Lattice Boltzmann Simulations of Self-Rewetting Drops Impinging on Nonuniformly Heated Fluid Interfaces and Solid Surfaces

Self-rewetting fluids have parabolic dependence of surface tension on temperature with a minimum, and the resulting peculiar interfacial flows have recently been exploited in a variety of applications. For simulating such variable surface tension-driven multi-fluid flows with energy transport, we have constructed a robust phase-field based central moment lattice Boltzmann (LB) algorithm. The latter involves solving one LB equation for interface tracking based on the conservative Allen-Cahn equation, a second LB equation for the motion of fluids with temperature-dependent normal capillary and tangential Marangoni interfacial stresses, and a third LB equation for the energy transport. Moreover, a geometric formulation is used to incorporate wall wetting and contact angle effects. We utilize such a novel algorithm to study the impingement of self-rewetting drops on another self-rewetting fluid layer as well on a solid wall, where both the fluid interface and the solid surface are heated nonuniformly. We report the effect of various characteristic parameters on the post-impingement interfacial fluid dynamics of drop-interface and drop-wall interactions involving self-rewetting fluid drops and compare them with those based on regular fluid drops.