• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.981-987
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• 2011

In this study, single cylinder engine experiment was carried out to investigate combustion characteristics spray guided direct injection spark ignition engine. In the result of engine experiment, it was shown that flammable window of injection timing was existed. The combustion efficiency increased with retarding injection timing, reaching a peak value, subsequent to decrease again. These results were likely due to the effect of ambient pressure on stratified-premixed mixture preparation. 150 bar injection pressure condition and retarded injection timing from the best combustion efficiency injection timing showed the highest IMEP value due to the advanced combustion phase of the maximum combustion efficiency condition. HC emission showed same trend of combustion efficiency, and smoke emission was increased as injection timing was retarded due to the increased locally rich area in the high ambient pressure. NOx emission showed decreasing trend as injection timing was retarded. This is likely due to the maximum in-cylinder temperature was decreased with retarded combustion phase.

• Journal of The Association for Neo Medicine
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• v.1 no.1
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• pp.103-113
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• 1996

It is thought that the quantity and quality of the heat stimulation and the mechanism of heating process are important to understand the moxa-combustion. In order to get the basic data on the effective moxa-combustion method, combustion temperature changes (average temperature, peak temperature, average gradient temperature and maximum gradient temperature) of the heating period were measured respectively by the density of moxa material. For the experiment, samples of $300mg/0.26cm^3$ , $400mg/0.26cm^3$ and $500mg/0.26cm^3$ of moxa material were molded in a conical mold with each 10mm in diameter and height. 1. The average temperature and peak temperature of heating period on the moxa-combustion showed higher in the $400mg/0.26cm^3$ and $300mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. 2. The average gradient temperature of heating period on the moxa-combustion rose quickly in the $300mg/0.26cm^3$, $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in that order and the maximum gradient temperature rose more quickly in the $300mg/0.26cm^3$ and $400mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. According to the above results, it is concluded that the density of moxa material is (the) more important (factor) than the weight or volume of moxa material on the combustion temperature changes of the heating period for the evaluation of the quality and quantity of moxa-combustion.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.8-8
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• 2000

In this paper are presented main power and gasdynamic characteristics of C-l6VK hypersonic test cell of Research Test Center of CIAM. Gasdynamic adjustment of the C-l6VK test cell was carried out with the working section constructed on scheme of Ramjet/scramjet test in free stream. Gasdynamic adjustment was conducted stage by stage in tile following sequence. First, check and preparation of all technical systems and checking measuring system. Than determination of the characteristics of test cell on cold (without the heating of air at entrance) regime and determination of the characteristics of test cell on regimes with the heating of air. Finally determination of tile characteristics of test cell with the loading of the working part by object. On tile final stage of gasdynamic adjustment two experiments with tile axisymmetric Scramjet model loaded into the working part of test cell were conducted. The first experiment was conducted with the purpose of determination of flow parameters with the object leaded into the working part and verification of experiment cyclogram. The second experiment was conducted with injection of hydrogen into the combustion chamber of object, that is tile conditions on test cell simulated Scramjet flight Mach number M = 6. Such methodology of gasdynamic adjustment allows to determine influence of experimental object on flow parameters in the working part at different conditions of experiment (with the burning in combustion chamber of object and without the homing), and also to compare flow characteristics in the object duct.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.443-451
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• 2021

This study compared and analyzed the thermal characteristics based on the ratio of moisture content of infected and non-infected Bursaphelenchus Xylophilus by heat of combustion experiment. The experiment results are as follows. The analysisresult of the ratio of water content shows that 19.92% on average for infected Bursaphelenchus Xylophilus and 26.27% for non-infected which decreases water content as the size of conduction, convection, and radiant heat increases in case of fire. As the vaporization of the moisture content accelerates, the average moisture content is reached, and the result is contrary to the thermal characteristics of the wood that the moisture content is not ignited by a heat source when the moisture content is under 15%. The combustion heat analysis result showed that infected and non-infected Bursaphelenchus Xylophilus had no significant difference in combustion heat at about 3%. However, it shows that combustion heat is higher than other species. In conclusion, decreasing in moisture content based on the increasing conduction, convection, and radiant heat is one of the direct causes of ignition, and the lower the moisture content, the faster the fire spreads.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.74-80
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• 2007

An experiment was conducted with a common-rail direct injection diesel engine operated with neat dimethyl ether (DME). In order to investigate the effect of combustion characteristics and emission reduction of DME fuel, the experiment was performed at various injection pressure from 35 MPa to 50MPa. Also, the exhaust emissions from the engine were compared with that of diesel fuel. In this work, Cooled EGR was implemented to reduce $NO_x$ exhaust emissions. The results showed that DME has shorter ignition delay than that of diesel fuel. Despite of the increased $NO_x$ emissions with DME at an equal engine power compared to the case of fueling diesel, the engine emitted zero soot emissions all over the operating conditions in this work. $NO_x$ emission can be decreased greatly by adopting 45% of EGR while maintaining zero soot emission. Judging from the result of engine test, DME is a suitable fuel for common-rail diesel engine due to it's clean emission characteristics.

