Numerical investigation of Marangoni shear stress induced by temperature gradient in falling liquid film flow

Marangoni shear stress induced by temperature gradient is introduced into a three-dimensional CFD model to investigate the hydrodynamic characteristics of the heated or cooled falling liquid films flowing down along a vertical flat plate. The influence of Marangoni shear stress on velocity and vorticity, as well as the wetting ratio are obtained. Shrinkage and increased instability of the falling liquid film is found under heat condition and small flow rate. Moreover, Marangoni shear stress in the transverse direction of the falling liquid film is the main control factor, and the radial modified Marangoni number is 8 times larger than the axial modified Marangoni number. The increase of the vorticity at sides of the liquid film is significant, and it is averaged 20% larger than that without Marangoni shear stress.