Análisis de la reacción hidrógeno-aire mediante métodos de perturbaciones singulares

Cuando en el estudio de las reacciones químicas se da simplemente la reacción global, se esta haciendo realmente una descripción muy parcial de la reacción química. Dar la reacción global es dar las proporciones en que intervienen los reactantes en la reacción, asi como las proporciones en que aparecen los productos. Implicitamente se supone que la reaccion tiene lugar adiabaticamente, que el proceso es a presion constante y que se parte de las condiciones standard. Se supone, además, que los productos se encuentran finalmente en equilibrio termodinamico. Asi, cuando se escribe que la reacció

On diffusive supersonic combustion (chemical kinetic effects in diffusive supersonic combustion)

Simple analytical methods are presented for the analysis of chemical kinetic effects in supersonic combustion. Three different regions are shown to occur in supersonic diffusive combustion. The first region is close to the injector exit, where the flow may be considered frozen for the main reacting species and where the radical concentration is being built up. This is the ignition delay region. A simplified kinetic scheme of the H2-air reaction is deduced for this region. The linear differential equation giving the H concentration has been discussed and integrated in a representative case. In terms of this solution the limits of the ignition region may be determined. Far from the injector exit the flow is close to chemical equilibrium. The reaction region is very thin, so that convection effects may be neglected. Then the governing equations reduce to ordinary differential equations, that may be integrated by using an integral method. In this way, deviations from equilibrium may be determined in terms of the reaction kinetics. An extension of the integral method, developed for the analysis of the near-equilibrium region is proposed for the study of the transition region

Diffusion flames and supersonic combustion 1

The paper describes some analytical work connected with the purely diffusive mode of supersonic combustion. The basic problems considered have been: the study of the hydrogen-air diffusion flames, under hoth close to and far from equilibrium conditions, and the study of the aerodynamic field near the injector exit when the ratio of injected to outer total pressures is small. The internal structure of hydrogen-oxygen diffusion flames close to equilibrium has been studied using the first order approximation of an asymptotic expansion method, in which the large parameter represents the ratio between a characteristic mechanical time and a chemical time. Far from equilibrium conditions, the above mentioned solution fails. However, when a free jet of hydrogen, parallel to the air stream is used for injection purposes, a very simple near frozen approach may be used. The main simplifying features of such an approach being; the use of an overall chemical reaction, the assumption that fuel and oxidizer mix without appreciable depletion and chemical heat release, and the linearization of the mixing problem. Finally a discussion of some means of improving the mixing process, near the injector exit, is made, using some experimental evidence from work on related problems by other groups

Development of an analytical model of hydrazine decomposition motors

No hay resume

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research