Design of a test chamber for investigation of moisture transport in air flows and porous materials

This paper describes the design of a test chamber for the investigation of the interaction of moist air and porous materials. Currently computational fluid dynamics (CFD) is gaining in importance as a tool to model the indoor climate in buildings. Meanwhile coupled CFD-material models are being developed which are capable of modelling moisture exchange between air and materials. The newly developed climate chamber can be used to validate these models. The test chamber, in which different materials can be placed, represent a small room (height: 1.8m, width: 1.8m, depth: 2.1m). This allows full scale experiments for different flow regimes: natural as well as mixed and forced convection can be induced. Two operating modes are distinguished. In the first mode hygroscopic materials are placed in front of an air jet entering the room. Temperature, air speed and relative humidity of the jet are closely controlled. Local heat en mass transfer coefficients are calculated using the CFD models. These models are validated by measuring the temperature and relative humidity in and around the material. The velocity field is measured by a 2D hotwire anemometer. These measurements are then compared with the calculated values resulting from the CFD simulations. Thus the accuracy of the calculated heat and mass transfer coefficients can be determined. In the second mode hygroscopic buffering of materials is evaluated. Different hygroscopic materials are placed inside the test chamber. Air at a predetermined temperature and relative humidity enters the room at a controlled flow rate. Local heat and mass transfer coefficients are again determined by CFD calculations. The response of the test chamber with hygroscopic materials to different moisture loads is then measured.Presenters: name: Marnix Van Belleghem affiliation: (Department of flow, heat and combustion mechanics - Ghent University) email: marnix.vanbelleghem@ugent.b