Virtual process engineering on a three‐dimensional circulating fluidized bed with multiscale parallel computation
The combination of (quasi‐)real‐time simulation on industrial processes and virtual reality technologies may lead to a new paradigm of research and development in chemical engineering, that is, virtual process engineering (VPE). However, as the main engines of VPE, accurate and efficient simulation methods are still in urgent demand. In this paper, with substantial improvements to a discrete particle method (DPM), namely, energy‐minimization multiscale (EMMS)‐DPM, such an engine was established for a typical multiphase system, the circulating fluid beds (CFBs). To improve the accuracy, the coupling of particle and fluid flow solvers was updated to be more sensitive to local flow structures, and different drag laws were used for different flow regimes. To speed up the computation, heterogeneous central processing unit (CPU)‐graphics processing unit (GPU) computing is developed for solving the fluids and particles. A two‐layer domain decomposition method is developed to improve the load balance for real applications with complex geometries. Thus, a computer virtual experiment on a three‐dimensional (3D) full‐loop CFB has been achieved by simulating 1.27 × 1011 real particles with 1.27 × 108 coarse‐grained particles at the speed of 1.5 × 107 particle updates per GPU per second on 135 NVIDA K80 GPUs. To our knowledge, this is the largest‐scale and highest‐performance DPM simulation of a 3D full‐loop CFB in terms of the computational particles used. It is a strong indication that VPE can be realized for industrial systems in the near future.
Keywords: discrete particle method, energy‐minimization multiscale model, three‐dimensional circulating fluidized bed, virtual process engineering,