Numerical modeling and analysis of heat transfer for floatation nozzle with a flexible substrate

Abstract

Floatation nozzle is employed to guide the flexible substrate without contact in simultaneous double-sided coating. The deformation of the flexible substrate is significant to the flow and thermal fields. The heat transfer for floatation nozzle with a flexible substrate is studied in this paper. A fully-coupled fluid-structure interaction numerical model is developed to investigate the heat transfer characteristics and deformation for floatation nozzle with a flexible substrate. The fluid domain is updated by diffusion-based smoothing dynamic mesh formulation that is fully coupled to the deformation of the flexible substrate. The deformation profile of flexible substrate coupled to fluid domain is approximated by cosine series, and the coefficients in cosine series are calculated by Galerkin least square method. The steady state solutions of floatation nozzle with a flexible substrate can be obtained by a pseudo transient approach. The numerical results show that the deformation of flexible substrate changes the relative magnitude of potential core length and nozzle-to-plate distance. The size increase, position move and disappear of recirculation bubbles of flexible substrate change the streamline, turbulence intensity, temperature distributions. Three peaks of heat transfer coefficient for rigid substrate are observed and the mechanisms are elucidated. The average heat transfer coefficient of flexible substrate is larger than that of rigid substrate, although the maximum heat transfer coefficient of flexible substrate is smaller. Furthermore, a significant decrease of centerline pressure of flexible substrate is observed. Reynolds number and inlet width are the most significant parameters influencing the flow and thermal fields.