Modelado y simulación de flujos turbulentos en canales parcialmente obstruidos / Simulation and modeling of turbulet flux in partially obstruct media

Giulio, Ezequiel M. (2019) Modelado y simulación de flujos turbulentos en canales parcialmente obstruidos / Simulation and modeling of turbulet flux in partially obstruct media. Integration Project in Nuclear Engineering, Universidad Nacional de Cuyo, Instituto Balseiro.

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Abstract in Spanish

En este trabajo se realizan simulaciones directas de turbulencia (DNS) de flujos turbulentos en medios parcialmente obstruidos. El estudio de este tipo de flujos es de extrema importancia en la industria nuclear, entre otras, pues muchos elementos que componen los reactores nucleares pueden ser modelados de esta manera. Se modela matemáticamente el efecto del medio obstruido sobre el flujo con un termino adicional en la ecuación de Navier-Stokes. Al adimensionalizar la ecuación surge un parámetro que permite regular la obstrucción del medio. Se estudian siete casos distintos variando este parámetro. Se muestran los perfiles instantáneos de velocidad y se analizan además variables promediadas tales como la velocidad media, las tensiones de Reynolds, las tensiones viscosas, las intensidades turbulentas y la energía cinética turbulenta. También se estudia el espectro de potencia y se analiza la sensibilidad de los resultados en función del tamaño del dominio. Se compara el resultado de las simulaciones con el obtenido por otros autores. El principal resultado obtenido en esta investigación radica en la caracterización de del coeficiente de arrastre en un canal a partir de la obstrucción presente en el mismo. Se cuántifica este coeficiente en función del parámetro adimensional antes mencionado y se analiza la causa de la variación a partir del estudio de las variables promediadas.

Abstract in English

In the preset work direct numerical simulations (DNS) are performed in order to model turbulent flow in partially obstructed channel media. Studying this type of flow is of extreme importance in the nuclear industry, among others, because many components present in nuclear reactors can be modeled this way. The effect caused by the obstructed media in the flow is modeled mathematically with an additional term in the Navier-Stokes equation. Thus, the obstructed medium is then characterised by a new dimensionless parameter. Seven different cases are studied varying this parameter. The main objective of this work is to study the influence of the porous media on the dynamics of turbulence. Instantaneous velocity proles together with averaged variables such as mean velocity, Reynolds and viscous stresses, turbulent intensities and turbulent kinetic energy are thus studied. The energy spectrum is presented and the influence of the domain size in the nal solution is studied. The results of the current simulations are then compared with that obtained by other authors in previous works. The main result obtained in this work is related with the characterization of the drag coefficient from the amount of the obstruction present in the channel. This coefficient is quantied as a function of the dimensionless parameter mentioned above. The variation of such a coefficient is therefore analyzed by studying the value of the mean variables of the flow.

Item Type:Thesis (Integration Project in Nuclear Engineering)
Keywords:Turbulent flow; Flujo turbulento; Navier-Stokes equations; Ecuaciones de Navier-Stokes; Permeability; Permeabilidad; Porosity; Porosidad; Velocity; Velocidad; [Reynolds]
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Subjects:Nuclear engineering > Mecánica de fluidos
Divisions:Gcia. de área de Aplicaciones de la tecnología nuclear > Gcia. de Investigación aplicada > Mecánica computacional
ID Code:828
Deposited By:Tamara Cárcamo
Deposited On:19 Sep 2023 14:38
Last Modified:19 Sep 2023 14:38

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