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Search Results: 1 - 10 of 327343 matches for " Antonio J Bula "
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UNCOUPLING LAMINAR CONJUGATE HEAT TRANSFER THROUGH CHEBYSHEV POLYNOMIAL
BULA,ANTONIO J.; VáSQUEZ,RICARDO S.;
DYNA , 2010,
Abstract: the conjugate heat transfer process of cooling a horizontal plate at the leading edge, in steady state condition, was solved considering the fluid flowing in laminar condition and hydro dynamically developed before interacting with a heated plate. the fluid was considered deep enough to allow the growth of a thermal boundary layer with no restrictions. the conservation of mass, momentum and energy equations at the solid and fluid were converted into a non dimensional form. the heated body presents a constant heat flux at the bottom side, and convective heat transfer at the top side. the interface temperature was obtained using the chebyshev polynomial approximation. in order to verify the results obtained using the chebyshev polynomial approximation, the results obtained from the analytical solution for the solid, were compared with the results attained with commercial cfd software, fidap?. the solution considered the calculation of the local and average heat transfer coefficient, the local and average nusselt number, the local and average biot number, and different temperature distributions at the interface.
UNCOUPLING LAMINAR CONJUGATE HEAT TRANSFER THROUGH CHEBYSHEV POLYNOMIAL
ANTONIO J. BULA,RICARDO S. VáSQUEZ
DYNA , 2010,
Abstract: El proceso de transferencia de calor conjugada para enfriamiento de una placa en estado estable ha sido resuelto considerando el fluido laminar e hidrodinámicamente desarrollado antes de entrar en contacto con la placa. El fluido es lo suficientemente profundo y permite el crecimiento de la capa límite térmica sin restricciones. Las ecuaciones de continuidad, cantidad de movimiento y energía, en el sólido y en fluido fueron adimensionalizadas. La temperatura en la interface se obtiene por medio del polinomio de Chebishev, y los resultados obtenidos fueron verificados con la solución obtenida por medio de software CFD comercial, FIDAP . La solución ncluyo el cálculo del coeficiente de transferencia de calor, el número de Nusselt, el número de Biot, todos tanto local como promedio. La distribución de temperatura en la interface también fue obtenida.
Análisis Exergético de la Gasificación de Biomasa
Mendoza,Jorge M; Bula,Antonio J; Gómez,Rafael D; Corredor,Lesmes A;
Información tecnológica , 2012, DOI: 10.4067/S0718-07642012000500009
Abstract: this paper shows the exergy analysis applied to the gasification process of residual biomass with the purpose of obtaining useful energy. a model for the biomass gasification based on chemical equilibrium of the reactions is proposed. the model allows predicting the syngas composition as a function of temperature, pressure and ultimate analysis of palm oil and grapevine pruning waste (determining hydrogen, oxygen, carbon and nitrogen). it was found that the carbon monoxide and hydrogen concentration significantly increase at high pressure and temperature independently of the gasifying agent. furthermore, it was also noticed that the exergy efficiency increases as temperature increases, and decreases as the relative fuel/air ratio increases.
Análisis Exergético de la Gasificación de Biomasa Exergy Analysis of Biomass Gasification
Jorge M Mendoza,Antonio J Bula,Rafael D Gómez,Lesmes A Corredor
Información Tecnológica , 2012,
Abstract: El objetivo de este estudio fue realizar el análisis exergético de la gasificación de biomasa residual con la finalidad de obtener energía útil. Se desarrolló un modelo para la gasificación de biomasa basado en el equilibrio químico de las reacciones. Este modelo permite predecir la evolución de la composición del gas de síntesis en función de la temperatura, las presiones y la composición elemental de los residuos del proceso de extracción de aceite de palma y orujo de lavado de uva (hidrogeno, oxigeno, carbono y nitrógeno), como también hacer un análisis exergético. Se encontró que independiente del agente gasificante, la concentración de monóxido de carbono e hidrógeno tienden a incrementar significativamente a altas presiones y elevadas temperaturas. Además, se muestra que la eficiencia exergética incrementa con la temperatura y disminuye con el aumento de la relación aire/combustible. This paper shows the exergy analysis applied to the gasification process of residual biomass with the purpose of obtaining useful energy. A model for the biomass gasification based on chemical equilibrium of the reactions is proposed. The model allows predicting the syngas composition as a function of temperature, pressure and ultimate analysis of palm oil and grapevine pruning waste (determining hydrogen, oxygen, carbon and nitrogen). It was found that the carbon monoxide and hydrogen concentration significantly increase at high pressure and temperature independently of the gasifying agent. Furthermore, it was also noticed that the exergy efficiency increases as temperature increases, and decreases as the relative fuel/air ratio increases.
