Modelling of complex microscale flows with the lattice Boltzmann method

Abstract: The lattice Boltzmann Method (LBM) is a comparatively new computational fluid dynamical method which solves the Boltzmann Transport equation, and yields results equivalent to the solutions of the Navier-Stokes equations. However, its inherent parallelism, implementation of complex boundary geometries and ease of use make it an attractive alternative for modelling complicated industrial problems. Such problems involve multi-fluid flow, heat transfer, and reactions., In this work, Triply Periodic Minimal Surfaces and other irregular three-dimensional geometrical shapes form the bounding domain for microscale flow. We are especially interested in how heat is transferred and the possibility of endothermic chemical reactions through the complicated domains. An efficient but accurate representation of the boundary is vital, and we present a novel methodology for this representation. LBM results are compared to a classical Navier-Stokes solver (based on the Finite Volume method) to assess the accuracy and robustness of the LBM method for such applications. It is shown that LBM is an accurate and efficient numerical tool which deals especially well with complicated boundary shapes. Our general methodology can be implemented in autonomous digital workflows for analysing the performance of multitudes of varying designs. Keywords: Lattice Boltzmann Method, heat transfer, fluid flow, irregular geometrical domains