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It is our pleasure to present the proceedings of the 14th International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions (ISHPMIE). Despite the ongoing global challenges, we are happy to compile proceedings consisting of 60 high-quality papers that reflect the scientific state-of-the-art in the following topical categories: Advances in explosion protection: Strategies, measures, and protective equipment; Explosion modelling and simulation; Explosion testing; Hydrogen safety; Explosion prevention; Dust explosions; Explosion-protected devices; Hybrid mixture explosions; Flame propagation and acceleration; Ignition phenomena. All articles in this volume have been subject to a peer-review process administered by the Proceeding Editors. We are thankful to the 70 expert referees who guaranteed the professional and scientific standards expected of ISHPMIE.

En el presente trabajo se estudia el comportamiento de llamas de premezcla en una celda Hele-Shaw, la cual permite aproximarse a una geometría bidimensional. En concreto se analizará una mezcla de gas propano como combustible, con tres dosados diferentes (pobre, estequiométrico y rico). El objetivo del trabajo es averiguar cómo afecta a parámetros de la llama (como la velocidad de propagación o la temperatura adibática), el utilizar tapas en la celda de distintos grosores y materiales. El parámetro en el que se hará más énfasis en el trabajo es en la inestabilidad termo acústica. Para realizar el experimento se hará uso de las instalaciones del departamento de ingeniería térmica y fluidos de la Universidad Carlos III de Madrid. A parte de la ya men- cionada celda Hele-Shaw se precisará la utilización de la cámara súper lenta "Memrecam HX3", con la que se grabará la propagación de la llama a través de la celda. El video obtenido se procesará con un código de Matlab usando tratamiento de imagen para obtener los datos necesarios. Se realizarán experimentos con cada una las diferentes tapas y se hará un análisis comparativo de los datos para observar cómo afecta a las variables de interés. Antes de realizar los experimentos ya se prevé que las variaciones sean significativas. El trabajo se dividirá en una introducción teórica sobre combustión para poner en contexto el experimento a realizar; posteriormente se explicará el experimento y el procedimiento seguido para la ejecución del mismo; además se presentarán los resultados obtenidos, y, finalmente, se analizarán éstos datos. In the present dissertation it is studied the behavior of premixed fames in a Hele-Shaw cell, which makes it possible to approximate to a bidimensional geometry. Particularly a mixture of gas propane, used as combustible, will be analyzed. The objective is to discover how the parameters of the flame (such as propagation velocity or adiabatic temperature) are afected by using covers for the cell of different thickness and materials. The parameter which will be studied with more emphasis is the thermo-acoustic instability. To perform the experiment, the facilities of the thermic and fuid-mechanic department of the University Carlos III of Madrid will be used. Besides the Hele-Shaw cell, it will be necessary to use the super slow camera "Memrecam HX3", that will film the propagation of the flame. The video will be processed with a Matlab code using image treatment to obtain the necessary data. Experiments will be carried out with each of the diferent covers and a comparative analysis of the data will be done in order to fgure out how it afects the variables. Before the experiments are carried out, signifcant variations are expected. The dissertation will be divided in a theoretical introduction of combustion to give context to the experiment that is being performed; subsequent to this, the experiment will be explained along with the process to perform it; also the data obtained will be presented, and, finally the data will be analyzed. Ingeniería Mecánica

The present dissertation aims at automating the propagation of a premixed flame in a quasi-bidimensional geometry using as a combustion chamber a Hele-Shaw cell. This project is carried out by the Thermal and Fluids Engineering Department of Universidad Carlos III de Madrid. The work done explained in this document includes the synchronization of a high-speed camera recording the flame front as it advances through the cell (at a rate of 1000 frames per second), with a DAQ charge amplifier which collects pressure and acceleration signals provided by sensors distributed along the cell domain, with the objective of relating each pair of data with a real image so as to characterize the flame. Also, the control of all the gases participating in the experiment (methane is used as fuel, and air as oxidant), as well as the mechanisms used to ignite the mixture are incorporated. Finally, the process by which the pneumatic actuators open and close both ends of the combustion chamber has been achieved to be automatic. All this automatization is accomplished using the software LabVIEW. Lastly, a verification of the program is presented where three different cases (with different equivalent ratios) are analyzed and compared with previous studies, providing as a result the right functioning of the code and thus, its validation. For this task, a MatLab code is needed to undertake the image processing procedure in order to convert the pictures taken by the camera into useful data employed for the calculation of the flame front velocity. Ingeniería Aeroespacial