Simulación del comportamiento termodinámico de un sistema de refrigeracion solar por absorción
Antonio J. Bula S.,Diane Luz Herrera,Luis Fernando Navarro,Lesmes Corredor
Ingeniería y Desarrollo , 2000,
Abstract:
SYNGAS FOR METHANOL PRODUCTION FROM PALM OIL BIOMASS RESIDUES GASIFICATION
Antonio Jose Bula
International Journal of Thermodynamics , 2012, DOI: 10.5541/ijot.401
Abstract: In Colombia, Biodiesel is produced from palm oil and methanol; this methanol could be obtained from gasification of the raw palm oil residuals. The complete process includes: pre-treatment of the biomass, gasification, the cleaning and conditioning of the gas and finally the synthesis of methanol. In this article, a review of the gasification stage is carried out, a classification of the existent gasification reactors is presented and the characteristics of three types of gasifiers are detailed. Furthermore, a summary of certain chemical and physical requirements of the gas obtained by the gasification process are introduced. Some conditions are highlighted: the ratio hydrogen to carbon monoxide (H2/CO) must be close to two and, the quantities of diluted nitrogen, sulphur and water in the gas must be low. Keeping in mind these characteristics we proceeded to recommend the gasifier and gasification medium convenient for the results preferred. Finally, a chemical equilibrium – fluid dynamic model is introduced to estimate the composition of the gas produced and to study the effect of the temperature and operation pressure in the quality of the gas produced. The gasification process considers a fluidized bed gasifier and the simulated results are compared with experimental data. The results showed that the simulation approach accurately represents the gasification process and allows considering the simulation for some other biomass residues.
Modelación matemática y simulación de un sistema de acondicionamiento de aire en estado transitorio
Antonio Bula,Antonio Márquez
Ingeniería y Desarrollo , 2002,
Abstract:
Estudio de la variación en la conductividad térmica de la cascarilla de arroz aglomerada con fibras vegetales
Carolina Giovanna Cadena,Antonio José Bula Silvera
Ingeniería y Desarrollo , 2002,
Abstract: Ante la necesidad de desarrollar alternativas tecnológicas que permitan la utilización de elementos desechados en procesos productivos para aprovechar su potencial y contribuir a la disminución del impacto ambiental que puedan generar por una inadecuada disposición, surge la oportunidad de aprovechar productos vegetales de desecho que permitan innovar en el área de los materiales de ingeniería, campo en el cual la cascarilla de arroz se perfila como un aislante térmico de alta efectividad, competitividad y de fácil obtención, lo cual contribuye al reemplazo de productos derivados del petróleo. Este estudio se propone desarrollar nuevos materiales para aislamientos térmicos a partir de cascarilla de arroz y fibras vegetales, para lo cual se han realizado pruebas según la norma ASTM C-177, para la cuantificación de su capacidad conductiva de calor, lo cual ha puesto en evidencia su potencial aislante. Palabras claves: Fibras vegetales, aislamientos térmicos, materiales compuestos, transferencia de calor, subproductos, recursos naturales
Analysis of heat and mass transfer in a mixed convective diffusion flame attached to a vertical fuel surface
Bula,A. J.; Rahman,M. M.;
Latin American applied research , 2008,
Abstract: analysis of heat and mass transfer in a burning vertical surface exposed to a fluid flow parallel to the surface is presented. the combustion process considered is steady and the burning surface is in equilibrium vaporization. a fast gas phase reaction is assumed to occur between the fuel and the oxidizer. the flame sheet approximation is used to describe the reacting flow. the governing equations describing the conservation of mass, momentum, energy, and species concentrations were solved numerically along with appropriate boundary conditions. schvab-zeldovich variables were used to eliminate the mass and energy generation terms from the governing equations. calculations were done for two different fuels and for a range of reynolds number. computed results included the distributions of velocity components, enthalpy, and concentration of fuel, oxidizer, products, and inert gas, and the position of the flame sheet.
Analysis of heat and mass transfer in a mixed convective diffusion flame attached to a vertical fuel surface
A. J. Bula,M. M. Rahman
Latin American applied research , 2008,
Abstract: Analysis of heat and mass transfer in a burning vertical surface exposed to a fluid flow parallel to the surface is presented. The combustion process considered is steady and the burning surface is in equilibrium vaporization. A fast gas phase reaction is assumed to occur between the fuel and the oxidizer. The flame sheet approximation is used to describe the reacting flow. The governing equations describing the conservation of mass, momentum, energy, and species concentrations were solved numerically along with appropriate boundary conditions. Schvab-Zeldovich variables were used to eliminate the mass and energy generation terms from the governing equations. Calculations were done for two different fuels and for a range of Reynolds number. Computed results included the distributions of velocity components, enthalpy, and concentration of fuel, oxidizer, products, and inert gas, and the position of the flame sheet.
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