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Gas-to-liquid sprays at different injection and ambient conditions / Dung Ngoc Nguyen in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 3 (Mars 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 3 (Mars 2011) . - 10 p. Titre : Gas-to-liquid sprays at different injection and ambient conditions Type de document : texte imprimé Auteurs : Dung Ngoc Nguyen, Auteur ; Hiroaki Ishida, Auteur ; Masahiro Shioji, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Nozzles  Sprays Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Alternative fuels exhibit potential as a clean fuel and suitable to address problems of energy security and environmental pollution. The main objective of this research was to provide the fundamental data of ignition delay and combustion characteristics for gas-to-liquid (GTL) fuels. Experiments were carried out in a constant-volume vessel under diesel-engine conditions to study the effects of various injection and ambient conditions on ignition and combustion characteristics. The results showed that all tested fuels exhibited similar ignition-delay trends: Ignition delay increased as ambient temperature, ambient pressure, and oxygen concentration decreased. The result of changing injection pressures and nozzle-hole diameters did not significantly affect ignition-delay values for all tested fuels. The variation in ignition-delay values was small at temperatures higher than 700 K but large at temperatures less than 700 K. In addition, the result showed that GTL fuels with high cetane number corresponded to shorter ignition delay and smoother heat-release rate than those for gas-oil (conventional diesel fuel) at the same temperature, pressure, and oxygen concentration. The blend GTL fuel improved ignition quality and combustion than that of gas-oil. Shadowgraph images showed that GTL fuels exhibited shorter spray penetration and mixed with the hot air quicker than gas-oil. In addition, GTL fuels showed suitability for premixed charge compression-ignition operations owing to ignitability at low temperature. The obtained results provide useful information for finding the optimal conditions for the design and control of diesel engines fuelled by synthetic GTL fuels. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Gas-to-liquid sprays at different injection and ambient conditions [texte imprimé] / Dung Ngoc Nguyen, Auteur ; Hiroaki Ishida, Auteur ; Masahiro Shioji, Auteur . - 2012 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 3 (Mars 2011) . - 10 p. Mots-clés : Nozzles  Sprays Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Alternative fuels exhibit potential as a clean fuel and suitable to address problems of energy security and environmental pollution. The main objective of this research was to provide the fundamental data of ignition delay and combustion characteristics for gas-to-liquid (GTL) fuels. Experiments were carried out in a constant-volume vessel under diesel-engine conditions to study the effects of various injection and ambient conditions on ignition and combustion characteristics. The results showed that all tested fuels exhibited similar ignition-delay trends: Ignition delay increased as ambient temperature, ambient pressure, and oxygen concentration decreased. The result of changing injection pressures and nozzle-hole diameters did not significantly affect ignition-delay values for all tested fuels. The variation in ignition-delay values was small at temperatures higher than 700 K but large at temperatures less than 700 K. In addition, the result showed that GTL fuels with high cetane number corresponded to shorter ignition delay and smoother heat-release rate than those for gas-oil (conventional diesel fuel) at the same temperature, pressure, and oxygen concentration. The blend GTL fuel improved ignition quality and combustion than that of gas-oil. Shadowgraph images showed that GTL fuels exhibited shorter spray penetration and mixed with the hot air quicker than gas-oil. In addition, GTL fuels showed suitability for premixed charge compression-ignition operations owing to ignitability at low temperature. The obtained results provide useful information for finding the optimal conditions for the design and control of diesel engines fuelled by synthetic GTL fuels. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Ignition delay and combustion characteristics of gaseous fuel jets / Dung Ngoc Nguyen in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 4 (Avril 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 4 (Avril 2010) . - 08 p. Titre : Ignition delay and combustion characteristics of gaseous fuel jets Type de document : texte imprimé Auteurs : Dung Ngoc Nguyen, Auteur ; Hiroaki Ishida, Auteur ; Masahiro Shioji, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Ignition  Jet  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gaseous fuels, such as hydrogen and natural gas, are utilized in internal combustion engines for spark-ignition operation. To improve thermal efficiency and to ensure control at good heat-release rates, combustion systems with direct-injection and spontaneous-ignition operation may be preferable. The main objective of this research was to provide fundamental data for the ignition and combustion of hydrogen, natural gas, and methane. Experiments were conducted in a constant-volume combustion vessel to investigate the effects of ambient temperature on ignition delay and combustion characteristics for various injector and ambient conditions. Experimental results showed that all gaseous fuels exhibited similar ignition-delay trends: ignition delay (tau) increased as ambient temperature (Ti) decreased. Among these fuels, hydrogen jets exhibited much shorter tau than natural gas and methane jets at the same Ti and could be ignited at a lower temperature, Ti=780 K. A shorter ignition delay of hydrogen may be attained by controlling the mixture formation by lowering the injection pressure (pj), enlarging the nozzle-hole diameter (dN), increasing the ambient pressure (pi), and increasing the oxygen mole fraction (rO2). In contrast, the methane jet exhibited the longest tau over the whole range of Ti and suffered from misfiring at a higher Ti of 910 K. For natural gas, ignition delay was observed to be shorter than that for methane, owing to a small amount of butane with good ignitability. More specifically, the ignition delay of natural gas differed slightly when dN and pj varied but changed drastically when pi and rO2 decreased. Based on these data, the feasibility of gaseous fuels for compression-ignition engines is discussed from the viewpoint of mixture formation and chemical reaction. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000004 [...] [article] Ignition delay and combustion characteristics of gaseous fuel jets [texte imprimé] / Dung Ngoc Nguyen, Auteur ; Hiroaki Ishida, Auteur ; Masahiro Shioji, Auteur . - 2010 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 4 (Avril 2010) . - 08 p. Mots-clés : Combustion  Ignition  Jet  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gaseous fuels, such as hydrogen and natural gas, are utilized in internal combustion engines for spark-ignition operation. To improve thermal efficiency and to ensure control at good heat-release rates, combustion systems with direct-injection and spontaneous-ignition operation may be preferable. The main objective of this research was to provide fundamental data for the ignition and combustion of hydrogen, natural gas, and methane. Experiments were conducted in a constant-volume combustion vessel to investigate the effects of ambient temperature on ignition delay and combustion characteristics for various injector and ambient conditions. Experimental results showed that all gaseous fuels exhibited similar ignition-delay trends: ignition delay (tau) increased as ambient temperature (Ti) decreased. Among these fuels, hydrogen jets exhibited much shorter tau than natural gas and methane jets at the same Ti and could be ignited at a lower temperature, Ti=780 K. A shorter ignition delay of hydrogen may be attained by controlling the mixture formation by lowering the injection pressure (pj), enlarging the nozzle-hole diameter (dN), increasing the ambient pressure (pi), and increasing the oxygen mole fraction (rO2). In contrast, the methane jet exhibited the longest tau over the whole range of Ti and suffered from misfiring at a higher Ti of 910 K. For natural gas, ignition delay was observed to be shorter than that for methane, owing to a small amount of butane with good ignitability. More specifically, the ignition delay of natural gas differed slightly when dN and pj varied but changed drastically when pi and rO2 decreased. Based on these data, the feasibility of gaseous fuels for compression-ignition engines is discussed from the viewpoint of mixture formation and chemical reaction. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000004 [...]