• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1022-1027
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• 2011

A diesel engine works in high compression ratio due to injection of diesel fuel after compression of air. Therefore the engine has a high thermal efficiency, while nitrogen oxide is produced a lot in high flame temperature regions. In order to solve the problem this study HHO gas is added into the intake air of the industrial diesel engine. The test conditions are loads of 0%, 50% and 100% and engine speeds of 700 to 1900 rpm. The results show the maximum torque and pressure is increased, fuel consumption, smoke and CO emissions are decreased and NOx emission is remained at same level.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.136-144
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• 2010

Exhaust gas recirculation (EGR) is an emission control technology allowing significant NOx emission reduction from light-and heavy duty diesel engines. The future EGR type, dual loop EGR, combining features of high pressure loop EGR and low pressure loop EGR, was developed and optimized by using a commercial engine simulation program, GT-POWER. Some variables were selected to control dual loop EGR system such as VGT (Variable Geometry Turbocharger)performance, especially turbo speed, flap valve opening diameter at the exhaust tail pipe, and EGR valve opening diameter. Applying the dual loop EGR system in the light-duty diesel engine might cause some problems, such as decrease of engine performance and increase of brake specific fuel consumption (BSFC). So proper EGR rate (or mass flow) control would be needed because there are trade-offs of two types of the EGR (HPL and LPL) features. In this study, a diesel engine under dual loop EGR system was optimized by using design of experiment (DoE). Some dominant variables were determined which had effects on torque, BSFC, NOx, and EGR rate. As a result, optimization was performed to compensate the torque and BSFC by controlling start of injection (SOI), injection mass and EGR valves, etc.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.582-589
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• 2011

The fuel cell technology has been considered as a technology to reduce greenhouse gases emission from a ship. In this research, internal reforming 500kW solid oxide fuel cell system fueled by methane for a ship were developed. Characteristics of gas temperature, stack power and system efficiency depending on the air flow rate, $CH_4$ flow rate, $H_2O$ flow rate, and system operation pressure are evaluated. As a result, air and $CH_4$ flow rate directly affect the temperature of inlet and outlet gas in the fuel cell stack. When the air and $H_2O$ flow rate increase, the stack power and system efficiency increases. However, the case of $CH_4$ flow rate increase, the efficiency decreases.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.119-119
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• 2012

섬유염색산업 중 면섬유의 염색과정에서 발생되는 머서라이징 폐액은 폐수처리장의 pH(수소이온농도)를 올리는 주원인이 되고 있어, 높은 pH에 따른 폐수처리 부과금이나 황산을 이용한 폐수 중화에 사용되는 약품비용이 과다하게 소요되고 있으며, 머서라이징공정에 사용되는 약품인 가성소다 비용이 계속 증가하고 있어, 기업의 환경처리비용 및 약품소모비용에 대한 부담이 매우 큰 실정이다. 본 기술은 머서라이징 폐액에 멤브레인 공정에 적용하여 폐가성소다로부터 가성소다를 회수할 뿐만 아니라, 회수된 가성소다를 다시 머서라이징 공정에 재이용할 수 있도록 하여 약품 절감효과 뿐만 아니라 폐수의 발생량과 오염물질의 농도의 획기적인 저감이 가능한 것이다. 본 연구에서는 서로 다른 기공크기를 갖는 막을 적용하여 투과플럭스, 부피회수율, 부유물질 및 유기물 제거율, 가성소다회수율, 파울링지수 등을 고려하여 폐수 특성에 맞는 가장 적합한 막을 선정하고, 각각의 막에 대하여 온도조건, 압력조건, 화학세정 등의 운전변수를 최적화, 고효율 폐알카리 회수 장치의 경제성 및 기술적 타당성 평가를 통한 가성소다 회수공정을 구성하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.138-141
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• 2015

K-water operates many Water Treatment Plants(WTP) to supply clean water to people. There are automation process control equipments collecting data at each step in WTP. The data collected is big enough to 370,000Tag/min from the K-water Water Treatment Plants. In the past, this big data was not important, we focused on the operating water purification process using the data. Currently, we increased the importance of attention to take advantage of Big Data. The research about the accident reduction and efficiency improvement in WTP are ongoing by data collection and analysis. In this paper, we analyzed the flow rate, power and pressure obtained in the accident case in WTP. We researched the methods for accident prediction and reduction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.759-765
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• 2012

