Experimental Investigations on Spray Characteristics of Potential Fuels for Advance Low Temperature Combustion Engines

( Saurabh Kumar Gupta ),( M. Murugesa Pandian ),( Anand Krishnasamy ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-

Advanced low temperature combustion (LTC) strategies including Premixed Charge Compression Ignition (PCCI), Reactivity Controlled Compression Ignition (RCCI), Stratified Charge Compression Ignition (SCCI) and High Efficiency Clean Combustion (HECC) are proposed to simultaneously reduce oxides of nitrogen (NOx) and particulate matter (PM) emissions to near zero levels along with higher thermal efficiencies. However, precise control of ignition timings is difficult to achieve in these LTC strategies as it is primarily controlled by the molecular composition of fuel by altering physical and chemical delay period and creating reactivity stratification. Fuel spray characteristics plays a vital role in varying the rate of fuel-air mixing and physical delay period. The potential fuels for advanced LTC modes include fuels with optimal reactivity and better volatility. The effects of physical properties and its impact on spray behavior of potential fuels for LTC are sparsely available. The present work intends to study the effects of changes in properties and injection pressures on the macroscopic spray behavior of potential fuels for advanced LTC engines. The experiments are carried out in a constant volume spray chamber with different potential fuels for advanced combustion engines, viz. Diesel with 10%,20% and 30% gasoline (DG10, DG20 and DG30) and Diesel with 10%,20% and 30% kerosene (DK10, DK20 and DK30). The fuel injection pressures and the injection strategies have been chosen as representative of direct injection diesel engine working conditions. The spray characteristics such as spray tip penetration distance, spray cone angle are obtained by using a high resolution spray visualization system for the different fuel blends. The obtained results show that the changes in physical properties of the fuel blends affect the macroscopic fuel spray behavior. Further, as compared to that of conventional diesel, all the fuel blends show a significant difference in the macroscopic spray characteristics.

Influence of the mixture of gasoline and diesel fuels on droplet atomization, combustion, and exhaust emission characteristics in a compression ignition engine

Park, S.H.,Youn, I.M.,Lim, Y.,Lee, C.S. Elsevier Scientific Pub. Co 2013 Fuel processing technology Vol.106 No.-

The purpose of this study was to investigate the fuel properties, droplet atomization, combustion performance, and exhaust emission characteristics of gasoline-diesel direct blended fuels in a four-cylinder diesel engine. The gasoline fuel was blended as a volumetric fraction of conventional diesel fuel. The droplet size of test fuels was measured using a phase Doppler particle analyzer (PDPA), and the combustion and emission characteristics were investigated for a four-cylinder diesel engine with a common-rail injection system and emission analyzer. In this study we found that increasing the gasoline volume fraction decreased the fuel density, kinematic viscosity, and surface tension. The temperature for 10% distillation (T10) decreased as the gasoline fraction increased. The blending of gasoline caused a decrease in droplet size by increasing the small droplets and decreasing the large droplets because the surface tension decreased with the addition gasoline fuel, thereby inducing an increase in droplet instability. On the other hand, gasoline blending resulted in an extension of the ignition delay and the formation of a more homogeneous mixture. These combustion characteristics caused the simultaneous reduction of ISNOx and ISsoot. However, the ISHC and ISCO emissions were slightly increased. The difference in ISHC and ISCO emissions between pure diesel and gasoline blended diesel fuels decreased as the engine load increased. An increase in engine load diminished the effects of gasoline blending on combustion performance and exhaust emissions.

