Heat and water transfer for lacquer drying and thermal signatures : modelling, simulation and experiment

Sammanfattning: The coupled phenomenon of heat and water transfer is essential in many scientific and industrial problems. This thesis focuses this phenomenon on two areas; lacquer drying and thermal signatures. Simulations of physical phenomena may in some cases replace extensive experimental investigations, which may be complicated and expensive. In other cases simulations may provide means to reduce the number of experiments necessary to perform. In the thesis models, as simple as possible, are used to simulate heat and water transfer. Experiments were made and are compared with the simulations in order to verify the validity of the simplified models.In the first part of the thesis the drying of a waterborne lacquer coating used in wood manufacturing industry is investigated. Problems concerning upward water transfer resulting in a specified drying period, and downward water transfer resulting in fibre swelling are addressed. Experiments were made in a full-scale drying plant.In the second part of this thesis heat and water transfer in solar radiated sand is investigated. The main purpose of these investigations is to improve the predictions of thermal signatures related to detection of buried objects, e.g. buried land mines. Among several factors, influencing the thermal signatures received by optical systems, water movement in the soil and water evaporation from the surface have been found to be of particular interest. Experiments were made in an indoor test landscape.In two related papers two other methods for investigating problems connected to lacquer drying are presented. In the first paper two-way factorial design is used to optimise the drying process of waterborne lacquer coating in a full-scale drying oven. In the second paper the inverse heat conduction problem is used to predict the surface temperature of a particleboard based on measurements inside the board.