Parallel CFD Simulations of Multiphase Systems: Jet into a Cylindrical Bath and Rotary Drum on a Rectangular Bath

摘要

Most of the developed commercial CFD (Computational Fluid Dynamics) packages do not attempt to document (or don't want to publish !!) the detailed algorithm for parallelising the code; even the ordinary solution strategies are tedious to learn sometimes. However, industrial engineers are more concerned about quick and correct solutions of their problems. Key features of this paper are the use of the domain decomposition and encapsulated message passing to enable execution in parallel. A parallel version of a CFD code, FLUENT, has been applied to model some multiphase systems on a number of different platforms. The same models considered for all the platforms to compare the parallel efficiency of CFD in those machines. Two physical models: one is a liquid jet directed into a cylindrical bath to disperse buoyant particles suspended on the top of the bath (3D), and the second one is a rotary drum rotating on a free surface to drag down particles from the free surface. The free surface, high gradient of the velocity, particle-particle, particle-wall collisions make most industrial flow simulations computationally expensive. For many complex systems, like here, the computational resources required limit the detail modelling of CFD. The implementations of computational fluid dynamics codes on distributed memory architectures are discussed and analyzed for scalability. For commercial CFD packages, in many cases the solution algorithms are black boxes, even though parallel computing helps in many cases to overcome the limitations, as shown here. The performance of the code has been compared in terms of CPU, accuracy, speed etc. In short, this research is intended to establish a strategic procedure to optimize a parallel version of a CFD package, FLUENT. The parallelised CFD code shows the excellent efficiency and scalability on a large number of platforms.