정적연소기에서 직접분사식 바이오 에탄올-가솔린 혼합연료의 연료온도에 따른 분무 및 연소 특성에 관한 실험적 연구

박기영 ( G Y Park ),김종민 ( J M Kim ),이성욱 ( S W Lee ) 한국액체미립화학회 2014 한국액체미립화학회 학술강연회 논문집 Vol.2014 No.-

As environment problem became a worldwide issue, countries are tightening regulations regarding greenhouse gas reduction and improvement of air pollution problems. With these circumstances, one of the renewable energies produced from biomass is getting attention. Bio-ethanol, which is applicable to SI engine, showed a positive effect on the PFI(Port Fuel Injection) type. However, Ethanol has a problem in homogeneous mixture formation because it has high latent heat of vaporization characteristic and in the GDI(Gasoline Direct Injection) type, mixture formation is required quickly after fuel injection. Particularly, South Korea is one of the countries with great temperature variation among seasons. With this reason, South Korea supply fuel additive for smooth engine operation during winter. Therefore, experimental study and investigation about application possibility of blending fuel is necessary. This paper demonstrates the spray and combustion characteristic by using the CVC direct injection and setting the bio-ethanol blending fuel temperature close to the temperature during each seasons: -7, 25, 35℃. The diameter and the width of the CVC are 86mm and 39mm. High-pressure fuel supply system was used for target injection pressure. High-speed camera was used for spray visualization and combustion visualization. Exhaust gas was measured by using the gas analyzer after combustion. Fig.1 represents the schematic diagram regarding the experimental apparatus. The experiment was conducted by setting the injection pressure and ambient pressure according to each temperature of bio-ethanol blending fuel as a parameter. The result of spray visualization experiment demonstrates that as the temperature of the fuel is lower, the atomization quality is lower, and this increase spray penetration and make mixture formation difficult. Injection strategy and combustion strategy according to fuel temperature and bio-ethanol blending rate is needed for improving characteristics.

초음파 개질 경유의 연소특성

이병오(Byoungoh Lee),송용식(Yongsik Song),김용철(Yongcheol Kim),류정인(Jeongin Ryu) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

This paper describes the effects of the combustion characteristics as cylinder pressure, heat release rate, mass fraction burned, and combustion duration of ultrasonically reformed diesel fuels in the indirect injection diesel engine. From the study, following conclusive remarks can be made. 1) The maximum combustion chamber pressures were increased by a maximum of 3㎏/㎠ in case of ultrasonically reformed fuel in comparison with that in the conventional fuel. In case of the retard of fuel injection timing, the maximum combustion chamber pressures of the ultrasonically reformed fuel showed nearly the same those of the conventional fuel. 2) Considering mass fraction burned, under operating with 2,000rpm and load 75%, the combustions of ultrasonically reformed fuel started a little early and ended rather early more than those of conventional fuel. When the injection timing was delay, the combustions of ultrasonically reformed fuel started a little later and ended rather early more than those of conventional fuel. 3) Within all the operation condition ranges of this experimental test, the ultrasonically reformed fuel decreased the combustion duration by a maximum of 7% and the ultrasonically reformed fuel delayed decreased the combustion duration by a maximum of 10% in comparison with conventional fuel.

에탄올-바이오디젤 혼합연료의 미립화 특성

박수한(Su Han Park),서현규(Hyun Kyu Suh),김형준(Hyung Jun Kim),이창식(Chang Sik Lee) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The aim of this study is to investigate the atomization characteristics of biodiesel-ethanol blending fuel in a common-rail diesel injector. Test fuels used in this work are a diesel, neat biodiesel and a biodiesel with 20% ethanol as volumetric rate. Test injector that applied in this study has a single hole with a diameter of 0.3㎜ and a nozzle length of 0.8㎜. Sauter mean diameter (SMD), the axial and radial velocity distribution are measured to investigate the atomization characteristics of ethanol-biodiesel blending fuel using the droplet measuring system. It was also analyzed a injection quantity and injection rate characteristics of each test fuel under the same experimental coniditions. It was founded that unlike the diesel fuel, biodiesel fuel is well mixed with ethanol and the degree of dissolution stability is a high in a room temperature. The ethanol blending fuel has a lower droplet size than that of biodiesel fuel. The axial velocity distribution of blending fuel has a larger than that of biodiesel fuel and a lower than that of diesel fuel. The radial velocity distribution has a contrary characteristic compared to the axial velocity distribution.

