Efficient compact micro DBD plasma reactor for ozone generation for industrial application in liquid and gas phase systems

Ozone is well known as a powerful, fast reacting oxidant. Ozone based processes produce no by-product residual as non-reacted ozone decomposes to molecular oxygen. Therefore an application of ozone is widely accepted as one of the main approaches for a Sustainable and Clean Technologies development. There are number of technologies which require ozone to be delivered to specific points of a production network or reactors construction. Due to space constraints, high reactivity and short life time of ozone the use of ozone generators even of a bench top scale is practically limited. This requires development of mini/micro scale ozone generator which can be directly incorporated into production units. Our report presents a feasibility study of a new micro scale rector for ozone generation (MROG). Data on MROG calibration and indigo decomposition at different operation conditions are presented. At selected operation conditions with residence time of 0.25 s the process of ozone generation is not limited by reaction rate and the amount of ozone produced is a function of power applied. It was shown that the MROG is capable to produce ozone at voltage level starting from 3.5kV with ozone concentration of 5.28*10⁻⁶ (mol/L) at 5kV. This is in line with data presented on numerical investigation for a MROG. It was shown that in compare to a conventional ozone generator, MROG has lower power consumption at low voltages and atmospheric pressure. The MROG construction makes it applicable for both submerged and dry systems. With a robust compact design MROG can be used as an integrated module for production lines of high complexity

Caminando en la ruta sentipensante: configuración de experiencias pedagógicas nivel inicial

494 páginasEste texto es realizado en el contexto del Plan de Desarrollo 2016 – 2020, “Bogotá mejor para todos”, en el que se señala: Bogotá es entendida como una ciudad educadora, en la que todos los ciudadanos son agentes educadores y todos los espacios pueden ser escenarios pedagógicos para el aprendizaje. Una ciudad educadora tiene como centro el conocimiento e inspira aprendizaje, formas y lenguajes para reconocernos, para reencontrarnos; los espacios para el aprendizaje son entendidos como espacios para la vida, en los que se posibilita la investigación y la innovación para vivir mejor, para reinventarnos como ciudad, una ciudad mejor para todos. Los dieciocho textos aquí presentados, fruto del acompañamiento pedagógico realizado por el IDEP en 2019, son base y referente para seguir aportando en la configuración y consolidación de comunidades de saber y práctica pedagógica de la ciudad, así como en la conformación de colectivos y redes de maestros. Son la evidencia de un potente trabajo de acompañamiento a experiencias de nivel inicial, caracterizadas por contar con ideas o avances para problematizar, estructurar, fundamentar, elaborar estrategias y un plan de acción

Computational Characterization of Turbulent Flow in a Microfluidic Actuator

In this contribution, an unsteady numerical simulation of the flow in a microfluidic oscillator has been performed. The transient turbulent flow inside the device is described by the Unsteady Reynolds Averaged Navier–Stokes equations (URANS) coupled with proper turbulence models. The main characteristics of the complex fluid flow inside the device along one oscillation cycle was analyzed in detail, including not only velocity contours but also the pressure and turbulent kinetic energy fields. As a result, two-dimensional simulations provided good estimations of the operating frequency of the fluidic actuator when compared with experimental measurements in a range of Reynolds numbers. Moreover, with the objective of altering the operating frequency of the apparatus and, in order to adapt it to different applications, geometrical modifications of the feedback channels were proposed and evaluated. Finally, a fully three-dimensional simulation was carried out, which allowed for the identification of intricate coherent structures revealing the complexity of the turbulent flow dynamics inside the fluidic oscillator

Computational characterization of turbulent flow in a microfluidic actuator

In this contribution, an unsteady numerical simulation of the flow in a microfluidic oscillator has been performed. The transient turbulent flow inside the device is described by the Unsteady Reynolds Averaged Navier–Stokes equations (URANS) coupled with proper turbulence models. The main characteristics of the complex fluid flow inside the device along one oscillation cycle was analyzed in detail, including not only velocity contours but also the pressure and turbulent kinetic energy fields. As a result, two-dimensional simulations provided good estimations of the operating frequency of the fluidic actuator when compared with experimental measurements in a range of Reynolds numbers. Moreover, with the objective of altering the operating frequency of the apparatus and, in order to adapt it to different applications, geometrical modifications of the feedback channels were proposed and evaluated. Finally, a fully three-dimensional simulation was carried out, which allowed for the identification of intricate coherent structures revealing the complexity of the turbulent flow dynamics inside the fluidic oscillato

Cálculo de densidad de neutrones utilizando el método generalizado de Adams-Bashforth-Moulton

