Numerical study of the falling film wettability and heat transfer on the inclined plates with different corrugated structures

Abstract

AbstractIn this study, 2D and 3D models of corrugated plates using the volume of fluid (VOF) model were set up to simulate the influence of corrugated structure on the wettability and heat transfer. The results show that compared with the triangular corrugation, the rectangular corrugation has a slower growth rate of wetting ratio (WR) as the Weber number (We) increases under the same corrugation length Le and corrugation depth De. The average WR of the triangular corrugation is 2.8% less than that of the smooth plate. For the triangular corrugation, the higher Le contributes to improving wettability, but the average heat transfer coefficient havg first decreases to the minimum at Le = 5 mm and then increases 8% to 9% to a steady value until Le = 8 mm. WR decreases with De at We ≤ 0.76. A WR correlation considering the corrugation steepness St (St = De/Le) and a critical Re correlation corresponding to the minimum wetting rate were fitted for the liquid oxygen. As the inclination angle ϕ increases, the average film thickness decreases and havg increases until ϕ = 75°, while the variation rate slows down afterwards. At Re = 1200, havg has a decreasing trend at St ≤ 0.13, increases at St ≥ 0.14 and reaches a plateau after St = 0.24 as St increases. It increases by 30.6%, 47.4%, and 44.4% for the inclination angle ϕ = 30°, 60°, 90° cases from St = 0.14 to 0.24. The enhancement is caused by the vortices existing at St ≥ 0.14.