• Solar Energy
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• v.2 no.2
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• pp.11-20
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• 1982

This paper presents the experimental investigations of a system as a second treatment means to increase boiler efficiency and heat transfer from combustion gas to heating surfaces in the case of spray combustion. In order to reburn residual combustible components accelerate the burning rate of sprayed fuel droplets, improve the diffusion flame and delay the residence time of the flame, advice with slit type nozzles for spouting preheated supplementary air is used in this study. In the experiment, boiler efficiency and smoke concentration in the exhaust gas at given conditions are measured in both case of installing and not-installing device in the model of combustion chamber which was designed to be equipped with five surfaces. The results obtained in this experiment are as follows ; 1. The optimum values of air rate ${\lambda}$ are about 1.3 in both case. 2. The exhaust gas temperature in the case with device increases about $30{\sim}70^{\circ}C$ above that of the case without the device. 3. Boiler efficiency and reduction effect of smoke emissions are improved considerably.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.65-71
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• 1999

An experimental study was carried out in order to investigate the effect of shock waves on the supersonic hydrogen-air jet flames stabilized in the Mach 2.5 model scramjet combustor. This experiment was the first reacting flow experiment interacting with shock waves. Two identical $10^{\cire}$ wedges were mounted on the diverging sidewalls of the combustor in order to produce oblique shock waves that interacted with the flame. Schlieren visualization pictures, wall static pressures, and combustion efficiency at two different air stagnation temperatures were measured and compared to corresponding flames without shock wave-flame interaction. It was observed that shock waves significantly altered the shape of supersonic jet flames, but had different effects on combustion efficiency depending on air temperatures. At the higher air stagnation temperature and higher fuel flow rates, combustion of efficiency showed a better result.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.8
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• pp.613-621
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• 2009

Coal is the energy resource which is important with the new remarking energy resource. Coal combustion produces more NOx per unit of energy than any other major combustion technology. Pollutant emission associated with coal combustion will have a huge impact on the environment. Coal conversion has three processes which are drying, coal devolatilization and char oxidation. Coal devolatilization process is important because it has been shown that HCN which is converted from volatile N contributes 60 to 80% of the total NOx produced. This paper addresses mass release behavior of char, tar, gas and HCN in an experiment of Laminar Flow Reactor with two coals such as Roto middle coal (Sub-bituminous) and Anglo coal (Bituminous). The experiment is compared with the data predicted by CPD model for mass release of HCN about Roto south, Indominco, Weris creek and China orch coals. The results show that HCN increases as a function of decreasing the ratio of fixed carbon(FC)/ volatile matter(VM of the coals contain.)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.8
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• pp.574-581
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• 2008

The characteristics of combustion and flow for a lean premixed flame in lab-scale gas turbine combustor was studied through experiment and numerical analysis. From the experiment, flame structure and heat release rate were obtained from OH emission spectroscopy. Qualitative comparisons were made line-integrated OH chemiluminescence image and abel-transformed one. NOx analyzer was implemented to get the characteristic of NOx exhaust from the combustor. From the numerical analysis, the thermal distribution and characteristic of recirculation zone with the change of fuel-air mixing degree, the characteristic of methane distribution with equivalence ratio in the combustor respectively. Total heat release rate is increased with increasing equivalence ratio. Thermal Nox is reduced with increasing fuel-air mixing degree. Increasing equivalence ratio results in the decrease of the size of reaction zone and alteration of the position of the reaction zone into the entrance of the combustor.

• Journal of ILASS-Korea
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• v.27 no.2
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• pp.94-100
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• 2022

Even in non-road UTV (Utility Terrain Vehicle), spark ignition engines are often used to reduce emissions. In this study, gasoline and LPG (Liquified Petroleum Gas) fuels were applied to UTV engines, and the exhaust gas and combustion stability were compared through engine tests. A 0.8-liter two-cylinder SI engine was used in the experiment. Experiments were conducted while changing the IVO (Intake Valve Open) and EVC (Exhaust Valve Close) at 1500 rpm 14 N·m, 40 N·m, and 3000 rpm 17 N·m, 44 N·m conditions. As a result of the experiment, when the valve overlap increased according to the change of IVO and EVC, combustion stability decreased and THC emission increased, but NOx decreased. Comparing the LPG engine with the gasoline engine, the amount of CO₂ and PN (Particulate Number) generation decreased in the LPG engine, and the combustion stability was good.