El presente trabajo final de grado analiza experimentalmente el comportamiento de llamas de premezcla en una geometría cuasi bidimensional. Para ello, se hace uso de una celda Hele-Shaw como cámara de combustión. Se presentan tres casos, en función de cómo estén dispuestas su entrada y su salida: cerrado-abierto, abierto-abierto y abierto-cerrado. En particular se estudiará un gas altamente inflamable y de reconocida aplicación como biocombustible, el Dimetiléter (DME). El principal objetivo, es la caracterización del proceso de combustión de este combustible modificando las condiciones de contorno. Para llevar a cabo los ensayos experimentales se dispone de una instalación perteneciente al Departamento de Ingeniería Térmica y de Fluidos de la Universidad Carlos III de Madrid. Los principales elementos que la forman son: la celda Hele-Shaw, donde tiene lugar la reacción de combustión y la consecuente propagación de la llama; y la cámara de velocidad súper lenta “Memrecam HX3”, cuya función es capturar y digitalizar el fenómeno físico, permitiendo el posterior tratamiento de imagen con Matlab. El proyecto se divide en tres partes principales: La primera, se basa en el análisis teórico de la combustión y del movimiento fluido dinámico de las llamas laminares de premezcla; la segunda parte presenta el experimento, y el uso del tratamiento de imagen como método de análisis; y por último, se analizan los resultados obtenidos en los diferentes ensayos. Para dicho estudio, se ha calculado la posición media de la llama y su velocidad de propagación en función de la relación combustible-aire. Se ha observado que dichos parámetros cambian mucho dependiendo de la configuración. Pudiendo observarse desde una llama muy rápida con forma de dedo en el caso cerrado-abierto, hasta una llama que oscila en el caso abierto-cerrado, en la cual se estudiará su frecuencia de oscilación. Para los tres casos analizados la velocidad de propagación tendrá su máximo entorno al dosado estequiométrico haciéndose cada vez más lenta a medida que la mezcla se empobrece o enriquece. The present dissertation experimentally analyses the behaviour of premixed flames in a quasi-bidimensional geometry. In order to do so, it makes use of a cell Hele-Shaw as combustion chamber. Three cases are presented, depending on how its inlet and outlet are arranged: closed-open, open-open and open-closed. A highly flammable gas, whose application as biofuel is very well-known, Dimethyl ether (DME), will be studied. The main objective of the study is to characterize the combustion process of this fuel by modifying the boundary conditions. So as to undertake the experimental tests, an installation that belongs to the Department of Thermal and Fluid engineering of the university Carlos III of Madrid was used. The installation is comprised of the following main elements: the Hele-Shaw cell, where the combustion reaction and the consequent propagation of the flame take place and the super slow speed camera "Memrecam HX3", whose function is to capture and digitize the physical phenomenon, allowing the subsequent image treatment with Matlab. The project is divided into three main parts: The first one is based on the theoretical analysis of combustion and the fluid dynamic movement of the laminar premixed flames. The second part presents the experiment in question, and the use of the image treatment as a method of analysis. Finally, the results obtained in the different tests are analyzed. For this study, the mean position of the flame and its propagation speed according to the fuel-air ratio has been calculated. It has been observed that these parameters remarkably vary depending on the selected configuration. For instance, it has been possible to observe from a very quick finger-shaped flame in the closed-open case, to a flame that oscillates in the open-closed case, in which its frequency of oscillation will be studied. For the three analyzed cases, the propagation speed will have its maximum around stoichiometric dosing, becoming slower as the mixture becomes impoverished or enriched. Ingeniería en Tecnologías Industriales