Este artículo presenta una solución numérica a las ecuaciones de cinética puntual para reactores de energía nuclear, un conjunto de siete ecuaciones diferenciales acopladas que describen la variación temporal de la densidad de neutrones y la concentración de precursores de neutrones retardados. Debido a la naturaleza del sistema, proponemos resolver numéricamente las ecuaciones de cinética de puntos mediante la implementación de los métodos de Adams-Bashforth y de Adams-Moulton, que son esquemas predictores-correctores con sus respectivos modificadores para aumentar la precisión. El método propuesto se probó computacionalmente para diferentes formas de reactividad con hasta seis grupos de precursores de neutrones retardados. Este método se utilizó en una publicación reciente para resolver el problema inverso de encontrar la reactividad. Adicionalmente, se muestra que también se puede utilizar para el cálculo de la energía nuclear, que es simple y fácil de implementar, y que produce buenos resultados en comparación con los de la literatura para la densidad de población de neutrones y la concentración de precursores de neutrones retardadosThis paper presents a numerical solution to the equations of point kinetics for nuclear power reactors, a set of seven coupled differential equations that describe the temporal variation of neutron density and the concentration of delayed neutron precursors. Due to the nature of the system, we propose to numerically solve the point kinetics equations by implementing the Adams-Bashforth and Adams-Moulton methods, which are predictor-corrector schemes with their respective modifiers to increase precision. The proposed method was tested computationally for different forms of reactivity with up to six groups of delayed neutron precursors. This method was used in a recent publication to solve the inverse problem of finding the reactivity. In this work, it is shown that it can also be used for the calculation of nuclear power, that it is simple and easy to implement, and that it produces good results when compared with those in the literature for neutron population density and concentration of delayed neutron precursorsEste artigo apresenta uma solução numérica para as equações da cinética pontual para reatores de energia nuclear, um conjunto de sete equações diferenciais acopladas que descrevem a variação temporal da densidade de nêutrons e concentração de precursores de nêutrons atrasados. Devido à natureza do sistema, propomos resolver numericamente as equações da cinética pontual implementando os métodos de Adams-Bashforth e de Adams-Moulton, que são esquemas preditores-corretores com seus respectivos modificadores para aumentar a precisão. O método proposto foi testado computacionalmente para diferentes formas da reatividade com até seis grupos de precursores de nêutrons atrasados. Este método foi usado em uma publicação recente para resolver o problema inverso de encontrar a reatividade. Além disso, mostra-se que também pode ser utilizado para o cálculo da potência nuclear, que é simples e fácil de implementar e que produz bons resultados quando comparado com os da literatura para densidade populacional de nêutrons e concentração de precursores de nêutrons atrasado

Novel fluctuation reduction procedure for nuclear reactivity calculations based on the discrete fourier transform method

A new method for calculating nuclear reactivity based on the Discrete Fourier Transform (DFT) – with two filters: a first-order delay low-pass filter and a Savitzky-Golay filter – is presented. The reactivity is calculated from an integrodifferential equation known as the inverse point kinetic equation, which contains the history of neutron population density. The new method can be understood as a convolution between the neutron population density signal and the response to the characteristic impulse of a linear system. The proposed method is based on the discrete Fourier transform (DFT) that performs a circular convolution. The fast Fourier transform algorithm (FFT) with the zero-padding technique is implemented to reduce the computational cos

Numerical simulation of the transient behavior of the turbulent fow in a microfuidic oscillator

In this study, the transient numerical simulation of the flow in a fluidic oscillator has been performed. The proposed device includes several geometrical modifications of a previously patented apparatus intended for the synthesis of ozone-rich bubbles in an oxygen plasma. Prior to the experimental construction of the proposed fluidic oscillator, the present work performs a numerical study of the internal flow in the proposed design, aimed to determine its feasibility. The unsteady simulations are based on the unsteady Reynolds averaged Navier–Stokes equations coupled to the transition Shear Stress Transport (transition SST) turbulence model due to the low Reynolds numbers considered (3500 and 5000 based on flow bulk velocity). The behavior of the complex fluid flow inside the device, where four main vertical structures develop and interact, along one cycle is described in detail including the turbulent kinetic energy and intermittency in the analysis. Moreover, the effect of increasing the Reynolds number on the pressure oscillation frequency and amplitude is analyzed. In particular, the frequency is increased around a 38% and the amplitude a 100% when switching from a Reynolds number of 3500–5000. The numerical results obtained are encouraging, and the evaluated fluidic oscillator design will be fabricated and analyzed in an upcoming experimental stud