几何参数对壁面上气液降膜流传热传质性能影响的研究

Study of the Influence of Geometric Parameters on the Heat and Mass Transfer Properties in Gas-Liquid Falling Film Flow

基于VOF方法,在考虑表面张力动量源项和气-液两相间传热传质源项的条件下,建立了水和空气在平板和波纹板壁面中降膜流动传热传质的CFD模型。利用该模型对比了平板和波纹板的传热传质性能,并进一步研究了波纹结构参数a、λ对两相间传热传质的影响。结果表明:采用波纹板能有效增强气液两相间传热传质;影响波纹板两相间换热的结构参数主要是波纹波长λ,λ越大的波纹板换热性能越好;采用波纹较浅,即结构参数a/λ较小的波纹板,或者波长λ一定,波幅a较小的波纹板都能获得更高的传质效率。

By considering the surface tension momentum source term and the heat and mass transfer source term in gas-liquid two-phase flow, a CFD model based on the Volume of fluid（VOF） algorithm was established to describe the heat and mass transfer of falling film on flat plate or corrugated plates. The model was used to compare the heat and mass transfer properties between two kinds of plates, and furthermore analyze the influence of various structural parameters of corrugated plates. The results indicated that corrugated plates can effectively improve the heat and mass transfer; v is a main parameter that effects the heat transfer between air and water, the bigger the better; By adopting corrugated plates with shallow ripples（ with a low α/λ ）, or smaller amplitude with a constant λ, higher mass transfer efficiency can be reached.