A Zonal Different-Time-Step Algorithm for Multi-Physics Simulation in Closed System

摘要

In the present paper, a Zonal Different-Time-Step algorithm (ZDTS) is developed to overcome the difficulties of the flow, chemical reaction and heat transfer couple simulation in a domain-closed system. The system is decomposed into reaction zone and flow zone. The CFD simulations are performed in each zone individually, using different characteristic times, the physical information is effectively passed via interpretation at the interface. A case study of shell-and-tube reactor is presented for the validation. Numerical simulation based on ZDTS is performed to understand the catalytic reaction in porous media at tube side and the flow and heat transfer of the molten salt at shell side. The effects of selected interpolation methods and asynchronous factor (A f) on the computational accuracy and efficiency are investigated. The numerical results show that the ZDTS provides the details of flow field and heat transfer at different zones, predicts the accurate positions of the stagnation zones and the dead zones accurately, and reveals the characteristic of the heat transfer between each zone. The ZDTS significantly increases the computation efficiency by 50 %, and the numerical results show good agreement with the measured results. The ZDTS can be applied for the flow, chemical reaction and heat transfer couple simulation in a closed domain.