Bienvenida y bienvenido a la página de inicio de la LGAC Dinámica de fluidos computacional.
El área de estudio relacionada con la modelación numérica en mecánica de fluidos y transferencia de calor, llamada dinámica de fluidos computacional (CFD, por sus siglas en inglés), se aplica prácticamente a cualquier desarrollo de ingeniería. En particular se puede citar su aplicación en el diseño y análisis de fenómenos de transporte (mecánica de fluidos, transferencia de calor, transferencia de masa, combustión, etc); recientemente, con el advenimiento de los dispositivos microelectromecánicos (MEMS, por sus siglas en inglés), su utilización se ha expandido hacia la simulación de microflujos y nanoflujos, en los cuales, debido a las escalas que se manejan, resulta muy complicado realizar experimentación. Desde el punto de vista macro, el CFD tiene un gran uso en el análisis de problemas meteorológicos, oceánicos, análisis de interacciones de estructuras sólido-fluidos, aerodinámica, entre otros. Su uso proporciona una gran versatilidad al análisis y diseño en numerosas aplicaciones, tanto científicas como de ingeniería. Con el creciente advenimiento de mayor capacidad de sistemas de cómputo, nuestro país debe contar con personal calificado para usar adecuadamente software de diversas aplicaciones; aunado a esto, se debe tener la infraestructura humana necesaria que sea capaz de desarrollar software propio que evite la dependencia tecnológica de otros países.
Numerical study on buoyancy and inclination effects on transient laminar opposing mixed convection in rectangular channels with symmetric and discrete heating
Researchers: J. Marroquín-Desentis, C. Treviño, J.C. Cajas, E. Salcedo, L. Martínez-Suástegui
Abstract: Detailed numerical simulations are carried out for transient laminar opposing mixed convection in a rectangular inclined channel with both walls suddenly subjected to discrete isothermal flush-mounted heat sources simulating electronic components. Using the vorticity-stream function formulation of the unsteady two-dimensional Navier–Stokes and energy equations, the governing equations are solved numerically using the control volume method. Simulations are performed for fixed values of the geometrical parameters, Reynolds number of Re = 500, Prandtl number of Pr = 7 and channel inclination of 0o ≤ γ ≤ 90o. Results illustrate the effects of buoyancy strength or Richardson number Ri = Gr/Re2 and channel inclination angle on the overall flow structure and nondimensional heat flux (Nusselt number) from the heated slabs. It is found that for the horizontal configuration (γ = 0o), due to the indirect effect of buoyancy, much higher threshold values of buoyancy strength are required for the appearance of the recirculation flows that take place downstream of the heated slabs. However, for increasing values of the inclination angle, vortex migration to higher positions inside the channel occurs and higher heat transfer rates are obtained. In addition, transition from steady to time-periodic flow takes place for values of the buoyancy parameter larger than a critical one, and the threshold value between the two regimes strongly depends on the value of the Reynolds number and channel orientation. The results include the effects of Reynolds and Prandtl numbers along with heat losses to the channel walls on the evolution of the final flow and thermal response.
Publications: J. Marroquín-Desentis, C. Treviño, J.C. Cajas, E. Salcedo, L. Martínez-Suástegui, Int. J. Heat Mass Tran., 84 (2015) 766-785.
Numerical investigation on buoyancy and inclination effects on transient mixed convection in a channel with discretely heated plane symmetric contraction-expansions
Researchers: F. García, C. Treviño, E. Salcedo, L. Martínez-Suástegui
Abstract: In this work, transient mixed convection in a channel with discretely heated plane symmetric contraction-expansions at the mid-channel section emulating electronic components is studied numerically. The facing walls of the obstructions are isothermal, the other bounding walls of the constriction and the channel have non-adiabatic walls. The impact of changes in the cross section and their corresponding sensitivity to duct orientation on the overall flow and thermal evolution in space and time is analysed for fixed Prandtl number of Pr = 7, Reynolds number in the range 100 ≤ Re ≤ 1000, channel inclination of 0o ≤ γ ≤ 90o, and different values of buoyancy strength (Richardson number). Results indicate that as the duct approaches the horizontal configuration, buoyancy strength reduces and higher threshold values of the Richardson number are required to induce instability. Also, depending on the parametric set, the flow and temperature distributions can experience an oscillatory behavior associated to variations in size of a complex vortical structure that occupies the spatial region near the partial blockage and that extends to downstream positions of the latter. Numerical predictions demonstrate how the blockage height affects the wake structure and vortex dynamics, and the effects of the Prandtl number and heat losses to the channel walls on the evolution of the flow and heat transfer response are presented and discussed in detail.
Publications: F. García, C. Treviño, E. Salcedo, L. Martínez-Suástegui, Int. J. Heat Therm. Sci., 146 (2019) 1060465.
