Investigation on Effect of Turbulence Intensity and Rib Tabulator in Moisture Diffusion through Membrane

The principal aim of the present work is to study the maximum amount of moisture diffuses through membrane in ventilation ducts with the emphasis of Computational Fluid Dynamics.For thermal comfort reasons, indoor air-conditions around 25°C temperatures and 10 g / kg humidity ratio are the accepted set points. However, the SouthernChina and other Southeast Asian countries have a long summer season with a daily average temperature of 30°C, and humidity ratio above 17.6 g / kg. Outdoor relative humidity often exceeds 80 % continuously for a dozen of days, leading to mildew growth on wall and furniture surfaces, which affects people's life seriously. Conditioning ventilation air typically requires 2040 % of the thermal load for commercial. The exchange of moisture between exhaust hot humid air and incoming cold dry air can reduce loads on air conditioning unit to a large extent. The moisture exchange between the two air streams (hot and cold) can be achieved by placing a PVAL / PVDF membrane between the two streams. The objective of the current work is to establish the best practices for Computational Fluid Dynamics (CFD) simulation and validate the results with experimental data available in the literature. The moisture transfers through the membrane would be modelled using source / sink terms for moisture mass and energy transfer. A number of mesh sensitivity and turbulence models are to be considered for best practice establishment. Optimization is carried out by using Rib Turbulator and varying the turbulence intensity at inlet. The computation results have been compared with the experimental data available in the literature. Gambit software is used for geometry creation and mesh generation. FLUENT is used for solving 3D Navier-Stokes equations and for post-processing.