This study investigates the effect of diesel combustion strategies on exhaust emissions and hydrocarbon species emissions for a 1.7 L common rail direct injection diesel engine at 1500 rpm and 3.9 bar BMEP. The first strategy is a method to adopt no EGR with a split injection composed of pilot and main injection (split injection). The second is to adopt a moderate EGR rate with main injection only (single-1). The third is to use a high level of EGR and main injection with rail pressure increase, $i.e.$ low-temperature diesel combustion (single-2). Split injection and single-1 showed a renowned phenomenon of a PM-NOx trade-off, whereas single-2 was observed of a PM-NOx trade-off to reduce PM and NOx simultaneously. HC speciation results show that the split injection produced the least amount of HC species, regardless of the carbon number bin, followed by single-1 and single-2. The ratios of methane, acetylene, and CO to THC increased as a combustion A/F ratio is richer due to reduced oxygen content in the vicinity of the combustion zone, thus enhancing pyrolysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.169-177
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• 2015

Because technology of the sintering process is highly advanced, the gerotor used in the internal gear pumps of vehicles has advantages for manufacturing complex profiles and obtaining durability and minimization. However, it has been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency. The existing rotor was designed using a translation algorithm. This caused a discontinuity of the rotor profile, which had adverse effects on the performance. In this study, to improve the discontinuity of the profile, a new design program using a rotation and translation algorithm was developed, and two types of combined multiple profiles (three-ellipses and ellipse 1-involute-ellipse 2) were generated. Then, the performances (flow, flow rate, specific sliding, and pressure angle) of these profiles were calculated. On the basis of the calculation results for the performances, optimal designs of the two types were carried out and verified by comparing their performances with those of the existing rotor profiles.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.863-868
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• 2009

The drag reduction(DR) for Betaine+Amin and Xantan Gum as kinds of surfactant and Polyacrylamide as kinds of polymer solution according to the fluid velocity, temperature and surfactant concentration were compared experimentally. For this study, two kinds of experimental apparatus for short time and long time measurement were established. Each experimental appratus was equipped with hot water storage tanks, pumps, testing pipe network, flowmeter, two pressure gauges and data logging system was built for them. Results showed that Betaine+Amin and Xanthan Gum as kinds of surfactant had appeared optimal DR around 200-500 ppm and their DR tended to be decreased when flow velocity increased but Polyacrylamide as kinds of polymer solution showed the opposite trend to be increased when flow velocity increased. The both of them showed above 40% DR in the case of better condition by the short term measurement. But Polyacrylamide as kinds of polymer solution showed more degradation than Betaine+Amin and Xanthan Gum as kinds of surfactant by the long term measurement. As a result, Betaine+Amin and Xanthan Gum as kinds of surfactant showed better materials to use to the district heating system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.439-445
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• 2011

Forensic Engineering is the art and science of professionals qualified to serve as engineering experts in courts of law or in arbitration proceedings. Buses using compressed natural gas (CNG) trend to be extended in use internationally as optimal counterplan for reducing discharge gas of light oil due to high concern about environment. However, CNG buses have to be equipped with composite pressure vessels (CPVs); since the CPVs contain compressed natural gas, the risks in the case of accident is very high. Hence, the investigation of such accidents is usually associated with engineering analysis. Among the possible reasons for such CNG explosion accidents is vehicle fire and vessel fracture. By conducting formal inspection and engineering tests, in this study, the cause of vessel explosion is investigated by analyzing the failure mechanism by fractography and by comparing the material properties of a reference part with those of a problem part by adopting instrumented indentation technique.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.6
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• pp.499-503
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• 2016

Dual fuel engines are suitable for stricter regulations as they significantly decrease exhaust gas output. Hence, research and development of double wall bellows for dual fuel engines is important. In this study, optimum forming methods and welding conditions were derived to develop double wall bellows made of austenite stainless steel. The reliability of the prototypes was ensured by various performance evaluations. In this study, the buckling load and bellows stress were obtained by structural design, buckling, and stress analysis to design optimum bellows. As a result, the buckling load in the embossing shape of bellows increased by approximately 1.6 times, and no buckling and squirming occurred at 30.0 bar, which was twice that of the maximum design pressure.