• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.450-459
• /
• 2010

고체추진제의 첨가제 또는 연료로써 주로 사용되는 알루미늄 단일 입자 연소시험 장비를 제작하고 연소 실험을 수행하였다. 산화 알루미늄으로 피복된 금속입자는 약 30~100 ${\mu}m$의 크기를 사용하였다. 단일 입자는 Electrodynamic Balance (EDB) 방법에 의해 공중 부양된 상태로, 중력에 의한 영향이 배제되어 금속입자 고정용 또는 측정용 장치들의 접촉에 의한 열손실을 제거시켜 실험 정확도를 높였다. Standard Hyperbolic Electrodynamic Levitator (SHEL) 내에서 부양된 입자에 $CO_2$ 레이저를 사용하여 점화시킨 후, 입자로부터 방사되는 열복사를 이용한 two wavelength pyrometry를 적용하여 알루미늄 입자 크기에 따른 연소시간, 평균 화염온도, 점화온도, 점화시간을 획득하였으며, 단일 알루미늄 입자의 점화-연소특성을 평가하였다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.1
• /
• pp.10-16
• /
• 2004

The Homogeneous Charge Compression Ignition (HCCI) engine has advantage for reducing the NOx and P.M. simultaneously. Therefore, HCCI engine is receiving attention as a low emission diesel engine concept. This study was carried out to investigate the characteristics of combustion and exhaust emission for operating conditions in a direct injection type of HCCI engines such as supercharged and naturally aspirated using diesel fuel and additive. From the experimental result, we found that cool flame was always appeared and also it was difficult to control combustion characteristics by changing the injection timing in HCCI. In addition, at the lean air-fuel ratio and high speed range, it was observed that charging air pressure, additive or increasing intake air temperature is effective to increase combustion performance and reduce exhaust emission. We concluded that chemical reaction by the increasing intake air temperature or additive without physical improvement has limitation for reduction of exhaust emission.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.2
• /
• pp.374-384
• /
• 2016

Concern about air pollution is gradually rising up in domestic and foreign, automotive and fuel researchers are trying to reduce vehicle exhaust emissions, through a lot of approaches, which consist of new engine design and innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research is proceeding by two main issues : exhaust emissions and PM particle emissions of gasoline vehicle. Exhaust emissions, non-regulated emissions and PM (particulate matter) particles of automotive are causing many problems which ambient pollution and harmful effects on the human body. The main particulate fraction of automotive exhaust emissions consists of small particles. Because of their small size, inhaled particles can easily penetrate deep into the lungs. The rough surfaces of these particles make it easier for them to combine with other toxins in the environment. Thus, the hazards of particle inhalation are increased. Based on the oxygenated fuel additive types (MTBE, Bio-ETBE, Bio-ethanol, Bio-butanol), this paper discussed the influence of oxygen contents on gasoline vehicle exhaust emissions, non-regulated emissions and nano-particle emissions. Also, this paper assessed exhaust emission characteristics at 2 type test modes. The test modes were FTP-75 and HWFET. All measurement items be verified less than the value of regulated emissions. It could be known difference increase and decrease by each measurement item depending on increase the oxygen contents.

• New & Renewable Energy
• /
• v.18 no.2
• /
• pp.1-8
• /
• 2022

This study aimed to determine the optimal conditions for fabricating pitch pine (PCP) and Mongolian oak (MOK) pellets using chestnut-shell tea waste (CSW) and castor oil (CSO) as additives. For pellets fabricated using a pilot-scale flat-die pellet mill, all moisture content (MC) was in line with A1 wood pellet standards for residential and small-scale commercial uses designated by the National Institute of Forest Science at the Republic of Korea (NIFOS), regardless of fabricating conditions; the durability of PCP pellets prepared using PCP particles with 10% MC, and CSW addition also satisfied these criteria. The moisture tolerance of PCP pellets improved with combination of 2 wt% CSW and 2-6 wt% CSO. Overall, use of 20 mesh CSW as an additive, PCP with 10% MC, and MOK with 12% MC was found to be optimal. Moreover, using CSO as an additive, high-quality PCP and MOK pellets can be fabricated by adjusting the particles to 12% MC. However, the durability of PCP and MOK pellets prepared using these conditions did not meet the wood pellet standards for residential and small-scale commercial use. Therefore, further research is needed to improve the durability of these pellets.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.20 no.2
• /
• pp.20-23
• /
• 2012

본 연구는 유기성폐기물을 처리하고 그것을 이용하여 고체연료 또는 퇴비를 생산하는 종합시스템에 관한 것이다. 유기성폐기물은 90% 전후의 높은 함수율을 나타내고 있기 때문에 처리에 중점을 두어야 할 부분이 수분 처리 방법이다. 따라서 기존의 처리방법으로는 고액분리하여 처리 후 하천에 방류하는 시스템에 의해 처리되고 있다. 하지만 본 연구에서는 기술개발의 차별화 및 선행기술의 회피 전략을 위해, 유기성폐기물의 수분을 건조시키는 방법으로 미생물이 유기성폐기물의 유기물을 분해하여 발생 되는 $80^{\circ}C$ 이상의 열에너지에 의해 수분을 제거하는 발열반응을 적용하여 수분을 제거하는 무방류시스 템이다. 뿐만 아니라 고체연료의 발열량을 높이기 위해서 무연탄, 코크스, 기름 등의 열량보조제를 첨 가하는 대신에 유기성폐기물을 첨가 한 후 적당한 발열반응 및 건조시켜 고체연료를 제조하는 방법으 로 4,000kcal/kg 이상의 높은 발열량을 얻을 수 있으며 불완전연소 등에 의한 2차 오염을 방지할 수 있는 기술이다. 따라서 친환경 미생물 발열반응에 의해 유기성폐기물을 저렴한 비용으로 액상 및 고상 을 동시에 처리 할 수 있으며, 고체연료를 제조할 수 있는 새로운 신기술이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.489-494
• /
• 2017