The effects of the air-fuel ratio on a stationary diesel engine under dual-fuel conditions and multi-objective optimization

Cho, Jungkeun,Park, Sangjun,Song, Soonho Elsevier 2019 ENERGY Vol.187 No.-

<P><B>Abstract</B></P> <P>The fundamental combustion characteristics and engine performance of a dual-fuel engine, fueled with diesel and natural gas, were investigated using a commercial 1D simulation program (GT-Power). Furthermore, the effects of air-fuel ratio under dual-fuel combustion conditions were studied, and optimized design points that minimize brake-specific fuel consumption (BSFC) and nitrogen oxides (NO<SUB>X</SUB>) emissions simultaneously were determined using a multi-objective Pareto optimization method. The engine model was validated based on experimental results and previous work under various engine loads. The thermal efficiency of the engine, which was modified from a diesel to a dual-fuel engine, showed a decreasing tendency as the natural gas substitution ratio (NSR) increased due to changes in the combustion characteristics. The decline in thermal efficiency in dual-fuel combustion could be improved somewhat by optimizing the injection strategy. Under dual-fuel combustion conditions, an optimum air-fuel ratio value for BSFC could be determined, especially for higher NSR conditions. However, NO<SUB>X</SUB> emissions showed a tendency to increase with increasing air-fuel ratio. The relationship between the trends was more than a simple tradeoff, so multi-objective Pareto optimization was conducted to minimize both BSFC and NO<SUB>X</SUB> emissions, with start of injection timing and air-fuel ratio as variables. Ultimately, optimal design points were determined.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The large stationary engine was modeled and modified to dual-fuel engine. </LI> <LI> The characteristics of dual-fuel combustion were investigated. </LI> <LI> The effect of air-fuel ratio under dual-fuel combustion condition are investigated. </LI> <LI> The optimal design points for improving fuel economy and NOx emission are suggested. </LI> <LI> Helpful methodology for conceptual design of virtual engine system was suggested. </LI> </UL> </P>

디젤-에탄올 혼합연로의 혼합기 형성에 관한 연구

최기봉 ( Ki Bong Choi ),이동곤 ( Dong Gon Lee ),노현구 ( Hyun Gu Roh ),이창식 ( Chang Sik Lee ) 한국액체미립화학회 2014 한국액체미립화학회 학술강연회 논문집 Vol.2014 No.-

The aim of this work is to investigate the effect of ambient conditions in the constant volume spray chamber on the mixture formation of diesel-ethanol blended fuels. In order to analyze the air and fuel mixture formation, spray behaviors were obtained from the visualization system, and the effects of ethanol blending fuels on the spray characteristics were compared to that of neat diesel fuel. In addition, the spray characteristics such as spray tip penetration, spray cone angle, and spray area of ethanol blended fuel were analyzed by using the visualization images obtained from visualization system. In order to visualize diesel-ethanol sprays, a visualization system composed of a blending fuel supply system, a high-speed CCD camera, a high-pressure spray chamber, and an image data acquisition system. This experimental results showed that the spray penetration of diesel and ethanol blended fuel was slightly longer than that of a neat diesel fuel. The spray cone angle of ethanol blends showed wider angle than that of diesel fuel by increased amount of the ethanol blending ratio. The spray tip penetration of diesel-ethanol blends decreased with the increase of fuel injection pressure, and spray cone angle increased in accordance with the increase of ambient pressure. In this work, the effect of ambient pressure on the spray macroscopic characteristics was conducted under the various ethanol blending ratios.

