Creating lifting force in liquids via thermal gradients

In this paper, we explore a concept and present the first experimental evidence to show that it is possible to form a stable liquid film and create lifting force at the interface via thermal gradient to minimize inter-facial rubbing of surfaces and the associated wear. The approach is based on manipulating the flow behavior via thermocapillary, which describes how a liquid can be made to flow from warm to cold regions purely by inducing a thermal gradient. We show that liquid bridges between two parallel plates can be manipulated and stabilized under a combined effect of the thermocapillary flow and the Couette flow, which describes the motion of a viscous fluid between two parallel plates in a relative sliding motion. The equilibrium stage is confirmed under different experimental conditions of a thermal gradi-ent, interfacial gap, liquid viscosity, and liquid bridge volume. A strategy is proposed to control liquid motion and create lifting force between two plates. A theoretical model is also presented to illustrate the principle of the equilibrium stage. Creating lifting forces at the interface offers a new thermo-hydrodynamic tool for manipulating liquids behavior. This approach has the potential for controlling liq-uid motion in mechanical components and nature.(c) 2022 Elsevier Inc. All rights reserved.