This paper describes the combustion characteristics of aluminized paraffin fuel on the contents of micron-sized aluminum particles with nominal diameters of $8{\mu}m$. Aluminized paraffin fuels with mixture ratio of aluminum 0 wt%, 5 wt% and 10 wt% as fuel and GOx(Gaseous Oxygen) as oxidizer were used to perform the experiments. The experimental investigations were performed on the regression rate, the chamber pressure and the combustion efficiency. Increasing a content of micron-sized aluminum particles, the results of regression rate, chamber pressure and combustion efficiency show minor increase compared to those without particles.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.7
• /
• pp.573-580
• /
• 2021

Paraffin wax is attracting many attentions for promising solid fuel of hybrid rocket because of its higher regression than other fuels. However, even with paraffin fuel combustion, unsteady low-frequency oscillation of combustion pressure is still observed. And, this is related to the formation of liquid layer and the entrainment of fuel droplets entering the axial combustion gas flow. This study investigates the effect of additional combustion of fuel droplets on the occurrence of low-frequency combustion instability. On the other hand, the formation of fuel droplets depends on Weber Number (the ratio of the inertial force to the surface tension of the liquid) and Reynolds Number of the oxidizer flow. Therefore, a laboratory-scale hybrid rocket was used to monitor the occurrence of combustion instability while changing We number. A series of combustion tests were conducted to control We number by changing the oxidizer flow rate or adding LDPE (low density polyethylene) to base fuel. In the results, it was confirmed that there is a critical We number above which the low-frequency combustion instability occurs.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.6
• /
• pp.501-511
• /
• 2014

Bio-oil derived from biomass through fast pyrolysis process has the potential to displace a significant amount of petroleum fuels. However, the use of bio-oil in a diesel engine is very limited because of its poor properties, e.g., its low energy density, low cetane number, and high viscosity. Therefore, bio-oil should be emulsified or blended with other fuels that have high centane numbers. Because bio-oil has poor miscibility with petroleum fuels, the most suitable candidate fuels for direct mixing are alcohol fuels. In this study, bio-oil was blended with ethanol, and two types of cetane improvers were added to a blended fuel to improve the self-ignition property. The two types of cetane improvers, PEG 400 and 2-EHN, made it possible for bio-oil blended fuels to combust in a diesel engine with a maximum bio-oil content of 15 wt%. A high-compression-ratio piston is also proposed for the combustion of bio-oil in a diesel engine.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.7
• /
• pp.877-882
• /
• 2014

The reduction of CO2 emission has been discussed in the Marine Environment Protection committee in the International Maritime Organization as the biggest causes of GHG for the purpose of indexing CO2 amounts released into the atmosphere from ships. Accordingly, various methods including the change in the hull design to improve energy efficiency, the coating development to reduce friction resistances, the additives development for improving thermal efficiency in an engine, the low-speed operation to reduce fuel consumptions, and etc. have been applied. The main engine of a ship is an electronic engine for improving the efficiency of the whole load area. However, marine generator engines still use mechanical drive engines in intake, exhaust, and fuel injection valve drive cams. In addition, most of marine generator engines in ships apply a part-load operation of less then 80% due to an overload protection system. Therefore, marine auxiliary diesel engine set at 100% load is necessary to readjust in order to efficient operation because of part-load operation. The objective of this study is to report the results of the part-load fuel consumption improvement by injection timing readjust to identifying the operational characteristics of a marine generator engine currently operated in a ship.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.5
• /
• pp.588-598
• /
• 2017

Currently, bioethanol, a fuel additive for transportation, is produced mainly by using biomass (first generation) such as corn and sugar canes. First generation biomass can cause various problems in terms of increase in agricultural prices and ethical reasons. To address these problems, a nonedible lignocellulosic biomass can be utilized. Agricultural byproducts such as straw, bagasse, and forest byproducts from the wood processing industry. Therefore, production of wood based bioethanol can be an effective utilization route of second generation biomass, and its raw materials are more abundant than first generation resources. Furthermore, it is possible to secure cheap raw materials. One of the biggest advantages of using biofuels is that it contributes to the reduction of greenhouse gases by minimizing the environmental impact, unlike fossil fuels. In this study, we investigated the greenhouse gas reduction effects that can be achieved through the use of Lignocellulosic bioethanol and government policies on renewable energy currently being implemented in ASEAN countries (Indonesia, Malaysia, Thailand and the Philippines). In these four countries, policies and incentives related to biofuels have been developed. It is expected that the reduction ratio of carbon dioxide emission and the mixed biofuel will be gradually increased in the future.