smoke control in cases of fires in electric rooms. This study analyzes the characteristics of smoke and combustion products in fires in a cubicle-type switchboard in an electric room using PyroSim, which is based on the program Fire Dynamics Simulator (FDS). The fire modeling consists of four scenarios according to the operation mode of the mechanical ventilation equipment, the amount of air supply and exhaust, and the location of the air supply slot. The analysis shows that the mechanical ventilation equipment improves the smoke density, visibility, carbon monoxide concentration, and temperature characteristics. The visibility and temperature characteristics were improved when the air flow rate and the location of the air supply slot from fire defense regulations were applied.

• Journal of Energy Engineering
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• v.17 no.4
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• pp.227-232
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• 2008

Carbon dioxide is considered a major greenhouse gas that contributes to global wanning. $CO_2$ is a major component of the exhaust in the combustion of any hydrocarbon fuel. The regulation for $CO_2$ emission from vehicles has become much more stringent in recent years. These more stringent regulations require vehicle manufacturers to develop alternative fuels that reduce exhaust emissions. This paper evaluated the correlation of $CO_2$ emission and fuel economy in the Gasoline, Diesel, and LPG vehicles according to FTP-75 and NEDC(ECE15+EUDC) driving mode. From this study, we discovered that the decrease rate of $CO_2$ emission is higher for fuels of lower carbon concentration. When the relationship between $CO_2$ emission and fuel consumption rate according to used fuels is expressed as a function, one can find out that they have a high correlation. LPG vehicles produce less $CO_2$ emission than gasoline and diesel vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.133-140
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• 2007

The purpose of this study was to evaluate the effects of gasoline fuel to the LPI engine. Firing test bench was used in order to assess the effect on gasoline-injected LPI engine. Gasoline fuel was supplied into the reverse direction(3-4-2-1 cylinder) at 3.0 bar with commercial gasoline fuel pump. Engine test was performed using the firing test mode at end of line. The deviations of excess air ratio of each cylinder and maximum combustion pressure using gasoline fuel were within 0.1 and $1{\sim}2\;bar$. Engine start time was measured with changing coolant temperature at $20^{\circ}C,\;40^{\circ}C,\;80^{\circ}C$, respectively. Residual gasoline volume in the fuel line was measured about 32 cc after firing test and it was less than 2 cc within 10 seconds purging. To simulate the end of line, the residual gasoline in the fuel line was purged during 5 and 10 seconds. Start time of LPI engine with LPG fuel were 0.61 and 0.58 seconds. This work showed that severe problems such as misfiring and liner scuffing were not occurred applying gasoline fuel to LPI engine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1433-1438
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• 2009

The purpose of this study is to investigate how the ignition spark timing conversion influences the engine performance of LPG/Gasoline Bi-Fuel engine. We propose the control system which can advance the ignition spark timing in LPG fuel mode more than used in gasoline fuel mode. In order to investigate the engine performance during combustion, engine performance are sampled by data acquisition system, for example cylinder pressure, pressure rise rate and heat release rate, while change of the rpm(1500, 2000) and the ignition timing advance($5^{\circ}$,$10^{\circ}$,$15^{\circ}$,$20^{\circ}$) As the result, between 1500rpm and 2000rpm, the cylinder pressure and pressure rise rate was increased when the spark ignition was advanced but pressure rise rate at $20^{\circ}$was smaller value. Also, the heat release rate at 1500rpm was increased but it was lower around $20^{\circ}$at 2000rpm.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.16-23
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• 2012

This study has been conducted to scrutinize agitation effects of an ultrasonic standing wave on the dynamic behavior of methane/air premixed flame. The propagating flame was caught by high-speed Schlieren images, through which local flame velocities of the moving front were analyzed in unprecedent detail. It is revealed that the propagation velocity agitated by the ultrasonic standing wave is greater than that without agitation at the stoichiometric ratio: the velocity enhancement diminishes as the equivalence ratio approaches upper flammability limit or lower flammability limit. Also, vertical locations of the wave-affected frontal distortions do not vary appreciably, unless the propagating-mode characteristics (pressure amplitude and driving frequency) of ultrasonic standing wave were not changed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.165.1-165.1
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• 2010

In the past, drivers bought a fuel additives to treat a combustion chambers or injector nozzles for carbon or gum deposit at market. But, nowadays, as raised cost of fuel for a vehicle the consumers also start focusing on a function of fuel additives that increases fuel economy of one. Some fuel additive manufacturers and agents advertise that their goods make a car it's initial state. This paper shows data for 3 years that were acquired during test for registration of an additive in domestic. The data were sorted according to kind of vehicle, kind of fuel, test mode, CO, HC, NOx, PM, total emission, fuel economy and accumulated mileage. And than by using simple linear regression analysis changes according to accumulated mileage was displayed. Normal distribution and histogram of rate of increase and decrease were displayed. the analyzed data indicated that a fuel additive maintain and make a car the first state of one but can't make a car be batter than initial the one.