Innovative mixer design for an anaerobic reactor

• Main Author: Zhang, Lili
• Other Authors: Ng Wun Jern
• Format: Theses and Dissertations
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Environmental engineering::Water treatment
• Online Access: http://hdl.handle.net/10356/60468
• Institution: Nanyang Technological University

Several challenges are present in the operation of a continuously stirred anaerobic reactor by impeller mixer/mixers. The current study aimed to develop an innovative mixer design for a continuously stirred cylindrical anaerobic reactor, as well as to optimize the design parameters of the mixer in the light of the hydrodynamic performance. Attempts of the flow modeling have been carried out. Theoretical background and boundary conditions for a 3D model of flow in stirred tanks have been developed in this work. The CFD software, CFX, was employed to model the flow fields of a lab-scale reactor, in which the liquid medium was assumed to be water. Re-meshing technology/tools of CFX were used to incorporate linear motion mixer in the simulation, and the flow patterns generated were identified and the detailed flow fields were presented. The mesh independence test has been conducted and the reliability of the simulation results has been tested through the continuity equation. This study also introduced a novel modeling method, the “immersed solid” in CFX, to simulate the linear motion of mixer, and compared the simulation results with those obtained from the Re-meshing approach.