Prediction of the flame kernel growth rate in spark ignition engine fueled with natural gas, hydrogen and mixtures

Producción CientíficaThe knowledge of combustion duration is a key tool in the development of engines, specially nowadays for engines adapted to new fuels with low C/H ratio such as natural gas and hydrogen. This work is aimed to develop a correlation that predicts the duration of the first phase of combustion until the process becomes turbulent in a SI engine. The flame kernel radius when this transition occurs, , is the study variable. To determine this variable from the experimental pressure records, a flame kernel growth predictive model is used. The predictive model is adjusted to the experimental data, determining the most appropriate value. The pressure records of 500 consecutive cycles of 48 test points have been processed. The averaged values of of each test point have been correlated with the characteristic parameters of the process: turbulence and properties of the fuel–air mixtures. Finally, and integral length scale ratio is correlated with Damköhler number. A wide range of operating conditions have been studied, reaching the novel conclusion that it is possible to analyze the kernel growth phenomenon from a spatial point of view rather than from a temporal point of view, as had been studied in many previous works. The developed correlation can be used in combustion predictive modeling to support SI engine design. Other practical conclusion from the work, that can be used in SI engine development, is that decreasing the integral length scale reduces the time of the first phase of combustion.Ministerio de Ciencia e Innovación (PID2019-106957RB-C22). “Analysis and characterization of dual fuel combustion for the reduction of CO2 emissions in the transport sector

Simulación de la producción de energías eléctrica y térmica, y de emisiones de CO2, mediante una pila de combustible

En este TFM se ha desarrollado una herramienta de simulación para poder estimar las producciones de energías eléctrica y térmica de una pila de combustible alimentada con hidrógeno, a fin de satisfacer las demandas energéticas de una aplicación de pequeña potencia. Teniendo en cuenta las posibilidades para el origen del hidrógeno, se han estimado también las emisiones asociadas de CO2 correspondientes a dichas posibilidades, así como un análisis económico. La herramienta de simulación permite plantear diversos escenarios de generación a evaluar con distintos indicadores de ahorro energético, de emisiones y económico. A su vez, se consideran distintos niveles de detalle de la pila de combustible, caracterizándola mediante sus rendimientos eléctrico y térmico, o bien mediante una simulación dinámica de la misma, con potencias eléctrica y térmica variables a lo largo del día.In this TFM it has been developed a simulation tool to estimate electric and thermal energy productions of a hydrogen fuel cell, in order to cover energy demands of a low power application. Considering different possibilities for the hydrogen origin, it has also been estimated CO2 emissions for those different possibilities, as well as an economic analysis. The simulation tool allows to propose diverse generation scenarios evaluable with different energy, emissions saving and economic indicators. Moreover, it has been considered different detail levels for the fuel cell, characterizing it as a means of its electrical and thermal performance, as well as a dynamical simulation, with electrical and thermal daily variable powersDepartamento de Ingeniería Energética y FluidomecánicaMáster en Ingeniería Industria