The development and evaluation of new microwave equipment and its suitability for wood modification

The present research offers an assessment of the computer modelling process for developing new microwave equipment suitable for wood modification. To understand the functioning of the new projected microwave equipment and moreover, to make its operability as safety as required by the Australian and International Safety Organization, the computer modelling process was completed by developing the customised devices, setting the appropriate testing procedures and measuring the specific parameters. Initially, the fundamentals of microwave heating including the history of utilisation of these technologies, electromagnetic theory, details about volumetric and selective heating, and also basics regarding microwave heating of the wood are examined. Subsequently, an insight into the main microwave systems components and current developments in the industrial microwave heating is provided. The overview report ends with details about the expansion of computerized numerical microwave modeling techniques and comments about some of their relevant features. A practical and innovative way able to control the intensity and distribution of the microwave energy and to enhance the microwave treatment pattern within dielectric is then presented. It was accomplished through computerized 3D electromagnetic simulations and validated using pilot plant microwave equipment. To complement the microwave applicator to highly reduce the energy reflection towards the generators, a novel idea is put forward. The experimental tests show that the reflected energy can be reduced up to 50 %. A custom-designed microwave leakage suppression device for wood treatment in continuous flow microwave industrial systems presented together with its evaluation completes the research work. Finally, the importance of the research, the key facts and the recommendations for further work are emphasized.