Numerical simulation of thermal flow problems using the immersed boundary method
- Autores: Federico Daniel Favre Samarra
- Directores de la Tesis: Assensi Oliva Llena (dir. tes.), Carlos David Pérez Segarra (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: Cristóbal Cortés Gracia (presid.), Jesús Castro González (secret.), Antonio Pascau Benito (voc.)
- Materias:
- Texto completo no disponible (Saber más ...)
- Resumen
Conjugate heat transfer (CHT) problems, present both in consumer and industrial technologies, range from the cooling of electronic devices or the design of energy-efficient buildings to heat exchangers applications or the heat losses analysis of furnaces. Computational Fluid Dynamics and Heat Transfer (CFD&HT) has proved valuable in the study of these problems, since it can produce reliable fields of fluid flow, temperature and heat fluxes. Moreover, thanks to the recent advances in high-performance computers, CFD&HT numerical simulations are becoming viable tools to study real-life problems. The conventional approach to simulate CHT problems, which consists of employing body-conformal meshes to the solids¿ and fluids¿ regions, often result costly and ineffective in applications with moving parts or very complex geometries. For these cases, an alternative approach which employs a non-body conformal mesh that discretizes the entire domain using a special treatment in the vicinity of the solid-fluid interfaces has proven more effective. This approach is known as the Immersed Boundary Method (IBM).
In this work, an IBM based on the discrete forcing approach was developed and implemented in the TermoFluids code. It was designed to work with any type of mesh (domain discretization) and to handle any body geometry, since the fluid-solid interface is represented by means of an unstructured surface mesh. The most time-consuming tasks of the IBM were parallelized using a dynamic load balancing strategy, obtaining a significant scalability of the solver. The implementation was verified by several simulations of benchmark cases. Moreover, the IBM was extended to simulate problems with CHT boundary conditions taking into account the radiative exchange between surfaces.
The methods developed and implemented in this thesis were applied in two industrial applications, which are illustrative examples of the two situations where the IBM approach is the most adequate option to perform a CFD&HT analysis. The first one consists of the simulation of a Smart Antenna Module (SAM), a problem with many objects, where the body-conformal approach requires the generation of a large number of complex meshes. Using the IBM approach, a detailed thermal analysis of the SAM was carried out, testing numerous configurations. The second case consists of the simulation of a 3D printer whose moving parts with huge displacements makes the body-conformal approach almost unusable. The use of the IBM allowed a detailed study of the fluid flow and the heat transfer inside the printer.
All in all, the carried out studies resulted in a monolithic methodology for the simulation of realistic situations, where all three heat transfer mechanisms can be considered in complex geometries and moving boundaries.
