Three dimensional simulation of AC electrothermal pumping by lattice boltzmann method with non-uniform meshes using GPU

Alternating current (AC) electrothermal flow induced by electric field and temperature gradient due to Joule heating or thermal boundary conditions in an aqueous solution have been widely used to manipulate the fluid flow in microfluidic systems. Due to the importance of pumping of electrolytes in microfluidics, AC electrothermal pumping has become an attractive research topic. As numerical modeling of AC electrothermal flow can be used to design and direct the experiments, there are a few efforts focusing on the simulations of electrothermal flow by different methods or commercial software. However, most of the simulations are limited in two dimensions because of the huge computational load in three dimensional cases. Due to the low cost, GPU makes high performance computing possible on personal computers since the advent of CUDA by NVIDIA in 2007. With thousands of cores, GPU can be used to accelerate the computational speed. As a mesoscale numerical method, lattice Boltzmann method (LBM) has been developed as a powerful numerical approach for heat transfer and fluid flow problems during the past two decades. LBM is very well suited for GPU computing. In the current work, LBM is applied to simulate 3D electrothermal pumping using GPU. To further save the memory of GPU and improve the computational efficiency, non-uniform LBM meshes are used. AC electrothermal pumping is presented in terms of electric field, Joule heating, temperature field, electrothermal forces, and fluid velocities.