금속연료 소듐냉각고속로 중대사고 고유안전특성 SAS4A/SASSYS-1 코드 전산해석

강석훈(S.H. Kang),Adrian Tentner 한국전산유체공학회 2021 한국전산유체공학회지 Vol.26 No.1

The inherent safety characteristics of the metal fuel core sodium-cooled fast reactor (SFR) are investigated using the SAS4A metal fuel version code, originally developed for the analysis of postulated severe accidents in oxide fuel SFR and significantly extended to allow the mechanistic analysis of severe accidents in metallic fuel SFRs. The paper provides an overview of the SAS4A key metal fuel models and the safety characteristics of the metal fuels. The analysis is performed for a postulated unprotected fuel assembly inlet blockage accident in the metal fuel Prototype Gen-IV Sodium Fast Reactor (PGSFR). The evolution of local fuel components during the pre-transient irradiation, molten fuel relocation behavior inside and outside of cladding, and their impacts on reactivity and power history during the transient are numerically analyzed. The favorable characteristics of the metal fuel, significant decreases in reactivity and power due to favorable molten fuel relocation and the fuel thermo-physical property change, are analyzed in the results.

직접분사식 바이오 에탄올-가솔린 혼합연료의 연료온도에 따른 분무 특성에 관한 실험적 연구

이성욱,박기영,김종민,박봉규 한국수소및신에너지학회 2014 한국수소 및 신에너지학회논문집 Vol.25 No.6

As environment problem became a worldwide issue, countries are tightening regulations regardinggreenhouse gas reduction and improvement of air pollution problems. With these circumstances, one of therenewable energies produced from biomass is getting attention. Bio-ethanol, which is applicable to SI engine,showed a positive effect on the PFI (Port Fuel Injection) type. However, Ethanol has a problem in homogeneousmixture formation because it has high latent heat of vaporization characteristics and in the GDI (Gasoline DirectInjection) type, mixture formation is required quickly after fuel injection. Particularly, South Korea is one of thecountries with great temperature variation among seasons. With this reason, South Korea supply fuel additive forsmooth engine operation during winter. Therefore, experimental study and investigation about application possibilityof blending fuel is necessary. This paper demonstrates the spray characteristics by using the CVC direct injectionand setting the bio-ethanol blending fuel temperature close to the temperature during each seasons: -7, 25, 35℃. The diameter and the width of the CVC are 86mm and 39mm. High-pressure fuel supply system was used fortarget injection pressure. High-speed camera was used for spray visualization. The experiment was conducted bysetting the injection pressure and ambient pressure according to each temperature of bio-ethanol blending fuel asa parameter. The result of spray visualization experiment demonstrates that as the temperature of the fuel is lower,the atomization quality is lower, and this increase spray penetration and make mixture formation difficult. Injectionstrategy according to fuel temperature and bio-ethanol blending rate is needed for improving characteristics.

연료분무 및 연소 1 : 폐식용유 바이오디젤 연료의 분무특성에 관한 연구

안상연 ( Sang Yeon Ahn ),김웅일 ( Woong Il Kim ),이창식 ( Chang Sik Lee ) 한국액체미립화학회 2013 한국액체미립화학회 학술강연회 논문집 Vol.2013 No.-

This study was performed to investigate the effect of biodiesel derived from waste cooking oil on the spray behavior and macroscopic spray characteristics. To analyze quantitative characteristics of test fuels, injection quantity was measured at various injection pressures and the spray images of injected fuels in the pressurized chamber were obtained by using a high speed camera and image analysis system. Based on the measured spray images, the spray tip penetration and spray cone angle were investigated at various energizing timings and injection pressures. In this work, the experimental results showed that the injection quantity of waste cooking biodiesel indicated the higher quantities than diesel at high injection pressure. As the injection pressure was increased, the spray tip penetrations of biodiesel were higher value than diesel. The difference of penetration between biodiesel and conventional diesel fuel was reduced in accordance with the increase of injection pressure. Also, the spray angles of diesel were larger than that of biodiesel because diesel fuel has lower viscosity than biodiesel. In addition, the spray evolution processes of biodiesel fuel at various injection pressures and the elapsed time after the injection were compared to the conventional diesel fuel.