Simulating drop-wise condensation using lattice Boltzmann method*

Drop-wise condensation (DWC) was first identified as an important heat transfer mode in the 1930s. Relative to film-wise condensation (FWC), DWC results in approximately an order of magnitude increase in heat transfer. Understanding the role microstructures serve in enhancing the DWC mode is critical to improve heat transfer in various applications. Here, we simulate drop-wise condensation of a single component multiphase (SCMP) fluid on 2D structured surfaces using the lattice Boltzmann method. A non-ideal equations of state is specified and the LBM fluid solver is coupled to a thermal solver. Compared to other SCMP models, the model does not require empirical correlations to describe phase transition, it enforces interface conditions in a diffuse manner with complex morphological transitions captured on an Eulerian grid, and it does not require an elliptic pressure solver. We validate the model by comparing with the Nusselt's falling film and the Stefan problem. We then quantify the non-dimensional heat transfer for selected microstructure geometries as a function of surface wettability.